Scientist says cleaning indoor air could make us healthier and smarter | Hacker News Reader

Scientist says cleaning indoor air could make us healthier and smarter

sciencemag.org

476 pointssohkamyung445 comments

This reeks like a con-artists rephrasing perfectly normal and mundane observations into scary-sounding situations so that people would buy the air-filter companies that are funding your research.

I'm all for cleaner air and I don't doubt that the already well-established negative effects of high CO2 or VOC concentrations on us, but can we at least keep any discussion to non-anecdotal, strong scientific evidence? None the articles linked both here show any rigorous statistics that pinpoint cause and effects, it's all handwavy conjectures with "common sense" evidence and statistical dressing to show correlation. Correlation doesn't even necessarily mean causality. Some of the articles even have *may" in the title, you can be the judge.

Probably an unpopular opinion given the large amount of anecdotal science already posted.

Dust on carpet is bad and particularly if you don't clean it and let stuff grow - we all know that already and we don't need a laser pointer to show kids how scary it is. Just because you can see it doesn't necessarily mean it's worse, and just because you can't see it doesn't necessarily mean it's better.

It's just insanity that everyone is suddenly a scientists with a few anecdotes or links to articles that show correlation but not causality.

Yes media is bought and paid for and is the boogeyman.

Tuned it out May 2020 and get my news like for Covid directly from friends working in hospitals (docs, nurses, admins, etc) in various cities.

How can it not be causality when it's a double-blind intervention? This isn't an epidemiological study that is merely observing correlations in the wild.

https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037

> How can it not be causality when it's a double-blind intervention?

The design of the study looks solid and results are certainly statistically significant. With N=24 and the limitations quoted below, I think it's fair to take these results with a grain of skepticism.

But on balance, I found the criticism in GP's comment to be a little over the top.

- "By testing on subsequent days, it is possible that effects from one condition were reflected in the scores obtained on the next day."

- "The environmental factors that were not experimentally modified exhibited some variability owing to changes in outdoor conditions and participant behavior."

- "This study used a controlled environment to individually control certain contaminants. Assessments performed in actual office environments are important to confirm the findings in a noncontrolled setting."

It's not just N=24 because those same participants took 9 independent tests which generates more data. Also, the p-value should be considered along with the N, since the sampling variance of the test statistic will go up with a small N and this is accounted for in the test thresholds, which somewhat offsets that limitation.

But, a larger N and replication studies are needed.

Good points, one question - did you mean to say "6 independent tests", or am I missing something?

I thought it was 9, but I might have misread the study.

I think air quality is often neglected severely. Best personal solution would probably to move to the countryside.

I have no sources at hand, but some said that electric cars don't solve the worst pollution because tire wear and breaks causes the worst problems.

You find many articles that state it is 1000 times worse, but they aren't too credible in my opinion. Still, the pollution is real.

Dust can also come from pollen. Aside from allergies, it is probably not as unhealthy as plastic.

Or to city that is not car dependent.

Moving to the countryside will just worsen the problem for other people while a city that is not car dependent has other advantages:

* Less air pollution

* Less travel time for groceries/errands

* Less noise pollution

* More activity

* Kids can play on most streets

* 5-20k more disposable income per year because you don't need a car

Reducing car dependence really ought to be in the top 3 of environmental action points. Clean up energy production, reduce car dependence, start removing CO2 from the atmosphere. There are about 1 BILLION cars in use. It boggles the mind.

It is not only an environmental necessity. It is also an economic one.

Car dependent suburbs are bankrupting cities left and right. They don't pay for themself.

Not just bikes made a really good series about the concept of cities, that don't bankrupt themself:

https://www.youtube.com/playlist?list=PLJp5q-R0lZ0_FCUbeVWK6...

This is the big thing hidden behind all projects (renewables, capture, efficiency upgrades) that claim "this is the equivalent of taking 60,000 cars off the road." Think of the savings for health and the environment if we just spent the money trying to get an actual 60,000 cars off the road in the first place.

Many electric cars use the motors for regenerative braking instead of the actual breaks. I also have no sources at hand, but I believe brake dust is greatly reduced with electric cars.

Tire wear, well, from what I can tell electric cars seem to chew through tires more quickly due to the weight of the vehicles and the high torque. No sources at hand for this, either…

Even in a PHEV that effect is very noticable. I have a Volvo XC60 T8, 2.2 tonne SUV, and 10k miles in the brake pads are like new. When I had the car serviced recently all pads measured the same thickness as new pads - I'm 100% convinced it's because I just use regenerative breaking all the time, extremely rarely engaging actual brakes. In a car this heavy the pads should be at least half gone after 10k miles, but since they are rarely used they just don't wear out.

>>Tire wear, well, from what I can tell electric cars seem to chew through tires more quickly due to the weight of the vehicles and the high torque.

I think part of it is the incidental result of most electric cars being both very high torque and very high horsepower. Any 400bhp+ car is going to chew threw tyres quickly, and that's what a lot of the big expensive EVs are. I'd like to see if something like the the Leaf or ID3 use tyres anywhere near as quickly - I suspect very much not.

Not as quickly as the Teslas, but my 21K mile LEAF is due for front tires soon. That’s significantly sooner than OE tires on a typical competitive car.

The value priced EVs typically come with narrow low rolling resistance tires that have the kind of friction coefficient that tends to get online comment sections whipped into a frenzy of pearl clutching about safety when poor people buy them for their 20yo ICE cars. It's hard to make a 1 for 1 comparison with the luxury EVs that use soft wide tires to take advantage of all that torque.

Nitpick: Most EVs are pretty low horsepower. You just don't care because you have ~100% of it available at any RPM.

> electric cars seem to chew through tires more quickly due to the weight of the vehicles and the high torque. No sources at hand for this, either…

A Nissan LEAF weighs about the same as a Honda CR-V. Smaller EVs weigh less.

A large-battery EV will weigh more. The Tesla Model S, for example. But not all EVs have large batteries.

As for living near roadways in general, it has an unhealthy effect on "30%-45% of the North American urban population" according to the American Lung Association. [1]

[1] https://www.lung.org/clean-air/outdoors/who-is-at-risk/highw...

Despite the screeching of many an online commenter ICE vehicles can make similar torque in normal driving situations. Most new cars can roast the tires through the first several gears if the traction control will let you.

I think the difference is that EVs make no extra noise when you step on it so people feel more free to use more of the acceleration capability of the vehicle.

The other difference is that for most modern ice, you get plenty of torque, but only a quarter second after you asked for it due to turbo lag. With an EV, the torque is instant.

Sure, “torque” wasn't appropriate terminology.

EVs, as a rule of thumb, accelerate more quickly, because it's so easy. Just press the pedal. No noise, no fuss, no revving the engine, it just goes.

Acceleration is pretty much the equivalent of tire wear. That's what I was thinking about.

I have never heard the brake and tire argument, but it sounds like the 'batteries are worse for the environment than gas' argument which is not very accurate.

Makes you wonder if there are companies who benefit from information such as this being believed. Companies such as Shell maybe?

Edit: Not saying it isn't true! Just saying there might be more sides to this.

It's not a showstopper, because the environmental argument for EVs is CO2 and climate change rather than PM2.5 and air quality. But it's worth bearing in mind that they only solve the former.

Don't lower diesel and gasoline emissions matter at all?

>>But it's worth bearing in mind that they only solve the former.

That's....almost categorically not true, the PM2.5 emissions should be solved with in ICE cars with inclusion of DPF and GPF filters, but there is plenty of cars without those still on the road. A taxi driver sitting outside of my house at night in his 10 year old Skoda Octavia diesel is definitely contributing to the air pollution around me, and that wouldn't be a problem if he drove an EV or a modern diesel with all the filters functional - but the economics of taxi driving mean they almost always drive crappy old cars which pollute a lot.

> the PM2.5 emissions should be solved with in ICE cars with inclusion of DPF and GPF filters

Unless they filter the tyres, this will not be "solved".

"Non-exhaust emissions (NEE) .. are currently believed to constitute the majority of primary particulate matter from road transport, 60 percent of PM2.5 and 73 percent of PM10"

https://www.emissionsanalytics.com/news/pollution-tyre-wear-...

Tire wear is a matter of friction. Higher weight, higher friction, thus more wear. In this isolated instance, electrical cars are likely to be worse off than regular cars due to generally higher weight. Perhaps this is offset by regenerative breaking systems though. I'm sure you could make that argument on other parts of the EV as well.

Outside of isolated areas like that, I would be seriously surprised if electrical cars comes worse off than gasoline cars on the whole. There has been some talk about CO2 emissions made when making hydro electric dams, for instance, but then there's also CO2 emissions when making oil platforms, and so on, so IMHO those kinds of discussions quickly become very theoretical. Either way, I'm sure EV's are better off in terms of local emissions, meaning that they reduce local smog, and so on.

On the other hand, EV's can very well run on coal, if that's how your local electricity is produced. In that case, how well EV's do environmentally speaking is due to the total effort made by society. For that reason I'd love to see a comparison of gasoline and diesel versus coal. Which one is the cleanest?

AFAIK there are some real issues with the way lithium is mined for the batteries, however, that doesn't strictly involve emissions. So there are many pros and cons in the debate on electric vs gas cars that aren't obvious to the casual on-looker.

I don't have a particular horse in this race myself, but I do note that those who do, tend to offer arguments that are more strongly coloured by their preference.

Personally environmental safety isn't the only deciding factor. There's also such things as cost and reach. And I don't just mean how many miles a car can run on one tank, but also its longevity. On the whole it seems to me that EV's have a higher capital cost (up front cost), that might not make up for the savings you make by running it.

On the whole it seems to me that gasoline cars have far better overall longevity than EV's, with the offset that EV's are cheaper to run, though with slightly more hassle in the "refuelling" department. For me personally, winter cold is an issue, since it severely affects battery capacity. On the other hand, those Teslas do look pretty cool.

Brake pads on my Nissan Leaf have lasted 6 years (~90,000 km).

> electrical cars are likely to be worse off than regular cars due to generally higher weight.

Given that a Nissan LEAF weighs about the same as a Honda CR-V, and that there are many EVs that have the same weight or are lighter than the Nissan LEAF, I would say that you are considering only a select group of EVs.

From https://www.easyelectriccars.com/how-much-do-electric-cars-w...

Here are some examples of popular electric cars and how much they weigh in order of weight:

    Model X Long Range – 2459 kg without passengers or fuel (7 adult capacity).
    Tesla Model S Performance – 2241 kg without passengers or cargo (5 adult capacity).
    Tesla Model S Long Range – 2215 kg without passengers of cargo (5 adult capacity).
    Model 3 Performance and Long Range AWD – 1847 kg without passengers or fuel (5 adult capacity).
    Nissan Leaf – 1775 kg without passengers or fuel (5 adult capacity).
    Chevrolet Bolt – 1616 kg without passengers or fuel (5 adult capacity).
    Opel/Vauxhall Ampera-E – 1611 kg without passengers or fuel (5 adult capacity).
    Renault Zoe, 44 kWh – 1480 kg without passengers or fuel (5 adult capacity).
    Hyundai Kona – 1399 kg without passengers or fuel (5 adult capacity).
    BMW i3 – 1343 kg without passengers or fuel (5 adult capacity).

Based on this, and the upcoming plans of many automakers to launch pickup truck and SUV type EVs, I would say that a significant portion of EVs will be heavier than the average car on the road currently.

The EV market is about 2% of car sales in the US. I doubt that we would be right to predict double-digit growth happening suddenly.

A Ford F150 (the most popular pick-up truck) weighs about the same as the Tesla Model 3. The top-selling vehicles in the US are all pick-up trucks.

The Toyota Camry (a popular sedan) weighs about the same as the Nissan LEAF. The Prius Prime is also in this weight range.

A Honda Fit (a popular small car) weight about the same as a Smart EQ. Small cars are not what US consumers are choosing.

Your argument is a hypothetical projection of Tesla-class EVs into a very large market-share. In reality, consumers are choosing larger, heavier ICE vehicles.

Your argument proves my point. The customers that are currently choosing larger, heavier ICE vehicles will choose the same form factor of EV when given the option, and that F150 which currently weighs the same as a Tesla Model 3 will add on however many hundreds of pounds a battery pack weighs. Same goes for the Camry, it weighs the same as a LEAF (a much smaller car) now, but when you add the battery pack in the bottom, now it weighs the same as a Model S.

I see, you imagine the current ICE-Vs with batteries. But US consumers want large vehicles and ICE-comparable range.

Very large EV batteries are expensive. Your conjecture may hold if the cost of Tesla-sized batteries becomes much cheaper (approximately half the current 2021 cost).

EVs are likely to remain a small market in the US. Hybrids make more sense for cost and range. In Europe, the EV market is growing rapidly. Although some people can afford the Tesla, small EVs are popular in Europe. And the small EVs are not especially heavy vehicles, as the data show.

Our two cars are a 2015 LEAF and a 2005 CR-V. These aren’t directly competitive cars IMO. The CR-V has much more interior and cargo space, obviously longer range, and better winter road performance.

The LEAF is more directly comparable to a Nissan Versa in size and capability (3500# vs 2500# curb weight).

* Weight of the average Small family car (C) (same class as the Nissan Leaf): 1,365 kg ^[1]

* Weight of the Nissan Leaf: 1,560 kg ^[2]

Difference: 1,560-1,365 = 195 kg.

So about two washing machines in difference... :) And that's by giving you credit by comparing the heaviest average within the same car class. The lightest one yields a three washing machine diff.

[1]: https://carroar.com/average-car-weight/#:~:text=An%20average....

[2]: https://www.guideautoweb.com/en/makes/nissan/leaf/2019/speci...

I think we differ in our perception of "small" and "mid-size" car.

But even so, 195 kg is the weight of a driver and passenger. If we consider this to be a decisive factor in pollution, we had better also consider the obesity epidemic as a factor in tire wear. ^_^

Excuse me, "perception"? I used an industry standard, pal.

One possible explanation is that I live in a different market. In any case, the weight comparisons are the real data to use. The Nissan LEAF is heavier than some cars, but much lighter than the most popular ICE-V choices being made by consumers.

I can't find it but I did recall there was some rule in France or some Scandinavian country that banned early childhood centres away from within certain distances to highways and a like

> I have never heard the brake and tire argument, but it sounds like the 'batteries are worse for the environment than gas' argument which is not very accurate.

It's not quite the same thing as "the long tailpipe fallacy".

it's established fact, e.g.

https://www.bbc.co.uk/news/business-48944561

https://www.thetimes.co.uk/article/microplastics-from-car-br...

https://airqualitynews.com/2020/03/09/air-pollution-from-tyr...

https://www.emissionsanalytics.com/news/pollution-tyre-wear-...

Electric cars are great, but let's be clear about what issues they will solve, and which they will not. They will produce _less_ particulate matter pollution due to not having an Internal Combustion Engine, but will not eliminate all sources of particulate matter pollution.

Or even come close - the last link above estimates 60% is "Non-exhaust emissions" from "brake wear, tyre wear, road surface wear and resuspension of road dust"

The tailpipe emissions on modern gasoline vehicles have very low particulates (and low NOx, which reduces particulate formation in the resulting air).

>Makes you wonder if there are companies who benefit from information such as this being believed.

If there is one thing I've learned from the Corona virus, it's that sometimes people push misinformation for ABSOLUTELY no reason at all.

The tire thing is real, but EVs are better for brake dust too, as well as local and atmospheric pollution, so it's an overall win.

In some countries they're also displacing leaded gasoline which is a double win when it comes to intelligence affects of pollution.

>>In some countries they're also displacing leaded gasoline which is a double win when it comes to intelligence affects of pollution

Excuse me, but what? Leaded petrol has been phased out almost everywhere in the world, even according to wiki:

"only Algeria, Yemen, and Iraq continue widespread use of leaded gasoline. None use it exclusively".

I doubt any of those countries are seeing significant EV uptake either.

The only potential real connection here is how in some countries where leaded petrol is still legal but extremely rare(UK), and pretty much only ever used by classic car owners and even then rarely due to its extreme cost, maybe some of these cars are getting converted to EV drivetrains and therefore don't actually burn leaded petrol anymore. Maybe. But that will be extremely negligable, and literally a statistical error compared to the amount of leaded fuel still being burnt by the aviation industry.

Ah yes, the countryside. Not quite sure how we're going to be housing 7+billion in the countryside.

Doesn't seem like a practical solution. Not in the least because moving the countryside will increase car dependence and pollution. But I guess the view might be nicer in the short term.

I agree that air quality is probably neglected. Mechanical ventilation (with or without heat/enthalpy recovery) with filters seem like a net win in every dwelling. I haven't had to open a window since installing mine. Less pollen, way less mosquitos, and constant fresh air. A lot cheaper in the long term than those gimmicky devices which circulate indoor air and filter out a bit. If it's in your house, you've already inhaled it.

Mechanical ventilation (with or without heat/enthalpy recovery) with filters -- what should one look for when evaluating what to purchase? Do you recommend specific brands?

I opted for Zehnder using a DIY package. If you have basic DIY skills you can install it yourself in a couple of days. Comes with semi-flexible ducting, which is super easy to use. I have fresh air delivered to the living room & bedrooms, and extraction in the kitchen/bathroom/utility room. The unit does heat recovery in winter, which ought to save a bit on the heating bill. It's early days, so we'll see how that goes.

Thanks!

* Do try to get an HRV/ERV if you live in places where the outside air temperature gets >30C or <10C. Otherwise bring in fresh air will cause issues.

* Make sure your system can handle MERV16 filters: they catch more things, but may create more back pressure, so the system has to be designed to handle it. Further nice-to-have upgrades would be HEPA capabilities, and (if you live in wildfire zones) charcoal filters (for smoke/fire smells). You don't have to (always) use the finer filters, but having that option is useful.

* The filter should ideally be 4"/10cm, as they have more surface area, so reduce back pressure and often only have to be swapped every 6 months (sometimes even every 12). They do cost a bit more because of the extra material, but you get convenience. Don't go less that 2"/5cm though.

* The mentioned Zehnder is a good brand, but AFAICT, are higher end systems, and so may be a bit more pricey:

https://www.youtube.com/watch?v=OrG7oG8Tvp8

https://www.greenbuildingadvisor.com/article/urban-rustic-in...

* Consider getting a separate whole house dehumidifier, depending on your climate: sometimes the indoor air temperature may be comfortable (20-25C), but if the relative humidity (RH) gets too hight (>60%) it will feel hot. But the AC won't run because its thermometer will say everything is fine. Temperature and moisture needs to be dealt with via separate mechanical systems.

Thanks!

>Temperature and moisture needs to be dealt with via separate mechanical systems.

Are there dehumidifiers on the market that aren't air conditioners with a bucket under the condenser coils to collect the water? And if you have a whole-house version of one of those, do you need another whole-house air conditioner?

Yes, there are "portable" dehumidifiers:

* https://www.goodhousekeeping.com/appliances/g27192069/best-d...

It's a matter of volume: one of the portable ones could be useful in a small apartment/condo, or (if you close the door) a bedroom. But if you have something that is 1000 sq. ft. / 100 sq. m. or larger, you may need multiple portable units. It may be simpler to just install a fixed unit and patch it into your existing ducts.

There's also the fact that you have to empty the portables, so they may stop at 'random' times until you do so. Not sure about their efficiency, given that have space-volume and weight constraints compared to a fixed whole house unit. Plus you have the noise of the unit running in your living space, compared to having it in your mechanical area.

I don't see how what you just wrote supports your assertion that "temperature and moisture needs to be dealt with via separate mechanical systems" or answers my question, "Are there dehumidifiers on the market that aren't [essentially just] air conditioners?" but you don't have to explain if you don't want to.

Sorry, misunderstood:

Yes, a dehumidifier does work on a similar principal as an air conditioner: there's a cold (metal) surface that causes condensation to remove moisture from air as it passes over.

An AC system would then take the heat that is also removed from the air and send it via a refrigerant loop to some place else (usually an outside device). A dehumidifier simply takes the extracted heat to another coil inside itself and reheats the air to (roughly) the same temperature.

The purpose of a furnace is to put heat into air, of AC to take heat out† (which just so happens to also change the RH), and that of a dehumidifier is to remove moistures while not altering temperature.

If your thermostat already reads (say) 25C, but your RH is 70% (e.g., due to a lot of cooking), then it's going to feel much higher than 25C. So do you crank the AC? You drop the temperature down to 20C, but the RH may still be 60%, and still feels too warm/muggy for you. Do you crank it to 18C? Running the AC, even though the thermostat says things are "fine", can use a lot of energy just so you can feel comfortable. There's a reason why the "humidex" / 'feels like' concept is often mentioned in weather reports: it has both psychological and physiological effects (wet-bulb 35C is a real thing).

Also note that, in winter, even if the temperature and humidity are okay, it may still feel too cold because of mean radiant temperature:

* https://www.energysolutionsnc.com/designing-spaces

* https://en.wikipedia.org/wiki/Mean_radiant_temperature

* https://en.wikipedia.org/wiki/Thermal_comfort

MRT is why people feel a "draft" near windows. There is 'extra stuff' going on the walls and windows and thermal bridging. Do a search for ASHRAE 55 for various factors that go into making a comfortable (indoor) environment:

* https://en.wikipedia.org/wiki/ASHRAE_55

† AC was actually originally created for humidity control by Willis Carrier specifically for printing, to keep the ink and paper consistent and not runny. Cooling humans was only "discovered" as a use case later.

>Not in the least because moving the countryside will increase car dependence and pollution.

Not if you move AND stay in the countryside for the most part.

Countryside != suburbs, where you might come and go to some city everyday.

Having lived in the "countryside" most of my life, it would absolutely increase "car dependence" (and thus pollution) for people to move there. Public transportation simply isn't possible on those scales.

We had maybe a dozen neighbors within a mile of us. Town was 5 miles away. School was in town. We had a nursery next to us, but the next nearest job was in town.

Even if you restricted what you're saying to the actual towns, that town currently has 3000 people in it. It only had 1000 when I lived there.

I just checked, and they do apparently have "public transportation" there now. They recommend that you book it 3 days in advance to make sure there's availability. It's pretty clearly designed for people who can't otherwise get around, but does clearly state that it's available for everyone.

>Having lived in the "countryside" most of my life, it would absolutely increase "car dependence" (and thus pollution) for people to move there. Public transportation simply isn't possible on those scales.

It's also not needed most of the time, and surely not everyday.

Plus, the US model of "countryside" life is not the same as in Europe or elsewhere: e.g. "We had maybe a dozen neighbors within a mile of us. Town was 5 miles away. School was in town. We had a nursery next to us, but the next nearest job was in town."

That's not countryside, that sounds like some a rural desert.

Countryside in most of Europe e.g. is networks of villages, that are more or less autonomous.

> networks of villages, that are more or less autonomous.

Apart from the fact that most people there have to do a big shop once a week at the nearest supermarket, or that all the professionals commute out of the countryside to their urban workplaces?

Only the islands are properly autonomous, and even then that just increases the length of time between supermarket trips.

>Apart from the fact that most people there have to do a big shop once a week at the nearest supermarket

The nearest supermarket is often directly in the village area. And if you not, it just takes 1-2 trips per month to go there.

And people live and work there, they don't commute to "urban workplaces". These are rural villages, not suburbs.

Not sure how that impacts car usage?

In that most of the month you just walk around your village, go to your shop, your field, the grocers, the super/mini/medium-market, to neighbors and friends, etc, and don't need a car.

You might use it a few times a month if you need something special, to visit another village or the nearest city, and that's it.

So like 1/20 to 1/50 the car use of the average suburban dweller.

Do these "more or less autonomous" villages have electricity, internet, and running water?

Yes, they have all three. They have pipes connecting them to the country-wide electrical and phone network, and the regional water system.

Autonomous as in "you don't need to visit some city to get all your basics nor you need a car to go miles away to some Walmart to shop", not as in "they make their own electricy locally".

>Ah yes, the countryside. Not quite sure how we're going to be housing 7+billion in the countryside.

A short-term solution may be viable for the individual while not doing anything for society at large.

Mind you, the short-term solution still seems crap to me anyway since "lolz just move your life" is bollocks.

Seems like on of those cases where "what is good for the individual is bad for the whole population if every body follows the advice" I remember seeing this when I took economics but I can't remember how it is called.

Tragedy of the commons

Sounds like a prisoner's dilemma, where from an individual perspective it makes sense to make a certain decision, but the same holds true from anyone else's perspective, and when everyone does it you end up in a worse-off situation than if everyone had cooperated.

The universal principle of Kant's categorical imperative is likely this.

Something like, take actions that were the principles behind them applied to and adopted by all of society, that society would still be one you'd like to live in.

FWIW, I moved outta the city and bought a farm and it's been the best move of my life.

It sounds like you violated the very imperative you mentioned, though. If everyone did what you did, the world would be worse. This doesn't address the problem at hand.

I didn't say I agree with it. And I disagree the world would be worse.

The world would be much less filled with stress.

Everyone here seems so insanely focused on carbon emissions that anything rural is like verboten--THINK OF THE CAR DEPENDENCE!! lol

First off, there's not enough land for the world's population to live like that. If everyone tried to do that, there'd actually be more stress because people would be fighting over their precious extra acre.

>Everyone here seems so insanely focused on carbon emissions

Given climate change and what drives it, is it any wonder? Creating some disasters in the future so we can have less stress now isn't a very good tradeoff.

It's like voting--if you know game theory, you know that voting is a waste of your time.

If I spent all my life avoiding "car dependence" at all, much less with the goofy fervor of the virtue-signalling green crew on the internet, I'd have roughly zero impact on climate change.

As it stands, I get to enjoy big ol' diesel trucks and dirtbikes and motorcycles.

Plenty of people don't enjoy these things and are happy sitting on the bus and enjoying things in cities, movie theaters or museums or whatever.

I just have different preferences.

Luckily, my preferences seem rare, so it's no worry.

Also, the biggest driver of climate change is the sun.

>Also, the biggest driver of climate change is the sun.

Absolute nonsense.

Supposing I'm wrong about that.

Are you saying farmers should drive teslas?

No, I'm not saying farmers should drive Teslas.

> It's like voting--if you know game theory, you know that voting is a waste of your time.

Please explain! I don't know game theory that well.

A 2019 UK government report found tyre wear, brake wear and road surface wear to be problematic:

From "Report: Non-Exhaust Emissions from Road Traffic" (https://uk-air.defra.gov.uk/library/reports.php?report_id=99...)

"Data from the UK National Atmospheric Emissions Inventory indicate that particles from brake wear, tyre wear and road surface wear currently constitute 60% and 73% (by mass), respectively, of primary PM2.5 and PM10 emissions from road transport, and will become more dominant in the future. Currently they contribute 7.4% and 8.5% of all UK primary PM2.5 and PM10 emissions. Therefore to achieve further gains in PM2.5 and PM10 air quality in relation to road transport sources requires attention to reducing non- exhaust emissions, not solely a focus on lowering exhaust emissions.

The magnitudes of non-exhaust emissions are, however, highly uncertain, particularly when compared to data for exhaust emissions."

That's pretty scary, don't brakes contain asbestos?

this is a fallacy, I drive around countryside a lot. And they use a lot of chemicals. You just end up swapping one set of nasty chemical with another.

> Best personal solution would probably to move to the countryside.

Depends on the country. In Central and Eastern Europe countryside often has worse air quality than cities during winter (because in the cities there's central heating system and co-generation and in the countryside almost each house burns coal for heating).

Or just use (at least) MERV13, and ideally MERV16, filters in your fresh air intake ducts:

* https://www.greenbuildingadvisor.com/article/understanding-f...

* https://www.researchgate.net/figure/Mean-PM-25-removal-effic...

You'll take care of >70% of PM2.5 particles.

Careful with this, the increased resistance can damage systems that aren't designed for it.

In another comment I mention back pressures:

* https://news.ycombinator.com/item?id=28085720

The country side is not a silver bullet. It has its own set of problems with pesticides and second-order pollution such as ozone which can be higher than in urban areas. And as other have pointed out, moving to the country side does induce significant extra driving.

Not all countryside have clean air. Air from more polluted areas can carry pretty far (like Wildfire smoke, Ozone).

For current air quality levels and maps, you can check AirNow[1] for US and Canada, or IQAir[2] for anywhere in the world.

It fluctuates every day (like today for me it's just under 50 or 'good', but just yesterday it was over 100) so it's better to look at trends. AirCompare EPA[3] can tell you how many poor air quality days over the past several years on a county by county basis, although not every county reports this (and probably generally the more rural counties don't).

[1]: https://www.airnow.gov/

[2]: https://www.iqair.com/us/earth

[3]: https://www3.epa.gov/aircompare/

"Move to the country side" is clearly "go to where the air is better".

I do appreciate the links though.

What happens if the air quality changes a couple years after you move? Do you uproot your life again?

Brake and tire wear is the pollution that harms humans, EVs are worse. Greenhouse emissions harm the environment and EVs are far superior.

There are legitimate studies that correlate increased CO2 levels with decreased performance.

https://pubmed.ncbi.nlm.nih.gov/25117890/

There are also many more legitimate studies (and decades of experience) showing that submarine crews working at an order of magnitude or more of CO2 concentrations experience no cognitive effects.

It’s very likely the study you linked is flawed or there is a confounder.

Having worked in filtration, aerosols and the built environment - this has been known for years, the challenge was creating broader understanding of the value of better iaq.

> I'm all for cleaner air and I don't doubt that the already well-established negative effects of high CO2 or VOC concentrations on us, but can we at least keep any discussion to non-anecdotal, strong scientific evidence?

They're so well established that there are industry guidelines, ASHRAE 62.1 and 62.2:

* https://www.ashrae.org/technical-resources/bookstore/standar...

Pull/return air from places like bathrooms and kitchens, and supply air to (e.g.) bedrooms, and in between temper the filtered, fresh air you bring in from the outside with an HRV/ERV:

* http://www.mnshi.umn.edu/kb/scale/hrverv.html

Renovating this into an older building which has less room for equipment could be a challenge though.

There are plenty of peer-reviewed papers from reliable sources showing correlation between CO2, VOC, *particulate* and health issues.

I agree with your point that this article does use a lot anecdotes and not enough strong evidence to back up the terrifying conclusions it suggests and throws around "may" quite a bit.

I will say though, that similar to investigations on microplastics exposure and health impacts, it can be prohibitively difficult to really have "rigorous statistics" or fully control in studies when it's become so ubiquitous in nearly every environment and when the exact types of pollutants people are exposed to can be very hard to quantify. For any of the more complex compounds it will be very hard to discern what aspect of it causes what exact health outcomes. For example, with microplastics its nearly impossible to find any population without exposure to or detectable amounts of microplastics in their bodies, meaning fully controlling for it in the stats is not possible. The types of plastics people are exposed to can also be very difficult to quantify meaningfully as they don't all accumulate in our tissues and as a result it can be difficult to quantity the actual exposures people have to what pollutants, short of some very unethical experiment designs.

Yes, and maybe we should start doing the science before we make stuff ubiquitous in our environments, rather than trying to figure stuff out after the fact. Leaded gasoline is an example where it took us a long time to understand the effects, and we'll never really be able to quantify the damage caused. And the data you get later from phasing something out at a systemic level gives you only a kind of crude single crossover result, with lots of potential confounding variables. Why did crime in the US decrease in the 90s? We can't be sure.

I'm not saying microplastics are like lead of course. Just that in some cases, we're pretty sure we've caused a lot of damage by filling our environment without sufficient advance consideration.

Yeah it's a really tough problem with no clear answers.

Microplastics and other pollutants with potential long-acting health impacts are very hard to predict far in advance. Strong evidence for or against any adverse health effects would take considerable effort to gather while in the mean time they offers such clear advantages and solve so many problems. Plastics have massively reduced costs in almost every industry and have become almost irreplaceable in some applications such as medical equipment (think packaging for syringes, surgical tools, or anything that requires contamination control).

With lead there were viable cost-effective alternatives, it wasn't in nearly every product we consume, and we already had pretty clear evidence that its highly toxic so the only evidence needed was to show that the low levels being used in gasoline, while not acutely toxic, could be harmful given enough exposure to it over time.

I doubt anyone working on plastics early on anticipated microplastics would end up in nearly all of our food, living spaces, and even build up in our bodies. By the time there would be any alarm bells sounding, it would've been too late, the sheer number and ways it solves problems makes it far too difficult to retreat from when, due to the nature of how its potential effects could arise, wouldn't give any strong evidence that its harmful.

Outside of plastics many air pollutants are similar in that manner. The processes that release them are so convenient and solve so many problems, while any health effects would be long-term and extremely difficult to gather strong evidence for.

I agree, there is a lot of already well-established knowledge on the topic. I'd also argue though that a lot of ordinary people probably don't know much about the importance of air quality in the home. I never thought about it until I had a house. I suspected something in it was making me a little ill and so I looked into it and bought an air quality testing device. The illness went away so I don't think it was sick building syndrome (unless me using all the water outlets in the house again helped make it go away), but I did find that in my basement, CO2 tends to build up quite a bit. I never knew that this was something that could happen, and that I should open the windows once in a while. So maybe articles like this might raise awareness?

I lived with some roommates for a year in a big house covered in carpet and we never vacuumed, not once. One of them allegedly had asthma too. We were all fine and I couldn't tell the difference between that place and a vacuumed place. It validated my lifelong supposition that vacuuming is truly a waste of time, a bizarre cultural neurosis we would all be better off without.

I can assure you, as an allergy sufferer, that vacuuming makes a huge difference in my well-being. Dust and pollen build up and make me miserable. Carpet is tougher to clean, and we're having wood floors installed in part to make cleaning easier.

Maybe it's useful for people with allergies, but I'm not convinced it matters for people with no allergies or severe asthma or anything.

There are studies on AQ and classroom performance[1][2] that seem to arrive at similar conclusions. Obviously there can be conflicts of interest if the backers manufacture air filters, but I don't see any disclaimers on those, at least.

1: https://www.edworkingpapers.com/ai20-188 2: https://pennstate.pure.elsevier.com/en/publications/the-rela...

Using an home air sensor in my home office, I've become keenly aware of CO2 levels during the day...

Despite having a sizeable HVAC system, the absolute best way to reduce CO2 is to open the windows - which I now do when I wake up each morning.

Here is a visualization of the impact of opening doors/windows in the morning: https://i.imgur.com/4Ac8QHP.png

As my family of 5 wakes up, the CO2 comes down with them as their bedroom doors open (CO2 is heavier than air), and the CO2 level spikes downstairs - and can take a couple hours after opening the windows and doors to get down to the outside baseline CO2 level of about 420 ppm.

Here is a visualization where I did not open the windows right away, and had to close again due to the heat: https://i.imgur.com/1alDAfB.png

On summer days, my servers don't love the heat and humidity of outside air, otherwise I've learned to keep the windows open all day. I do seem to notice a difference in how I feel if the level goes over 1000ppm, but that's really hard to quantify.

Adding plants has not had a noticeable effect.

Yes, unfortunately houseplants don't do much for air quality[1]. But they do look nice, and they can be satisfying to take care of (unless you kill them, that is).

1: https://www.nature.com/articles/s41370-019-0175-9

> already well-established negative effects of high CO2 or VOC concentrations on us

I don't know about this. Research is mixed and the US military has tested supposed mental impairment at higher levels of CO2 in sailors inside submarines and found nothing suggesting CO2 levels can effect noticeable cognitive performance.

I’ve been harping on this since learning covid was aerosol based early 2020.

I like to tell new parents a trick that worked well for us: use a nice filter-based air purifier for white noise. It has deep bass, and it keeps the air near the child extremely clean. We have been doing this for our kids for almost 10 years now since birth.

A fun experiment for kids: if you have a laser pointer, shine it close to the ground indoors and kick up dust near the floor. If you see any light in the air, that is all stuff you are breathing in (works really well on carpet)…

Air quality associated with:

Alzheimers: https://www.scientificamerican.com/article/the-new-alzheimer...

Cancers, plural: https://www.aacr.org/patients-caregivers/progress-against-ca...

Sperm Quality: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4443398/#sec995...

Female Fertility: https://www.newscientist.com/article/2207560-exposure-to-air...

Autism: https://www.sciencealert.com/particulate-matter-in-air-pollu...

Bipolar/Depression: https://www.nationalgeographic.com/environment/article/air-p...

I've suffered from terrible allergies my entire life. I bought the best air filter I could find and then bought two portable HEPA air filters running the best filters I could find. It's been great. I went months without allergy medicine. A total quality of life improvement.

Love both of these ideas / tips! Any suggestions on specific air filters?

You have to look quite carefully because "HEPA" became branding rather than rating, and you can find it labelled on filter appliances which vary in capture rates by several orders of magnitude.

You want ones with numbers, 99.97% is a good number to find, you can get it on big Honeywell filters.

While incredibly difficult to find, there are MPR 2800 rated furnace filters which are better than HEPA.

If you're recirculating the air through the filter many times, the capture rate doesn't really matter. What you don't catch on the first pass you'll catch in the 2nd.

From that point of view, even a 90% catch rate sounds fine.

When you're dealing with a machine that is exchanging air in a room a certain number of times per hour and a continuous influx of particulates, with less efficient filters you need more air exchanges which means more filters, bigger fans, etc.

The takeaway is that less particle efficient filters won't ever get you down to the same steady state as better filters in real world applications.

And from personal experience with filters and devices to measure airborne particles, it is hard enough getting good numbers with the best filters I can find.

Careful though. Those things can destroy your hvac system, which is not designed to deal with a severe restriction like that. Plus, they won’t last long with no pre-filtering at all. Shame to have a great filter like that just clog up with hair and pollen in three weeks.

I got a cheap tower Holmes from Walmart for not that much (less than $100) and I put 2 99.99% filtration HEPA filters in it and have been running at half speed most of the day for over a year.

I shake out the pre-filter (gets covered in dust and pet dander) and toss out the filters every ~6 months. I use a filtrate 1900 filter for the home air filter.

Tip: never use the "ionic" button. They come on most filters for some bizarre reason, but ionically charging the air is a bad idea.

“ ionically charging the air is a bad idea.”

Why?

Ionic means ozone generation. The idea with charged filtration is that microbic particles are attracted to the filter. However, ozone is a lung irritant.

> Ionic means ozone

No it doesn’t. Who told you that? Ozone generators are a completely different thing and air ionizers must conform to low ozone emission standards.

> > Ionic means ozone

> No it doesn’t.

Yes, it does.

> Who told you that?

Among others, the EPA [0].

> Ozone generators are a completely different thing

They are, but ionizing air cleaners still generate ozone even though they are different than “ozone generators”. [0, again]

> and air ionizers must conform to low ozone emission standards.

No, only the small minority that claim health benefits in a manner which brings them under FDA medical device regulatory authority do. [0, again.] But even those so regulated in ozone emissions are net ozone generators.

[0] https://www.epa.gov/indoor-air-quality-iaq/what-are-ionizers...

Dyson

Getting a filter that is properly sized for your space and that meets your unique requirements (ACH, efficiency, etc) is likely sufficient.

Here’s an outline on how to go from the common rating, CADR, to various parameters that are of interest:

https://frdmtoplay.com/nagivating-air-purification/

If I were you I’d sign up for Consumer reports and buy their second highest rated air filtration product. The most expensive one tends to be really expensive and the second best tends to be almost as good at a significant discount. This is how I make most large purchases these days.

After looking at CR and buying quite a few others I'm pretty solid on alen.com standalone units, altho a central HVAC definitely seems more effective, esp. given that you aren't necessarily recirculating a build-up of CO2 all night long.

In terms of bang for buck nothing comes remotely close to having a furnace filter strapped to a 20" box fan. This gets you most of the benefits of an expensive filter for a fraction of the price.

People will talk about CADR but also look at TCO.

It’s only a good price for a bit though. Without any kind of pre-filter, large dust will clog that expensive near-hepa filter in a couple months. Plus, an axial fan can’t really move air though a good filter very well.

I still recommend just spending the 150 bucks on a Winex or Coway. Then you have true hepa, plus filters that last a year.

where can i buy this filter?

We purchased a filtrete room air purifier 10 years ago, and amazingly it hasn’t broken down after essentially continuous usage (low speed during the day, high speed at night to make more noise :)). These are on amazon or wherever.

yes, but what about the hygiene hypothesis of increasing allergy/autoimmune disease prevalence?

Air indoors should be clean, but children should spend hours outside in nature every day.

This won't be an option in some urban environments, but those are simply bad for the health of children (and adults).

I'm all for cleaner air (especially reducing dangerous gases and pollutants), but at what point does the over-sterilization of our environment (specifically with regard to microbes) do more harm than good? People in my family suffer from various allergies, and many suspect there may be at least some link to not being exposed to enough allergens at an early age (father was a surgeon and our home was always clean – nearly to the level of an O.R.).

Being exposed to allergens at home is the worst.

I grew up with a dog, and never tasted or smelled anything until a few years after the dog died

The particulate matter that I worry about isn't microbes, it's all the crap that we're creating and putting into our environment with things like power generation and vehicles, which makes up the majority of the small particulate matter.

Sorry for the crappy source, but I'm short on time right now to find you a better one: https://laqm.defra.gov.uk/public-health/pm25.html

The composition of airborne particles depends highly on what size you're measuring. The stuff you see when you kick the carpet is the "big" stuff like cotton breaking down.

Radon buildup is also a potential concern if you have your house sealed up. Opening the windows is the best way to clear it, but activated carbon filters should capture it.

Just make sure you're masked when you clean or replace any of the filters.

My gut feeling tells me activated carbon is not enough but you need HEPA.

Many purifiers contain a carbon and HEPA filter.

> Radon buildup is also a potential concern

Citation needed?

As far as I am aware unless you are building deep underground or have built your house on radon rich bedrock, or your house is entirely made of granite, this is absolutely not a concern for the average person.

If you are in doubt you can look up what is the expected radon exposure on the ground region where you live. Most people will have a higher radiation exposure from an arm x-ray than from ground leaking Radon.

It's location dependent, but more people live with radon seeping up from the ground than you would think. Some countries now have building codes that demand the foundation gets sealed to prevent it.

in the UK there are many areas that Radon can be an issue

from: https://www.ukradon.org/information/ukmaps

"Every building contains radon but the levels are usually low. The chances of a higher level depend on the type of ground. Public Health England has published a map showing where high levels are more likely."

getting a sensor at a reasonable price is tricky since Radon emits Alpha radiation - I managed to get one at around £300

Radon is an alpha emitter which gets into your lungs, so that comparison to an arm x-ray isn't entirely fair. Otherwise I agree, it shouldn't be a concern unless you live in the first floor on granite.

Alpha particles penetrate barely any at all. An arm x-ray would also hit you with particles that hit more (and more valuable) cells in your body.

It's right they don't penetrate. However, the lungs is one place they don't need to penetrate, they get direct access to some very valuable (to us) cells in our bodies, which are especially vulnerable to cancer, and do grave damage to them. From 10 to 1000 times more damage than equivalent energy gamma or beta radiation, according to Wikipedia. Radon as a health problem isn't some crank thing.

It's not that much of a concern, but mostly because tests are widely available. Test your basement for radon, and only worry about it if the levels are high.

For radon, we installed a suction fan inside our house that sucks air from under the house. That lowers the pressure under the house, and radon doesn't seep in. It made the measurements go from ~120bq to 20bq.

This is a legitimate concern. What we do is monitor the outdoor air quality, open the windows when it's good, close them when it's bad, and skip the air filters inside unless indoor air quality is measured to be bad. Which only happens during wildfires as our house is modern and pretty well sealed.

Once our children are past the age of 10 or so we will probably go back to running air filters all the time. But the early years are crucial for immune system development and lack of exposure to the natural environment in early years is likely to be one of the biggest reasons for the rise in allergic diseases.

Oh, and stop using gas appliances indoors.

>Oh, and stop using gas appliances indoors.

If you get a particle meter you quickly learn that the biggest source of particulate isn't gas but cooking (and especially lightly burning) food. The slightest smell of smoke means your home is going to be like (insert terrible air quality city) for a few minutes to a few hours depending on filtration.

One of the worst sources of this is the fact that so few places have real vent fans above cooking surfaces (the sucking through the microwave business does essentially nothing).

It depends... some microwaves are a) connected to an actual vent and b) have decent suction.

However, they cost a sizeable chunk more than the cheap shit you find in rentals. (In SV, that cheap shit is looking spiffy, but it's still cheap shit. If it says Frigidaire, you know it's not exactly high end)

I guess I have never encountered a microwave that was actually vented outside. Even so, a real hood would be much preferable.

Yep - but it's a space question. (I live in a house from the '40s, I have no idea if people back then were somehow 30% smaller or something, but having a full hood and a microwave is just a fantasy given the available space. One day..)

People were slightly smaller in the '40s, but the main difference is that they had a lot less stuff. Compared to the purchasing power, furniture was more expensive and a vast majority of today's appliances did not exist at all.

A typical kitchen had a stove and either an old-fashioned icebox or a fridge, and that was it.

I noticed some toilets in older houses in the bay area were comically small for me at 6'2" and I as I rule couldn't see my face in mirrors standing up (they were mounted so the tops were about at shoulder level. People from different places around the world are also different sizes (a lot of this has to do with multi-generational semi-inherited nutrition availability)

This is my only dealbreaker in rentals. I will happily pay more for a unit with a real exhaust fan. Its crazy that we expect them in bathrooms but don’t expect them in kitchens. Health concerns aside, who wants their whole house to smell like fish for hours after cooking.

Mould will damage a house, cooking fumes will only damage the temporary residents. Smells go away by the time someone else moves in.

FWIW I think every place I've lived in Australia has had a vented rangehood over the stove, but maybe that is just blind luck.

Combustion products from gas stoves are specifically implicated in asthma. Children in houses with gas stoves have asthma at higher rates and the effect is not small. People with electric stoves cook too, but their children get less asthma.

Source?

I guess what I have is personal experience measuring things.

Maybe people with gas stoves burn their food more because of the higher potential heat?

Perhaps the higher heat has something to do with it. I still suspect that not all particulates are made equal, so even though burning food makes more PM2.5, perhaps the particulates from the gas combustion are worse for us in some way.

Still, I try to avoid any of it! I have an induction stove, but now do things like skin-on salmon in the air fryer because it produces basically no smoke, whereas it used to smoke my house out when I did it on the frypan. Requires a lot less supervision than to stop it burning in the pan too, which is nice (but perhaps I was always just doing it on too hot a pan)...

If your gas is burning yellow, it is producing soot. If it is burning blue, it is producing very little soot. (the yellow you see is actually hot particles of soot glowing, but at a much lower temperature than the gaseous fuel-air mixture which glows blue. Gas flames can just get pans quite a lot hotter than electric or induction, generally.

I have both gas and induction. I don't think it makes sense to cook higher than 250C, because all oils will burn at that temp. And the induction works surprisingly well in this conditions, subjectively seems to be even better than gas (faster heating, better heat uniformity), did not expect that.

>Gas flames can just get pans quite a lot hotter than electric or induction, generally.

This claim doesn't really pass the smell test for me. My induction burner gets plenty hot really fast, much warmer than I could ever practically use while cooking, even. After a quick search I was not able to find any data supporting the claim either - the only data I was able to find seemed to support induction peaking out at significantly higher temperatures than gas.

Do you have any data on gas vs induction- max temperatures?

The gas flame is as big as your burner is, there is a lot of variation there that has to do with the physical characteristics of the burner and gas line pressure.

An induction burner will be limited to about 1.5 kW if it's a portable unit and maybe 2.5 kW on a built-in range.

A gas range will usually have a high rating of 15-20,000 BTU/h which works out to ~4.5-6 kW.

But thermal transfer efficiency is different, they both depend on the size of the pan, the material, shape, etc.

Stick a needle into a 3000F flame and it will be red hot in a second. A thin smallish pan can get super hot. You can't just have a "max temp" rating. However induction ranges will have some thermal protection for their insides.

If you spill something, the flames will also burn what you spilled.

> our house is modern and pretty well sealed

Sounds like you will have excessive CO2 problem. Have you measured that?

the primary reason I disagree with this is because I didn't have allergies and I grew up with that theory, my immediate circle would criticize allergy prone people as being weak and coddled too hard, not allowed to be exposed to things

and then I travelled to another country with different kinds of pollen in the air and I wound up suffering from allergies there, how humiliating! so I thought, but really just humbling

looking up how to remedy it I found that one accepted train of thought now is that people are prone to develop allergies at any age, let alone being exposed to things different than where you grew up

so I would nip the over-sterilization argument right there. keep indoors clean, go outside.

Shouldn't your experience make you believe more in the over-sterilization argument?

When you traveled you got into contact with allergens that your body hadn't encountered before. If you had been in contact with those allergens when growing up then perhaps you wouldn't have had an allergic reaction?

>I found that one accepted train of thought now is that people are prone to develop allergies at any age

If you've never had soy before then how could you know whether you have a soy allergy or not?

I'm not trying to convince you either way. Just some holes in the argument.

I'm allergic to grass pollen myself. I have no idea how that squares with the argument, because I certainly never shied away from grass in the summer. But it's a fairly weak allergy.

You can develop allergies to things you had been exposed to early in your life. That's not a hole, if I didn't make that clear that's what I also meant, in addition to new allergens.

Put in other terms, your body can overreact any time for any reason causing inflammation.

Two categories, VOC and particles, I don't worry about eliminating from the home.

I aspire to have zero particulates in my home air, it takes some doing. Much of the particles are of human/industrial origin anyway. Exhaust and tire particulate and various broken down human built materials. (and an overabundance of human pieces that fall off and collect in ways that wouldn't happen outside)

I also aspire to have a low CO2 PPM inside, this conflicts with the previous (i.e. it is difficult without intense forced air exchange with the outside to achieve CO2 levels less than twice outside levels.

But to the contrary, I do not use disinfectants ever except in very specific circumstances. I go out of my way to not buy products which make disinfectant claims.

I think human beings need to be out in nature, to regularly come into contact with living soil. Not just "nature" of curated footpaths and manicured, fertilized lawns and parks, but actually getting dirty outside where other organisms live. It's hard to do in cities, and growing up on a farm it still seems absurd to me that I have to aspire and do great organizing to find myself somewhere in a city where I am not standing on a surface that has been engineered by people. The closest I can get is usually the strips of grass along the sidewalks that act as nothing but dog toilets. (I love dogs, but city dogs offend me. They're animals, they want to be outside and not just tethered to you or for the occasional adventure to a park)

An somewhat gross anecdote:

Several weeks ago I got a cut on my foot from some shattered glass that developed into an odd looking infection with red stripes/blotches that I was on the edge of scheduling an appointment for a doctor. I happened to visit a local lake and dipped my toes in for a bit. The next day I was amazed, the redness which had been growing in intensity for a couple of weeks was just completely gone. Maybe it was a coincidence but I strongly believe that whatever was having a grand ol time eating my foot seems to have made a tasty meal for whatever cocktail of microorganisms were hanging out in that lake (I assume it was a fungal infection which was outcompeted by a restored microbiome seeded from the lake)

Particulates seem to be the easiest to remove -- much easier than VOC's and other gases.

My new furnace has a MERV 11 filter that I've been playing around with in recent days as we've had AQI close to 100.

I have an air quality monitor (that measures PM1, PM2.5 and PM10) in the house, within about 20 minutes of turning on the furnace blower, AQI of 70 inside the house drops down to less than 10, and 20 minutes after that, it's down in the low single digits.

I have a MERV 13 filter that I could put in the furnace, but I'm not sure I need it since the MERV 11 seems to handle it.

Yeah I lived maybe 100 meters from a busy road so I bought an air cleaner out of concern, but also got an Arduino with a serial device monitoring PM 2.5. PM 2.5 was always low teens or single digits, until I blew out a match next to the device and it went to 100s but dipped very quickly, so I think particulates aren't the biggest concern in most houses, unless maybe they spend all day with the windows open.

How do you know your measurements are accurate?

I tested my indoor sensor (Davis Airlink) by comparing to others in my neighborhood -- I set it up outside on the first bad air quality day we had and an hour later it was with 5 AQI points of the 4 PurpleAir sensors within a quarter mile.

Certainly not professional level calibration, but shows that it's within the ballpark. Unfortunately I don't think there's an official EPA monitoring station within 10 miles so I can't really check it against a calibrated monitor.

Aside from trying to buy a commonly used reliable device, that what the match test was for. When my device was reading 12ppm pm2.5 and a blown out match made it read in the 100s clearly the device is working to some degree of accuracy. I could've checked it outside I guess but I think local air conditions would predominate over any official city average I could have compared it against.

Could have been bacteriophages? https://www.statnews.com/2016/12/07/virus-bacteria-phage-the...

I actually assume it was a fungal infection which was attacked by bacteria.

You could try growing some plants of your choice and that'll increase your involvement with mud and soil and nature etc. It's also kinda therapeutic.

To a degree, but a lot of potting soil is sterilized so the "life" you're interacting with is pretty incomplete.

> at what point does the over-sterilization of our environment (specifically with regard to microbes) do more harm than good?

This is a valid concern, here is a relevant peer-reviewed paper that models the impacts that interventions such as lock-downs, masking, and excessive sanitization may have in the context of the ongoing pandemic [1].

Quotes from [1]:

> Nonpharmaceutical interventions (NPIs) have been employed to reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), yet these measures are already having similar effects on other directly transmitted, endemic diseases.

> we consider the implications of SARS-CoV-2 NPIs for two endemic infections circulating in the United States of America: respiratory syncytial virus (RSV) and seasonal influenza

> Using laboratory surveillance data from 2020, we estimate that RSV transmission declined by at least 20% in the United States at the start of the NPI period.

> We simulate future trajectories of both RSV and influenza, using an epidemic model. As susceptibility increases over the NPI period, we find that substantial outbreaks of RSV may occur in future years, with peak outbreaks likely occurring in the winter of 2021–2022.

> Longer NPIs, in general, lead to larger future outbreaks although they may display complex interactions with baseline seasonality

The most important takeaway from this paper is that it will be critical to prepare for this phenomenon to prevent the over-utilization of healthcare facilities across the globe. Personally I don't see how anyone could argue for longer and more intense NPIs if we begin to see this play out.

[1] The impact of COVID-19 nonpharmaceutical interventions on the future dynamics of endemic infections https://www.pnas.org/content/117/48/30547

Is there any evidence that the "clean environment causes allergies" story isn't just explained by "common cleaning products cause allergies"?

That is how I’ve understood it: residues of bactericides everywhere which become inhaled dust.

From what I've understood on the subject is that it's not super-well understood yet, with the common advice early on having been to avoid exposure to common allergens for young children (because potential anaphylactic shock being a bad thing), until it was observed that children i Israel generally showing a lot lower rates of peanut allergies, and that very young children in Israel are exposed to peanut-containing snacks early on. At this point, the advice was reversed to that young children should be exposed to potential allergens early on (because developing a life-long allergy from under-exposure to an allergen is worse).

The rest I'm guessing is extrapolation from that - lack of early exposure = negative.

Studies have shown reduced rates of asthma in children who grow up on farms, which I suspect supports your concerns [0].

A damp and mouldy environment is clearly not good, but I wouldn't want my home to be a sterile environment whichlimited opportunity to build immunity.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1069066/

I grew up on a farm with a lot of animals around, and spent a ton of time in the woods until I was 18. I have terrible allergies and asthma, so farm life was pretty awful. YMMV

No, it almost certainly does not. There are lots of reasons why farmers would have less asthma, one being the fact that there is a correlation with asthma and ASD, a correlation with ASD and intellectual excellence and therefore a potential reason why you don’t find many farmers with asthma or other disorders on the autoimmune spectrum. This study is a heuristic at best. Kill epidemiology with a rusty pocket knife.

It’s not just about the #’s. There is a huge difference between indoor air composition (which humans haven’t evolved for millions of years to account for) and outdoor air composition for the same, say, PM2.5 metric. E.g. indoor air might be mostly dead skin and dust mites, outdoor air might be mostly burned ash and bacteria, etc.

Unfortunately, the fact is that most people are now spending something like 20 hours a day inside… there is no easy answer. I sometimes wonder how much the sterilization hypothesis is wrapped up in the effect of prolonged indoor air exposure.

This is why I feel a run or bike ride outside is worth far more than the same amount of time indoors in a gym. Combined with a bit of weight lifting (which you can do at home), it's a pretty good total body workout.

I am happy many folks around where I live started to go out for their exercise during COVID but I hope they keep that outdoor habit after the pandemic is over.

If you can take your bike ride where there isn’t much traffic and more nature by any means it’d probably be not only better for your body but also for your mind. A lot of us are spending way too much time indoors and should take any ocasion to be outdoors

I switched from biking to work to riding a spin bike after the pandemic lockdowns, and since I'm no longer riding on roads with traffic, I've probably increased my life expectancy since I'm not going to get hit by a car in my livingroom.

I usually ride my bike around 5:30-7am when traffic usually isn't a concern. I also choose routes that are also low-traffic but still rewarding (decent climb and scenery).

If you look at statistics there are more fatal crashes between 4am and 8am than between the 4 hours after. [1] I looked it up, because I would've thought the missing light during night and dawn times and the more sleepy drivers probably offset any safety gains from less traffic on the roads. It's also much easier to speed with less traffic.

That sleepyness is a factor in car crashes can also be observed with increased rates shortly after winter/summer time changes.

[1] https://injuryfacts.nsc.org/motor-vehicle/overview/crashes-b...

True, but I think the parent comment was referring to less congestion. When it comes to bicycling, I always feel that it's my responsibility as a rider to look out for my own safety. Always regard all and any cars as being driven at 4AM by a drunk driver - regardless of time of day. In the middle of the day that means keeping track of multiple vehicles in different directions relative to my path.

During low traffic, there may be one vehicle to keep track of, and few pedestrians or other bikes.

That safe environment is quickly turned into an enabler for more aggressive and careless riding though. For fun and for getting from A to B faster.

Interesting - the data you shared isn't bicycle related, just all motor vehicle crashes.

It might be more interesting to look at bicycle fatalities than fatal car crashes [1]. Looking at the time-of-day distribution, fully 50% of such fatalities happen between 3pm-midnight. 6-9am is a higher risk slot (12%), but I'd probably avoid biking during 8-9am regardless.

[1] https://www.iihs.org/topics/fatality-statistics/detail/bicyc...

I usually do the same thing, but most of my route is on a local shared use path. Getting out there before most of the joggers is just so much more relaxing.

Air pollution is probably one factor in the development of allergies:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3192198/

Playing in mud and with animals is probably beneficial, but unclean air isn’t.

Unclean air is as vague a term as any.

The link he references does a pretty good job establishing what he meant by the phrase "unclean air."

I'd say: look at what they're allergic to and check in with anti-nutrients.

Sometimes ppl are not just allergic to gluten, but the whole category of lectin(which is in every seed), they just don't react as strongly, but they're never really healthy and suffer from all kinds of ailments.

This is something that I've been told over and over - early exposure to things like dust, pollen, nuts etc basically eliminates allergies when older.

As an example, I was never exposed to cats early age but dogs yes. Now I have a mild reaction to cats hair and nothing with dogs. Of course this isn't a scientific study that can be validated but it does sort of make sense in my mind.

A la antibodies etc.

My wife was exposed to both from an early age and this continued until she was 15. Then she developed a mild allergy to dogs and a stronger allergy to cats (can't be in the same room with one).

Allergies aren't a simple phenomenon.

I strangely had the same experience with hay fever. Never suffered from it then right around 15 it hit me pretty bad. I moved countries 5 years ago and again I no longer have hay fever symptoms so for sure they are not simple.

Nice list. I live car-free because it seems immoral to contribute to Alzheimers, cancers, fertility problems, autism and mental health issues. Anyone using a car (including electric) for a journey under ten miles needs to really think about the damage they are part of (disabilities excepted, as in all walks of life). If fewer people used cars, public transit would become more sustainable, more and more routes would be added. Fewer people would die.

Why electric included?

Probably because tire ware is a (the primary?) Cause of vehicle air pollution.

I dunno what the author meant, but probably alluding to the fact that the electricity powering your EV comes from a plant burning fossil fuels.

I've been curious about this topic for a while: what contributes more pollution per mile traveled -- an internal combustion engine or a Tesla charged with power from a coal/gas/wind/nuclear plant. If anyone encountered an analysis like that, please link!

Electric cars can make noise.

They make less noise than a bicycle

Depends on where you live. Electricity in BC is all hydro.

A study that emerged in the last few days says that in such scenarios in OECD countries, and including all life cycle costs, EVs generate only about 40% of the CO2 emissions of ICEs. No link at hand, sorry.

Two directly relevant health reasons:

"'London throat': Toxic brake dust could cause condition, scientists say" [1]

"Pollution from car tires is killing off salmon on US west coast, study finds" [2]

[1] https://www.bbc.co.uk/news/uk-england-london-51049326

[2] https://www.theguardian.com/environment/2020/dec/03/coho-sal...

Then secondary problems such as sedentary lifestyles and children unable to play on their street because of the dominance of cars (car numbers increased almost 3x in Ireland since 1990, when I was a kid).

There are more reasons cars are bad for society and bad for the individual – loss of communities dues to freeways [3]; loss of sense of community due to people not walking around and meeting their neighbours [4]; a ticket price to society when a car is deemed a requirement just to work and shop [5]; the 1.35 million people who die in road traffic accidents each year [6].

[3] https://www.pewtrusts.org/en/research-and-analysis/blogs/sta...

[4] https://www.theguardian.com/society/2021/jul/16/cars-are-fue...

[5] https://www.tampabay.com/news/florida-politics/2021/03/21/fl...

[6] https://www.who.int/publications/i/item/9789241565684

The reason I asked why electric included was because brakes within electric cars can operate very differently than that of combustion cars. Whereby the brake pads within electric vehicle almost do not need replacing for the life of the car.

Vastly reducing the amount of brake dust that is given off the vehicle in comparison to combustion vehicles. The same way in which riding a bicycle produced brake dust but not in the same volumes are combustion cars.

Car tires I completely agree however almost anything that rolls uses rubber and as such if we introduced more bicycles instead of cars we would also be polluting the streets with rubber. You could argue however that this is offset by the health benefits this would provide people rather than being sedentary in a car.

With regards to communities I would argue that nothing is stopping people from walking around and meeting their neighbours. However, people can visit other communities or extend their community boundary using cars and railways etc. Therefore our sense of community isn't just those immediately, but those across town as well.

Based on another comment, tires shed off much more rubber the more weight is on them. So an electric car will use much more than a regular one, and a bicycle will use basically none compared to that.

My long term plan is to have a solar array dedicated to charging my future electric truck, since panels and inverters are near cheap as dirt now on Alibaba.

edit: \/ didn't know thanks, did a quick search - https://www.greencarreports.com/news/1129809_tire-dust-is-po... is something like this available? Also it won't help as I am a person that needs a truck. I transport shit all the time. I'm constantly trucking stuff - I'm not one of those show-offs that own a truck just because.

Electric cars don't solve the problem of particulate matter, in fact if you buy an electric truck, it may make the problem worse because of the weight (wear on the tires is one of the biggest sources of particulate emissions).

I'm pretty sure that with sufficient R&D we could invent better tyres that either didn't wear much or were made of less damaging materials.

Just nobody is putting money into it.

Tires are a multibillion dollar industry, why would you think no one is putting money into R&D for it?

Tyres that didn't wear wouldn't need replacing... Thats why lightbulb companies famously stopped making bulbs last longer.

A good chunk of wear can be eliminated by ensuring tyres never skid by having per wheel torque control, which future 4-motor EV's will have 'for free'.

The Phoebus cartel only worked because it was a cartel… and it only worked until it didn’t. Again, why would you think no one is putting money into this rather than it’s simply a hard or unsolvable problem? What material would you suggest to be hard wearing yet pliable enough for good grip and comfort?

Imagine a world that wasn’t built on the profit margins of petroleum refinement. No tires, no plastics, no bitumen; defaulting to some other mode of transport, not a state-subsidised automobile cult.

Another mode of transport will still be state-subsidised. That is what states do since Antiquity. Already the Romans invested huge money into ports and their famous road network.

Criticizing cars is fine, but "state-subsidized" is just superfluous there. This is not somehow unique to cars.

Inherent in creating force between the tire and road surface is micro-slippage. What humans see as skidding/slipping is only the gross slippage. Every time you turn, slow, or accelerate, the tires deform internally and slip against the road surface (and wear).

I think brake dust is even worse than tires, and EVs rarely use friction brakes.

Cars are the number one cause of microplastics near waterways. It is insane we allow cars in our modern society. I too am car free.

Excellent! Do you grow your own food? Make your own clothes? Or do you purchase things transported with vehicles?

I’m really sorry but your attitude is very toxic.

More or less toxic than condemning cars but then benefiting from them?

Much more, because one is just self-deception, but you are being an asshole towards other human beings, on purpose.

Calling out hypocrisy is being an asshole?

Is it hypocritical to make the first step and reduce car traffic overall, just because they're not yet a perfect human being that prevents all suffering indirectly connected to them?

Complaining about that (and in that tone) helps nobody.

Imagine if there were no abolitionists in 19th century America because everyone wore cotton clothing.

Did abolitionists call people wearing cotton "immoral" or did they focus on actual slavery?

https://en.wikipedia.org/wiki/Nirvana_fallacy

Many urban areas (especially poor ones) have had fewer miles driven per person, but it didn't lead to more transit in those areas. You have to actually allocate budget to get more transit. But even when it's sorely needed, budget doesn't get allocated to transit, for a whole host of reasons. So public transit isn't going to grow just because you gave up a car.

There are many towns in the USA where transit will never be viable because they are too low density - no one is going to walk 20 minutes to a bus stop a mile away to wait up to 20 minutes for a bus to take them on a 20 minute ride to town if the other option is a 10 minute drive in a car.

I was jokingly asking a friend the other day if we might ever have to ride horses again. Probably not, but it's interesting to imagine the scenarios that would lead to that. Americans take personal vehicles for granted. Addressing climate change is going to require some uncomfortable changes.

Addressing climate change is going to require some uncomfortable changes

I really don't think we're up to the challenge of really stopping (or significantly slowing) climate change (if it's possible at all now) and will end up spending much more money (and discomfort) mitigating the more severe effects of climate change than if we'd just started making changes a decade or more ago.

> they are too low density

This is by choice and can be changed.

You're dismissing the scope of the problem, yes, given unlimited resources and people's willingness to change, anything can change. But we don't have unlimited resources, and many people don't want to change.

But the fact remains that America has many low-density areas that will never be affordably served by transit. That's not just in this country, Europe has areas that aren't well served by transit, even Japan has areas that aren't well served by transit.

This is a ludicrous philosophy.

I suppose you also take no part in any activity that has any negative impact?

There is an indirect negative impact of ANY modern lifestyle. The really expensive impact comes from of industrialization and technological advancement.

Clearly you have a device to write this message, as well as power and internet connection. You might use AC or heating, you might rely on supply chains for food. Own any index funds? You own minuscule pieces of companies that produce cars, tobacco, or frack for oil. Your very existence is expensive for the earth and for society. Same applies for your kids if you have any.

Most drivers cannot practically manage walking/biking or public transit as their sole means of travel. Frankly that idea comes from a privileged and niche bubble perspective.

As I become aware of how my decisions affect other people, I do my best to minimize what I can.

The four most impactful lifestyle choices you can make to reduce your effect on climate [1] are:

* have fewer children

* live car-free

* become vegetarian

* avoid transatlantic air travel

I now live car-free and vegan. I've no kids, yet (maybe never). I live in California but I'm from Ireland - I'll probably take a flight home soon.

So no, I don't totally avoid everything that can cause harm, but at least I try.

What is ludicrous is using a car for journeys under ten miles.

It is abhorrently selfish to do so knowing that your pollution contributes to sickness in people.

People should maybe take a pay cut, or live in a smaller home, closer to where they work. But instead they trade the health of others for their own standard of living. ("some of you may die, but that's a price I'm willing to pay")

> Most drivers cannot practically manage walking/biking or public transit as their sole means of travel.

In a large part because of cars. Cars beget cars. Car companies conspired to shut down public transit. Now people in those areas need a car. Then it's held as a example of why we need cars.

Urban sprawl was enabled by cars. Now people need cars to get to those areas.

It's very difficult to find a problem that cars solve that wasn't itself caused by cars.

What is ludicrous is to call how I actually live ludicrous. I enjoy a high standard of living. Without a car.

[1] https://iopscience.iop.org/article/10.1088/1748-9326/aa7541

So in your mind, despite being in the top 1 percentile of historic carbon output, you have the moral high ground for not owning a vehicle?

Yeah those impoverished parents sure are pieces of shit for driving thier kids to school and commuting between multiple underpaid jobs. They should just take a pay cut and quadruple their commute time for the earth!

Let me paint it another way:

A vegan, car free, childless, software engineer in a big city has the carbon output of 100 Ugandan farmers.

Why do you get to use electronics, power, internet, and take occasional trips to Iceland while everyone else is morally bankrupt for having a vehicle?

The person you're responding to is asking themselves questions about the decisions they're making, the impact of those decisions, and if they can make better decisions to reduce the harm they might be causing. Is this so bad?

Yes. It completely misrepresents the actual complexity of the problem. Instead of discussing effective solutions like political activity the climate change debate gets dumbed down to reusable cotton bags and paper straws.

The purpose here is probably not to be a “better person” but to inflate their ego while belittling others.

What does it accomplish to shame drivers while simultaneously using AC and running water in the California desert?

I replied to a comment about the detrimental effects of air pollution with how I try not to be part of the problem.

If it were conversation about activism, I can talk about my engagement with the city council and contributions to relevant charities.

If this were a conversation about energy use in California I could talk about the premium I pay on my electricity so it is from renewable sources.

https://www.smud.org/en/Going-Green/Get-Green-Energy/Residen...

Reducing car usage is, in that journal article I referenced, the number 2 thing you can do to reduce your climate impact.

I have not misrepresented anything.

You’re right about the water. That’s something I’m still learning about.

> Yes. It completely misrepresents the actual complexity of the problem. Instead of discussing effective solutions like political activity the climate change debate gets dumbed down to reusable cotton bags and paper straws.

I've encountered this sentiment many times here. It's a bit baffling to me, to be honest. Yes, we all know that personal actions are small compared to massive structural changes. But why exactly do you think that it's one or the other? I'd wager that the majority of politically active people trying to change things at a high level are also changing smaller things in their day-to-day life, because it's an issue that they are passionate about.

In my opinion, the attitude that you promote ("why do the little actions when only the big ones matter") is more likely to cause inaction, and the people I've met who espouse that viewpoint say a lot and do nothing at all.

I must be coming off the wrong way.

Sure people should make those lifestyle changes where possible! I’m not against small change.

I get frustrated when I see people generalize the rest of the population as “abhorrently selfish”. Especially when their own lifestyle comes from a position of excess and privilege.

To clarify my position:

If you wanna make lifestyle changes for the environment, more power to you! I’ve got no beef with that. Just don’t use those tiny aspects of your modern life to paint the rest of the world as immoral.

I see, that's fair. Labeling and generalizing others in that way is not productive.

The simple action proposed was to not drive if your journey is under 10 miles. I don't think it was ever suggested that this would solve all our problems. Just that, if you can avoid contributing to the pollution, then maybe you should consider not contributing if you are an able-bodied person who could as easily bike that distance.

Most car journeys are under 5 miles. Imagine the benefit if the majority of these journeys were made by bicycle instead! Public health from less air pollution and more exercise. Less stress, less traffic, less potential for vehicle accidents. Governments might even decide to improve pedestrian/cycling/public transit infrastructure and turn car parks into people parks with green spaces (which would reduce absorption of solar radiation and cool your city and clean its air).

It's a really simple proposal with many obvious benefits and no clear downside whatsoever. And just because it isn't a silver bullet you are all up in arms against it? Tell us more how BrianHenryIE is the actual source of the problem here and how you should still drive everywhere because of his equivalence to 100 farmers...

You’re missing my point. FWIW, I agree people should try to minimize driving where feasible.

OP isn’t just suggesting that people drive less. According to him, drivers are “abhorrently selfish” and are directly responsible for death, disease, and need to take pay cuts and live in smaller homes so they can more easily fit into his little box that defines a good person.

I’m not up in arms about the idea of biking. I’m up in arms about people with extremely carbon expensive lifestyles claiming that everyone else is reprehensible for engaging in $specific_activity.

I have the moral high ground over the person I was a few years ago.

The fact of the matter is: car use kills people through pollution. Minimizing car use kills fewer people. To use your car less is OFTEN an available choice.

Morally bankrupt would be someone arguing against reducing car use.

> To use your car less is OFTEN an available choice.

Only to wealthy privileged people who can discuss their first-world problems on forums like this. As folks get poorer on the scale the more a car becomes an unavoidable necessity for many.

I applaud to your personal choices and sacrifices, but please don't make it sound like everybody can and should make the same/similar ones.

Most of us here have/want kids. I say something very opposite to what you say - folks here, please have kids! Not many, but take your time and raise them properly. It basically means sacrificing large portion of your life to them, without a guarantee they will even appreciate it. Which is fine, that shouldn't be the motivation for it anyway.

You who are reading this, are a part of smart elite in this world, whenever you are, and can raise next generation of elite with disproportionally large amount of decisive powers in their hands.

Why, you may ask? Raise them well so they are balanced happy individual with clear drive to help make this world a better place, and they may very well become next leaders, business captains, politicians, or just good citizens helping those around them, environment, mankind.

Now imagine what kind of world would that kind of attitude bring. Don't just minimize your 'bad' footprint on this existence, try creating more of the positive one.

>Only to wealthy privileged people who can discuss their first-world problems on forums like this. As folks get poorer on the scale the more a car becomes an unavoidable necessity for many.

I'm living on countryside in Eastern Europe and by no metrics I'm anywhere near to being wealthly

You don't have to be wealthly to have privilege of not having to own car, it's often about job.

Majority of people I know needs their cars due to their jobs. Of course part of people I know actually enjoys driving and stuff.

WFH helps with it significantly, but even before I've been commuting by train due to it being cheap and allowing me to e.g read a book, sleep and generally have time for me

For things that are within e.g 10km radius like shops, services, then I tend to use bike (unless its winter ofc)

but I think it's hard to do it pernamently, at some point I think I may need to get one just in case.

In cities it may be easier cuz you can always call Uber/Taxi

______________

> As folks get poorer on the scale the more a car becomes an unavoidable necessity for many.

Sometimes I believe that car is what actually keeps people poor

When I look at friends they spend significant amount of their salary on car - insurance, fuel, maintenance - it ranges between like 3k PLN to 10k PLN where minimal wage is around 2K

So if you have to pay 4K per year for your car when your year salary is 24K

then shit's no cheap and I think we're optimistic here, but often it allows you to have job, so it's terrible situation.

I live in a small non wealthy town in the UK, it's five miles across and everything is accessible without cars.

My neighbor has five to seven cars on their driveway. To let others out they start them all and play musical cars. Two of them drive to jobs less than two miles away. They use them for practically every trip over 200 metres. Their extended family visit every weekend, in separate cars and all live within five miles.

My other neighbors have three cars for two people, including a pickup truck. Again, they drive literally everywhere. Even walking distance.

Many of the young people here drive terrible modded cars up and down all day for no actual purpose than vanity.

If you tried to have to have a conversation with these people about their car use, they would claim it's their right and that they "pay for it". Yet what they pay is < 10% of the damage they cause.

Obviously, if you are remote, or have a disability or need to carry a heavy load you should probably use a car.

But many people think it's literally their God given right to drive a dangerous metal box, badly, burning irreplaceable oil, spraying pollution, noise pollution and brake dust literally straight into your home.

Every single car journal under 10 miles should be excessively taxed, with extreme taxes for trips under three miles. You should literally be forced to think twice, then twice again.

All of these people are literally saying: "Fuck other people's health, their sanity, their happiness, their time, their environment, the environment as a whole. Me drive metal box"

The entitlement of drivers is literally staggering.

I’ve got no problem with taxing carbon-emitting fuel much higher than today.

If you tax three mile trips extremely enough, you turn a 4 mile roundtrip into around 15 miles of driving in a lot of cases. Need to go A to B to A which are 2 miles apart? Drive A to C (3.5 miles) to B (4 miles) to C (4 miles) to A (3.5 miles). Does that policy make sense in light of the obvious workaround?

Tax the fuel and you align the incentives much more closely and much more difficult to workaround in ways that work against your intention.

> A vegan, car free, childless, software engineer in a big city has the carbon output of 100 Ugandan farmers.

citation needed

> citation needed

seriously, it's got to be more like 1000 or 10,000 farmers.

I agree, for what it's worth. You're not alone with this.

Of course, there are many individual life circumstances that mean a car is an absolute necessity, but for many people it's a choice, whether they acknowledge they've made that choice or not. This is especially true for people who are more affluent.

> I've no kids, yet (maybe never).

IMO this is short term thinking. What happens to the planet when you are gone? If all the like minded individuals who cared about the climate opt to not have kids, then those who inherit the earth will keep polluting.

"The Marching Morons", Cyril M. Kornbluth

Polluting is not some habit that people inherit genetically from their parents.

All these things are great except one point in my opinion. I never understood "I won't have any children so I can minimize the effect on the climate". How about "I will have 2 children at max and teach them what I've learned so far but at younger stage? so that they will act responsibly in the future regarding climate issues while living and maybe doing things to lessen the climate change effects in the future?".

In the end, it is your choice with what you want to do. Things you're doing to contribute less like being car-free etc. are good, but I really find this extreme stance of "not having children for climate change" short-sighted.

Edit: typo

Since you refer to Ireland as home I'm reminded of a conversation with a colleague where we were talking about pollution. I suggested flying be restricted to migrants who needed to visit family. My colleague thought that was a great idea. Then I continued that migration should be restricted since it creates demand for air travel. Colleague liked that far less.

Disclosure: my spouse is a migrant and we both fly to visit.

I don’t really care that much that other people die so this isn’t a convincing argument. Most people are like me.

Obesity related conditions are some of the leading causes of death. There are also advantages to simplifying your lifestyle and expenses. Sometimes less consumption can be an end unto itself.

We can disagree about climate change and the rest of it, but the results of a sedentary lifestyle can't be ignored. There's also no room for indignation at an imagined holier-than-thou position when you take this approach.

I've found this simple, obvious observation about obesity especially interesting in regards to the current public health scare and the rise of the bio-security state.

Thank you for this. It's amazing how HN defends the existing car culture despite the alternatives.

recently replaced a robot vacuum with a corded plugin model with 3x the suction power and the amount of dust it removed from carpets already 'clean' by the robovac was pretty incredible.

I have the robot vacuum still doing its thing every other day but at least once a week I do a deep clean and it removes a ton of dust.

I also have a HEPA filter air purifier going 24 hours.

Carpets are the worst.

Maybe the carpet acts as a filter for dust that you would otherwise be breathing?

Carpets really just molt and let its shit go into the air.

I dont think it filters anything - it just provides the dust a place to lay down until something knocks it up into the air. It would have to have some mechanism for getting the dust to the other side to act as a filter, and then you'd still have to clean/dispose of it somehow.

More of a grinder to make sure anything big enough to fall out gets smashed up into particles small enough to stay floating. (Less the occasional cleaning, which... isn't comprehensive. wash a used rug someday. ick.)

What vacuum would you recommend?

I would recommend doing a bunch of research as there are third party reviewers who test them. I went with a shark uplight apex but I am not a vacuum professional, I just have asthma and hate dust.

I bought a cheap used miele canister after reading this: https://old.reddit.com/r/IAmA/comments/1pe2bd/iama_vacuum_re...

It has been great so far. The bags are a little expensive, but worth it. It is quiet and pleasant to use and has strong suction, and parts are available if we need them.

the shark I bought doesn't use a bag at all - it has an integrated hepa filter I clean off once a week but aside from that no ongoing costs.

I am wary of taking 7 year old advice in general, given how quickly things change and how companies put out new products each year, but I hope you like your vacuum. I paid $215 USD for my vacuum new with a 5 year warranty - there's very little a tech could do on this vacuum that wouldn't cost more than a new vacuum.

I used to have the same opinion, then I used a Miele and it's really quite shocking how good it is. Not trying to sell you on one, but if you have the chance to try one out you may be surprised.

Rtings recently started reviewing vacuums which does a nice comparison: https://www.rtings.com/vacuum

I love my Miele canister vacuum. Crazy expensive, but I’d rather skip a generation of cell phone and have a great vacuum instead. I owned a lot of crap vacuums before this one.

Miele canister, hands down. It's the best vacuum I've ever used in my life, nothing else even comes close.

The high cost was hard to get over, but I waited for a sale and now I only wish I had done it sooner.

Carpets should be illegal.

There was a paper I saw about ten years ago that made the claim the influenza is airborne too. And that temperature and humidity have a large effect on how persistant it is in indoor spaces. And that badly ventilated workplaces and schools are large driver of infection.

Another thing I saw very recently is ventilation standards for buildings have been reduced by 75% over the last 70 years.

Basically anything that gets labeled as "spread by droplet transmission" is probably primarily aerosol. I mean, sure. If somebody spits in your mouth you're likely to catch the thing, but most people who get the flu probably got it via aerosols.

This is terribly inconvenient, because droplets are easy to control, but aerosols are not.

As a German I have a reflex to wanting to open the windows in most indoor situations regularly, when I am in AC'ed/ventilated situations. Of course in my AC'ed office, the windows wouldn't open, but surely the air does not feel 'fresh' enough.

Pretty sure when returning to the office post-covid we'll see some discussion on Meeting room CO2 levels. I occasionally had a hard time keeping my eyes open in crowded meeting rooms which never happens even in the most boring meetings that I have remotely.

Hi, could you please recommend a product you have found worked well?

>use a nice filter-based air purifier for white noise. It has deep bass

I went nearly insane when this constant humming sound started to appear inside my apartment seemingly coming from several directions. It would start at the oddest times and then go out again after a while, making you think it's over, only to start again after a minute. I wasn't able to focus on work or reading anymore, I was starting to get really irritated and aggressive. Even with active noise-canceling headphones I could feel the bass sound. It took me the six weeks to pinpoint the origin of the sound to my upstairs neighbors, who eventually admitted that they had bought an air purifier because of allergies and kept it running all day long and through the night. If you recommend it to friends please let them know that the bass sound and the vibration translates through walls and might make a helpless neighbor's life miserable.

The transmission of vibrations can be reduced by putting the device on a thick rubber mat or similar. It also helps to reduce the sound inside the room, so it's not just for the neighbours' benefit.

Why not just open the windows?

Guessing they live in a city or by a road

Germany has a practice called "Luft" ("Air"), where tenants are _required_ to throw open the windows for X minutes each day. Seems smart. The room & furnishings retain heat long enough while the air is changed in toto. Can someone who knows about this practice comment ?

Seems smart why? If we check the air two hours later, is it meaningfully better than before we started?

A daily changeover seems much worse than constant exchange, and both of those pale in comparison to filtering.

The air particles that are visible to you will mostly be caught in your nose and cilia, and either swallowed or spat out. They can still cause plenty of allergies. They are also too heavy to float long enough in the air to pass through the filter. That's why you need to kick it up from surfaces to see. You can remove it from surfaces with vacuum and wiping.

Smaller invisible particles, for example pollution or pollen, hang in the air and move with the circulation, so they will eventually be caught as air passes through the filter.

The amount of these particles could be reduced by cleaning the air at the "intake" of the house. If there is intake air passing through pipes, these pipes need to be kept clean. If the house is set up such that air moves in both direction through passages, the whole thing is fucked and need to be fixed. Even detecting where intake air is entering the house can be really difficult.

Because of indoor temperature and outdoor wind, a house functions like a pump that sucks in outdoor air, heats it, and ejects it. Intake air may be sucked from any crack in the walls, floors and foundation, where it picks up dust and mould. Equipping the house with an intake fan (and filter) will pressurize it and prevent this "sucking".

Do they look at the relative contribution between CO2 and VOCs? These two require very different solutions. The first is about ventilation in closed spaces, and the second can be solved with only a $300 air purifier.

EDIT: Here is the original study: https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037

I really don't understand their methods pertaining to VOCs. Maybe someone can fill me in. Their method pertaining to CO2 seems straightforward.

They didn't clean the air. Their methods were to inject air of different concentrations.

As stated in the article, the best approach to cleaning CO2 and VOCs is increasing the flow of outside air into closed spaces. The headline involving the word "cleaning" is misleading since it should not be your first choice unless outside air quality is poor.

I've been using a dehumidifier with a hepa filter for the last 4 years or so.

I mainly bought it because I moved from an inland region with about 10% humidity to a coastal city with 40% to 60%. Things around the house didn't get dry like I was used to (dishes, shower, towels, laundry, water spills) and on top of that, occasionally had to wash ceiling when they get moldy. Thus I bought a dehumidifier. It was quite expensive at the time and I didn't at the time realize the significance of the hepa filter. I don't have any allergies.

Lets just say its been running for 4 years in my place. The trick is to keep windows/doors shut and let it do its work. I move it around in the apartment - in the mornings I move it to the bedroom to get the human smell out. Later on I'll move it to the bathroom or to the spare room to dry some laundry. While all of this is happening, it sucks up all the pollen and dust, odd smells, basically most moisture (no more wet windows). Haven't had to wash a ceiling since I bought it. When you enter the apartment, it smells neutral/clear/crisp - It's kinda hard to describe the smell of clean air, but it is a distinct sensation. You still need to air out your living space every once in a while to get some "fresh" air from the outside.

I'd recommend anyone/everyone give this a shot! And remember to replace your hepa filter every once in a while. If you have carpets, you'll have to do it regularly (on that note, get rid of all carpets if you can).

I use a "Meaco 12L Low Energy Dehumidifier and Air Purifier". It uses about 150W of power so basically the same as running a fairly large fridge (in my country about $4 of electricity per month). There are larger models but they make more noise. You can also attach a drain pipe to the back so you don't have to empty the water container every day (useful if you aren't going to move it around).

If you keep the doors and windows shut, aren't you getting lots of CO2 building up?

Hence the airing out once in a while. Keeping windows open is bad, esp if you live on a busy street, not to mention impossible to control the moisture then. So you would have to find a balance that fits your living space.

I meant, keeping the windows open are bad while running the dehumidifier/filtering.. as it will constantly battle to keep the "fresh" incoming air clean/dry, you might as well switch it off then. Most houses are very "leaky" anyway around windows, doors and so on, so for some rooms it is kinda pointless to use in. So for bedrooms, bathrooms and other smaller areas where you can shut the doors and windows and let it do it's work, it works very well! But a bigger area like an open plan kitchen and lounge, rather just crack a window or buy a larger dehumidifier/filter but then you have to battle noise and electricity usage. If you have pets that sheds a lot of skin/hair, the filter will also clog up faster but you will have less of that animal smell in your place. If you have pets that pee/poo in your house, no amount of filtering going to help you with that.

Overall, I do recommend people still buy one, they are helpful for all sorts of things.

I bought a few co2 and voc detectors and air purifiers to try and help with this. Air purifiers are useful during pollen season and for dust not sure anything else. The co2 detectors were actually great for knowing when to open the door or window in my office or living room

Which brand of detector?

Awair Element. Looks nice enough to keep on a shelf too

Do you see consistency between your CO2 detectors?

Early on in the pandemic when I started working at home, I became very cognizant about the impact of CO2 and built a little project with a microcontroller and the MHZ-19B CO2 sensor. Calibrating the sensor is an ongoing challenge and while I have 18 months of data, I'm still not 100% confident about the accuracy of the data at any given time.

Still...I literally can feel when the CO2 level is above 800 - 1000ppm and it isn't always as easy as opening a window to counteract. There are certain conditions - maybe the barometric pressure or temperature gradient, but sometimes forced ventilation is necessary to get into the "comfortable" 400-600ppm range.

They seem accurate within 100ppm or so which is enough to give me the information I need. Looking at their specs their claim is 75ppm https://support.getawair.com/hc/en-us/articles/360060843933-...

Yeah, that is more than adequate.

When I posted my project online I got the not-unexpected feedback that the sensor was hard to calibrate. I don't care about 400 vs. 600 ppm. I do care about 600 ppm vs. 1600 ppm.

I'm not sure about the MHZ-19B, but I've been using the SenseAir S8 and the data that comes out of it has been rather noisy when powered by a switching power supply. If you have an oscilloscope, you might want to check whether your 5V rail changes in voltage when taking measurements. For example, mine looked like the picture in the middle of this blog post: https://blog.jean-francois.im/2021/05/08/building-a-simple-a...

If that's the case, I've found that the quality of the measurements fare better when there's a linear regulator supplying the power. I bought some LM7805s off DigiKey and they should arrive sometime soon, ping me if you want to know how that experiment went.

That's great advice and I will definitely look into it. I have a servo and a LCD panel on the same 5V supply as the ESP32, and while I think the USB power supply I have is sufficient, it is definitely worth investigating.

FWIW, this is my current temperature/CO2 plot: https://imgur.com/a/LhUoPcS

The temperature graph is pretty easy to understand as you see the A/C kick on twice during the day. The CO2 level is maybe not as obvious but I can see when I was in this room and when I closed the window when I was leaving.

I imagine co2 not being perfectly mixed and maybe wafts of it hitting the sensor? The overal trend is clear though. Try transforming the data with a moving hour average or something.

Oh that's not too bad, mine looks like this: https://imgur.com/a/7weijF7 with a sampling rate of 1Hz, without smoothing.

As another poster pointed out, with automatic background calibration and opening the windows daily it doesn't get too out of whack.

Out of curiosity, do you have any more details on how you built yours, I'm curious to see how you have done things differently from mine. :-)

For nearly all sensors, you need to do one of two things:

- Make sure auto-calibration is disabled and manually calibrate the sensor once a year or so by taking it out into fresh air and running its fresh-air calibration routine.

- Leave auto-calibration enabled and make sure that the sensor is exposed directly to fresh air for at least an hour every single day.

These sensors are first and foremost designed for use in HVAC systems in commercial buildings, which usually (always?) have an overnight fresh-air purge, so to keep them calibrated, the manufacturers just assume the sensor will always see fresh air at least once a day calibrate them based on that assumption. In a residential environment, that usually doesn't work.

And FWIW, I've run a bunch of Sensirion SCD30 sensors for a few months and they worked quite well, with auto-calibration disabled. They're supported by ESPHome as well.

Sensirion also recently released their SCD4x sensors [0] which measure CO2 with some kind of black magic [1] instead of the usual NDIR. The coolest thing is that the sensor is relatively tiny and built for SMD assembly.

[0]: https://www.sensirion.com/en/environmental-sensors/carbon-di...

[1]: https://www.sensirion.com/en/about-us/company/pasensr-techno...

This is one other aspect of remote work people don’t discuss. I brought my CO2 detector to a friend’s office and I was shocked. 800ppm was where it started when we were having lunch. How you can be productive when you are breathing toxic air is beyond me.

800ppm of CO2 is not toxic. 800ppm of CO is.

CO2 isn't toxic at CO levels and maybe not even performance impactful at 800 ppm, but there have been studies[1] that seem to indicate that even moderate levels of CO2 have measurable impacts.

My personal experience is that CO2 levels above 1000 ppm are easily noticeable once you can correlate how you feel with a measurable value.

[1] https://pubmed.ncbi.nlm.nih.gov/25117890/

800ppm is "on the line" per what's industry recommended for an office http://www.energy.wsu.edu/documents/co2inbuildings.pdf

Conversely, at present rates, the CO2 in the atmosphere can approach a stuffy room in the future, making us have to actually run oxygen purifiers indoors to remain smart.

https://climate.nasa.gov/vital-signs/carbon-dioxide/

whereas this is what humans can handle:

https://www.kane.co.uk/knowledge-centre/what-are-safe-levels...

Current value: 417 ppm

With ocean acidification, acid rain, etc. it's not just about "global warming".

This is quite an interesting phenomenon unfolding.

Those with high-CO2 performant genetics may have better cognitive development in the future.

(Also, it's sad to see kids wearing masks all day with zero regard for the science on CO2 concentration & health).

I am sad to see kids eating genetically modified food sith high fructose corn syrup, products from cows with antibiotics, and so on, getting diabetes and obesity at a young age, and being addicted to screens

And this is correlated to the morbidity from the actual virus

The USA and its factory farmed agriculture industry doesn’t really care about the public health outcomes. They care about cheaper hamburgers and industrial level farming. For-profit industries often have to do it.

The same way that so much ink has been spilled about the exodus of people from big cities during the pandemic, in a “ha ha too much socialism” way, but very little about the decade of slowly emptying small towns across America, from the rust belt to the mining towns. None of these political pundits care to talk about the slow plight of the little guy. The situation before the pandemic saw half of all employed Americans living paycheck to paycheck, very low savings, while the government doubled down on trickle down economics.

Which science do you mean? Found a redacted study from Germany and doctors saying there's no effect on blood O2 or CO2 levels https://uihc.org/health-topics/do-face-masks-make-you-retain...

I've been wanting to buy an air purifier but not sure if it is a necessary buy or not. Before spending another 200-300$ for some stuff that I usually find reason to spend on, I need to know if it makes a huge difference from day to day basis.

This article definitely supports it, however has anyone actually ever felt that much difference after getting their purifier?

Bought one about a week ago, because of similar research studies. I don't notice anything different. I use it in the bedroom when sleeping.

May be my air quality was already pretty good. I will check the status of the filter after a few weeks to see how much purifying it had to do.

Do you feel any slight difference on your breath, health, body at all? Something worth noticing?

You probably won't notice a difference unless you have allergies, or there's some other issue causing abnormally high amounts of VOCs to be in the air (such as mold or dust)

Nothing

Get a $20 box fan and slap a house intake HEPA filter replacement on the back of it. It will do just as well if not better than an expensive HEPA filter.

If it makes a difference and you want something that sounds different or has some extra features, then you could get a nicer one.

Probably want an activated carbon layer in there too, but that's only another $20.

This is what we did after wildfires. Way cheaper than buying a truckload of purifiers. And we could actually buy them - purifiers were completely sold out.

You’re right that it’s better than nothing, but it’s a far cry from “better than an expensive HEPA filter.” The best efficacy I’ve seen claimed in rigorous testing is 87%, compared with well over 99% for a good HEPA filter: https://www.nytimes.com/wirecutter/reviews/best-air-purifier...

Have little knowledge on this field so this might be a dumb question: How noticable or significant is that 12% difference? On the same thought, if I had one that had a 95% efficacy, how does it compare to the 87% one and the 99% one in terms of day-to-day or long term effects?

I’ve spent a good amount of time in this space, mostly WRT cleaning air in wood shops. One of the problems is that the 12% difference there is mostly the smallest particles, and those are the most harmful.

It’s hugely noticeable with smoke, for instance. Humans don’t have a great sense of smell, but we do very well with smoke. The difference between air with <1% leftover smoke and air with 13% leftover smoke is obvious to everyone.

The EPA has a lot to say about this, if you’ve the patience to wade through it — https://www.epa.gov/indoor-air-quality-iaq/air-cleaners-and-...

What were you using? The filter should be MERV14 or higher. It will remove >75% of all small particles too.

You shouldn't end up with 13% leftover, if you're doing it right. Air will pass through the filter multiple times, and it removes >75% each time.

Below MERV14, you'll have that problem. Above, it should do as well as HEPA. The gap between 13% and 0% will be made up for with a 13% stronger fan.

It's the wrong metric. The question isn't how much stuff it lets through, but how much stuff it removes.

A filter with 99% efficacy at a flow rate of 30cfm will remove the same amount of stuff as a filter with 50% efficacy at 60cfm.

A 99% sealed HEPA system isn't cleaning the air that's not passing through it right now, which is most of the air in the room. It reduces the pollution by some nominal rate. After it's been running for a while, the air is a lot cleaner.

The major problem with box fan with filter are noise, aesthetics, and similar. Box fans aren't designed for for high loads, and just don't work great in that context. It will clean the air just fine, but a proper filter will do so much more efficiently and pleasantly.

In terms of effect:

I have allergies. I feel a lot better post-COVID, with HEPA filters, face masks, and similar precautions everywhere. I can't pin that down to any root cause, though. Particulate pollution? Allergens? HEPA filters at home? Masking outside. Dunno.

I tried that, the box fan had pretty anemic airflow through the filter. I'm sure it was doing something, especially if it was blowing directly at me, it didn't seem like it was really cleaning the whole room. Then I got a $200 air purifier with a HEPA filter and it has much better airflow, thus more air exchanges per hour.

I think fan blades aren't that efficient at pushing against the high flow resistance of a HEPA filter, while the squirrel cage blower in a dedicated air purifier is.

Doubt it. A self build filter basically outperforms all bought systems in tests.

The answer is easy: A self build system blows the air through a filter. Nearly all commercial systems suck the air trough a filter. Big difference.

What’s the difference between blowing or sucking air through a filter?

The Particle Counting folks[0] blew it through, and they seem to have done their research. I’m sure they wrote about it in their blog somewhere.

[0] https://particlecounting.tumblr.com

Hmm...that doesn't really answer the question and since so many high ranking purifiers (plus many industrial HEPA filters) use the same "squirrel cage fan to suck air through the filter" design, I don't believe it's true that there's a big advantage to blowing versus sucking.

I can believe that some home built box fan purifiers out perform some commercial units, but not as a blanket statement that a home made filter outperforms all commercial units.

I’m not saying I necessarily agree with this:

> A self build system blows the air through a filter. Nearly all commercial systems suck the air trough a filter. Big difference.

But if you’re strapping a filter to a fan, it’s probably more efficient to blow through, since the air will be more focused (plus, it’s easier to mount due to front being flatter).

> I can believe that some home built box fan purifiers out perform some commercial units, but not as a blanket statement that a home made filter outperforms all commercial units.

Agreed. I recall seeing the stats they published and it looks like there are good purifiers among the more expensive ones (US$1000+), but apparently even in that price class they’re hit or miss and don’t always perform as well as a DIY solution could. Generally there’s a lot of information asymmetry, manufacturers want their margins so commercial air purifiers might often use something custom rather than a standard-compliant HEPA filter (either worse or slightly better but 10x more expensive than it should be) and make it difficult or impossible to swap it for something from a trusted third party. They’re counting on very small percentage of customers having properly calibrated particle counting equipment set up at home, they get away with providing misleading tech specs like CADR (or not providing them at all), and so on.

Can you give a link to the best setup?

if you are getting slow airflow, then you can increase the surface area of the filter medium by either buying a thicker, pleated filter or, you can duct tape multiple filters together in a cube shape with the fan being one side of the cube. That will give much more surface area for the fan to pull through.

> This article definitely supports it

The article clearly states that the best way to "clean" the air is just to bring in more fresh air from outside. The article doesn't strongly support filtration unless your outside air quality is poor.

Xiaomi sells ones with particle detection for about 100. No reason not to get one, plug it in and just forget about it.

It really depends on where you live and what the air's like.

I have a $100 HEPA air purifier, and separately an air quality monitor. I live in a very residential area of Brooklyn on a side street.

On normal days the air purifier makes absolutely no difference because PM10/PM2.5 are relatively low just generally.

But the other week when wildfires were producing smoke that smogged up NYC? It absolutely made a difference (brought indoor levels back to "normal", far lower than outdoors that day) and I was happy to be able to run it.

Before you buy a purifier, buy an air quality monitor. This is the one I got, based on reviews it seems to be the most accurate for any under $100:

https://www.amazon.com/gp/product/B08P4QN2NN?psc=1

It's worth noting that a majority of American east-coast homes have some amount of black mold, which is scary stuff. Run a HEPA filter in your home, you won't regret it.

I have 5 20 x 20 box fans running 24/7/365 with Merv 13 HEPA filters placed against the back (held on by the fans suction). The whole house has Merv 12 HEPA filtration through forced air system. The air in the house is incredibly clean, to the point where after working from home and not going out much for the last 1.5 years, I am finding that I'm way more sensitive to allergens outside. Otherwise there is almost zero dust, the house has no odor, and there is a nice hum that drowns out outside noise and makes sleeping very comfortable. Lasko now sells a fan specifically made for cleaning your air.

https://www.lasko.com/products/air-flex-air-purifier-and-roo...

I don't know where you live, but that is way excessive for the developed world (minus wildfires).

But as long as you are changing out those filters on a regular (3 months?) basis, you can go on being you and being healther for it.

If we can’t open a window because the outdoor air quality is poor (polluted city) how can we reduce indoor CO2?

There are a growing number of companies selling algae-based CO2 scrubbers. You grow algae and force air to bubble through it. When the algae fully grows you can harvest it to eat or compost.

However, you need to really run the numbers to see if the particular volume of algae is sufficient to clean the levels of CO2 you’d like to. In my case, I’d need ~20 of these to negate the CO2 generation in the space.

https://algenair.com/

and if you don't want to spend $250, the DIY version seems pretty easy, too: https://www.greenhousetoday.com/growing-spirulina/

Any plants that purify air? I've read online about the NASA study that says Snake plant purify air but then I read that there wasn't really a conclusive end to that study. And that it's all mis information

I am not comfortable with an air filter at home so am searching for anything apart from that

There are plants that are pretty good at removing VOCs. I think spider plants were a winner.

yep, check this 4 min video https://www.ted.com/talks/kamal_meattle_how_to_grow_fresh_ai...

Surprised not to see more mention of MVHR in the comments. This approach constantly brings in fresh air while retaining heat pretty effectively and also filtering incoming air for particles etc.

I'm just in the process of retrofitting this to my old home (which definitely has elements of 'sick house' syndrome at the moment).

It's not that cheap, and can be tricky to retrofit - usually alongside improving airtightness and insulation - but is one way to dramatically improve air quality in a building, especially over colder months.

https://en.wikipedia.org/wiki/Heat_recovery_ventilation

When is there going to be the Apple for houses? I want to buy a house that incorporates all this research and thought.

Question as an aside, does anyone here have experience with indoor air quality meters? I've had a hard time finding some good recommendations for something reasonably accurate and not too expensive...

It's a bit tricky, because one of the most expensive parts of an air quality meter appears to be the CO2 sensor. Less expensive sensors approximate CO2 concentration (it's referred to as "eCO2") and can be wildly off due to the way they sense gas concentrations.

If you have the equipment to make electronics at home and are willing to DIY, it can be done for less than $100 and will be comparable to an off the shelf unit.

I’m partial to the no-name monitor described here since all the sensors are removable and can be moved into a DIY unit if it breaks. The sensors used are the same parts used in big brand monitors.

It also helps that the processor is unlocked and custom firmware can be cooked up:

https://frdmtoplay.com/patching-in-fahrenheit/

Those are subjective but there's a good paper on accuracy here https://www.sciencedirect.com/science/article/pii/S036013232...!

tldr for CO2 best is https://www.kaiterra.com/en/laser-egg-co2

I have felt way better with a HEPA-filter in my room and better ventilation. (Also got a vacum-mop-robot that reduced dust a lot by vacumming and mopping daily my main working area and bedroom)

I was thinking about a home setup. Opening the window lets in VOCs from outside, which the HEPA-filter is supposed to clean up. Seems a bit counterproductive or self-defeating, no? A more proper setup that you'd find in an office building is probably too expensive for home.

I open the back windows not the street facing ones

Sure, but I just wonder about the effectiveness of a filter when we do that. If all of the air in the room is completely replaced with air from outside via the open window, then what does the filter achieve? It seems that there's a trade-off between lowering CO2 and lowering VOCs.

Not all, just the rate has te be somewhat balanced, there is definitely a breeze and the air filter helps mostly with PM and indoor sources.

HEPA removes only particulates, not VOCs and not CO2.

My big problem right now is adding a filtered fresh-air intake to my house. CO2 in my rooms spikes when working at home and above 600 is cognitive impairment and you definitely feel it (I'm pretty sure meetings which go off the rails at work have this problem too - I really need a wearable monitor so I can cancel them when it starts happening).

The thing is I also need to do heat recovery, and since it's Australia, I definitely want to be able to do a filtered air overpressure in winter.

Just open a window a crack. The CO2 drops rapidly.

The problem with ultra insulated homes are that C02 and moisture get trapped. So then you need filtered fresh air, and then heat recovery.

My windows face the street - and that's the issue, heat loss in winter is a big deal. And I have to actively monitor in order to know I should do it - this isn't something you really think about, and its terrible when you're in the flow while working.

There's also other reasons - for example I want to ensure the flow of air through the house concentrates and exits via the bathrooms and kitchen.

It isn't quite that easy. Even if there aren't impediments to opening a window a crack, it is not guaranteed that passive measures will reduce CO2 levels.

I've been tracking my home office's CO2 level for about a year and a half and obviously opening a window helps, but there are certain conditions (pressure, temperature, wind?) that require fans to normalize the levels.

Heat Recovery Ventilators can be used to address the moisture issue

https://photos.app.goo.gl/kBoR9MCsGwfHG6NB6

One week given west coast wildfires - perhaps 1-2 months in regular NYC air.

Obviously, the healthier, happier and more financially efficient solution is to not pollute the air in the first place. This is wishful thinking given west coast wildfires.

Scaremongering aside, it's obvious that air quality matters enough to health, to be worth addressing. Heck, if you're buying organic milk or filtered water, then filter your air.

Filtration doesn't need to be expensive or fancy - a 20" box fan with 20" filters works great, no duct tape required - when you turn it on, the filter "sticks." I've proven it's effective with an air particle meter.

https://photos.app.goo.gl/YgUnGbNzpYfNW2yr5

Is that box fan any more effective than the same/similar filter in the HVAC plenum?

"Scientist says" - okay, that's not very useful, which scientist? What science? What research? What's it being backed by? What money flows are behind it? What's the conflict of interest report?

Any time a headline says "scientists say" that's just some sort of crappy marketing signal, not actually a useful thing to put in your headline because those words in that way lost their value.

It used to be that a scientist was someone who was an actual scientist, applying scientific principles and having an accredited master or maybe even doctorate. And then it also wasn't "they said" but "published" or "reported" or "found evidence of".

In this case it happens to be:

- Joseph Allen

- runs a major public health research project at Harvard University (Associate Professor)

- consults with companies on ventilation and air filtration

- writing dozens of op-eds

- washed out as an FBI recruit

- doctoral thesis at the Boston University School of Public Health

- a bunch of Director, Co-Director, Deputy Director, Commissioner, Chair, Advisory Group things

- Has a bunch of publications which has his name on it, but also a billion other names, and as far as I know people tend to stick on a bunch of names that didn't actually 'do the work', but simply were guiding tutor style personal advisors.

The Boston thing seems to be:

> We used personal air samplers to measure indoor air exposure to polybrominated diphenyl ethers (PBDEs) for 20 residents of the Greater Boston Area (Massachusetts). Area air measures were simultaneously collected from two rooms in each participant's home.

So the entirety of what's visible on the surface doesn't tell me much, except:

- Does a lot of management type of thing

- No quantitative hard science, just low sample sized tests

- Mostly busy being 'visible' (be it marketing or talking head for a group that did the actual science)

Now, don't get me wrong, I'm not saying "this person is bad, this advice is bad, and there is nothing here to support any of this". I am saying that some magazine headline with a "scientist says" just doesn't have a lot of meaning. This guy might very well know his stuff, but it's pretty hard to derive that from whatever is published in magazines and sites.

At the same time it seems somewhat obvious that if we, as mankind, go and modify the air we live in by constructing boxes to live and work in with minimal airflow (be it cycling or fresh air replacement) that you would normally have done by general weather patterns and nature, we're probably not going to be better for it. That doesn't mean we need a company to invent an 'outdoor air simulator' to buy, but it might mean that having a well-sealed building requires some compensating features (be it air replacement/flow from outside, or some other method like strategic vents that make use of differences in airflow speeds around the building). Making sure that you don't collect a lot of particulate matter and just floats through the air all the time has an impact. (or, as others have posted: cleaning up your durst and mopping) Measuring your air quality can give you an idea if what you are doing is making things worse or better (i.e. if you have forced-air AC and you turn it on, you can probably see CO2 levels either rise or drop, same as when you have air vents or windows to the outside you can open - requires the air outside to be reasonable of course).

The growing problems of particulate pollution, airborne viruses, and carbon accumulation all make me think we’re on a path to building systems that will process and filter the entire planet’s atmosphere - a network of giant intake vents and towers.

Trantor?

This sentence raises questions for me:

> Allen came to see businesspeople as natural allies who could act on his public health findings faster than government officials.

When I see a cliched narrative or meme, I suspect it that's its only basis - reality doesn't match the memes so neatly - and also this one benefits their busines partners. Also, why aren't public health officials acting? When I see someone say they are too slow, IME it's usually because their claims aren't sufficiently substantiated. Accelerating approval and reducing government oversight hasn't had great results.

You can go a long way by just not polluting your own house with VOCs, as mentioned in other comments here.

Basically, you have to abstain from most "cleaning" products, new furniture, and ... something else, I think?

Wait, what's the thing with cleaning products? Do dish detergents and surface cleaners create VOCs?

A lot of people like to use "fabric softeners" that are heavily fragranced, and they also like to purchase plug-in oil wick "air fresheners" that soak into every porous surface as well as your lungs. This is in addition to the regular stuff. So it's not just VOCs anymore, but also HAPs--hazardous air pollutants.

Example, those clip-in auto air vent air fresheners that people buy for their cars. Spend 20 minutes in that person's car, notice how the next day your clothing still smells strongly of the oil-based air freshener. You were also inhaling that. And this is somehow perfectly fine?

I use an air monitor from Awair. Every time I cook at home, the VOCs go up tremendously. Should I stop cooking?

You should use a range hood, or you should have much better kitchen ventilation.

I have a range hood. I haven't compared the VOCs when using it or not, but I can tell you they are rather high even with it.

Is it a recirculating hood or does it vent outside, and do you have a gas range/oven?

Gas and it vents outside.

Airflow is hard, but any combination of fan isn't powerful enough, too far away, or a strong cross-current (from A/C, say) will prevent the hood from moving enough waste outside

Does the hood vent outside? Or does it throw air right above your face? I think we are supposed to change the filter in a range hood every so often but I’ve never done that even once in my life nor do I know anyone who has…

I didn’t think of it until one time I was in the kitchen of a restaurant. Those are real hoods with a really good suction capacity.

It vents outside.

You may want to stop frying things in oil, perhaps?

Even just putting food in the oven, without using the cooktop or oil, will cause VOCs to spike.

I think that all VOCs are not created equal, also.

Can anybody recommended a device for testing home CO2 levels? I tried to do a quick search, but there is a wide range of products across many price points and it's hard to make sense of it.

after a bunch of looking, the paper that had the most detail on quality and sensors used is https://www.sciencedirect.com/science/article/pii/S036013232...!

the most accurate readily available for CO2 seems to be the "Laser Egg+ CO2" for $200 https://shop-usa.kaiterra.com/collections/frontpage/products... which uses SenseAir S8 but looks and sounds a little silly

and the $150 "Awair Element" https://wiki.liutyi.info/display/CO2/Awair+Element+inside which uses the Amphenol Telaire T6703-5K

Just open the window

I’ve bought air filters and detectors to protect against wildfire smoke. “Just open the window” is actually pretty good advice in most (non-wildfire) times. My indoor air quality improves sharply as soon as let in an outdoor breeze.

I installed a whole-house fan [1] when AQI outside is good (especially during fire season) - usually early mornings or late evenings - outside air, despite being somewhat dirty is often better than stale indoor air. We do this every day even when it's cold outside for at least 15m. In summer sometimes we leave on the "low" setting all night instead of running the AC.

[1] https://www.hoffmannbros.com/electrical/whole-house-fans/how...

Without adequate measurements, you would be surprised how wrong your advice is. If there are wildfires anywhere upwind, you're better off (barely) with the windows shut and recirculating the air through the furnace filter.

I believe it will become necessary sooner than we imagine. 32 continuous days of air pollution warnings in Denver this summer (ozone and smoke). This comes with a recommendation to not drive unless you have a zero emission vehicle. It's bad enough I'm not running or biking much at all or I end up coughing for hours afterward, and have itchy eyes. It's terrible.

Air purifiers do not remove co2. The green way to get fresh air into a well insulated house is to use a energy recovery ventilator (ERV)

If there are others like me that have been searching for this, Daikin sells the holy grail: an air conditioning unit that does everything, including true ventilation, (de)humidifying and air purification. Basically a compact size HVAC. Currently saving for one. Here they're about 2000 eur.

Keeping an air purifier running efficiently requires me to keep all the windows closed which negatively effects the temperature in my apartment. Is it worth the trade off?

Without ventilation, you are increasing CO2 to over 1000 ppm doing that, which as the study points out is bad in itself.

I was wondering about similar things a while back. I don't know if there are any easy options, but if you were, say, looking to do a custom house build, it seems that a passive house with mechanical ventilation heat recovery (MVHR), or alternatively a positive pressure system, would be ideal for indoor air quality. In either case you are getting a steady supply of purified, low-CO2 air to breathe.

Keeping plants in your house reduces CO2 levels and removes pollutants, perhaps try that.

- https://pubmed.ncbi.nlm.nih.gov/32170619/

- https://www.sciencedirect.com/science/article/abs/pii/S13601...

The pessimist in me likes to think this article is sponsored by the air purifier lobby. Healthier I can understand, but smarter? How do they prove smartness?

It seemed like a huge fluff article for a "science" mag. I felt like I had to scroll a significant amount to get passed the bio.

If anything it was sponsored by HVAC. Heat recovery ventilation units are expensive. (Would have one if a new house. Harder to justify for retrofit.)

There's a lot of evidence that people perform worse on intellectual tasks at high CO2 and VOC levels.

I'm aware what I'm about to say is a dumb non sequitur that doesn't really make sense, but: it's kind of unfortunate that we carbon-based animal lifeforms on this carbon-rich planet are so susceptible to harm from so many carbon-based molecules.

Carbon is the backbone of most complicated molecules. And of course all parasites and diseases run on the same basic chemistry as every other lifeform on earth.

Of course; that's why I prefaced it as a dumb non sequitur that doesn't make sense. It's just poetically a little woeful, especially since there's a chance it could also lead to environmental catastrophe.

I don't think it's fascinating at all. You could make the same argument about atoms or neutrinos. Nothing gets more deadly than nuclear radiation from neutrinos found in every. single. atom.

water will kill you if you drink 5-6 liters fast enough. Pure oxygen will burn you, and pure nitrogen will suffocate you.

People love being scared. Struggle against external threats gives meaningless lives a soothing story to tell to our egos.

I agree it's not fascinating. But I actually was going to initially include an addendum about how I think it's not quite the same as pointing out the harms of something as fundamental as atoms or fermions or something. Carbon isn't necessary for matter and possibly not necessary for life; just necessary for our particular implementation of it.

> Carbon isn't necessary for matter and possibly not necessary for life

Well in a way it is, because that's what evolution had to work with. Maybe in some other multiverse atoms wouldn't be necessary, but that's just not the way it is in our reality.

It's probably necessary for Earth life, but we don't know for sure that there can't be non-carbon-based life elsewhere in the universe.

That's my point. The fact that carbon is ubiquitous to life on Earth is analogous to atoms being ubiquitous in our universe. There could be another universe where atoms don't exist, but who cares we don't live there, neither do we live in a part of the universe where life is not made out of carbon. There is absolutely nothing interesting about the fact that life is made out of carbon and that at the same time carbon can cause harm to said life if used improperly. Not sure why we keep going in circles.

I'm not sure why we keep going in circles, either. The first few words of my post made it clear that I understand the utter banality and lack of sense in the point:

>I'm aware what I'm about to say is a dumb non sequitur that doesn't really make sense,

Obviously it's not interesting and isn't actually saying anything, since carbon is so general and fundamental as a building block on Earth.

I was speaking thematically or poetically. We generally don't refer to ourselves as "atom-based lifeforms" or "quark-based lifeforms", but we often do refer to ourselves as "carbon-based lifeforms". I could elaborate, but hopefully that captures what I'm referring to, here. It's mostly a matter of wordplay, not matter.

to be precise: we perform worse in conditions dramatically different from our natural habitat.

Fish also can't breathe on land, despite much higher concentrations of oxygen. What does that mean?

Those studies are often mis-used as doom porn fodder, and are really only useful for occupational limits and employment liability, not some future forecasts for the next few centuries.

The only constant thing about climate is that its constantly changes, and large fluctuations have happened many times in the past, and mammals survived.

Some of the dinosaurs that survived (birds) even developed a whole different type of super efficient hemoglobin, and if CO2 keeps going up - so will we. Some people already retain large amounts of fetal hemoglobin, maybe that's the way?

At any rate, the best view on climate change I've read online: http://timtyler.org/end_the_ice_age/

Can't Google right now but there was a story about, I think, Californian schools that installed air purifiers to deal with some kind of temporary pollution problem (fires?), and apparently they then found that after the problem had ended, the students in schools or rooms with air purifiers scored higher in some sort of testing.

(Pardon the vagueness, I'll edit later if I can)

It was Porter Ranch, due to a gas leak:

https://www.latimes.com/local/lanow/la-me-ln-air-purifiers-f...

(Not that leaking gas would get meaningfully filtered by the average air purifier.)

This study found improvements due to the air purifiers:

https://www.edworkingpapers.com/sites/default/files/ai20-188...

That's the one. From the conclusion:

> Indeed, with a benefit-to-cost ratio of 0.2σ increase in test scores per $1,000 of expenditure, air filter installation is one of the most cost-effective education policies available to policymakers today.

> Specifically, economically disadvantaged students disproportionately attend schools in highly-polluted regions. Given this, installing air filters in polluted regions should both raise student achievement and reduce the pervasive test score gaps that plague public education.

The article says they had double blind cognitive tests. Seems pretty straight forward?

>>The pessimist in me likes to think this article is sponsored by the air purifier lobby.

Well that makes the two of us. For an article on a website called science, there's lots of info about the person doing research, his background and his life story than the actual numbers on what they define as "smarter"

In one part they mention the study was done in 2015 (no link to article) on 24 people where these people did 61-101% better on some test.

But then when they did the study on 100+ people the improvement was just 26.4%

Wut??

But like others have mentioned there is evidence better quality air helps with performing better on cognitive tasks. This article is just really badly written.

>In one part they mention the study was done in 2015 (no link to article) on 24% where people did 61-101% better on some test.

I think this is the study

https://dash.harvard.edu/bitstream/handle/1/27662232/4892924...

>Results: On average, cognitive scores were 61% higher on the Green building day and 101% higher on the two Green building days than on the Conventional building day (p < 0.0001). VOCs and CO2 were independently associated with cognitive scores

> on a website called science

"Science" is one of the two leading scientific journals in the world, along with Nature.

And your point is ?

For whatever it's worth, I spent a ton of time researching this and came to the conclusion that cleaning your indoor air is probably the first thing you should do for your health: https://dynomight.net/air/

But I suggest you DIY a purifier instead of spending a ton of money on one: https://dynomight.net/better-DIY-air-purifier.html

I like the data collection, but the design he uses for a box fan is VERY poor. You can get a large 20x20x1 filter that will cover the entire fan surface area of the box fan. Just from inspection, that should increase the total volume of air which is cleaned by a factor of 2.

Just buy a box fan and slap a filter on it.

> Just from inspection, that should increase the total volume of air which is cleaned by a factor of 2.

Are you aware of any data that supports this? It could be true for all I know but (contrary to my expectations as well) the experiments I've done don't really seem to support this. See the "taping" experiment here: https://dynomight.net/2020/12/15/some-real-data-on-a-DIY-box...

You might be referring to non-HEPA furnace air filters which (by design) have much better airflow, but typically don't capture the smallest particles, which have the largest health impact.

Box fan with a 20x20x1 filter makes the fan work much harder.

20x20x2 or 20x20x4 filters have much larger surface area, which is better.

Creating a cube with four 20x20x2 is the best in terms of energy use and air output.

And then you add a fan shroud for even more efficiency.

https://www.texairfilters.com/how-to-improve-the-efficiency-...

Just run highly rated MERV filters. I use a bit of a bulky MERV 14, but as long as you can cycle the total air volume of the space you're cleaning quickly, anything with 20+% uptake on small particles will work over time.

The experiments and data on that site (I assume it's yours?) don't give me nearly the same conclusions you do - Almost all decent filter setups will hit the same particulate equilibrium asymptote with the only real difference being the duration it takes to get there - a negligible plus or minus half an hour. Speed is not aim. It's the maintenance of the steady-state that is.

If the filter stays on, the air stays clean (barring total capacity issues - you can't filter a huge house with a single box fan).

So the only real roadblocks are human factors that would 1) make people skip making a filtering setup and 2) make people want to turn off the filter. This is where the real UX comes into play.

> Almost all decent filter setups will hit the same particulate equilibrium asymptote with the only real difference being the duration it takes to get there

I'm not doubting this, but do you have any evidence? According to the specs, by definition a MERV 14 should leave at most 25% of all particles size 0.3 microns or larger in one pass, while a HEPA filter can leave at most 0.03%. It's plausible but not totally obvious to me to me that this means that a MERV 14 will leave at most a fraction 0.25^k after k passes (though it's plausible). If so, that would suggest you need around 6 passes through a MERV filter to get equivalent filtration to 1 pass through a HEPA filter. (Airflow might be 6 times as high.)

Box fan with a 20x20x1 filter makes the fan work much harder.

20x20x2 or 20x20x4 filters have much larger surface area, which is better.

Creating a cube with four 20x20x2 is the best in terms of energy use and air output.

And then you add a fan shroud for even more efficiency.

https://www.texairfilters.com/how-to-improve-the-efficiency-...

>In the first study, published in 2015, they had 24 white-collar volunteers spend six working days in environmentally controlled office spaces at Syracuse University’s Total Indoor Environmental Quality Laboratory. On various days the experimenters would alter ventilation rates and levels of CO2 and VOCs. Each afternoon the volunteers were tested on their ability to think analytically and react to a crisis. (One test, for example put the volunteer in the role of a small-town mayor trying to react to an emergency.) All tests were double-blind: Neither the volunteers nor the study personnel knew that day’s environmental conditions.

Cognitive testing (detailed above) was used to test "smartness." I am, however, similarly pessimistic.

reminds me of a 4 minute TED talk I watched a while back, you can grow fresh air with only 3 plants https://www.ted.com/talks/kamal_meattle_how_to_grow_fresh_ai...

I didn't like the format of this article, bit too much back story, but think the basic conclusion is true.

Air quality has a quantifiable impact.

The shift to EVs and electric home cooking and heating will also improve this as a side effect.

Home stoves, including picturesque log fires are another source.

I didn't think the air freshness thing was particularly new, but maybe US regulations have fallen behind, I thought most building codes already considered this.

The buried lede in this article is the implication that all serving FBI agents are capable of being "unnerved by a polygraph test" -- so, they're credulous enough to believe fake science or they're influencable enough to break down for the interrogator.

I wonder who, or what, this serves.

For anyone building a house: «Balanced Ventilation»

It doesn't make sense to me - I'd think we all get enough oxygen even in stale air. Is there any hypothetical reason why they'd think it would make you healthier or smarter?

Throughout our evolutionary history, we were breathing in air with about 300 ppm of CO2. What makes you think everything will be perfect with our bodies and brains if we jack that up to 1000 ppm?

If you are indoors you are likely breathing 1000ppm already. Some large cities already at 900ppm.

So, absolutely nothing?

OSHA limits on CO2, might be useful: https://www.fsis.usda.gov/sites/default/files/media_file/202...

> If you are indoors you are likely breathing 1000ppm already.

Not if you have ventilation or leave the window open.

> Some large cities already at 900ppm.

Which ones? I read online that New York can go up to 500 ppm and Shanghai up to 550 ppm.

> OSHA limits on CO2, might be useful

I find it very plausible that higher order cognition is the first thing to be negatively impacted, before macro-level symptoms like headaches or drowsiness start manifesting at 10,000+ ppm.

https://pubmed.ncbi.nlm.nih.gov/17100666/

1000pm in Shanghai classrooms, windows open: "The air exchange rate was 2.9-29.4 ac/h (mean 9.1), because of window opening. Mean CO2 exceeded 1000 ppm in 45% of the classrooms."

1000pm is a non-event. Life survived multiple extinction-level asteroid impacts. We've adapted to much worse in the past.

At the worst, people will have indoor/car CO2-removers, just like you cannot really survive without an AC everywhere in Middle East (or Arizona) today. Maybe we'll just have to get some more indoor plants.

> 1000pm in Shanghai classrooms

You said "some cities", so I presumed you meant outdoors. Of course in a crowded room it can reach 1000 ppm (or much higher) without the proper ventilation. This finding has nothing to do with the city of Shanghai.

And yes, the "window open" comment I made was for a room with 1 person in it like a bedroom. If it's crowded then obviously more effective ventilation will be needed.

> 1000pm is a non-event

Well the study this thread is based on is directly contradicting that. Do you know of any studies that shows that 1000 ppm has no negative impact on higher order cognition?

> Maybe we'll just have to get some more indoor plants.

Indoor plants aren't effective at reducing indoor CO2.

In fact there are studies that show that even moderately high classroom CO2 levels are correlated with poor outcomes.

https://pubmed.ncbi.nlm.nih.gov/25117890/

There's a lot wrong in such a small comment.

First of all, the entire point of the article is the "hypothetical reason why...". Even if you didn't read the article, the title is pretty suggestive.

Secondly, it ought to be intuitive that just because you get "enough oxygen" doesn't mean you aren't getting other things as well.

Been saying this since the onset. Vaccinations were never going to be 70%+ in this country. How many people get flu vaccines and other ones that are non-compulsory?

We needed a solution with many different approaches to cover many ways to combat the problem.

Cheap box fans + 20x20 filters work wonders. I bought 30 for my place of work as well as jerry-rigged UVC lamps in enclosed boxes. That, combined with high vaccination rates through paying employees 0.5 days PTO if they opt for vaccination (and other common sense policies like distancing, copper-taped door handles, and improved general airflow), has led to 5 outdoor COVID cases coming into work with zero community spread.

Waiting for Elon Musk to disrupt the entrenched, uninventive HVAC industry.

I would settle for a Raspberry Pi board that combines sensors for temperature, CO2, VOCs, and particulate load. Maybe combined with fans that can easily be put into cracked-open windows to force air flow.

There are already makers that build heat exchangers, but there are a lot of catches and other unexpected impacts.

Install a heat pump and/or geothermal.

I meant more from an air cleaning perspective not efficiency. Tesla built a very efficient auto HVAC system that pressurizes, cleans, and recirculates air through a multistage HEPA filter ("Bioweapon Defense Mode"). That kind of cleaning is usually reserved for commercial/hospital use and very expensive to implement in the residential space right now. In the last Battery Day, Musk indicated he would like to adapt the design to home use.

This feels like a scam artist trying to push air purifiers.

Or maybe we could end up with frail immune systems that go haywire each time when stepping outside. "Scientist says"

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