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Grad Student Rigs Cheap Alternative To $1,000 Air Purifiers In Smoggy China
An anonymous reader writes "University of Virginia grad student Thomas Talhelm was living in Beijing on a Fulbright Scholarship during the winter of 2012-13, when air pollution was so bad scientists likened it to a nuclear winter. Those who could afford it were resorting to an expensive solution: air filters costing up to $1,000. Talhem built his own on the cheap, getting comparable particulate count results, and has started a company that both markets the product to middle class Chinese and shows others how to DIY."
Make sure everybody knows who created this idea.
Otherwise, as with all governments, the Chinese government will just commandeer production and distribution, and take all the credit for bettering the world.
How is anybody supposed to make money like that? Won't someone think of the shareholders?
But, seriously, that's pretty awesome and surprisingly simple.
Lost at C:>. Found at C.
He got similar results to a $1000 product, and told everybody how to do it.
That is newsworthy.
I suspect there are a lot of people in places with a lot of air pollution who would really like to have this.
Kudos to this guy.
Lost at C:>. Found at C.
Wouldn't it be simpler to strap the air filter to the smokestacks where the pollution is emitted? Nah, that'd never work.
He strapped a filter to a fan and managed to filter air... slow news day?
Agreed. Effective at reducing particle count, but not at removing harmful chemicals from the air. Still, much better than nothing.
It would be cheaper for everyone to just fix the pollution problem by putting heavy restrictions on emissions. Seriously, $1000 dollar air purifiers to remove the debris put in the air to save $0.05 on scrubbers is stupidity of the highest order. In a lot of cases the scrubbers are already on the factories because Chinese law requires them, just doesn't require that they be in operation. In about a year China could dramatically reduce this pollution to western world levels with simple installing or activating scrubbers on smoke stacks.
This continues to show China is a pay for play game, in that you are well connected enough in the communist party and laws and environmental rules just don't apply and it doesn't matter if it kills the little people.
Maybe China should try reducing the pollution at the source
Well, he went as far as confirming he was getting the same particle counts.
He's not saying "I just invented something revolutionary", he's just sticking it to the people selling over prices kit.
And in my book, that gets applause.
Lost at C:>. Found at C.
It's odd that people needed instructions on how to tape a filter to a fan?
How very un-American! He could have sold it for 800 bucks, and instead he hands it out for free!
He's been living in Commieland for too long!
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
As you say, none of them had the idea. In a country of 1.4 billion people.
A great many things seem obvious with 20/20 hindsight.
Hermes Conrad: I order you to dispose of that toxic waste properly, or bribe me. Either way, it'll cost you $500.
Bender: 500 real dollars? That's an outrage! Professor, I can take care of that waste for only $499 and one hundred cents.
Prof. Hubert J. Farnsworth: Hmm, I know that's a rip, but I'll pay for the convenience.
An enigma, wrapped in a riddle, shrouded in bacon and cheese
In China? Not really. If you're being conditioned that following the rules is good while thinking for yourself is bad and can even get you in trouble, you eventually end up with a mindset like that.
But don't worry, they're already exporting that success model. We're getting there. And, frankly, when I look around me, how people pay for "services" that hardly qualify as a service because they're too closed minded to even fathom how they could do it themselves for free and at little if any expense and effort, I dare say we're already there.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
He managed to attach a square filter to a round duct; that's NASA-level ingenuity right there.
How can I believe you when you tell me what I don't want to hear?
Well, there was a market for a $1000 product ... apparently nobody else thought of it.
Yes, this is the low-tech solution, but if it works just as well as the expensive one ... it's a damned fine solution.
How have you made the world a better place this week?
Lost at C:>. Found at C.
Probably could combine a HEPA filter with a charcoal filter to get both particles and volatile chemicals.
Like this:
http://www.instructables.com/i...
Or:
http://www.amazon.com/Rabbit-A...
Lots more here:
http://www.grainger.com/catego...
I don't read your sig. Why are you reading mine?
File under 'M' for 'Manic ranting'
Oftentimes, life gets in the way.
There are two types of people in the world: Those who crave closure
What un-American??? Seems like he took a leaf out of Benjamin Franklin's book. When Mr. Franklin discovered a more efficient wood burning stove he didn't patent it for the purpose of making sure it would be widely accepted. His design is still being used.
I'm sure people knew how to do that. What they didn't know was that by doing that they could match the results of a $1000 solution. They're no doubt thinking "It can't be that simple, there must be a trick to it". So they sell a pre-made unit at low cost.
So Franklin was against the American way of life too?
Won't somebody please think of the Founding Fathers?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
It's because he is a grad student, be nice to the mentally challenged. grad students are people too.
Do not look at laser with remaining good eye.
Comparable particle counts HOW? right up against the filter? What about over time? Zero details except you MUST go to his workshop for $33 to find out... Fishy...
I have a rock that keeps tigers away, My most recent tiger count shows zero so it's as good as a $10,000 tiger cage.
Need real data, full information on how the test was done and for how long. Anything else is made up BS or misinformation.
Do not look at laser with remaining good eye.
He got similar results to a $1000 product, and told everybody how to do it.
I think the problem we have here comes from the comparison to a $1000 product as little more than a red herring.
He strapped a (replacement) HEPA cartridge - A well-proven technology for removing particulates from the air - To a fan. He basically made a "ghetto" HEPA filter. I have little reason to doubt it would work.
I would, however, question how well that $1000 filter performs compared to a sub-$50 Holmes/LG/Honeywell/etc filter. If Talhelm managed to get the same performance from just a replacement filter for one of those strapped to a fan, I would expect "not at all" as the answer.
So we should certainly credit him for his real "discovery" here - That expensive consumer-targetted air filters don't do any better than the Wallyworld special. Anything beyond that amounts to marketing for his new company manufacturing something even crappier than those Wallyworld specials.
If you take a look at his site, it has all the data, comparisons with commercial purifiers, timeframes, and all the other details you are saying are missing. http://smartairfilters.com/index.html#data
It's not like they provide NO information. You can check out their website for FREE and see that the reduction test was done in a fixed size room over fixed time and plots the particulates over time. http://smartairfilters.com/ind.... I won't kid you, it's marketing material, but their graphs are totally better than the ones I've seen on your Tiger-Rock. They also mentioned in TFA that the $33 is for parts costs. Probably just another trick from these shysters.
A lot of ideas are obvious once somebody announces what the idea actually is. Honestly, I think that people who would criticize the inventor simply because of the idea's apparent simplicity or obviousness are being rather snobbish, if you ask me.
But hey.... some might find it comforting to think that such values, which might otherwise seem outdated in today's word, are still alive and thriving in our society.
File under 'M' for 'Manic ranting'
He's using the same rated filer and pushing air through it, so it would be expected to have the same count.
Also, the info is on his site.
The Kruger Dunning explains most post on
"That expensive consumer-targetted air filters don't do any better than the Wallyworld special. "
It's not the filter, it's the mechanism for pushing air through it that doesn't matter. Same rate of flow through the same filter produce nearly the same results.
A crap filter will still have crap results.
I don't shop and wally world, so I won't comment on their specific filter.
The Kruger Dunning explains most post on
"Not with a fan that size. and I highly doubt that a HEPA filter and a fan works. you need significant air pressure behind the fan to get any real filtering volume."
That sentence makes no sense.
IT's literally nonsense.
Are you unfamiliar with fans? HEPA filters?
Did you spend 1000 dollar on an air filter and are now angry you were a fool to do so?
Have you ever taken apart an air purifier? those fans aren't exactly the most powerful thing on the planet.
The Kruger Dunning explains most post on
I've already done the same thing. I had an air purifier where the proprietary filter was dirty and clogged. I couldn't find a replacement, so I just used a 3M Filtrete furnace filter trimmed to size. I suppose if you have central air on all the time, just having a good furnace filter would suffice.
A lot of ideas are obvious once somebody announces what the idea actually is.
In this case it's just plain obvious. Try doing a google image search for air filter fan.
Just guessing now, but maybe he is talking about basic skills everyone should have like, simple plumbing, carpentry, cooking, gardening etc.
http://www.acetonestudio.com
LOL ... Well, carry on then.
Lost at C:>. Found at C.
Yet, nobody else thought of selling it for cheaper to Chinese countries. Heh.
I don't care if I'm wrong. I only care about everyone obtaining something from the discussion.
...and that's precisely what the "overly expensive" Phillips filter does, that he compares himself to.
-=Lothsahn=-
So duct tape it to the back of the fan instead.
If he's never seen one before, it's ingenious. I've seen one (years ago) so it seems obvious to me. *shrug*
That you know how it works doesn't change the fact that you didn't actually implement it as a solution for China's air pollution before he did.
File under 'M' for 'Manic ranting'
If it was so obvious to you, then why didn't you suggest it before he did?
File under 'M' for 'Manic ranting'
Box Fan + Filter. Posted 6 years ago
Box Fan + Filter. Posted 3 years ago from a university
Not sure if these are the same thing. If it is, then it's sad this knowledge isn't more common place to help people out.
That you know how it works doesn't change the fact that you didn't actually implement it as a solution for China's air pollution before he did.
Of course I didn't. I don't live in China. I live in a country that enforces air purity laws. It's a blindingly obvious solution to a problem I don't have.
Go on AliExpress, there are loads of cheap air purifiers with HEPA filters. TFA says "up to $1000", and actually even high end Japanese models are usually much less than that. Chinese manufacturers sell many models that are basically the same as what this guy invented - a HEPA filter strapped to a fan - for $30-40.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Holy shit, quick somebody do a new Slashdot article with AC's idea!
Get free satoshi (Bitcoin) and Dogecoins
Why pay for sexual services? I got two fully functional hands right here!
Get free satoshi (Bitcoin) and Dogecoins
Oh stop being a paranoid dipshit. HEPA filters are well understood, aren't made by this guy, and have been being tested by hospitals for fourty years.
"OMFG he claims a hepa filter does what hepa filters do??!!?!? WHY SHOULD WE BELIEVE IT"
Because it's pretty obviously a sensible claim. Duh. Go to Target, spend the $20 it would take to try it yourself, and please grow up a little bit.
I mean seriously, what kind of person thinks putting an air filter in front of a fan doesn't actually filter air? Seriously.
StoneCypher is Full of BS
Curiously enough, my home air purifier consists of an HEPA filter strapped in front of a fan. In a box.
Are you sure about that? Other than this one article what makes you think that all or most Chinese citizens with air filtering fans were paying $1000 for them?
... that way we can pretend nothing is really happening. And the industry to make the filters? Produces pollution to do so... A cycle of foolishness.
Traditionally, having someone else do stuff for you was an indicator of how wealthy you were.
All very well to have the manor, but without a proper set of servants, where are you?
Shine one's own shoes and show up at the Opera with bootblack on one's hands? How terribly low-class!
because I was unaware that the going rate for filter units in China was $1000, and therefore didn't realize that there was a problem that this was a solution for.
Probably because he doesn't live in China.
This is China we're talking about, with 1.3 billion people. I'm sure that people have already strapped filters onto fans, this one guy just happens to be getting some feel-good-DIY publicity because he's marketing his product. Kudos to him because it seems like a good thing that he's doing this, but I would be amazed if this is actually considered novel in China.
The first thing that came to mind was "Won't eddy currents bypass the filter and reduce its effectiveness?
Then I saw the pictures.
They cheated and used fans with flat/concave shrouds. Most of the cheap chinese fans around here are more lens-shaped (convex).
Just one? Ok: Cell phone ring tones.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
Once it was a hallmark of wealth to be fat. Today, it's kinda the opposite. Times change.
And while letting a professional handle a job you could only do worse may be a wise decision, I happen to have met a lot of "professionals" who only meet the "I do it for money" definition thereof...
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
I've been doing this for years when I paint in my garage ... I'm not saying I'm brilliant but not everyone thinks of things as being this easy so some people need to be told.
I was refilling the refrigerant in my truck A/C with Propane last night... My neighbor came out with an "ummm, what are you doing?" look...
Newsflash: pressure differential is pressure differential. The filter can't tell whether you're pushing from one side or pulling from the other.
Which is my point.
Somebody had to think of the idea first... cut the guy some slack.
File under 'M' for 'Manic ranting'
Go to Amazon and look for HEAP air fliters for home use. You will find models from $50 to $250.
Yeah, A LOT of people have had this idea and brought products to market.
"He straps a filter on to a fan and this is noteworthy? Ok then."
Wait until the shit hits the fan, and you'll be glad it had a filter.
Well, he went as far as confirming he was getting the same particle counts.
He confirmed that the homemade filter reduced particle counts. But I don't see that he compared its effectiveness to filters costing "up to $1000".
http://particlecounting.tumblr...
Compares Blue Air 203/270E (3,600 RMB) and a Philips AC4072 (3, 000 RMB) to both of his setups. Those are only about $550 filters, but I think that is sufficient to cover the "up to" in "up to $1000". If you want to donate a $1000 one to him, it looks like he'd be happy to test it.
I don't know much about HEPA filters, but you, Sir, have just sold me on your tiger repellent rock. Where can I order one?
Yes, I'm sure nobody in all of China already has an inexpensive HEPA air purifier.
There are 0x40000000 types of people: those who understand 32-bit IEEE 754 floating point, and those who don't.
A lot of ideas are obvious once somebody announces what the idea actually is. Honestly, I think that people who would criticize the inventor simply because of the idea's apparent simplicity or obviousness are being rather snobbish, if you ask me.
But hey.... some might find it comforting to think that such values, which might otherwise seem outdated in today's word, are still alive and thriving in our society.
Reminds me of a conversation I had with my boss the other day.
Boss: Why did it take 2 days to write about 100 lines of code? That should have taken an hour or so.
Me: The same reason it took you 3 months to write a 10 page grant proposal and not the 30 minutes I could retype it in.
Yes, I'm sure nobody in all of China already has an inexpensive HEPA air purifier.
I'm sure someone in China does have an inexpensive HEPA air purifier. I am not sure what your US Google search has to do with what people have in China though.
Name one of the services you're talking about. Any single one.
Cooking. Someone who puts a little effort into feeding themselves can make a good dinner for a family in ten minutes but instead many people re-heat terrible-for-you processed food at much higher costs (which does not even end up saving them much time/effort anyhow).
You jest, but me being very cynical, suspect that the $1,000 filter probably cost $10 to make. Marketing ("How much would you pay for clean air?" "You can't put a price on your health, but $1,000 sounds about right") does the rest.
The original price might have been set by an American in the first place.
Fair point... more accurately, it would be a means of coping with China's air pollution than an actual solution to the underlying problem.
File under 'M' for 'Manic ranting'
I somehow would think that being ignorant of what the underlying problem might be would generally preclude a solution being particularly obvious to them, except in retrospect.
File under 'M' for 'Manic ranting'
My point was that the obviousness of a solution depends heavily on whether the observer has seen the solution before or is making it up from scratch. It seems to me that the visible characteristic of an 'obvious' solution is that when you tell someone the problem ("this air filter costs $1000") they come up with the answer immediately, without much thought ("why not just take a box fan and stick a filter on it?"). Not knowing a problem exists does not necessarily make the solution non-obvious, just irrelevant. For example: suppose you don't know the sink is overflowing. "turn off the water flow" isn't relevant to you because there's no point, but is it any less of an obvious solution to the actual problem?
Living is a basement apartment in Boston I had problems with particulates from the street. I removed the window screen, installed a filter in its place, and mounted a window fan on the inside. Whole house air filter and didn't even need the box. 15 years ago, I claim prior art if he patents it.
The reason we subjugate ourselves to law is to better procure justice. If law does not accomplish this purpose then it m
Once it was a hallmark of wealth to be fat. Today, it's kinda the opposite. Times change.
Yeah. You hire a personal trainer.
Have you heard about specialisation? I can cook myself, but for plumbing or complicated electrical works I will call a specialist.
There are reasons to want to own an air purifier even if you live in a place that doesn't have tons of pollution.
The most common would be allergies. If you get a decent one, it can nab pollen out of the air no problem. This can make living in a place where you have allergies to something much more tolerable.
They also help with dust accumulation. I live in the desert so we get lots of particles in the air, humans or no humans. An air filter can help clean that up. Makes it easier to keep the house clean.
Also the real good ones can get bacteria, even viruses, they filter things so small. So it can help limit the spread of disease in your house. Not a silver bullet by any means, but it can help keep the could a kid brought some from spreading.
Not saying China doesn't need to clean up their act, but these things weren't made because of their problems. The big names in it are western anyhow. IQAir (Switzerland) and Austin Air (US) are probably the two best known for high end, small units. In particular if you are talking a $1000 unit, that's IQAir. Their filtration is clean-room levels of good.
That's pretty much it. Or they think the $1000 is buying them some special features like running quieter.
The prices in this market are downright crazy, probably because it's a quasi-medical application. Yes there are some that offer things like UV sterilizers and engineer the air flow such that it goes through the UV sterilizer at a rate that actually allows it to work, but even the ones with features that actually work are completely overpriced, and that doesn't change as long as it's a small percentage of desperate people that need it. It's no surprise to me that once the need for the product becomes mainstream, gouging the hell out of the consumer gets harder, and no it has nothing to do with mass production, just exploitation of the sick.
Someone had to do it.
You can see it right in the Slashdot thread where people link to Youtube videos of this being done a long time ago. The idea of "stick a filter on a fan" isn't new because that's PRECISELY what air filters are. They don't make any bones about it.
So, why doesn't everyone do it? Well because it turns out DIY isn't much cheaper if you want it to work well. When I first heard of the idea, on Youtube, I said "let's try that!" Went and got out one of my box fans, bought a filter at Home Depot, and taped it all together. Well I quickly discovered two flaws with this system:
1) Furnace filters aren't near as good as HEPA filters, particularly not the multi-stage system good units have. It did reduce particle count, but not a ton. I could buy better filters, for sure, but then the cost goes up. Buying a filter with a large surface area like good units have gets quite expensive, much like the filters they have themselves.
2) A regular fan is not well suited to the static pressure you get trying to push through a filter. It had very little airflow. Better sealing would have helped some of that, but of course that's more money and effort, but part of it is you just need a good fan. That is again one of the things that the high end units have. They have a fan particularly made to deal with high static pressure, and a case made force lots of air through the filters.
So easier, and not really any more expensive in the long run, to just buy a filter unit. On the cheaper end of things, there's Austin Air units. Basically you pay $250 for a metal box with a powerful fan in it, and another $250 for a huge filter. Every 5 years or so, you pay another $250 for a new filter. Not the world's best filtration stats, but pretty good, better than furnace filters, and cheaper when you look at how long it lasts. At the high end that's IQAir. $1000 for a unit, but the unit and filters last a long time. I particular their HEPA filter can last a decade or more, provided you replace the prefilters when it tells you to.
That's the thing here: This is NOT a new idea, people were talking about it online a minimum of 6 years ago, and it is also not a hard idea since it is literally doing what the filters do. They are simple devices, they have diagrams of how they work on their websites. The cost is in a good fan, and good filters.
Finally, with regards to particle count, you need to be careful that you specify what size and have a counter that can deal with it. One of the reason IQAir units cost so much is they filter extremely tiny particles, like clean room level, viruses and so on. That is much harder to do than larger stuff. Now maybe you don't care, ok fair enough, but don't try and act like it is the same level of performance. You can very well get cheaper air filters that don't filter as well, or as small a particles.
There is a lot to that. It's amazing how overpriced anything medical is, often inflated by orders of magnitude.
I don't see how we can point the finger when most of us don't personally change the oil and oil filters in our cars.
Actually, this is not a new idea. Also, SmartAir has been around for a while - and he has done some events in various cities of China showing the whole DIY thing, and it's absolutely a reasonable and cheap solution for some people. I would argue, however, about the whole "thousands of dollars" nonsense - people pay premiums for high quality products all the time. What does my Philips air purifier do?
1) It has a much larger filtration and fan system, and a well fitting seal between the filter and the fan.
2) I can control the airflow much better than with far cheaper fans.
3) The front panel and filtration system is better than simply strapping an air filter to a fan - especially for people like me, with pets.
4) It looks *way* nicer as something sitting in my house.
5) It advertises a larger amount of airflow - hence cleaning - than the smaller fans.
6) It doesn't cost 'thousands' of dollars, although it's fun to grab the gold plated diamond crusted type nonsensical sell-1-a-month products for comparison, you can buy.. in China.. a mid-level Philips or Panasonic air filtration unit for a couple hundred USD. Entry level ones, about a hundred bucks. This canon unit is cheaper mind you, but the filters/etc are all smaller so obviously cheaper to buy as well, and at a $70 difference - I'd rather go with a unit that looks good and has a few 'convenience' features to go with it, as well as not having to literally strap two things together with a band and figure out where I can hide it in my house.
You mean the gigantic[citation needed] on the summary/headline?
So, I did a cursory search on Google and what I've found was that the lowest priced filter was around 1500 RMB*. Now, according to that table, it is easy to see that the pricier ones perform better and can handle larger amounts of air. There seems to be an issue with formaldehyde (HCHO), which the pricier ones seem to remove more than the cheaper ones. Wikipedia seems to think that HCHO is harmful to human health, but I'm no expert and we all know how reliable wikipedia is for facts (it suffices, though).
So, no. Not all air purifiers are 1000$. However, the ones that provide around 96% (which seems consistent with what would be a HEPA filter) and also filteer for that formaldehyde at a similar rate are the more expensive ones.
What this does show is that the summary is lacking information and we are being fed an apple to oranges comparison. Smart Air's website seems more sensible than the summary (what was I thinking, this is slashdot), at least mentioning that the filter is an alternative only if your only concern is particle pollution.
Also, I need to stop taking the summary at face value.
* other articles found in the search suggest that those values are not false
I don't care if I'm wrong. I only care about everyone obtaining something from the discussion.
How about over-specialization? Being good at just one thing is not really something to applaud, is it? I'm not going to call a plumber because my toilet won't flush properly. I'll fix it myself if I can. I'll unblock my own sink if it becomes blocked. I'll assemble shelves etc. Basic stuff that anyone should be able to do.
http://www.acetonestudio.com
I've done something similar, but I also tossed in a cheap 5kV ion generator and a grounding screen. You put the filter on the pull side, the generator in the middle and the grounding mesh on the push side and it does a decent job of filtering out particles and making the air smell fresh. You can get everything you need at Home Depot, except for the 5kV circuit, which is like $5 online.
X
Google "box fan shop filter"
Star Trek transporters are just 3d printers.
China? People obeying the rules? Yeah, that's why Chinese manufactured products are known for their highest quality.
Star Trek transporters are just 3d printers.
Ooh, I like donkeys! What's his/her name?
Star Trek transporters are just 3d printers.
Not only that, he's riding the capitalistic wave of the "tyranny of ideas". Fifty years ago a different guy would've told all his friends and family. They in turn would tell their friends and family. Maybe someone would go on radio or TV news and show everyone this very basic idea of helping themselves. No profit motive. Just showing other people how simple it could be (and perhaps how stupid they are). Take a farmer for example. He shows a neighboring farmer a cheaper method of feeding his cows. The first farmer doesn't expect to get rich on the idea. They help each other out just for the sake of helping a neighbor out. The cheaper method isn't something earth shattering and especially innovative. In fact other people have done it in different states or regions for years. They just passed the idea on from one farmer to another when they saw a need. But now... everyone wants to be a millionaire even if it means capitalizing on something as unchallenging as putting a filter on a fan. It also demonstrates (to some extent) just how limited the Chinese mind can be and perhaps that is a result of living under communist conformity. Either way, this guy should call on his local clergy to seek forgiveness from the Christ for his self centeredness.
"Those who can make you believe absurdities can make you commit atrocities." - Voltaire
Thomas here. I'm happy to see the word getting out that clean air doesn't have to cost $1,000. So far I've relied entirely on kind souls spreading the word because I don't want to make people pay for advertisements when they buy my filters, so I haven't paid for any advertising. I totally understand the commenters who are saying "this isn't an invention!" Some of the news articles have gone too far. One even called me a "genius." I really see this effort as less Thomas Edison and more Johnny Appleseed. I didn't really invent anything. I just "re-discovered" the simple fact that HEPAs cut particulate pollution, did systematic tests to demonstrate it, and tried to tell as many people as I could. My main motivation was the fact that so many people in China (myself included!) thought that reducing particulate pollution in the home has to cost $500 or $1,000. All of my tests and methods are on my Tumblr, Particle Counting: 1. Minute and hourly tests: http://particlecounting.tumblr... 2. Comparison tests with the expensive brands in the same room, same particle counter: http://particlecounting.tumblr... 3. Live test of the air coming out of the filter: http://particlecounting.tumblr... 4. Instructions for how to make your own: http://particlecounting.tumblr... Breathe safe!
Yup! All the tests and methods are on smartairfilters and my Tumblr, Particle Counting: http://particlecounting.tumblr... The direct comparison tests with the big brands are here: http://particlecounting.tumblr...