Or strap a $1 central A/C filter to a $10 box fan.
That is not going to filter out PM2.5. Those filters only exist to protect the internals of the A/C unit from large debris.
Smart Air
51–60 of 95 posts
Re: Smart Air
#52Hey, this is Thomas--I started Smart Air and the Particle Counting Tumblr that preceded it (http://particlecounting.tumblr.com/).
Thanks for all the useful suggestions! Our main philosophies are to (1) not rip people off and (2) be open about our data. I post data and testing methods to Particle Counting on a regular basis.
Simon--you're right about the fan speed. We've been doing experiments with more powerful fans, and we'll be coming out with a more powerful model soon. It'll be better for bigger spaces, and it cuts the particle counts down a lot faster. The fan is a bit more expensive though.
Re: Smart Air
#53I never thought I'd be pulled in by a product that essentially bills itself as "Clean your air CHEAP with this one cool trick discovered by a college kid", but they've executed well. What they're offering is just an easy way to buy a fan and HEPA filter ($27USD, or 166RMB, as the FAQ freely admits). Even so, their website makes me like instantly their business model, and because of their approach and willingness to r…
Hey, this is Thomas--Smart Air is my startup. Thanks for the ideas! I'll consider adding a subscription service. Several people told me at the beginning NOT to publish my findings (at http://particlecounting.tumblr.com/) because I should make money off of it instead. But I published it anyway because I thought (1) if I don't make a dime, but people learn how to protect their health without going broke, that alone is worth it and (2) there's space for an air filter company that publishes data openly.
There's so much trust involved in air filters because it's almost impossible to know if they're working if you don't have an expensive particle counter. So we're hoping that our open data and methods will show that they can protect their health without going broke.
Re: Smart Air
#54Errr - this is expensive for what you get. Among other things, the CFM is so low that it takes hours to reduce the particle rate any appreciable amount, as their own tests show. You'd do a lot better with a standard high velocity fan (also 35 bucks, and you can get them cheaper): http://www.northerntool.com/shop/tools/product_200361823_200... You want to be changing the air at a much higher rate than they are. They q…
This is Thomas--founder of Smart Air. Thanks for the ideas!
I totally agree--we've been doing tests with more powerful fans, and the results are great. We'll be coming out with a more powerful model soon. Of course, it's a bit more expensive to get a more powerful fan.
We've avoided using pre-filters because we don't want to cut down on air flow (and HEPAs aren't all that expensive), but we'll probably use a pre-filter on the more powerful model.
About where to put the filter, is there a reason to put it on the intake side? I've heard several people make that argument, but I've never heard a good justification for it.
Re: Smart Air
#55For someone living in a city with reasonably clean air and no smog problem, does filtering the air in their living space provide any long-term health benefits?
This is Thomas--founder of Smart Air. Interesting question. I've seen plenty of studies showing the effects of air pollution on people's health (the study showing pollution shrinks fetus size is particularly scary: http://www.news.qut.edu.au/cgi-bin/WebObjects/News.woa/wa/go...)
But I haven't seen experiments done with home air filters using health effects as the DV. I'd actually love to donate some filters to anyone in public health or medicine who wants to run that study!
Re: Smart Air
#56Are particles the whole story when it comes to air pollution, or do you have to worry about gases, too? Also, what would be a good source for obtaining HEPA or carbon filters in Canada/USA?
Hey, this is Thomas, founder of Smart Air.
Excellent question! Particulates are very important, but gases can be a problem too. We talk about gas pollution in our workshops, and I've written about it on Particle Counting:
http://particlecounting.tumblr.com/post/60881490803/the-limi...
However, I don't know of home filters that target gases.
Re: Smart Air
#57Earlier quoted context omitted.
From the FAQ: You can! We have links on our Particle Counting blog. We're more committed to spreading the knowledge that HEPA filters are a cheap way to effectively combat air pollution than we are to making money, so we'd never discourage anyone from buying the same parts elsewhere. We just try to make the parts easier to get for people who don't want to scour Taobao for the cheapest filters. People have also emaile…
The irony is that running all of these filters is consuming electricity, which in turn means more coal-fired power plants and even dirtier air for everyone. Beijing should move to clean up the environment.
The irony's not very strong, since these can clean a lot more than they contribute via electricity consumption.
Re: Smart Air
#58For someone living in a city with reasonably clean air and no smog problem, does filtering the air in their living space provide any long-term health benefits?
Negative ionic air purifiers may help with SAD (seasonal depression) [1] similar to daylight bulbs. Research is somewhat inconclusive. It also supposedly makes air have equivalent ionic levels to "country or mountain air". Apparently in the city/offices the ion levels in the air are quite lower than in rural areas which is harmful. This of course is the sales pitch from the companies selling them. But at the same tim…
Why is killing bacteria always good?
Re: Smart Air
#59Errr - this is expensive for what you get. Among other things, the CFM is so low that it takes hours to reduce the particle rate any appreciable amount, as their own tests show. You'd do a lot better with a standard high velocity fan (also 35 bucks, and you can get them cheaper): http://www.northerntool.com/shop/tools/product_200361823_200... You want to be changing the air at a much higher rate than they are. They q…
This is Thomas--founder of Smart Air. Thanks for the ideas! I totally agree--we've been doing tests with more powerful fans, and the results are great. We'll be coming out with a more powerful model soon. Of course, it's a bit more expensive to get a more powerful fan. We've avoided using pre-filters because we don't want to cut down on air flow (and HEPAs aren't all that expensive), but we'll probably use a pre-filt…
There are a couple reasons to put it on the intake side:
1. Otherwise you are pulling dust particles directly into the fan bearings/etc (though it may be that you don't have a good enough seal for this to matter anyway). All this does is lower the life of the fan. This is one of the reasons you see filters on the intake side of an A/C or furnace - to protect the innards.
2. If a non-dust particle gets dropped into the fan, with the filter on the outtake side, it is likely to get propelled through the filter at high speed. With the filter on the intake side, this will never happen (since it would not hit the filter), and even dropping it near the rear of the filter is unlikely to cause damage.
(There are other reasons that would matter more if this was an enclosed ventilation system, but it isn't)
Note that without pre-filtering, i can't imagine these filters are really lasting that long without being cleaned. Are you measuring static pressure increase at all to see how long they last before needing to replaced?
HEPA filters are not usually meant to be sole filters and last a long time. They are just too fine and load too quickly. Some form of coarse separation (IE >5 micron particles) is usually necessary to get any real life out of them.
Re: Smart Air
#60Errr - this is expensive for what you get. Among other things, the CFM is so low that it takes hours to reduce the particle rate any appreciable amount, as their own tests show. You'd do a lot better with a standard high velocity fan (also 35 bucks, and you can get them cheaper): http://www.northerntool.com/shop/tools/product_200361823_200... You want to be changing the air at a much higher rate than they are. They q…
This is Thomas--founder of Smart Air. Thanks for the ideas! I totally agree--we've been doing tests with more powerful fans, and the results are great. We'll be coming out with a more powerful model soon. Of course, it's a bit more expensive to get a more powerful fan. We've avoided using pre-filters because we don't want to cut down on air flow (and HEPAs aren't all that expensive), but we'll probably use a pre-filt…
I haven't tried both, but it does seem like on the intake side, suction from the fan blowing would tend to hold the filter in place. But I would expect you would still need the strap (partly to keep it together when it isn't running).