Children's stunted lungs show recovery in ultra low emission zone | Hacker News Reader

Children's stunted lungs show recovery in ultra low emission zone

bbc.com

417 pointsdabinat416 comments

China has 350 million electric two-wheelers, 20 million EVs. China reduced air pollution from transportation by 80% in a decade.

Delhi: 442. Lahore: 334. Beijing: 16. These are the levels of PM 2.5, one of the principle measures for air pollution, on November 19. How China cleaned up its air pollution – and what that meant for the climate: https://theconversation.com/how-china-cleaned-up-its-air-pol...

Outdoor pollution ---> Use these for transportation: walk, bicycle, e-scooters, public transit, electric 2 wheeler, EV

Indoor pollution ---> Use these for cooking (induction, electric resistance) stove, heatpump waterheater and furnace for HVAC

Would also be nice to do: stop using coal, gas power plants. These are usually farther out from cities and probably not the most urgent. (except when Elon Musk or new DCs decide to use gas turbines in cities).

Researchers say they have cracked how air pollution leads to cancer, in a discovery that completely transforms our understanding of how tumours arise: https://www.bbc.com/news/health-62797777 (discussion: https://news.ycombinator.com/item?id=32788706)

Surprise! Electric cars are already making California healthier (2023): https://electrek.co/2023/02/10/surprise-electric-cars-are-al...

Air Pollution Kills 10 Million People a Year. Why Do We Accept That as Normal? https://www.nytimes.com/2022/07/08/opinion/environment/air-p...

Tiny air pollutants may cause changes in brain structure that resemble those of Alzheimer’s disease: https://www.nytimes.com/2019/11/25/well/mind/air-pollution-b...

It is important to use metrics and language that people can understand. Cigarette smoking is very well known, because public health initiatives make sure the harm is labeled. Air Pollution and Cigarette Equivalence: https://berkeleyearth.wpengine.com/air-pollution-and-cigaret...

Delhi’s air pollution equivalent to smoking 50 cigarettes per day but experts say it can be fixed: https://epic.uchicago.in/delhis-air-pollution-equivalent-to-...

Almost all countries failing to meet mark for PM2.5, tiny particles expelled by vehicles and industry that can cause health problems: https://www.theguardian.com/environment/2024/mar/19/air-poll...

Bees struggle to find flowers because of air pollution: https://news.ycombinator.com/item?id=37434381

Cars and automobility have killed 60–80 million people since their invention. 1 in 34 deaths are caused by cars and automobility with 1,670,000 deaths per year. Car harm: https://news.ycombinator.com/item?id=39465354

Gas stoves pollute homes with benzene, which is linked to cancer: https://news.ycombinator.com/item?id=36364524

Amazon backs power plant that may become top source of US climate pollution: https://news.ycombinator.com/item?id=49249971

>Delhi’s air pollution equivalent to smoking 50 cigarettes

Per day, which for some reason the headline didn’t include. Two packs a day is a pretty terrible baseline. At least it’s not addictive.

Thanks for catching that, yes, per day is critical to understand the harm. I edited my post.

So you support nuclear power?

I support solar. Democratize energy, everyone should have the right to produce and store energy.

1) Plug-in solar and batteries are plug-n-play. This is the first step to teach everyone energy literacy and numeracy.

2) Vertical panels immediately add 3 - 4 hours. Vertical panels have zero real estate cost and no need to build costly and slow transmission infrastructure. Every building in a city can produce energy.

3) EVs to store excess energy during the day and supply power back to the grid later.

1.8 billion vehicles connect 4 billion buildings. Buildings can produce clean energy and EVs can store energy. The lowest hanging fruit is to make sure all new buildings are built to produce, and all new vehicles are EVs. New buildings can be built with vertical panels and rooftop. The easiest thing to do is change building code, thats it. Then, we can deal with the built environment.

What source of energy will provide energy at night or bad weather?

I would like to note that batteries at end of life are chemical waste and have to be disposed properly.

"End of life electric vehicle batteries in China to 2060 and related resource management implications"

https://www.nature.com/articles/s43247-026-03555-3

"The EOL batteries contain a wide range of toxic and hazardous materials that can leach into the soil and water, threatening human health and the environment. For example, lithium hexafluorophosphate (LiPF₆), a component in power batteries, hydrolyzes on contact with water to produce highly toxic hydrofluoric acid (HF). Additionally, cobalt, nickel, and organic solvents in the batteries can contaminate water and soil, leading to long-term ecological damage"

https://insideclimatenews.org/news/30072026/china-ev-battery...

There are startups like Redwood Materials. I'm sure China will figure it out. They are willing to put in the right policies, incentives and research dollars.

Redwood recycles end-of-life batteries to recover lithium, nickel, cobalt, and copper — creating one of the largest domestic sources of these critical materials: https://www.redwoodmaterials.com/

The question of how to supply daily and seasonal storage requirements demanded by intermittent sources remains unanswered, even if we assume battery recycling is performed. The US alone uses 12,000 Gwh of electricity daily and about 30,000 GWh of energy daily (transportation, burning gas for smelters, heating, etc).

Even just a day's worth of energy is decades worth of global lithium ion battery output. For just one country. People rarely appreciate the scale demanded to make grid storage feasible.

Solar plus batteries is the cheapest way to build a power plant in 2026. Nowhere gets so little sun that this can't be made to work.

Again, this glosses over the scale of grid storage. If the US decides to provision a day's worth of electricity storage then, that amounts to 12 years worth of global battery production.

>I would like to note that batteries at end of life are chemical waste and have to be disposed properly.

As far as countries like the US is concerned we need to mirror our policies with lead acid batteries. Recycling chains need to be setup and monetary penalties for not recycling a battery when buying a new battery. Ideally I think this should be for lithium batteries from BEV & Home Storage, all the way down to disposable vapes.

"As the United States tightened regulations on lead processing to protect Americans over the past three decades, finding domestic lead became a challenge. So the auto industry looked overseas to supplement its supply. In doing so, car and battery manufacturers pushed the health consequences of lead recycling onto countries where enforcement is lax, testing is rare and workers are desperate for jobs."

https://www.nytimes.com/interactive/2025/11/18/world/africa/...

This already happens. There are many companies recycling batteries. The batteries of tomorrow are the batteries of today. They are permanent infrastructure.

Expecting everyone to have a car cannot remotely be considered a serious solution

Centralized production and storage will always be more efficient

Solar can be deployed in months, produce immediately. Solar is dirt cheap and continues to get cheaper. 21 - 25% efficiency is normal now and most likely we'll have tandem (silicon + peroskvite) with 45% efficiency. With each doubling of production, solar costs continue to go down. In a decade or two, maybe we'll be able to print solar like paper or textile, or spray paint on any surface. Or grow solar from microorganisms (fastest and cheapest).

A nuclear deployment takes 3 - 5 decades, costs continue to skyrocket, actually needs nuclear scientists to design and run.

Which one do you think is a better choice? If you were an investor, would you put your money on a nuclear plant and wait 3 - 5 decades for returns?

It currently takes so long to deploy nuclear in the West, because the West mostly dismantled the nuclear supply chains, starting in 1990s. At that time coal and gas power plants were seen as better than nuclear power plants and no expansion of nuclear energy was expected.

For example Germany was still building new coal power plants in 2005-2007.

https://energytransition.org/2016/10/germanys-last-new-coal-...

https://us.boell.org/en/2014/06/06/german-coal-conundrum

Currently, in 2026, Germany is retiring coal power plants and replacing them with gas power plants.

https://www.cleanenergywire.org/news/german-government-appro...

China builds more renewables per month than the nuclear target they’ve very slowly expanded over a half decade and aren’t scheduled to reach until at least 2030. 70% of China’s electric generating capacity will be renewables by 2027. You could replace current global nuclear generating capacity at parity with capacity factor with batteries and solar in under two years.

Lazard Levelized Cost of Energy+ 2026 - https://www.lazard.com/media/kcfconhf/lazards-lcoeplus_vf.pd... [pdf]

> Renewables Remain Lowest Cost New-Build Generation; All Generation Faces Increasing Cost Pressure: Despite rising and inflationary cost pressures across all generation technologies, renewables remain the most cost-competitive form of new-build generation on an unsubsidized basis and will account for the majority of near-term capacity additions in the U.S. Continuous upward revisions to demand projections have driven a sharp increase in announced new-build gas generation despite a 15-year high LCOE, which is expected to continue to rise, and historically long development and equipment delivery timelines.

China Keeps Beating Renewable Targets And Missing Nuclear Ones - https://cleantechnica.com/2026/07/25/china-renewable-targets... - July 25th, 2026

> China set a 2020 wind target of 210 GW and finished the year with about 282 GW. Its solar target was 110 GW, while delivery reached roughly 253 GW. The later commitment to reach at least 1,200 GW of combined wind and solar by 2030 was crossed in 2024, six years early. By the end of 2025, China had about 640 GW of wind and 1,202 GW of solar, for a combined 1,842 GW. Nuclear moved in the other direction: about 50 GW against a 58 GW target in 2020, and about 62 GW against a 70 GW target in 2025. The current goal of 110 GW by 2030 may still be achieved, but the previous record gives no reason to convert it directly into a forecast.

> This is not evidence that Beijing has quietly abandoned nuclear power. China has the world’s largest reactor construction programme, continues approving new units and is building an increasingly domestic supply chain around designs such as Hualong One. The divergence lies between approval and operation. Another difference is that when renewables blow past targets China set much bigger targets, but when nuclear misses targets, the targets don’t change. That difference is harder to explain than the results.

China builds more new coal power to combine with renewables than any country in the world. With all implications for air quality, but the new coal development is concetrated away from most big cities, so air quality is slowly getting better in big cities.

"Operating coal power capacity in China has increased 44% since the Paris Climate Agreement of 2015."

"1,270 GW operating coal power capacity"

"533 GW coal power capacity"

https://globalenergymonitor.org/projects/global-coal-plant-t...

" Many of China's renewables-rich regions are also major coal-producing areas. While renewable development creates opportunities for economic diversification and industrial transformation, it can also provide a new rationale for expanding coal-based industries. The coal-to-chemicals sector illustrates this risk.

According to new GEM research, all coal-to-olefins projects currently under construction in China’s northwestern and northern regions include planned associated green hydrogen facilities, as regulators increasingly require renewable integration as a condition for project approval. However, in many cases, the renewable component represents only a small fraction of overall energy use."

https://globalenergymonitor.org/research/chinas-wind-and-sol...

China currently builds cheapest possible energy system based on renewables backed by coal power instead of expensive energy system based on nuclear energy.

China is using their coal plants as peakers until battery storage has ramped to replace them. Coal use has already dropped below 50%. They are building the largest hydro project in the world (60GW, Motuo / Yarlung Tsangpo project) in the Himalayas, with a 2k meter drop that will create more pressure than a nuclear driven steam turbine.

Ember Energy: China - https://ember-energy.org/countries-and-regions/china/ - Last Updated: May 28th, 2026

> China is rebuilding its industrial economy on a clean foundation as rapid renewable energy expansions begin to offload fossil fuels

> Hydropower remains China’s largest single source of clean electricity, contributing 13% in 2025. The share of wind and solar combined reached 22%, above the global and Asia average of 17%. Solar recorded another year of exponential growth, with 336 TWh of power generation, a 40% increase compared to 2024.

> The biggest shift in China’s electricity generation in 2025 was an absolute decline in coal generation. Coal output decreased by 71 TWh, the first such drop since 2015. Fossil fuels provided 58% of China’s electricity in 2025, down from about 62% in 2024.

> China could reach peak fossil fuel consumption by 2030, thanks to exponential renewables growth and electrification. In 2025, China’s fossil generation declined by 56 TWh (-0.9%), the first year without an increase since 2015. This represents a structural shift, and if current trends hold, China’s fossil fuel demand could begin falling soon, creating conditions for global fossil fuel demand to decline as well.

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

China’s energy storage market doubles in size for second consecutive year as price inflection point emerges - https://www.energy-storage.news/chinas-energy-storage-market... - August 18th, 2026

China Crosses Energy Milestone as Coal Falls Below 50% of Power - https://news.ycombinator.com/item?id=49110187 - July 2026

Ember Energy: From scale to system: navigating the next phase of China’s battery storage - https://ember-energy.org/latest-insights/from-scale-to-syste... - July 16th, 2026

China Battery Storage Use Surges After Policy Shift, Ember Energy Says - https://www.bloomberg.com/news/articles/2026-07-15/china-bat... | https://archive.today/QBXxV - July 15th, 2026

This particular brand of confrontational nuclear “advocacy” does not help nuclear. Please consider stopping it.

It isn’t really advocacy (there’s no argument for nuclear here, just a sort of distracting non-sequitur).

Stronger: This particular brand of rhetoric ("So you support X?" and little more, in response to a post that was not at all about X) is just a "gotcha" game rather than serious conversation, and doesn't belong on this site. I see it far too often, and not just on nuclear. (Also, it makes the one doing it look like a jerk, at least to me.)

So you support censorship?

Just kidding, I’ve seen it more and more as well, and feel the same as you about it.

I won't speak for him but I support consequences.

Behaving like that ought to get you shunned and persistence ought to get you marginalized the same way that overt racism or whatever would.

You get what you incentivize. And right now there's no incentive not to vomit dishonesty upon the public discourse so we've got a lot of idiots doing that.

Well, with me, it's getting to the point that it gets an almost automatic downvote.

In what world is simply asking if someone supports nuclear power confrontational?

It really is weird how many people are enthusiastic about stemming climate change but don't support one of the few non-intermittent sources for carbon free energy.

"Do you support nuclear power? I'm asking because I believe it's a requirement for grid stability/current battery solutions can't sustain demand during solar downtime"

That is a defensible question, that can be argued/countered, but it's not the question posed.

By simply asking "do you support nuclear power" is not? How is it less controversial to lead with an assertion that alternatives are not suitable?

"How do you know someone is pro nuclear?"

"Don't worry, they will tell you."

most pollution on my area is a steel refinery larger than my town :'). the air is less healthy than chainsmoking. we have heatpumps and electric everything. costs for civilization is super high, but these major main polluters just get billions given to them for cleaner systems which will never happen.

depending on where you live, its really hard to motivate to take part in generating less polition due to the involved costs and living costs already being too high

Indoor pollution --> open a window or two

One one hand you laud EV cars and on the other you say cars and automobility have killed 60-80 million people (nearly as many as communism).

However what you don't talk about is how much progress as been possible thanks to cars. Like researchers/scientists driving to work.

The switch to EV is happening: but things like packing as many people as possible in cities and preventing them from having a car and giving them authorization to go to the country-side once a year ain't happening any time soon.

We should be celebrating the switch to EVs and to safer cars instead of hating on individual transportation.

Now look how many capitalism killed

That’s part of it but I also think education, no caste system, efficient corruption etc. I sometimes watch those Indian manufacturing videos and it amazes me how much India is living in the past.

I live in a rich and socialist country. Guess who lives next to the highway...

> China has 350 million electric two-wheelers, 20 million EVs.

And yet they have the most coal plants, and the most coal plants under construction. This comparison includes India.

This is PM2.5 map of Beijing today: https://earth.nullschool.net/#2026/08/20/0200Z/particulates/...

This is London: https://earth.nullschool.net/#2026/08/20/0200Z/particulates/...

This is East USA: https://earth.nullschool.net/#2026/08/20/0200Z/particulates/...

They are not even close.

For the kicks, here is Delhi today: https://earth.nullschool.net/#2026/08/20/0200Z/particulates/...

Also lower than Beijing. (There's a hotspot to the west of Delhi due to wildfires.)

Those electric 2, 3 and 4 wheelers and electric busses even if powered by coal fired electricity, will do less damage to city dwelling kids lungs than traditional engines would.

And if the trend of China cleaning up their electricity supply continues (they just slipped under 50% coal) then even existing EVs will get cleaner every year with less pollution created at distant powerplants.

Pollution map don't lie... and what about kids who live near plants

Let's not compare Delhi or Mumbai in monsoon season. Get the readings from Delhi in summer or winter and then see the pollution yourself.

Meanwhile I was replying to a comment that just cherry-picked a day. Yes, autumn is the brief good time in Beijing due to prevailing winds, shrug.

Cherry picking a single day to try to demonstrate a widely accepted trend is lazy journalism.

Cherry-picking to try to portray the opposite of the generally accepted truth is much more problematic.

I agree. Some guy picks some specific a day in the past, says "look China good". Another one picks a random day (today) and it paints a diff picture. Meanwhile generally accepted truth rooted in facts is the number of coal plants and generally policies that put manufacturing first. individuals using EVs don't make a dent

Glad to hear Delhi solved its air pollution by doing nothing. Delhi's success stody is being studied by experts.

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

I didn't say Delhi solved pollution, I said Beijing didn't

Now compare the amount of renewables China is putting up?

They add coal power because it's super fast to build, but it's not a permanent solution.

Very few things built in china are designed to be permanent

Coal power is not a permanent solution, because there are only finite reserves of coal in China. At current rate of current rate of consumption (2,300 Mtoe of coal in 2025) they have still have reserves for 70 year.

https://chinadata.live/data/coal-consumption-china-vs-world/

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

We can look at more concrete promises by leadership of China:

"In a video statement to the UN in New York, President Xi Jinping said that China would reduce its greenhouse gas emissions across the economy by 7-10% by 2035, while "striving to do better"."

Too little, too late.

"Most scenarios to limit warming to 1.5C - or even well below 2C - would require China to make much greater cuts than that by 2035"

https://www.bbc.co.uk/news/articles/cj4y159190go

You are very optimistic. I see 35 years at current rate of extraction and if we assume 7% growth (like in 2022-2025, nothing crazy like a war) that would be just 17 years or so. At least this is what Google search overview tells me

It's convenient to say they will reduce reliance on coal if they forecast their coal reserves might run out in meantime:) But people here are persistent at praising PRC for their green achievements

> And yet they have the most coal plants, and the most coal plants under construction. This comparison includes India.

Well yeah, but not in Beijing

So what's the reason for those pm2.5 levels?

PM2.5 at 16 is pretty hard to believe.

China probably does lie about its pm 2.5 numbers, but it also seems objectively true that they (and really nearly everyone) are doing much, much better than New Dehli.

You can't trust any numbers China reports.

Anecdata I was living very close to a busy highway, and my young daughter was wheazing when she had a cold, we had to give her medicine via a nebulizer. When we moved out to the country more, far away from any major roads, these issues all disappeared within a couple months.

A friend of mine does research on air pollution from cars - the TL;DR is you should not live within a third of a mile of a highway. The falloff is pretty sharp, but you don't want to be in that zone.

Notably, most major cities have been building tons of housing (especially ‘affordable housing’) right next to highways, as it is the only areas that aren’t already built out with tons of high value houses.

Surprise surprise.

It's a dumping ground for poor people.

It’s not like they do it on purpose rubbing hands

Housing development happens at random?

Plus the US literally built highways in the middle of poor neighbourhoods.

Developers build apartments where they can make money from them, in other words where they can rent them for enough that they'll make back their investment. It's very expensive to build housing, so the only way to make the investment back and have low rental prices is to try to make the building costs as low as possible. A big part of those costs is the price of land.

What's even the point of this comment?

The parent and thread seemed to be arguing that low cost housing was intentionally built in places that disadvantaged the people who lived there.

Or, the only places to build houses with reasonable costs are in areas that weren’t already built out with very expensive houses.

Which will tend to be less desirable areas, by definition.

One approach, of course, would be to also make existing houses less expensive/desirable. Notably, wealthy people tend to have the resources to fight efforts to do that.

The other approach is to expand what land is available to build on. I understand that in the UK, farmers consider it a lottery win if they get planning permission for some of their farmland to become housing.

Despite what many in the UK think about it "being full", this is mostly an illusion from how cramped are the parts in which the houses are allowed to go; the country as a whole is mostly undeveloped.

(There are of course other considerations, with "why did you build on a flood plain?" being one of the failure modes in the UK).

Well, letting people build houses right next to freeways and/or on things like earthquake faults or flood plains is what is being done here. Which is, uh, also a problem. Since those people are now at much higher risk, eh?

Building on farmland has national security concerns (as countries are slowly realizing), as the country ends up dependent on foreign food imports after awhile. Can't grow food effectively when there is a subdivision there instead eh?

In most high demand areas (which are the ones everyone is complaining about, generally), all the decent land (or even just 'normal' land) is already developed.

Bonus - next time around, even the flood plain land might be 'too expensive' to develop on, and folks will only be able to afford houses at the dump, or in a swamp, or the like. Yay.

> or in a swamp

https://en.wikipedia.org/wiki/Ely%2C_Cambridgeshire

> The other approach is to expand what land is available to build on. I understand that in the UK, farmers consider it a lottery win if they get planning permission for some of their farmland to become housing.

I've seen that mentality in other parts of the world. The thing is that agricultural land is often protected because it is good agricultural land. It is literally the reason why the cities were built where they were built, since that land provided for the cities. Unfortunately, good agricultural land also tends to be easy to build on and we have a tendency to ignore features that may make it a poor decision to build on. (Such as the flood plains you mentioned.)

People don't build housing to intentionally disadvantage people but they do intentionally build housing for disadvantaged people

Woke activists love the word "systemic" for a reason.

If a bunch of good people acting in good faith produce a result an evil mastermind would want does it matter if they are good? On many levels obviously yes, on some practical levels the system and the incentives still need to change.

What about the vicinity of large or uphill streets inside a city? I am curious how the data compares with highways.

What about biking near a highway? E.g. in Chicago the lakeshore bike trail is next to a busy 8 lane highway

I remember I’ve read somewhere that jogging is actually net harmful for health in the city due the air pollution.

https://www.telegraph.co.uk/news/health/news/10817787/How-ch...

Generations of men have been taught that when walking with a woman on a pavement, they should always take the side closer to the road allowing her to keep further away from the traffic.

But Dr Iarla Kilbane-Dawe claimed that Londoners should avoid walking too near the kerb because on busy streets, air pollution can be up to a third higher than on the inside of the pavement.

So in effect, if you want to be the chivalrous man (which no one forces you to be) you still should choose the roadside side of the pavement.

Shame you cant remember the source. Ive long since wondered if its actually more deleterious for my health to cycle to work in London due to air quality. I came to the conclusion that youre damned if you do and damned if you dont in the end, as in London at least, many of the tube lines have particulates higher than is considered safe

Probably depends on the tube line; one of them, can't remember which now as I left the country in 2018, left me with black snot on each use. Cycling wasn't that bad, but neither were the other lines.

Add to the mix - indoor gyms are perfect for spreading respiratory viruses.

Which either kill you or make you stronger (marginally!). That is not the case of particles and corrosive gases.

Which sucks. I wish they'd seriously consider downsizing LSD or at least dedicating two of those lanes to transit only

Doesn't it depend on the mix of diesel/petrol/electric? In particular many cities ban or restrict diesel.

Tyre pollution is significant regardless of fuel source.

EV's have 100% reduction of NOx/tailpipe VOCs, 100% reduction in soot/tailpipe particulates, 70% reduction in brake pad dust (due to regenerative braking), in exchange for 25% increase in tire wear.

Vehicles are capped at emissions of 3mg/mile of particulates and 30mg/mile of VOC's. Something like 1-2mg of tire material actually becomes airborne PM10 particles every mile (and only about 10% of that for PM2.5 particles).

So, EV's really do a great job reducing emissions from 35mg/mile to <2mg/mile (PM10) or even <0.1mg/mile for PM2.5. A 95%-99.8% reduction in air pollution near highways would seem absolutely fantastic for me and my children!

https://pmc.ncbi.nlm.nih.gov/articles/PMC11636205/#:~:text=W...

  > EV's have 100% reduction of NOx/tailpipe VOCs, 100% reduction in soot/tailpipe particulates, 70% reduction in brake pad dust (due to regenerative braking), in exchange for 25% increase in tire wear.

I replaced the tires on my Tesla model 3 at 74,000 km and they still had tread above the indicator bars. I'm now at 140,000 km and the tires look great, the back ones look like they're only about halfway done. I might be an outlier but my previous Subaru needed tires every 50,000 to 60,000 km.

Needless to say, the brake pads have never been touched and when I saw the left front one at around 110,000 to 120,000 to patch that tire, it looked like it was just installed. The regen braking almost completely eliminated the brake pad or rotor as a wear item.

Yeah, aren’t the EV tyre’s compounded differently in some way to account for the extra weight?

If the weight on each wheel is greater I’d have assumed the tyre would need to be harder, for the same performance.

I would have assumed that would counter the otherwise additional wear, but I keep hearing EV tyre pollution is higher and yet everyone who owns one has always said they aren’t changing tyres an more than they did on their combustion cars.

Given that tires have a range of warranties from 40,000 miles to 80,000 miles ... it's possible that the tires are wearing 25% faster but the consumers aren't noticing because it's still around the normal 40k-80k mile range.

No matter the warranty - I still notice when I replace them.

And the warranty requires proof of periodic rotation. If the tires are wearing evenly, as is the likely case for a new vehicle, then rotation costs significantly more than the pro-rated rebate.

Until one has a battery thermal runaway event.

Or an entire truckload of batteries catches fire.

StasheD is an engineer and firefighter, quite eye opening.

https://youtu.be/diaUMNONpvw?si=7lxYS8iJHLvCTUkt

The odds of an EV catching fire are lower than for a gasoline vehicle.

And safer, less-flammable kinds of battery are in development. Less-flammable kinds of gasoline are not.

Is that an aged adjusted statistic?

Or is it comparing with the entire gasoline vehicle fleet?

Why ask things that you can easily look up?

Sea lions don't merely "look things up", they ask you to do it for them.

Oh, sorry, I thought we were having a conversation.

My mistake.

"A civil conversation about my statement" quite.

I'm not buying it and you shouldn't be selling it.

This is all very off-topic to the original discussion about reduction in air pollution.

Consider that every single human being on the planet carries around a lithium battery in their pocket, at a large percentage of those batteries have experienced such damage that would destroy the glass screen on those devices, and yet people are not bursting into flames regularly, and even the defective batteries that Samsung distributed for a while only made events extremely rare.

Lithium batteries are pretty safe in practice.

Safe enough to not be allowed on air freight.

Safe enough to not be allowed in checked baggage on commercial passenger aircraft.

Safe enough to kill e-bike riders, safe enough to kill people at home charging their e-bike / e-scooter / electric car.

Perfectly safe.

No trade offs, just safety.

All of those apply to gasoline

I want you to travel with half a gallon of gasoline (i.e. 2 litres of petrol) in your hold and/or hand luggage. See how that goes for you.

And yet, people travel with one or often more than one battery devices as a matter of utterly unremarkable routine.

One might similarly note the awe-inspiring destructive power demonstrated by tanker trucks of fuel catching fire and causing interstate bridges to collapse.

https://archive.ph/VadwU : Tanker Truck Fire Collapses Bay Area Overpass

https://archive.ph/4INYw : I-95 Overpass Collapses in Philadelphia After a Tanker Fire

Gasoline or diesel fires can be extinguished.

Lithium ion battery fires less so.

Surly you don’t mean to imply that a sufficiently large lithium ion battery fire couldn’t burn down a bridge?

You're speculating about something that hasn't happened, using something that doesn't exist; no body is driving batteries large enough to destroy a bridge about.

They are driving liquid fuel tankers that can do that around regularly.

Also consider that as battery tech improves new chemistries lower the risk of fire even more. E.g. sodium batteries are very stable right now and solid state will improve that further. There's no way you can make petrol less flammable.

You're going to have to face facts, battery powered vehicles are safer than petrol powered one.

Doctors used to prescribe a "change of air" in the 18-19th centuries. Maybe they still should.

Sanitariums

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

I guess the modern descendants are the health retreat, the rural airbnb, and the day spa that offers oxygen therapy.

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

I wanted to long for the time when people hated "Malaria" and wanted to move to "Beunos Aires". But they believed the arrows chase us at daytime and the plague engulf us at night, like in the Psalm.

Brother what are you even talking about

Since Eastern Europe is relatively poor and sensitive to energy prices a lot of households invested into insulation, new windows, etc. Last 20 years there was also a huge boom for heat recovery ventilation. Such a simple and inexpensive device that provides so much. Should be first item in every household to invest into.

Funny part is that locals here are absolutely scared of any sign of draft or direct aircon. All while it's what actually saves their health lol.

> Funny part is that locals here are absolutely scared of any sign of draft or direct aircon

I have always been and am still baffled by this. My whole family loses their minds if there is even a slight draft or AC, whether in the house or car. When my brother visits he incessantly closes car vents and windows. Parents constantly nag to put on warm clothes and avoid drafts etc., and when we inevitably get sick a few times a year mostly from school transmitted cold viruses they gloat about it.

Maybe it's a cultural thing from times without good heat/insulation where drafts meant an actual freezing house, which, yes that would actually have an impact on health.

I was in Sarajevo during COVID, I'm sure a reason the numbers were so bad there is from everyone being in enclosed spaces with no ventilation. Smoking without ventilation was bad enough, now add a virus on top of it.

As long as the country doesn’t involve large scale farms because the glyphosate sprayed on them causes serious issues.

Living very close to busy highways is known to generate poor air quality. I recommend anyone in those locations buy an air purifier for their kids' rooms.

I bought a couple reasonably priced HEPA purifiers and I change the filters on schedule. Replacement HEPA filters are very cheap.

Also watch out for things that we do indoors that can generate bad air quality. I had a friend who bought a VOC meter and noticed very high readings in his kid's room. He traced the source to his chemical and paint cabinet nearby, which he never considered because he couldn't smell anything. Throwing out a lot of the old containers dropped the measurements to the unmeasurable range.

It's a good start, but for VOCs and gases you'll need activated carbon. Those 2-in-1 filters do exist but cost more. And many are scams because they don't have enough volume of activated carbon.

Why would they cut corners? Activated carbon isn’t expensive.

But it does cost money and so… corners are cut

Because it’s not obvious to most customers that a corner’s been cut. Same reason most new construction in the US sucks.

You can safely put a washer and dryer on the upper floor of a house if you add a proper floor drain, but you’re unlikely to see anyone add a floor drain in new construction because buyers aren’t looking for it. Now multiply that by everything a buyer isn’t looking for and you’re talking real money.

> You can safely put a washer and dryer on the upper floor of a house if you add a proper floor drain

European here, we've always been placing washer/dryer stacks in our bathrooms without needing floor drains. We have machines with a system called Aquastop [1] that stop the water flow if the machine detects a leak inside the system.

[1] https://de.wikipedia.org/wiki/Aquastop

There’s a wide range of such designs due to the various different failure modes from false positives to the kinds of leaks resulting in 10’s of thousands in damages they are supposed to prevent.

In Denmark and I think Sweden it's a requirement that a washing machine is in a room with a floor drain.

Therefore the washing machine is usually in the bathroom, and the shower drain serves both purposes.

What brand of washer do you use so I can studiously avoid it?

If the seal between the washing machine and the water supply fails it doesn’t matter which brand you’re using.

They have improved over time, but you need to have a drain for the washing machine anyway so the cost is quite low vs the rather extreme damage a leak can cause.

You simply cannot put enough activated carbon in a little foam thing that goes in front of a filter to do anything useful.

The real activated carbon filters have 10s of pounds of carbon. The little black foam thing that comes with those 2-in-1 carbon filters is useless.

And manufacturers do a sneaky swap too, my Coway 150 which is a great air filter by the way, came with a nice thick grid of hexagonal cells each filled with carbon granules - that insert alone weighs like half a kg. I ordered official filter and carbon filter replacements off their website ....got a thin carbon "foam" that weighs maybe 50g instead.

If anyone wants to get serious about VOC filtering, these things have 7 pounds of carbon in them, they’re made for filtering the air of weed grow ops: https://terra-bloom.com/collections/carbon-filters

The clue is in your name

You have companies choosing the component that cost 10 cents instead of 15 cents even if the 10 cents component will break 10 times faster than the more expensive one.

Getting rid of the VOC source, if possible, is much easier than trying to filter it.

> Those 2-in-1 filters do exist but cost more. And many are scams because they don't have enough volume of activated carbon.

Any filter with a little bit of carbon added is going to be useless after a few days, or maybe even hours.

The only VOC filters that work have multiple pounds of carbon, with the good filters having upwards of 10-20 pounds. It also has to be replaced regularly.

I was referring to the gases from the cars on the highway more than easily removed indoor sources.

The pollution from highways is primarily particulate matter: Rubber from tires wearing down, brake pad dust, particles disturbed by fast vehicles and kicked into the air.

My common winix air purifier has a replaceable carbon filter.

Unless it has multiple pounds of carbon, it’s not doing much. These are for show.

Agreed, just buy air purifiers with HEPA filters and change them regularly. The main expense is buying one for every room, but it's one of those expenses you wish you had made sooner.

DHH is also a fan (pun not intended?): https://world.hey.com/dhh/air-purifiers-are-a-simple-answer-...

Might be better to upgrade your air handler if you're putting HEPA in every room.

Also he had the kid switch to smoking filtereds

If you’re so inclined, you can build your own air purifier with laser cut panels or 3d printed panels and use a cheap ikea air filter and standard PC fans. All the parts are readily available, and user repairable.

If you pair if with an Apollo AIR-1 you can have home assistant ramp up and down the fans with a PC fan controller based on live readings of PM2.5 in your home. I did this with the help of Claude code.

https://www.thingiverse.com/thing:6826527

https://makerworld.com/en/models/2470181-nukit-tempest-euro-...

I really wish the DIY folks would measure the airflow and sound levels on this sort of thing. CADR and decibels are going to vary wildly with fan choice

I came across this site which has pretty comprehensive data about PQ curves (the chart for determining CADR given filter impedance) at different noise and power levels: https://www.cybenetics.com/evaluations/fans/204/ (many other fans tested as well but I've been liking the value of P14 Pro PST)

However they look somewhat commercial and I'm not sure the funding/incentives so definitely corroborate with other sources.

DIY folks are not a commercial outfit with access to testing equipment.

Having said that, there are reviews of some DIY models reviewing CADR[1], and it's bizarre to complain about testing decibles since Arctic P14 fans, the most commonly recommended fans, are a thouroughly tested product. Running them at around 25% based on lower PM2.5 readings is almost inaudible from experience.

[1] https://www.youtube.com/watch?v=ZjGJN57DgA8

if you're going to IKEA for the filters you might as well buy the whole purifier. it's cheap and it works well

aye, it's ikea and is cheap. this seems like a "i had a ton of parts around + a 3d printer" sorta thing

Didn’t the Apollo 13 crew make an air scrubber out of duct tape and hope? Surely a cardboard box, a box fan and a hepa filter covered in tape gets you 90% there

This was done during COVID and made international news.

You are referring to a Corsi–Rosenthal Box. You are correct that they will get you 90% of the way there, but they also tend to be large, loud, and ugly. We can build better things now that we have time and resources.

Looks like a cool project, but the 99.97% HEPA filters are the expensive part. Building yourself only makes sense if you want to choose your own aesthetics or enjoy doing it.

It also makes sense if you're worried that a proprietary filter will be yanked off the market, leaving you with an unusable item. Also, for the money, you cannot get that kind of smart functionality from my research.

My $50 (without the HEPA filter) air purifier can detect particles and change fan speed accordingly. It also has a light sensor to go into really quiet mode during the night.

Though, looking it up it seems that prices for the Winix Zero (including one set of filters) have doubled since I last bought one.

HEPA filters are counterproductive in standard air purifiers. Air purifiers pump their cleaned air directly into the dirty air of the room. It doesn't matter if that cleaned air is extremely clean, because it's immediately mixed with dirty air. What actually matters is how much clean air you produce: the "clean air delivery rate" (CADR).

The more effective the filter the more it restricts airflow. If a filter is only 99% effective instead of 99.99% but allows double the airflow, it provides nearly double the CADR. To benefit from HEPA you need a clean side and dirty side, like in a clean-room setup.

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

Any air purifier should be able to cycle the air in a normal room often enough that it should be quite clean in a short time.

aye, like as long as you're not leaving the kids window open all night, or multiple other windows open nearby, it oughta fix itself soon enough

If the purifier can filter the air more quickly than air leaves the room it'll still reduce the amount of pollutants in the air. Most people aren't going to create a "clean side" and "dirty side" setup for filtering the air in a room.

I think that is what they're saying: the point is that if you're doing this, you don't want to optimize for the cleanest air leaving the filter, but more for throughput.

A reasonable compromise is achieved by an air purifier that has the outlet on top because it’s blowing the filtered air well away from the inlet side and generally circulates the air in the room.

I used to work in the cleanest room in the state, that wasn’t a lab, back when I lived in Adelaide, and top-inlet button-outlet in a raised floor data centre is how the air handling units in the main data hall worked, so you can simulate that to a certain extent.

> The more effective the filter the more it restricts airflow.

This isn’t the whole story. Surface area and flow rate are factors.

A residential home is aiming to improve air quality, rather than grow flawless silicon ingots etc.

What you wanna say is it might be more efficient with more CADR per minute with less filtration than less CADR an a higher filtration.

But a HEPA filter is better than no filter. Even if would be more effective with another.

(Also depends on size of hepa filter and room to clean. Large enough filter and small enough space and Hepa can clean all the air)

You don't need to seperate the clean and dirty air. Mixing them isn't as efficient but it should still be roughly 63% efficient (1-1/e).

The point isn’t that the HEPA filter won’t work under those conditions, it’s that if you can get away with not separating the clean and dirty air, you can achieve better filtration overall with a higher flow, lower resistance filter at a lower noise level. HEPA filters shine in use cases where you need single-pass filtration, like vacuum cleaner output filters or clean room air filters. If you don’t separate clean and dirty air, the filter will still work, but you aren’t taking advantage of its main distinguishing quality, which is its single-pass filtration performance.

If you get to recycle the air through the filter several times, MERV-13 offers much better performance tradeoffs for a residential air purifier because you can recycle the air through it much faster at acceptable noise levels. My home air purifier recycles the volume of my home every 15 minutes or so, vs HEPA filters which produce totally clean air, but since it just mixes with the dirty air that doesn’t matter as much as the rate at which it cleans air.

> If you get to recycle the air through the filter several times, MERV-13 offers much better performance tradeoffs

This level of filter goes in the central air system.

The HEPA purifiers are for scrubbing the finer particles.

And guess what 98% of consumer air filtering systems utilize a hepa filter. You’re really over optimizing a non problem. Unless you are constantly producing more contaminants than the system can keep up with it’s totally a fine solution.

If you only use 99% it means there are small particles you can't catch. Being faster is meaningless if you can never clean the air.

Air purifiers are designed to run 24/7 and all they do is catch particles. Eventually all the particles will be caught. The one I got also detects if there is a lot of particles and will spin faster accordingly.

>If you only use 99% it means there are small particles you can't catch.

Air filters don't work like sieves. The smallest particles are easier to block than the mid-sized particles. See:

https://en.wikipedia.org/wiki/Mechanical_filter_(respirator)

Clean Air Delivery Rate is often specified for specific pollutants. One is smoke, which is mostly small particles.

I am specifically talking about particles in the 0.3 to 1.0 micron range which according to the graph from your link are the most difficult to filter out. Can a 99% filter catch these? My understanding of this is that they cannot.

According to hepacart [1] 99% HEPA filters do not even exist, since HEPA seems to be clearly defined:

> HEPA filter definition, which requires a filtration efficiency of 99.97% for particles as small as 0.3 microns. "HEPA-type" filters may capture larger particles but are not effective against the finer particulates that true HEPA filters excel at removing.

[1] https://www.hepacart.com/blog/dont-be-fooled-by-hepa-filter-...

> It doesn't matter if that cleaned air is extremely clean, because it's immediately mixed with dirty air

What matters is the gradual removal of particles from the air.

The HEPA purifiers I have move enough air that everything gets scrubbed. It works.

My house has a separate central air system with a non-HEPA air filter with a decent MERV rating for the bulk filtering. The HEPA air purifiers do the scrubbing of finer particles.

Don’t overthink this. This looks like knowing just enough to be dangerous but missing the big picture.

Maybe overthink it a bit? I'm skeptical about the big picture.

You have an air purifier in your kid's room. If this is a fairly large apartment or a house, and you have central air running, how much purer is the air in that room? If your central air system is modern and continuously circulates air throughout the house at a low fan speed, you're effectively trying to purify your whole house with that low-output room-sized HEPA filter. Have you done measurements to see if it does anything?

(Not the person you replied to, but offering an anecdote)

There are ton of variables here. One is where the return air intake is. My house only has a single return air vent in the hallway on a 10' ceiling (the furnace is directly above that in the attic). I think this is not-uncommon in the western US.

I have a room-sized purifier in each room on the floor, and they accumulate considerable dust. What I don't know is how much of that would have been successfully pulled out into the hallway, if I didn't have the vacuum of the purifier.

This is impossible for me to A/B test meaningfully given all the environmental variables - wind (house isn't airtight, wind pushes into leaks harder), wind direction (wind from the desert brings sand and other small particles), humidity, etc.

If anyone has reading material on properly controlled experiments in this regard it'd be really interesting to see. I honestly don't know if they're more effective than disabling them and allowing the central HVAC a chance to pick it up sans airflow-tug-of-war. My hunch is it's not worse, though I have no expertise here.

Long-winded post but I'll close with an anecdote: when we had those wildfires in the Bay Area back during covid, they were absolutely more effective at getting the soot and smell out of all of our rooms than the status quo.

edit: One thing to be aware of if someone is evaluating these, all of the claimed numbers from manufacturers are based on you running the air purifier on the absolute highest speed it offers. Almost no one actually does this in on these consumer grade freestanding ones, especially in bedrooms, because they're quite loud.

I can buy a HEPA filter machine off the shelf. What I can't buy off the shelf is any other non-HEPA filter machine like you're describing. So while you might be right, there's no products readily available that meet the spec you're providing. We've got to work with what we have available and what time we're able to make for this stuff.

> What I can't buy off the shelf is any other non-HEPA filter machine like you're describing

In locations with central air handlers, the filter in that handler already serves this purpose. That’s how my house is set up: Central handler has a high throughout MERV filter. Several rooms have additional HEPA purifiers.

The parent comment also has a fallacious argument in assuming that the CADR is too low if a HEPA filter is present, but even the cheap HEPA purifiers I bought have sufficient CADR to cycle the room over and over.

If you’re in a location with no central air handler (only mini splits or no air conditioning at all) and you have a giant space to cover and you have a constant exchange of air from the outside to overwhelm your filtration (must leave windows open, for example) then what the commenter above would apply. You would be better with a higher throughput, lower rated filter.

For everyone else, it’s kind of a misplaced “well actually” take that has just enough information to feel truthy but misses the bigger facts.

My basic HEPA filter is keeping my (large) house at <= 1 ug/m^3 vs 17 outside for PM2.5

This reads as being overly confident and wrong. Optimizing for CADR is right but saying HEPA is counterproductive is simply wrong. We are not trying to filter out asbestos and consumer air purifiers are meant to mix the air. So long as over some acceptable period of time the air quality improves it’s a success.

The average person isn't going to have a clean-room setup and we're not looking for perfect here just marginally better when it comes to a bedroom.

If you put a standard sized air purifier with a HEPA filter in it into a room it will absolutely lower the dirty air of the room. Because over time you're lowering the particle count.

If I turn my air purifier on in my room even with the door open the air quality sensors improve their readings quite dramatically.

what a nice externality example "I recommend anyone in those locations buy an air purifier for their kids' rooms"

I drive the car, you buy the purifier.

What’s your suggestion? Just sit there and be angry that transportation exists?

You don’t think the parent commenter is also using transportation?

The pollution from transport also occurs with trains, buses, and any other vehicle that has wheels, brakes, or moves fast enough to stir up the air and kick particulates into the air.

People do what they can and control what’s within their reach.

So to give you other example. You live and nearby opens a chemical plant and starts smelling, so you just buy gas mask and hazmat suit or start complaining?

And yes other means of transport also does pollute, but amount is is critical here. You need much less public transport than you need individual cars.

I perfectly understand that there is no quick solution (only quick patch with air purifier) so thats why we should not normalise this and remember to complain (after buying air purifier)

I drive the car, you buy/rent cheap place because its shitty polluted noisy place, so compensate that with air purifier. There is no free lunch in healthy society, there are good reasons for rent for same amount of m2 do wildly differ across same city and its not just sunset views or distance to work

I got tired of that sort of argument when I realized that a great many of the people who argued that they have the right to tear down the side streets of walkable downtown neighbourhoods lived in unwalkable suburban neighbourhoods. Those unwalkable neighbourhoods were usually designed with a single access road to ensure there was no through traffic, so they would never have to deal with that problem. Then those same people had the audacity to ask everyone to pay for additional access roads when they realized that a single access road was a disaster when their neighbourhood needed emergency services and had to be evacuated (because it was burning to the ground). Of course, those additional access roads had to be designed to discourage through traffic.

Am I bitter about that? Yes. There is nothing wrong with wanting the best for you. There is something dearly wrong with using what's best for you to make life worse for others.

the purifier is $30 and low maintenance.

buying a new house will have $40k in reltor fees alone, $2k for movers, plus the, you know, hundreds of thousands for the new house. and what if I like my current house, it's in a busy hip area?

or should I launch a multi-year lobbying campaign in the city and/or state and/or national level to have roads moved?

Cant hurt to buy the filter and also lobby for safer transportation

My anecdote would be the revesre.

Living in the country gave me bad hay fever/asthma in the city much less asthma.

Same. I visit my family in London and my sleep improves because of no hay fever. Though then I get black boogers, horrible chalky hair, a renewed sense of misanthropy etc

You need a NMAID Non-Misanthropic Anti-Inflammatory Drug.

You discovered that you have an allergy.

Not exactly the same thing.

plus all available evidence suggests that allergies are getting worse due to changes in biodiversity.

the only plants that survive these days are the ones that spam a ton of pollen, so it gets selected for aggressively.

NO2 is a very hazardous air pollutant which doesn’t get a ton of attention. The main sources are combustion engines and gas stoves. Asthma looks to be mostly caused by gas stoves.

I’ve got a sensor that can detect no2 and it noticeably spikes when using gas. Switched to induction after that.

I’ve often wondered about this.

Does the area immediately above where the gas stove was have an exhaust fan that vents to atmosphere?

I would have assumed a properly specced exhaust fan would capture and remove combustion products from a gas stove?

I’ve never once been in a property that had an exhaust fan sufficient. I’ve had the exhaust on full blast and the spike on the air quality sensor on another floor of the house is rapid and massive.

I suspect a sufficient ventilation would require something more like a lab fume hood that can pull a negative pressure on the area around the stove.

And from what I have seen, a good number of exhaust fans are straight up fake and just ventilate back in to the room rather than ducted outside.

> And from what I have seen, a good number of exhaust fans are straight up fake and just ventilate back in to the room rather than ducted outside.

Culinary Cargo Cult.

There's a filter in it you're supposed to change regularly when they're in that configuration.

They contain a feels good filter to make you think something is happening. But to actually filter the pollution you'd need a activated carbon filter for the n02 and a hepa filter for the smoke. Which none of them contain and would clog rapidly.

It's massively easier to just not create the no2 by replacing gas with induction, and to vent the smoke outside rather than trying to trap it in a filter. I think the introduction of cheap consumer air quality sensors like from IKEA will start to make this problem a lot more visible to people.

Can you smell what's being cooked on the gas stove? If so, the combustion products from the stove are also reaching your nose.

That’s a good point, and obvious now you point it out.

On the other hand, when water turns into steam at standard atmospheric pressure, it expands in volume by about 1,700 times.

Whereas the gas in your stove is already a vapour, mostly methane, turning in to mostly water vapour and carbon dioxide. So the expansion ratio isn’t going to be anywhere near as high as that.

I’d say you’re still right.

Still, I wonder to what extent an exhaust fan does help.

If the exhaust fan can vent x cubic feet per minute and the room is y cubic feet in volume then it takes z minutes to full ventilate the room, etc etc.

Air molecules move randomly at over 300 meters per second (not coincidentally close to the speed of sound).

That’s a hyper local measurement, and temperature dependant.

You’d sure notice if the air in your kitchen was swooshing around at 671 miles per hour.

It squeezes me with approximately the weight of an elephant sitting on my chest. But humans are adapted to this and don't notice. It helps that the insides of my lungs are being squeezed outwards by the same force. Otherwise I surely couldn't breathe.

> It squeezes me with approximately the weight of an elephant sitting on my chest

Nope.

> It helps that the insides of my lungs are being squeezed outwards by the same force.

So you agree your first statement is incorrect. I’m glad we sorted that out.

>Asthma looks to be mostly caused by gas stoves.

Do you have a source for that? Because as far as I can see, asthma isn't _that_ less common in countries where gas stoves are barely used, such as germany. Still has like 60-70% of the asthma cases the US has. There's also a ton of other pollutants the US hasn't yet forbidden, but the EU has, which could also explain a lot of the difference in rates.

Don't get me wrong, it's certainly a good idea to get rid of gas stoves. I just think it's a bit much to declare them the primary cause of asthma.

Germany has a ton of NO2 for other reasons, for example diesel motors

> N02 is a very hazardous air pollutant which doesn’t get a ton of attention. The main sources are combustion engines and gas stoves. Asthma looks to be mostly caused by gas stoves

That makes sense but the unverified claim is that gas stoves are the main contributors to asthma.

This was in the news last month and might be referring to the same source

'Replacing gas stove can help asthmatics as much as some drugs, US experts find'

https://www.theguardian.com/environment/2026/jul/24/replacin...

I suffered a bit from NO2 living near Oxford Street which got mentions such as "London’s Oxford Street is world’s worst place for toxic NO2 pollutant" https://www.cityam.com/londons-oxford-street-worlds-worst-pl...

It's better now with more EVs and low pollution vehicles and the street should be pedestrianised from October.

I don't understand why we keep on building right next to highways which are some of the worst things for our health. You don't need to live in the countryside for that. Just stay roughly 1km away from them and the situation is significantly better.

There is evidence of a lot of ugly diseases caused by this, without even mentioning the constant 40+ dB background noise.

In London that is difficult – there is not a lot of space.

Plus the idea of having everything within a 15 minute walk including access to public transport.

highway != public transport

And pollution from bus or tram is much easier to control. Looking at you petrolheads who like to "Rolling coal"

Yes but in London you are never far from a highway you cannot get away from them.

In London now many if not most buses are electric.

Are we classing A-roads as "highways" now? If not, I have no idea what you mean when you say you're never far from a highway in London. There are no motorways through London.

Yes by the number of cars/lorries on them producing pollution.

Because the highways are built to the places where people and jobs are?

Once you build anything of significance, a highway gets built to it anyway.

A few things standout to me from the article.

1. London when the ULEZ was brought in was already a lot less polluted than historically.Are there gains from that? London was not that bad by global standards.

2. This was followed by the benefits of COVID lockdowns (not a phrase often used!) as pollution dropped much further.

3. Is this effect even across London? Suburbs vs centre, different types of housing etc.? I grew up a the edge of London and the difference in pollution was visible (i.e. you did not need instruments to see signs of it).

4. There was also a reduction in sales of diesel cars which had been heavily encouraged (because of lower CO₂ emissions) in previous decades.

5. As the articles notes, there have been a lot of other changes at roughly the same time. It only mentions one, but there have been significant lifestyle changes, so a lot of potential confounding variables.

Wouldn’t most of those effects also be in the control group too?

Much smaller place and starting from a better baseline so they would not have experienced the same changes.

1. Less than historically still has a quite high baseline compared to after ULEZ - if it was more polluted, presumably the change seen here would be more dramatic.

2. Definitely kickstarted it, but we're looking at taking that impact and continuing it for some 5 years after covid ended now.

3. You can look at the ULEZ map and it really covers everything but the outer tube line suburbs [1].

5. The control group in Luton, presumably, has the same lifestyle changes - it's not that far away (about 30 miles), so it is as close as you can get to a one to one comparison, not accounting for the fact that Luton is likely to be more deprived than London (especially in the council estates, which have horrible reputations).

[1] - https://tfl.gov.uk/ruc-cdn/static/cms/images/ulezdetailedmap...

1. yes, but there was probably a bigger gain before. Confirmation would be good.

2. does the study separate impact during lockdown from after?

3. my question is whether it had the same impact everywhere. I would guess very much not.

5. the impact of those changes might not be the same from a much better baseline, nor are lifestyle changes the same in a big city and a small town.

Particulate pollutant levels decay exponentially and have a substantial drop off with distance. So levels across a large area (like London) are not the whole story.

Yes, I am not claiming they are an alternative explanation by themselves, but an example of changes other than the ULEZ.

> strongest evidence yet that local clean air zones could help reduce some of the harm caused by pollution during childhood.

It's incredible this is even in debate. It's one of those intuitive things well known since the reduction of coal burning and smog during the industrial revolution in London?

The right (Conservative) and far right (Reform) parties both say they will abolish low-emission zones and other measures to reduce pointing traffic.

They made it into a culture war topic.

Bloody Sadiq Kahn and his militant sharia ulez improving the health of forriners. /s

You joke, but of course...

https://www.theguardian.com/politics/2023/aug/01/fake-tweets...

The right latches onto anything where a small minority are upset and amplify it. They are the ultimate rage baiters.

Somehow I don’t think that is the exclusive domain of the Right.

It is not, but all they have to offer.

Reform are latching on to anything to detract from the 5 million pound "gift" to Farage from a crypto billionaire, Christopher Harbourne..

Fact check, the conservatives want to block the expansion into outer London. Reform wants to end them all.

Ironic, considering it was Johnson that started it before Khan "took the flak"

Conservatives flipped on multiple of their policies after Reform's success on local election in 2025 and started to copy Reform UK. Even the Labour shifter right after 2025.

How's Reform UK Ltd. done since then? They've lost 2 by-elections and beaten a bin. Sterling job I guess if you listen to any of their members.

They dropped a few points in pools but for Conservatives they likely will be the main competitor - among Reform UK voters there are much more former Tory voters than former Labour voters.

They're polling at parity with the party in government...

https://www.pollcheck.co.uk/gb-polls

The amount of wailing about this was unbelievable. London is a terrible city for driving in in the first place, and the idea of 10% of them having to change cars provoked totally absurd responses.

We're going to see the same when EV-only mandates, true zero emissions zones, start appearing across the next decade.

It's madness but I hope abolishing ULEZ will have little impact at least for London - people who already drive modern cars will not start suddenly replacing them with older more polluting ones.

Reform is not a far right party. It is important not to polarise.

What is it, then?

Reform is a textbook far-right party, I'm not even sure why you'd try to argue otherwise.

Cultivating a voter base that consistently acts against their own interests seems to be a winning strategy.

Surely you're talking about all those people who voted the dirty heavy industry across the oceans where they can't even regulate them, as if we don't all share the same space rock.

>It's incredible this is even in debate.

Show you how people are out of touch with reality. Even something commonsensical like what you mentioned is often countered with - "Show me the data"

Using scientists being "stunned" should take the same amount of relevance as someone being "slammed" in article titles.

I'd like to imagine the stunned scientist is a scientist from another field, they show some medical findings to a guy who looks at snail butts all day and he's the one "stunned" by the findings

The scientist who used the word "stunned" is one of the study's authors.

Smokers don't magically undo the damage they did to their lungs after they stop smoking. Stunned might be hyperbole, but it is at least a little bit surprising.

"Stunned" isn't really a scientific term. It's the sort of editorializing you should expect to come from people who aren't the scientists themselves. More than hyperbole, it is classic click bait.

Also, quitting smoking definitely eases a number of symptoms, especially if you're not at the point of chronic emphysema. The reduction of inflammation triggers alone after a bit of time is fairly significant. Less coughing, less mucus buildup, etc.

But this isn't that at all. "Stunned" is used here because it's the word one of the study's authors actually used.

'"I was absolutely stunned when I first saw the results," Prof Chris Griffiths, a senior author on the study, at Queen Mary University of London, told the BBC.'

> “ Smokers don't magically undo the damage they did to their lungs after they stop smoking”

Except that they do undo the damage.

“ After 15 years, your chances of getting lung cancer are almost the same as someone who has never smoked.”

https://www.nhs.uk/conditions/lung-cancer/prevention/

4x the rate is "almost the same"???

https://www.verywellhealth.com/risk-of-lung-cancer-in-former...

The lifetime risk is approximately 1.3% for women and 1.8% for men. For regular smokers: 11.2% for women and 14.8% for men. So about 15 to 30 more likely to get lung cancer. Bringing that down to 4x is close to "almost the same".

Might be that I am not reading probabilities correctly, but how do 1.3% -> 11.2% and 1.8% -> 15% become "15 to 30 times more likely"? Sounds like less then ten times?

Good catch, wrote this on the go. The first stat is a study on Canadians, the second is from another source which is global.

No. But that only looks at heavy smokers and duration they stopped, so overselects for old age with higher cancer incidence.

This study looks more broadly, notably also at onset of smoking:

https://jamanetwork.com/journals/jamaoncology/fullarticle/27...

And this is the TL;DR:

“ Thus, those who quit smoking at ages 15 to 34, 35 to 44, 45 to 54, and 55 to 64 years avoided an estimated 100%, 89%, 78%, and 56% of the excess cancer mortality risk associated with continued smoking, respectively”

They absolutely do! Not all the way, but if you'd have smoked a pack a day for 15 years and then have given up for the last 15, there's absolutely no way you'd be saying this!

My Dad stopped smoking for 20 years and then died from long cancer.

Hey here is something for you to stun on:

https://old.reddit.com/r/OldSchoolCool/comments/1v73w9s/hydr...

It's a direct quote from one of the scientists:

'"I was absolutely stunned when I first saw the results," Prof Chris Griffiths, a senior author on the study, at Queen Mary University of London, told the BBC."'

The BBC should have put it in quotes in the headline; I kept the HN title faithful to the original article.

I agree. Though they did at least put it in quotes in the first sentence, which I hope doesn't indicate how far people are generally getting through an article before commenting on it on Hacker News.

I know, generally it is not a direct quote, hence "should."

Scientists are only allowed to be stunned when results exceed 5 sigma of deviation

Or when their papers are retracted for political reasons.

Sounds like an announcement of the latest AI news from Wes Roth. I'm surprised the Professor wasn't "shocked"

I'm obviously supportive of less pollution etc etc but looking at the actual graph results I wouldn't describe them as 'stunning', the needle barely moved. But of course, they have to have something to make headlines after spending so many million on the study and who knows how many billion on ulez. I'm not one of these anti ulez people I think it's good. But you can imagine the pressure to spin tepid results into headlines.

The entities with a ton of money tied up in the ULEZ are, perhaps with a layer or two of indirection, are likely the same ones funding this research, or if not this research then the guy across the hall in the same lab.

To be fair, BBC is aimed at the normies, not the scientifically literate. (No hate on BBC!) Stunned probably gets more clicks than surprised.

Yes, and I really don't care if they've got a direct quote from a scientist. Far too likely that word was coaxed out of the scientist by a reporter or PR hack. Or he thought he needed to use that word to get enough attention to keep his research funding. Or he was a relatively closed-minded scientist.

HN needs a 's/^scientists stunned by/Scientists notice/i' filter for Titles.

I've needed my inhaler way less since the ULEZ came in.

Visiting London used to mean blowing your nose to black snot for a week afterwards, these days living in London it's pretty good.

I've not lived in London for more than a decade. I always thought the black snot was from the Tube. Is it not?

It is, but not just from it.

I lived on Upper Street in Angel, London by some traffic lights and there was always a layer of black dust inside. I assumed it was brake particulate.

Every house inner London is covered in black soot from the days of coal fires. Have you ever seen one after it's been sandblasted?

Tire wear was probably a greater source than brake wear.

I've lived in London all my life and I only get black bogeys on days that I've been on the tube. Before COVID that was every day.

Yup, especially on the older lines (Northern, Victoria, Jubilee, Bakerloo). Particulate pollution can be two orders of magnitude higher than at street level. This tends to be glossed over when trumpeting the success of ULEZ measures pushing people away from cars and onto public transport, and I say that as a non-car-owner.

People tend to walk 10-15 mins at either end when taking the tube, and will walk more through the day. My understanding is this activity is net positive despite the extra particulates while on the tube. I might be misremembering this with a study I read on cycling in road pollution though

Almost certainly some asbestos dust still in there from prior decades as well, the tube is absolutely filthy and never cleaned properly

Indeed.

https://www.theguardian.com/uk-news/2026/jul/18/london-under...

Just one more reason to wear an N95 on the Tube.

Oh yeah "tube bogeys" are definitely a thing.

Whenever my best mate goes on about having access to "cultural experiences" that I don't have for living in the sticks I remind him it comes at the cost of massive tube bogeys. :P

Pretty sure that's due to the tube.

What's so uniquely bad about the tube in London? Poor ventilation and brake dust?

Its the oldest metro in the world. An achieviement, yes, but in old stations ventillation is crap, materials are poisonous, etc.

Yeah, seems way better now than it was in the 90s though. They’ve improved the ventilation a lot.

ULEZ massively reduced the amount of NO2, which is a trigger for asthma. It also seems to have reduced the hospital admissions for heart related emergencies.

Sources:

https://www.bbc.com/news/articles/c75q9d2pqyeo https://www.theguardian.com/environment/2026/jun/12/emergenc...

People don't fire their chimneys or have garden bonfires much any more, either.

Tell that to Germans. Winter air here is extremely bad.

Rising natural gas prices due to the Ukraine war also made even more people install fireplaces (as if that was cheaper).

More anecdata: I've been using my inhaler more since moving to a city with worse air quality than my previous location.

Anecdotal, but similar situation here for me (I don't need an inhaler, but visiting London around 2015 meant blowing my nose to black snot for a week, and then back in 2024 it was completely fine)!

There is a chap in London who does some great work with researching and spreading awareness of air pollution:

https://clara.southlondonscientific.com/

He also runs this repo:

https://github.com/southlondonscientific/aeolus

I'm not really sure the thing they were trying to measure was measurable with the study design and level of funding they had. To be fair, the paper is fairly clear on the limitations and much better than the press release.

The study is supposed to measure how clearing up pollution in London improved children's lung function. The decrease in London was meaningful — NO2 fell about 22%. But particulates fell faster in Luton and NO2 in London is still roughly double Luton's. The gap is larger than the decrease.

By 2022 both cohorts get the same results on blow tests. But how does this happen if we believe that the study's dose-response model is true?

Put another way, if the change in London NO2 is so crucial, how come it doesn't matter that the absolute value is still double Luton's?

Link to the original study below, free to access [0]. The key data appear to be this:

>At baseline, 184 (14%) of 1280 children with successful FEV1 measurement in London had a clinically low FEV1 (pre-bronchodilator FEV1 <80% of predicted value) compared with 126 (9%) of 1339 children in Luton (appendix p 8). At the end of the study, these values had dropped to 51 (9%) of 585 children in London and 41 (7%) of 606 children in Luton (appendix p 8).

So the proportion of children with low lung function dropped from 14% to 9% in London, and from 9% to 7% at the comparator site in Luton. It's not that much different, though any improvement is obviously welcome.

https://www.thelancet.com/journals/lanpub/article/PIIS2468-2...

completely anecdotal. my earliest childhood memories in india were of asthma, sinusitis and constant cold. this was consistent until i was 26 and since then I've moved to the US and lived in New York with 0 days of sinusitis or breathing trouble. and i fallback to trouble breathing when i go home again.

even New York is so much more better than Bangalore or my small village in the middle of coffee farms

Yes, pollution has both acute and chronic effects. What you describe here is an acute effect.

I just made a comment about having good air quality but with summer fires we were getting smoke for weeks at a time so I got an air purifier. My kid wasn't struggling horribly but I did notice right away after putting one in his room that he slept better and his breathing seemed so much more relaxed at night and it just felt like it made a noticeable improvement to me.

During my childhood, I lived across the street from a brewery. I suffered from chronic sinusitis for years, and no one understood the cause. When I moved to a different part of town, the problem immediately stopped. The same thing happened to one of my classmates who lived in the apartments next to me.

Bangalore has historically (over decades) been known to have a high incidence of asthma due to the high pollen in the air. It's been made worse in recent years due to pollution. The pollen is present for a significant portion of the year while other pollen regions in the world tend to have it for a smaller duration.

My anecdata: I have a Japanese friend who was born in 1964. She grew up in Yokohama for the first ten years. Japan didn't pass its first (serious) environmental protection law until 1967. She said many, many of her friends had asthma. Fast forward 50 years, very few children have asthma in Yokohama.

I will never forget watching this documentary about a Canadian man, Doug Rogers, who went to Japan in 1964 to train martial arts at a dojo. This YouTube video[1], watch it from 1:00 to 1:10. The air pollution is simply stunning. It shows you just how terrible the air pollution was in Tokyo in 1964. Today, it is night and day. The same is true for most large cities in highly industrialised nations.

[1] https://www.youtube.com/watch?v=CBFx1a4L2ig

I use air purifiers mounted on my windows, running continuously except in the deep summer and deep winter. This makes my air contain 50-100x fewer particulates than the outdoor air. In contrast, the best I can achieve with floor air purifiers as people have them is a 5-10x reduction. The window purifiers also keep excess CO2 and VOCs out.

> The window purifiers also keep excess CO2 and VOCs out.

I assume you mean that the increased air-exchange (purified or not) helps CO2 that originates inside the house to leave promptly? (Equalizing it with the outdoors.)

Literally "keeping CO2 out" is a much trickier and more-expensive proposition.

You are quite correct on both counts.

You have activated carbon to filter out the VOCs?

Yes, the filter absolutely has an activated carbon layer in it in addition to a HEPA layer. I understand that activated carbon doesn't last long. I have been changing the filter every two months.

Note that because this purifier is mounted at the window, it filters incoming air from outside, not the indoor VOCs that are already in the residence. The indoor VOCs will simply have to get exhausted from elsewhere due to the air pressure.

What I am suggesting is that my need for activated carbon is slightly less because I am rapidly pushing the VOCs out in the resulting exhaust.

Health improvements are not measurable any more if you go below 5 mcg/m2 average level of PM2.5 particulates. For 50x reduction to be beneficial, you need to live in an area where the pollution is 250 mcg/m2, which is an extreme level found only in a few unfortunate places on Earth. 5-10x reduction is reasonable almost everywhere.

I know precisely the subjective difference between a 5x reduction and a 50x reduction. Only the latter feels sufficiently good to me, and my brain operates better with it. You will know it when you experience it. Maybe it's my middle-aged brain that needs the extra support. I live in an urban area near traffic. Lately there intermittently also has been wildfire smoke coming down from Canada.

> Initial results showed children's lungs in London were smaller in capacity than those in Luton

Sure but they had to live in Luton

What is more amazing to me is I thought this wouldn't be localized. I thought we have on earth and one atmosphere but clearly not? Like the standard of living can wildly change if we change our own local area. We don't need people in Montreal or Paris to come up with a plan?

So unlike greenhouse gases, which can last in the atmosphere for years, seems like NO2 and particulates only stay in the air for less than a day or a few days. This is an amazing little fact because we can start small and call for meaningful reform where we live without requiring a global coordination. Maybe there will be a global consensus later but it doesn't matter because we can start making improvements today within our own local context. The bonus is we will likely also lower our own carbon footprint as we reduce our other emissions. I think this is the "selfish" breakthrough we need to convince people.

When I say it doesn't matter, I don't mean like cross border contamination does not happen but rather that we can improve our own lives with our own action regardless of what others do.

The obvious actionable thing that you can do for your own life is to stop using or being around gasoline or petrol powered two stroke engines such as in a leaf blower. But we can do more. We can completely ban these two stroke engines from being sold at all and that will bring meaningful improvements in weeks, not years.

The problem is to make more impact, we will need to actually get people to give up or retrofit their existing equipment. We will need to educate people about the harms that these things cause and why the change is good. However, in today's siloed world, I don't think it will be easy at all. So perhaps the most difficult part ironically in a very connected and yet siloed world is the marketing of this idea and connecting the required change in behavior with the benefits.

As we saw with the leaf blower example, the costs are concentrated, yes but so are the benefits! The benefits are NOT at all diffuse because guess who benefits the most from not inhaling in gasoline fumes? The person operating the leaf blower!

Most air pollution is pretty localized. CFCs and greenhouse gases are the biggest outliers for how global their effects are.

The localisation of it struck me when I read an Irish EPA report on traffic-related air pollution a few years ago that recommended carrying your child if you were walking regularly near heavy traffic. The air at 0.8m (their breathing height) has 5-15% more NOx in it than the air at 2m (the height they would breath at being carried by you).

I remember reading something similar about walking on the part of the pavement furthest from the road, because being an extra meter or so away makes a big difference

A quick note for my fellow US Americans -- A British speaker calling it 'pavement' is referring to what we call the sidewalk.

I live in British Columbia so we have fairly good air quality. But with the yearly fires lately summer air some years is poor. So one year with the fires smoking and air quality getting poor I got an air purifier for my kids room and the living room. It is only anecdotal but right away if felt like he had better sleeps. The smoke wasn't thick as it was from fires hundreds of miles away and it wasn't like any of us were hacking or coughing crazy but in hindsight I felt that my young son who would have been effected the most slept better and his breathing at night seemed quieter and easier.

How about chopping down all of the London Plane trees next? Absolutely disastrous for public health. They are also all over Barcelona and cause nothing but respiratory misery.

https://www.telegraph.co.uk/news/2026/05/04/scourge-of-londo...

Ugh, yes. They trigger my hay fever almost as soon as they start budding, a good month before pollen season kicks off properly.

What other effects would that have?

Newsflash, living in a healthy environment is healthy!

Pointless anti-intellectualism.

There is a big difference between believing something is true, and demonstrating it is true and measuring the effect. One is a vibe. The other can drive policy.

It's not pointless anti-intellectualism, it's pro-humanism.

History holds enough examples of intellectuals who out of absolute lack of any human compassion subjected fellow human beings to anti-humane conditions, hoping to find and push the limits of their bodies and psyches in order to maximize profits, ahem, sorry, optimize spending.

And those who you hope to be able to set "policies" on further cramming of people into the machine are either exactly those who profit off that, or eat crumbs from that table.

Yet there are always heart/right hemisphere dead morons who need precise numbers and conclusions written in blood instead of simply relying on common sense.

Found the government consultant!

It was news to me that the lung damage from pollution isn't necessarily permanent in children, if a change in environment happens early enough. Up until reading this, I was under the impression it would be.

We had a lot of construction work in the neighborhood, our house covered in fine dust particles each day. My kid got asthma in the same period, keeps asking when she can stop taking the medicines, and I say "I don't know" thinking "probably never". But maybe now the construction work is over, there is hope? (And if construction starts again, we know that it is better to move, because there is hope.)

Of course, but governments and corporations have consistently argued otherwise.

In the UK's far-right media culture, Khan's ULEZ is painted as fringe extremism, not as a common sense public health measure.

As a respiratory therapist in the US performing the same type of lung function and capacity tests this article speaks about, I find this research and journalism is so valuable to society! I have seen so many awlful situations with kids during poor air quality times. The lungs and respiratory track are exposed to the outside air. We simply are not designed to breathe particulate matter or emissions. Their lungs and alveoli are actively growing. Children breathe more rapidly than adults.When ultrafine particles and emissions bypass the upper airway defenses, they lodge deep in the lower respiratory tract, triggering acute inflammatory responses which can lead to deaths. I never want this to happen to anyones children. So many bad things in the world right now but seeing this made me smile today.

So punchline, probably a good idea to electrify all the cars yeah?

That doesn’t solve brake and tire particles. Although…rail might solve those?

https://www.emissionsanalytics.com/news/pollution-tyre-wear-... Rail, bike, even busses are better. Cars are uniquely bad transportation in urban environments

Do the numbers in that article make sense? 5.8g/km for tyre wear? Generally my tyres last maybe 25000 miles. So at that rate they would lose 230kg. Seems high.

They might be counting trucks?

"Non-exhaust emissions (NEE) are particles released into the air from brake wear, tyre wear, road surface wear and resuspension of road dust during on-road vehicle usage."

I guess they mean total non-exhaust particulates.

Tyre, no, but regen braking almost eliminates brake particles at the speeds I drive in London. But mostly I take the train. Unfortunately the highest I measured on my particulate sensor is not near the roads, but in the tube.

EVs use regenerative braking. So they hardly produce any brake particulates. And the tire particulates are heavy so they don't stay airborn for nearly as long. At low speeds, tires don't wear out as quickly.

Europe has quite a few cities where traffic is increasingly discouraged from going to the inner cities. Cities like Paris and London are much transformed from what they used to be and it shows in the health statistics.

It's not just the particulates but also nitrous oxides (nox) produced by combustion engines. Nox is correlated with lots of health issues. Take it away and you see lower rates of chronic lung issues, cancer, development issues with kids, etc.

But yes, tires are also an issue. But a fairly minor one to anything coming out of a combustion engine.

Mass transit indeed is nice in big cities. Removes the need for taking the car.

There is a generator at the end of my street in a shipping container sized metal box, it also has a mini office and loo, and is used by the construction workers digging holes in the road. It has company spiel written on the side, promoting the box's environmental credentials, including the punchline: 'Zero NOX when generator not in use'.

No shit Sherlock.

I look forward to the day coke is marketed as “zero fat!”

Why are you still looking?

During the 90s "Fat is evil" craze, all yogurt was replaced with "Fat free" yogurt that had 100 extra calories worth of sugar.

The yogurt aisle in the US is still primarily made up of this garbage product category which exists based on utter falsehoods pushed by the sugar industry. 30 years later and we are still constrained by what ignorant fad chasers in the 90s did.

Might instead refer to a start-stop / battery backup kind of system, where idling-but-on doesn't burn any fuel, but sudden loads can still be serviced.

> That doesn’t solve brake and tire particles.

Regen braking means significantly less brake dust, especially at city speeds and with blended braking.

> Although…rail might solve those?

Trains still have brakes. Some can regen brake but because they usually don’t have batteries they need the rail or overhead gantry to support inputs.

But on a passenger-mile basis, I expect an electric train produces essentially no particulates compared to a car, even a light rail on tyres. I do not however have numbers.

I believe at least subways tend to have lousy air:

https://engineering.nyu.edu/news/subway-air-pollution-dispro...

But I expect it's much better in open-air rail systems.

I was thinking open-air yes, tunnels do indeed have major issue. With pollutant concentrations, road tunnels are the same (https://www.sciencedirect.com/science/article/abs/pii/S13619...).

For all that I did not care for them originally this is probably something full-height platform screen doors help with, assuming the trains themselves are also filtered that would keep the pollutants clear of drivers and users, although it does not exactly resolve the question of managing their presence in the tunnels themselves (and track / tunnel maintenance personnel should probably already be wearing respirators if not full breathing apparatus), and I could see things get pretty dire in case of breakdowns.

Impossible to retrofit, of course, but what helps more are big tunnels. Modern ~9m diameter single tunnel systems are a lot better for this than old 3.5m diameter double tunnel systems.

The usual brake on a train that can't do regenerative breaking is a big grid of resistors to dump the energy as heat.

It's much less wear and tear than friction brakes.

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

And diesel hydraulic trains (and some buses) usually use these: https://en.wikipedia.org/wiki/Retarder_(mechanical_engineeri...

Probably a much better idea first to have a decent public transport and electric car support network throughout the country first.

We don't all live in the city.

And those of us who don’t can just plug in at home.

Except for the many many people who don't have off street parking.

Who lives in the country that doesn't have "off street parking"? I'm having trouble envisioning that.

I'm having trouble envisioning that.

Yeah that seems to be the general problem here. Electric car champions and city dwellers living in a bubble.

City dwellers are the ones that use public land to store their cars.

Of the three Villages I know well (my sisters, the one I lived in until moving to a larger 8000 person town, and the one with the primary school) I can’t think of any

Likewise the tiny hamlets I drove through on the way to school didn’t have people parking on the road, there’s simply no room. You occasionally get delivery vehicles stop and it causes chaos.

I'm thinking mostly of eg terraced streets in villages and towns. Similar to cities in that there tends to be a single space for parking on the street but multiple car owners per house on average.

Different to cities in that there isn't remotely the public transport infrastructure to support getting rid of cars, or the private facility to support electric overnight charging for the longer distance car-commuting etc that isn't generally needed if you live in cities.

Things are improving with technological advance but - again - not everybody can afford those advances and the latest models.

It's a completely different lifestyle living in those sorts of places in some respects.

We don’t even have streets. Think “dirt roads”.

So in rural areas there’s no parking for the street as that’s where the cars that drive are. You get pasig places and occasional some idiot will park in them briefly.

Even including your towns the vast majority of houses have off street parking, at least according the the rac

You have a very niche issue.

1) storing car on public land at home and office

2) driving excessively long mileage each day

3) having a small capacity car

This is a tiny number of people.

Not at all. You're quoting from a report based on data from a Net Zero campaign. But let's give it the benefit of the doubt and assume it's accurate, 60-70% having access to electric overnight.

That's still leaves millions (?) of households with on street parking.

Most commuters outside cities get on quite ok with normal cars - because they have to - and a third of them is hardly "niche".

It’s an RAC report, they are on the side of car owners.

You’re combining. My mother doesn’t have off street parking as she lives in a town. She’s one of the 30%

If she had a typical ev she’d have to charge it once a month.

You’re talking the 30% without off street parking and have high mileage (same needing more than one charge a week).

The average mpy is 7k, so let's say a weekly charge is more accurate.

You can probably get away with that in most cases with on-street parking with a mix of commercial chargers and work if you're lucky.

That "probably" is the point. Your average normal car user (especially in financially challenged times) fighting for a car space on their street is not motivated to take on that higher risk at higher cost in a less competitive market to keep the equivalent of HN demographics happy.

Very small number in the U.K. outside of big cities and towns. In England 65% have off-road parking outside of London, and most of that 35% will be in cities and towns.

I can’t think of a single house in my sisters village without parking. The village hall also has a carpark with two 7kW chargers.

100%, and not just due to no emissions / minimal break dust. The noise reduction is a massive dividend. I used to live in london 10+ years ago, and when I come back I’m stunned by the noise difference, it really is so much quieter especially in central london. EVs everywhere especially replacing the horribly noisy diesel black cabs and buses. Very noticeably different and much more pleasant, and improving all the time as EV adoption continues to accelerate, hooray

Absolutely.

It's annoying though that EV's need that extra Darth Vader on wheels sound to warn pedestrians, I'd prefer them to be as quiet as possible.

You can switch it off, or make it play one of several different ridiculous sounds.

On which vehicles can the humming in reverse gear be switched off? I understand the Tesla (my car) and the BYD (expires car) can not turn that off.

I find "expires" as a swypo for "exwife" somehow fitting.

A lot of jurisdictions have laws that say electric cars must emit thatbnoise while driving. Which is basically because you might not be able to hear them over the louder sound of gas cars. I hope that that requirement can go away if we get to near 100% electric.

That, and even better when coupled with good public transportation.

Noise reduction benefit is marginal. Most of the noise comes from tires rather than the engine. At 30 km/h tires are louder than the engine, so an EV driving at 50 km/h, which is the typical city speed limit, isn't any quieter than an ICE car.

Noise benefit isn’t marginal. Central London average speed is 7 to 10 mph (11 to 16 km/h) so engine noise is significant. There is lots of idling traffic: traffic lights, taxis at cab ranks, buses at bus stops, everyone in a jam - removal of idle noise is particularly significant.

Too bad the tire particulates likely get worse, both because EVs are heavy, and because they have more low-end torque and encourage driving that leads to more tire wear. I don't have sources but it's my educated guess from recent experience with a few EVs

But I'll take it if diesels and two-strokes will die in a fire

There’s a massive confound around vehicle size, too: EV buyers are less likely to get massive trucks and SUVs because that extra bulk drives cost up and range down, and when you’re comparing tire particulates the numbers will be more favorable for a EV sedan compared to an ICE SUV.

Electric vehicles are stills cars. But better than gasoline and especially diesel cars.

So yeah.

That said not clear to me about PM2.5 is I've never seen anything legit seeming that tries to characterize the harm based on the type/source. Though it seems agreed diesel is especially bad.

Yes, and...

In some areas of London the ULEZ has been so successful that the measured NOx is now coming mostly from gas boilers used for heating, probably mostly old large commerical units.

So shifting from gas boilers to heat pumps and from gas ovens and stoves to electric/indusction is also beneficial.

London's also been putting effort into improving safe bicycle routes lately. I visit London every few weeks and if I'm going somewhere in central, I'll often just grab one of the Santander hire bikes instead of the tube. Well, most of London (looking at you, Royal Borough of Kensington and Chelsea)

When I talk about health implications I often end up saying "but it's less bad than living next to a street" which statistically many things we spend time optimizing about are.

However most people live next to a busy street ...

The street isn't the problem. Cars and trucks are. If those streets were filled with people walking, cycling, etc., the health penalty of living next to one would vanish overnight.

Ok that's not what I consider a "busy street" but I get your point, need better wording there.

Why not? A lot of streets often seem busy simply due to the incredible space inefficiency of cars. What I like to do sometimes, when I wait at a traffic light with my bicycle, is to count the actual number of cars that cross during a phase. The amount feels large, but when you count, it's often not more than the amount of cyclists that cross in the next phase, and they take up just a tiny fraction of what cars need.

Sure it absolutely makes sense. But for me and my eyes 200 people passing by are somehow still less "busy" than 25 loud and stinky cars. That's what I mean with I need better wording

Generally, the busiest streets are pedestrianised; you just can't move that volume of people in cars.

(Actually, the _very_ busiest streets are probably major bus gates (where, again, there are no cars), those can have fairly ridiculous density at peak times.

A street full of EVs in a traffic jam is also pretty good. No exhaust pollution and low tire wear due to low speeds and low acceleration.

Sure, but it still has the 90% of issues caused by ICE cars.

EVs aren’t a panacea but they’re a lot better than a 10% improvement. You still have tires but losing engine particulates, fumes, noise, and heat is a huge win in a city - bike or walk near one and you can feel the difference.

The sad thing is... when the ULEZ went into effect, there were some wild conspiracy theories about it. Suddenly even my father was an expert and viewed it as sinister government intervention - all because of youtube crackpots. I couldn't get him to relate to my view that cleaner air must be a good thing.

I bet if some youtube weirdos pushed out videos against "big soap" for making us unnecessarily clean our hands after pooping... we'd have a growing following of angry "freedom from big soap" people.

> I bet if some youtube weirdos pushed out videos against "big soap" for making us unnecessarily clean our hands after pooping... we'd have a growing following of angry "freedom from big soap" people.

At one point during Covid, I tried (not very hard at all) to float a conspiracy that the vaccine was in fact not the poison, but the antidote. That Covid was deliberately designed by governments to filter the 'independent thinkers' (who won't take the vaccine) from the sheep (those who do take the vaccine). So by not taking the vaccine, you were giving the governments what they wanted.

This was because the conspiracy that governments were killing the loyal sheep with the vaccine, therefore only leaving the 'independent thinkers' behind, made absolutely no sense at all to me.

I grew up in a small town in the mountains in Norway. There is a children's "hospital" there (Geilomo Barnesykehus), where kids come to live because they can't live in the cities. Kids with severe asthma, eczema and some other conditions. It started as far back as the 1930s, still unfortunately a problem so kids have to come live there away from their families.

Better than having to go down a salt mine, I suppose

https://www.theguardian.com/world/2026/jul/29/respiratory-cl...

You can reasonably calculate the deaths caused by VW's diesel gate. We did that to ourselves.

https://energyandcleanair.org/publication/health-impacts-of-...

Opinion article on this by Sadiq Khan, the London mayor who introduced ULEZ:

https://www.theguardian.com/commentisfree/2026/aug/18/ulez-h...

In centuries gone past, members of the bourgeoisie would be directed by their doctors to summer homes and country estates so they could "convalesce in the countryside". It seems there was something to it, or at least there is now. (Even back then, it was explicitly about "fresh air".)

While having something done at Stanford's hospitals, at one point I was placed in a room with signs indicating it was on a heavily filtered ventilation system rated for COVID, etc. It was striking to be in an environment with air almost to clean room quality.

Seems electric cars produce the same or sometimes more non combustion particulates than ICE cars, eg. bits of road and tire that are flung into the air while driving.

So EVs are better than ICE for air quality, but fewer cars even better.

I think it’s mostly break dust. Electric cars are heavier but can also hopefully mostly use regenerative breaking instead of break pads. Road vibrations (and wear?) tend to go as the fourth power of weight over the axle and so it tends to be worse for (naturally heavier) electric cars but even worse for goods vehicles.

But london tube have order of magnitude of dust pollution and buses damage roads (aka pollute) 30,000 (yes 30k) times more due to weight.

How do you get 30k?

A new Routemaster double decker weighs 12.6 tonne and carries up to 80 passengers. A typical car weighs 1.6 tonne and carries up to 4 passengers, they both have two axles. If we guess at half the rated passenger count then we have:

  Bus damages the road (12.6/1.6)^4 = 3845 times as much as a single car.

But it carries 20 times as many people so the damage is only 192 times per person. Still a lot of course but other pollutants such as NOx are surely so much less that it can be justified.

I'm sure my calculation is imprecise but surely not that far out. What have I missed or misunderstood?

You forgot the passengers. Gross weight of electric double decker is 19.2 tones. (19.2/1.6)^4=20,736.

Which also means roads for heavy transport is 20k times more expensive!

Surely the relevant metric is danger per passenger so your 20 k needs to be divided by the number of passengers, that takes your 20k down to 20k/80 = 250.

I think that particle size is important.

Particles caused by tyre and brake wear are going to be much larger than, say, diesel particulates.

That size differences is going to affect how easily they can be absorbed into your lungs.

https://archive.ph/YpyHu

https://archive.is/YpyHu

I've been meaning to do some data mining on how much PM2.5 differs with even a few hundred feet of elevation. I have a theory that even around Silicon Valley, living even up a little bit in the foothills would have you breathing massively cleaner air most of your life vs living in the pits of the valley. I see it all the time when I'm out there for recreation or just driving, the smoggy haze all over that just sits in the valley and the Bay. It's probably not too tough of a data processing challenge to compare the stats on Purple Air AQI sensors in reasonably close geo proximity vs elevation to get some statistically-significant data on this.

Who knew that populating Earth with mechanical horses that shit into the air is not such a great idea.

This is a reminder that getting an air purifier with high airflow filters (NOT HEPA!) is lifechanging in cities with high pollution levels.

I recommend getting one of these https://www.youtube.com/watch?v=sQGfO4hNb60 and just slapping a MERV 12 to 16 filter on it, you can get a whole roll off aliexpress for cheap and replace them monthly if you wanted to and it would be cheaper than 1 hepa filter replacement. They can also filter vastly more air, while you can keep hepa for 6 to 12 months MERV will filter a lot more air.

Amazing what a non-toxic environment can do for your health. Who'd have thought?

Any advice on in and outdoor detectors os small particles for home use?

Isn't this common sense? What is being "stunned" !!

If you click the link at the top you'll find it goes to an article. The article will often expand upon the text in the link!!!

In this case:

"While we would expect children's lungs to grow year on year, our results indicate that the London children's lung growth had accelerated during the four years to 'catch up' with the control group in Luton to reach similar levels of lung capacity," researchers say.

"I was absolutely stunned when I first saw the results," Prof Chris Griffiths, a senior author on the study, at Queen Mary University of London, told the BBC.

"The speed of catch up in lung capacity in the London group was surprising and impressive."

- Fuck diesel cars

[0]: https://www.zh.ch/content/dam/zhweb/bilder-dokumente/themen/...

"High diesel-family averages were approximately 1–3 g NOx/km. Most gasoline-family averages clustered around approximately 0.02–0.15 g/km."

[1]: https://publications.tno.nl/publication/34635198/KxBBl3/TNO-...

"TNO tested in-use vehicles directly at the tailpipe. Three diesels with DPFs emitted: 3.9–5.3 million particles/cm³ at warm low idle. The same report measured warm Euro 5 direct-injection gasoline cars without gasoline particulate filters at: 50,000–60,000 particles/cm³ at low idle."

[2]: https://d-nb.info/137495313X/34

"In 2017, the highest diesel was approximately 12 g black carbon/kg fuel, versus roughly 0.4 g/kg for the highest gasoline car. In 2023, the highest diesel was roughly 8 g/kg, versus approximately 0.7 g/kg gasoline."

[3]: https://trueinitiative.org/insights/true-brussels-emissions-...

"approximately 5% of measured Euro 5b/Euro 6 diesel vehicles exceeded one million particles/cm³, and this small group produced more than 90% of the particle emissions from the tested diesel group"

- Fuck two stroke engines even more

"Levels in the raw 2S scooter exhaust were as high as 300,000 μg m−3 or 146 p.p.m.(v) from idling. The EU annual mean limit for the protection of human health is 5 μg m−3 (ref. 13), while the US National Institute for Occupational Safety and Health recommends that workers wear special breathing equipment when exposed to benzene at levels exceeding 1 p.p.m. for 15 min. Waiting in traffic behind a 2S scooter, for example, at junctions and while the scooter is idling, may therefore be highly deleterious to health." [0]: http://dx.doi.org/10.1038/ncomms4749

But cities are full of shitty mopeds and old Vespas, for no benefit but cultural cosplay reasons.

the framing of this headline - "scientists stunned" while conveying pollution hurts lung recovery is a gem

Europe should hurry up adopting ULEZ in every dense urban area. It's completely worth it in terms of health, neurological development, noise and quality of life, and has practically no downsides but "boohoo" from those who make everything into a culture war. A good start would be to immediately ban all two-stroke mopeds aka "super polluters" (emitting 50x as much PM2.5 as a truck), and then follow up with Diesel trucks and delivery vehicles.

It's ridiculous that we voluntarily emit fossil fuel and oil fumes in our densest urban areas.

s/stunned/pleased/

Rtfa. "Stunned" is the actual word the scientist used.

This would seem to be an issue MAHA would want to engage on. But they instead seem to be focused on issues for which there's no evidence or even substantial negative evidence like vaccines. What a wasted opportunity to actually improve public health.

cease all travel and live to 88

And yet we’ve still got people cutting down the enforcement cameras with angle grinders at night

Shame they're not doing it to Flock cameras.

Scientists stunned healthy living is healthy?

Pointless anti-intellectualism.

There is a big difference between believing something is true, and demonstrating it is true and measuring the effect. One is a vibe. The other can drive policy.

Kind of, but there’s a lot of ‘water is wet’ studies, and this falls firmly in the ‘why the hell are you surprised by this?!’ category.

Short-term gains are likely to produce long-term negative effects.

Hormesis and natural selection have been driving factor of evolution for a long time.

What is this, eugenics from first principles?

Better than dysgenics for sure.

Asthma is so common that this is not only easy to test, but has been. That's what the article was about.

Anyway, by your own line of thinking, wouldn't sensitive lungs be an advantage? The incentive to find cleaner air is also breaking away from the pack. Since humans are social creatures, that's more likely to look like new leadership for followers who have their own reasons to break away.

Every civilization in history has started out that way. It takes more than mere brute force to beat the competition. Survival is just as much about picking your battles and working smarter.

Are you suggesting that it would be advantageous for humanity to evolve to live in London circa 2000?

Larry Niven played with this in one of his stories; a time traveller from the far (and highly polluted) future has to use mechanical breathing assistance, because the levels of CO2 in the air in the past weren't high enough to prompt the breathing response properly (human breathing is controlled largely by blood CO2 levels).

Anything you can do externally will tend to evolve out. That's why humans can't make their own Vitamin C and half of them need glasses. Keeping a trait in the population does require keeping up the selective prrssure, which is eugenics.

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