Big Ass Fan’s Clean Air System | Hacker News Reader

Big Ass Fan’s Clean Air System

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118 pointsjosephpmay102 comments

Can someone please point me to actual studies validating the "ion" generation stuff? My dad insists that a wearable ion generator he bought works "because it's made by NASA" (it's not) but I can't find studies that validate the technology. Thanks in advance!

Veratasium dug into it in quite a bit of depth. TL;DR: It doesn't do much (if any good). Worth watching, regardless.

https://youtu.be/ZQ--scjcAZ4

That's not actually what Veritasium found. What they found is evidence that there aren't health benefits to the ions themselves, and there are potential harms from the ozone pollution that many of those generators create.

But for air filtration, properly working negative ion generators certainly cause particles to leave the air: https://www.youtube.com/watch?v=y7QFJgTjzcc

The thing is, that means they end up on surfaces near the ion generator. That isn't necessarily a good thing. Proper HEPA filters are more likely to be what you want, as they remove particles entirely, putting them in a filter that can be disposed of.

That's a really good video, although it seems to focus on the health benefits of direct ion exposure. I like how he methodically breaks down the claims and the purported science behind them. I would like to know more about the claimed Covid-related ion effects.

Ionizers work through two mechanisms: 1. Charged particles stick together, forming larger clumps that eventually drop out of the air. 2. Charged particles can build up on the surface of airborne pathogens, sometimes directly disrupting membranes or lipid layers, and if there is enough of a buildup they can induce an electric current through the organism that can kill / inactivate it. One study on bipolar ionization showed antiviral efficiencies were 64.3, 89.1, and 97.4% with exposure times of 15, 30, and 45 min, respectively (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7094352/).

The advantage to ion generation based air purification systems is that they are able to actively operate in occupied spaces, not relying on air to get pumped out of a return duct and through a filter or UV system.

It's not possible for them to achieve an instantaneous elimination of airborne pathogens, but any significant percentage reduction can help to lower the total viral load that people in the room are being exposed to.

That being said, it's unlikely that what he's wearing around his neck will generate a sufficient quantity of ions to make much of a difference. It wouldn't be enough to fill the room, and the amount of time any such ions would have to act on a particle that comes close to him really isn't enough to have a large impact.

I genuinely don't understand how this is supposed to work in a real-world environment. Let's say someone near a fan is infected with Covid and sneezes. The airflow from the fan would then immediately push covid-containing particles around the space and closer to other people than if there were no airflow at all. Is it really possible that their magic "ion" particles would counteract this negative aspect? I'm extremely skeptical.

It seems like a much better solution would be to point the fan outside and have actual air filtration systems at inlets to the space.

It doesn't "work". The fact that it made it to the front page of HN bodes badly for this community that has been going down hill for a long time. It just one step above a text based Reddit at this point.

Part of the reason I submitted it was because I was skeptical, and I thought HN would have interesting takes on how effective it might be.

At the same time, I think your non-constructive cynicism is the worst of HN, did your comment really add anything to the discussion.

Big Ass Fans is a pretty reputable company, so assuming out the gate that it has to be a scam doesn’t seem like a great approach

A german Max Planck institute is working on a DIY system for schools that will get rid of 90% of aerosols. It costs less than 200€ to build out of easily available parts.

German link: https://www.mpic.de/4770837/eine-lueftungsanlage-fuer-schule...

It's an exhaust fan with temporary tubing made of thin plastic.

The question with that system is: where is the replacement air coming from? To be effective for disease particle controls, it needs to come from outside, otherwise you'd just be sucking dirty air from the rest of the building into the classroom - or even worse: backdrafting CO2 and CO from any combustion appliances within the building envelope.

You can achieve a clean air supply by opening another window in the classroom, but then you also let hot or cold air into the classroom (depending on the season), making the heating/cooling systems work even harder.

The answer to this is to run the exhaust/intake air channels through a heat recovery ventilator (HRV), which transfers energy from the hotter to colder airstream, while also introducing fresh air back to the space.

Also: How do you make that system work in the winter?

A heat recovery ventilator works fine in the winter. Its whole purpose is to introduce fresh air into the conditioned space while preheating it with the heat in the dirty exhaust air stream.

HRVs have been designed to exchange heat, and ERVs to exchange heat and moisture, but have either specifically been designed not to exchange virus particles? One wouldn't want to make any assumptions...

At least with heat recovery ventilators, the air streams do not mix at all. Unless the virus finds a way to penetrate the metal fins of the heat exchanger, it should be completely fine.

There are several different designs, some there is a mix of streams.

Most are sadly not particularly efficient overall, but still much better than leaving a window open.

Is it really an HRV if the air streams mix? [1] The primary function of an HRV is ventilation. Any air stream mixing would nullify that objective.

1. https://www.greenbuildingadvisor.com/article/misconceptions-...

There are a few different types. One type blows air out "across rocks" to warm them up, and then reverses the fan pulling air in "across the same rocks" I simplified a lot in the above, but the idea should be clear - there is some mixing of streams in this style.

Is there a reason you can’t just recirculate through a HEPA filter? They capture viruses AFAIK. Seems easier than recovering exhaust heat and refilling from outside.

No reason at all. That's basically how most existing air purifiers work, they're a big fan attached to a HEPA filter.

Is that a UV-C bulb just exposed to the site above the fan?

That doesn't seem safe.

Depends on human level exposure. Probably fine as these are mounted on the ceiling.

Seems like they just reflect all the UV from the bulb up and are counting on the ceiling not reflecting a harmful amount. With the right ceiling material that could actually be a pretty good idea.

I wonder how one can test if the amount of UV light reflected from the surface is dangerous? Alternatively, determine what is the percentage of the UV light absorbed?

There are low cost armlets that change color when exposed to UV (they're supposed to tell you when you should get out of the sun). I imagine they would also work for UV-C.

Bananas work well for that according to BigClive:

https://www.youtube.com/watch?v=7lzq6LuVWH0

> With the right ceiling material

There's still a 'sunburn' on the linoleum floor in the basement pantry after I cleared some EPROMs with a germicidal fish-tank tube light. The kind that you can swap in place of a short (24"?) fluorescent tube.

You can really see where the EPROMs were :)

I have a wicking humidifier that uses a UV lightbulb to kill some germs on the way from the water tank to the wicking fan. Inside the machine, near the UV light, the dark gray plastic is now fully white.

Below the fan wouldn't be safe. UVC doesn't reflect very well off many surfaces, and it's absorbed in air, so not much light is likely to reach the human room occupants.

Can someone explain how a garden-varity HEPA filter duct-taped to a boxed fan is not a complete solution to airborne COVID droplet air filtration?

This device cleans up a medium size room from forest-fire smoke in 15 minutes and scrubs it squeaky-clean in a few hours (as measured with a laser particulate counter).

Not fast enough. The threat is not being exposed to droplets hours after someone with COVID was in the room, the threat is them expelling COVID particles at your face because to are right next to them.

HEPA filters are a good idea, but they can be in short supply and they need to be replaced on a regular basis.

Box fans are not good for attaching filters too because they are not designed to deal with static pressure from a filter. The gaps between the blades and the case mean if you put much/any obstacle in the way, it will just recirculate unfiltered air.

Here is information on their Ion cleaning system, which interestingly is ozone free (unlike many typical home ionizing air filters). If just ion generation is enough to reduce viral load so effectively, then that is a big boost to reducing indoor transmission rates (effectively reducing R0), and would be comparatively cost effective next to HEPA filtering large spaces (think: a Costco warehouse).

———

ION TECHNOLOGY

MORE IONS, MORE DISINFECTION

Clean Air System’s certified ozone-free ionizers generate tens of thousands of ions per second, safely eliminating airborne and surface pathogens and resulting in fresher, cleaner conditions. The ionizers’ precise integration allows for maximum ion production and delivery throughout your space.

DISTRIBUTED BY AIRFLOW

Our fans’ airflow amplifies not only the number of ions that are generated but also their effective coverage areas. Aside from disinfecting air and surfaces, our fans’ airflow improves occupant comfort, HVAC efficiency, and energy savings, providing real benefits for business owners.

KILL VIRUSES WHERE PEOPLE BREATHE

An ion’s lifetime is only about 30 seconds, so it’s essential that ions be delivered to the air your people breathe and the surfaces that they touch. Rather than concealing ionizers within ductwork, Big Ass Fans integrates ionizers into our fans to distribute ions directly to your people.

why is ozone free important?

Ozone is toxic. Great at high altitude for reducing UV transmission, not so good on the surface.

ETA: Negative ion generation, done badly, can result in ozone production.

Ozone is a pretty damaging chemical. It is very reactive with its extra oxygen atom. It can damage living and non-living things, although in small quantities it probably isn't an issue. Ozone is great at high altitudes where it can block some UV light.

And I would add that - seemingly - to reduce the amount of bacteria a very high concentration is needed for long periods.

I found this "experiment"[1], this is about cleaning/disinfecting a room, by starting an ozone generator in a closed room, keep the ozone level at a certain value for a given time, then switch off the generator and wait at least one hour before re-entering the room:

https://www.ozonetech.com/sites/default/files2/pdf/Ozone_dis...

BTW such a high concentration is likely to affect contents of the room, ozone can accelerate oxydation of most metals and rubber.

[1] it looks like a scientific paper, but it is not AFAIK published and actually comes from the site of a firm making ozone generators, so I would take results about the effectiveness with a pinch of salt, but I don't see how the dangers implied can have been overstated

Here is the EPA’s explanation https://www.epa.gov/indoor-air-quality-iaq/what-are-ionizers...

Would "Ion Technology" mean electrostatic disinfection?

It seems to be UV.

Seems separate from their UV systems, but they're very vague on it: https://www.bigassfans.com/faq/whats-an-ion/

Based on the standards they have approval for, yes, it's electrostatic disinfection:

https://standardscatalog.ul.com/ProductDetail.aspx?productId...

I'll be interested to see the advertising associated with its Q4 2020 Australian release [1]. Anything sold in Australia that makes a claim relating to COVID-19 is counted as a Therapeutic Good and must be approved by Australia's TGA (which involves evidence base studies).

[1] https://www.bigassfans.com/faq/can-i-order-big-ass-fans-clea...

[2] https://www.tga.gov.au/media-release/warning-about-products-... when the release

I’m kind of surprised that the people who make those pods at offices haven’t gotten into this.

Heat inactivation is shown to be effective at getting rid of sars-cov-2. Those little pod things could have a cleaning cycle where they heat up to 65C (~150F) for 15-30 minutes.

Add a UV-C light during the cleanse cycle, and you’ve probably got most things. If I were a wework, I would be building these as a place for people to work out of home.

The other thing you can do is put fans that suck air upwards, and then eject it outside, and replace the air inside with (clean) outside air.

You could build larger units for places like restaurants, where they can fit 4-6 people.

Part of me finds the idea of a “private dining pod” kind of nice — but real estate prices have never made it reasonable for restaurants to do.

> Those little pod things could have a cleaning cycle where they heat up to 65C (~150F) for 15-30 minutes.

can i stay inside of it and make it 180 at least (ready to sell my soul for 200), please :) 8 months without sauna, god, have mercy...

Ion generators are known health hazards. If you create enough ions to purify the air, the ions themselves create unsafe amounts of ozone: https://www.epa.gov/indoor-air-quality-iaq/what-are-ionizers...

Unconfined UV-C generators are skin cancer machines, and also damage paint, etc.

I hope use of the UV-C thing is rapidly banned (if it hasn’t been already...)

Per the EPA link, the ion generator is already illegal unless they’ve turned it down so far that it doesn’t work.

With all the technology we are making and retro-fitting into offices I'm curious what the long-term effects will be for health and productivity. Will mortality from flu be substantially lower next year?

It already is. People are: A) Wearing masks in public and more avoidant of contact with others. B) Getting Flu vaccine much more popular. It has sold out in the country. and C) Lot of people in the risk groups(where largest share of flu mortality comes from), are already dead from COVID.

If this works, it seems like a short-term substitute for retrofitting buildings with proper fresh air ventilation systems.

Big ass prices.

nice gimmick. Take regular fan, attach ionizer and UV lamp and sell for $1K+ as virus killing solution during the time when gullible are running around scared of the virus.

A HEPA filter should work pretty well too

How do you "kill" a virus??

How is this not an ad?

I was the one who submitted this to HN.

It is an ad in that I linked to the marketing site. It’s not an ad in that I have no association with the company, and I just thought HN would find it interesting.

We’ve got a beautiful newish library in downtown Austin, and they use Big Ass Fans in a number of the outdoor spaces, balconies, patios, etc., including the enclosed balcony in the children’s wing, with the brand name clearly legible on the fans. While it’s not something that bothers me, I do always wonder whether and how often they get complaints from parents about the word “ass” being there for children to potentially read.

The fans themselves seem to be well designed and beautiful in a stark kind of way.

> , I do always wonder whether and how often they get complaints from parents about the word “ass” being there for children to potentially read.

Clearly it's a double entendre, but the company's logo is an ass, as in the animal.

The logo is an ass of an ass.

And a big one at that. Triple entendre!

They make versions that have the logo without the name for cases where the name's a deal-breaker.

Big Ass is based in my hometown, and I've had a few friends who've worked there. They absolutely get a lot of complaints about the name and actively taunt people who are offended by it [1] Apparently they do have models without the logo that can get used in churches and schools, though.

[1]https://www.kentucky.com/news/business/article44375274.html

White-label BAFs?

The first time my mom flew out of LEX, she saw the "big ass fan" in the airport terminal and was so thrilled with the name and how she felt the fan working she bought one for her patio.

I've heard that they're a really good company to work for in LEX (between them and RJ Corman; some of the best non-technology places to work in central KY).

I always point it out to people when I go to IKEA, as they use them, and it makes me chuckle. I wondered about that myself...

I used to work there. They absolutely get complaints, but they have a really good sense of humor about it https://youtu.be/01WBxkweki8

Fwiw, I think you can get them without the logo

Some schools use their fans, and they don't have the "ass" part, all you have to do is request without the label (although last I checked the logo is visible, but small, at least it's less explicit)

This smells of magic unicorn shit to me.

Anything but. They’ve got validated 3rd party studies. Plus they’re a real Hardware product company with a long history of quality product. Not some Silicon Valley “ai magic virus eater”.

Yes aware of that.

I am mostly concerned about its applicability in places where it'd make a difference compared to other infection controls. Typically when someone comes along with magical unicorn shit, regardless of if it works or not, it's either as a measure to avoid other more inconvenient controls or isn't completely applicable to the scenario it is being applied to.

The 3rd party studies are quite unimpressive and lack basic elements of rigor like a control. They don't seem to show anything except that fans mix the air.

Those 3rd party studies seem like a pretty big joke

>"The test unit was installed in the center of the test chamber with a blade height of 93” from the floor. The test chamber measured 10' x 10' x 10' (3m x 3m x 3m) and a microbial suspension was aspirated into the chamber. Air samples were taken from the test chamber once the unit was turned on, and then at client specified intervals (0, 5, 10, 15, 20, 30, 45, 60, 90 and 120 minutes) over a period of 2 hours and then plated. "

https://www.bigassfans.com/docs/clean-air/104380072COL-010-i...

A small, sealed chamber were particulates were sprayed into the air once? Test that thing in a restaurant or a hair salon with a dozen people continuously interacting in it and then test the quality of the air

> Test that thing in a restaurant or a hair salon with a dozen people continuously interacting in it and then test the quality of the air

That's not how scientific studies work.

Of course not, scientific studies create artificial conditions so we can claim that overpriced fans are a magic cure for a virus. They should hire these people at Volkswagen, they'd make great emission testers and splendid scientists

So, do you have a point, or are you just waving around BS hoping something will stick?

That test procedure sounds similar to the standard test for CADR (ANSI/AHAM AC-1-2015), which uses a 1008 square foot test chamber and measures the ability of an air purifier to deliver clean air.

CADR is the product of air flow and fractional removal efficiency, and it's the industry standard value if you want to compare performance of one air purifier to another. The CADR test usually makes separate measurements for dust, pollen, and smoke (particulates). It looks like they adapted the normal test procedure to measure the reduction in live/viable microbes.

However, in a few minutes of looking at their homepage I don't see anywhere they list a number in CFM of purified air, which is what CADR measures.

https://cfpub.epa.gov/si/si_public_file_download.cfm?p_downl... [Appendix A]

If a company is making claims like this, the FDA should review that companies validation of the claims. Yes, I suppose fans' air-quality claims falls in some crack where it's not a food, drug, or medical device. But if you market your device to mitigate germs responsible for a pandemic, it should really fall under the domain of an appropriate agency.

The FDA was created to fight bogus miracle cures and tainted food.

> they’re a real Hardware product company with a long history of quality product. Not some Silicon Valley “ai magic virus eater”.

shrug then they shouldn't mind filing a 510k [1].

[1] https://www.fda.gov/medical-devices/device-approvals-denials...

The ionry is a normal Big Ass Fan is probably exactly what we need.

A big thing that moves air.

But people are to stupid to know that. The media (including HN) is too broken to deliver people simple messages.

So people can only listen to complex messages they don't fully understand, so it needs all the extra fluff to sell.

Yes, the same as surgical theatres and semiconductor labs have positive air pressure. So I'd rather see an objective comparison of:

1. big ass fan on its own. 2. big ass fan with UV gubbins. 3. No fan 4. Someone else's fan

Circulating air is what got 20 or so people infected with covid because someone decided to sit in front of a ventilator at a cafe South Korea. The staff, all of whom wore masks didn't get infected.

https://www.straitstimes.com/asia/east-asia/covid-19-outbrea...

Your link is the medias factoid about mask wearing. And this is the problem, no one is explaining first principals to you.

You are probably thinking of this factoid in China about air conditioners and this diagram, which is not what we are talking about at all. (The evidence is downward air is what you want)

https://www.businessinsider.com.au/how-restaurant-air-condit...

Fan blows to the ground and separates air from infectious constituents which stick to the ground like a ball of mud. Got it.

Although that is kinda close, I'd stop concentrating on the oga booga marketing you've picked up, like things sticking, and try and learn the science. Plenty of YouTube videos and HN articles have discussed it.

Get back to first principals.

I'm glad we agree.

Ionizer--probably unicorn shit.

The UV-C one? Probably real--and note it's the one labeled as "Verified by third parties". Moving air at some reasonable rate past a strong UV-C source really will sterilize it against a lot of stuff.

But isn't that boring old tech which is easily replicated in a DIY project, or copied by competitors? What makes it special?

Isn't a big ass fan just boring old tech which is easily replicated ...?

Just because something is easily replicated doesn't mean I want to spend the time doing it.

And, as a side note, I suspect you underestimate the engineering behind those fans. Making a large fan which doesn't vibrate or make annoying noise is non-trivial.

Ok, I agree, but a similar thing can be said about vacuum cleaners, coffeemakers, washing machines, ... you get the point.

Indeed, and there seems to be plenty of competition in those markets for quieter, more reliable vacuums and washers anyway. I'm not seeing how that changes the point though, unless I'm missing something.

Airborne transmission of COVID is sexy, requiring solutions like this, and individual impositions like wearing masks which are easy to police.

But I think the more likely spread of COVID is from mundane surface transmissions. One of the 'mystery' COVID cases in New Zealand was eventually tracked to people touching the same elevator button about an hour apart, for example.

Same here in Europe - everyone is wearing masks, but how many times is the apartment entrance handle touched by people each day?

Stairs, or press buttons with tip of key. Entrance Door with foot or paper tissues. If 1 in 200 have Covid, 50% chance elevator has been recently infected.

First it was the bats and the pangolins who gave it to the people. Then we gave it to the minks who gave it back to us, mutated. Now even the elevators can catch covid?! What's next? I sure hope it doesn't mutate and hop to vegetables or else we won't be able to eat anything!

Scientific research has not found much evidence for transmission by touch, known in the literature as fomite transmission:

"The principal mode by which people are infected with SARS-CoV-2 (the virus that causes COVID-19) is through exposure to respiratory droplets carrying infectious virus."

-https://www.thelancet.com/journals/laninf/article/PIIS1473-3...

You see this in the guidance by major health organizations. For instance the WHO clearly says:

"Current evidence suggests that the main way the virus spreads is by respiratory droplets among people who are in close contact with each other."

It probably can happen. But contact tracing hasn't found much evidence for it: the majority of infections can be explained by close contact from an infected person.

Re: masks, surgical masks and cloth mask far from 100% effective against small particles, with filtering efficiencies of 50% or less common though the fabric. Filtration is even less when you take into account air that bypasses the mask (the reason why your glasses fog up is because of air that isn't being filtered).

Also, very large numbers of people use them incorrectly, eg by leaving the nose uncovered, and leaving gaps. I don't think this is a matter of education: people know what correct wear is, and don't do it because it's much easier to breath if you defeat the mask's filtration.

Most people aren't wearing masks around family and friends anyway.

yes, masks are not a panacea and are highly politicized. we need to stop focusing on them, and focus on (semi-)private social gatherings of friends and strangers (high heterogeneous mixing coefficients) where most of the community transmission is happening, rather than wearing masks on the street (or even in grocery stores) where transmission risks are practically non-existent but compliance is conspicuous (but ineffective).

Relevant XKCD:

https://xkcd.com/37/

expertsexchange

While there's an XKCD for every occasion, it's been a while since I got to use this one: https://xkcd.com/37/

Does it also clean induatrial pollutants most people smear throughout their spaces?

Slightly off topic; I've been reading about putting dispersal disinfectants like Tea Tree Oil [1] into ventilation shafts so they spread around the building.

Works similar to O3, but is safe around people. I'm wondering what sort of concentrations these dispersals need to be to actually make a difference.

[1] https://www.pathology.uwa.edu.au/research/microbiology/tea-t...

As someone who is strongly irritated by (and perhaps allergic to—I've not been tested) tea tree oil, please do not do this.

your link mentions nothing about ventilation. vodka is also a good disinfectant, but you wouldn't want to necessarily aerosolize it and vent it through a building.

Here's a link for a case study on an oil rig. However, the illness was thought to be fungi-related, not viruses.

[1] https://www.germxit.com/wp-content/uploads/2015/06/CSOilRigC...

> vodka is also a good disinfectant, but you wouldn't want to necessarily aerosolize it and vent it through a building.

That pretty much describes both my job and leisure lifestyle in my 20s, and I’m still above ground two decades later.

As an anecdote on HN that’s irrefutable gospel.

Essential oils in concentrations that are germicidal are definitely not safe around people for prolonged exposure.

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