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 run workshops, I immediately trust goods from them more than than I trust buying the parts directly from the manufacturer.
It will be interesting to see what they do with their new, loyal customer base. I imagine they could easily start a filter-replacement subscription service, where they send you as many new filters as you need for XXrmb/year. If you're needing more than is profitable, they could add a phone call into the process "to diagnose why your home is needing filters than it should". This is the kind of honor system that only works if your customers already like you. Assuming their product actually works, I think they will easily achieve that.
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.
Note that high quality air filters also have a carbon pre-filter that gets changed more often than the HEPA filter, and having one ought to make your HEPA filter last much longer, especially in somewhere like Bejing. They also play a part in controlling odors.
This is what I'm currently using and love it to death. Note that the customer photos with the "dirty" filters are actually the carbon pre-filter and not the HEPA
health is the easy way to a fool's wallet.
that said I have 3 expensive of those filter at my home. not that one, 3 other different brands. The main factor for my purchases were silence. and ironically the only one that was silent is a discontinued sharp model that sold for $150. all the $300 models are awful. specially the blueAir one that focus all it's marketing on being silent.
No it's not, especially with a preemptive health solution (solving a problem people don't feel they have).
and i wrote wrong! i don't have a sharp one. the silent one is from sanyo! it also has the ONLY truly silent humidifier included, though very low volume as it is only used for the ionizing shenanigans.
is a good choice if you want a single large room done.
I'd like to rent one of those air quality testers for a week, anyone know where/if that's possible.
The air pollution ATM is at 366 PM 2.5 when this post was made. The chart now tops out at 300 with the hazardous description; the US embassy got rid of the crazy bad description given that the Chinese government wasn't so happy about that.
We went all the way up to 800 and 900 last January; we got up to 424 just last week. 0-50 is considered clean air, Salt Lake City institutes burn bans whenever their AQI goes above...35. There was a scandal when it got to 55 or so last year.
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.
Shipping is free, and with the coupon code TWITTER10, you'll save some money.
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!
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 time the filters kill bacteria and pet dander (which is always good).
I found a HEPA air filter that contained negative ionizer for around ~$50 on Amazon which I use in my home office.
Assessing indoor exposure to PM is challenging because it is highly dependent on location, the physical properties of the home, and human behaviour. Consequently, it can be difficult to clearly identify/quantify health benefits.
Even though you live in a reasonably clean city,
you can still further reduce your exposure to indoor PM by changing your behaviour, filtering your air and using existing equipment in your home properly.
1) In non-smoking homes, the biggest indoor source of PM is cooking (especially frying and broiling). You can reduce your exposure by a) keeping your range hood in good working order (change filters), b) using the range hood every time your cook, c) opening a window while cooking and d)stepping away from the stove whenever possible.
2) There are multiple other sources products that can produce shocking amounts of PM through direct emission and secondary reactions involving ozone. I would describe these exposures as completely unnecessary and can be eliminated by simply not using the products in the first place: a) candles, b) incense, and c)air fresheners and cleaning products with lemon & pine scents.
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 quote a 13.5 square meter bedroom. This is 145.313 square feet. If they have 8 foot high ceilings, it's 1160 cubic feet.
In order to be changing the air so little as they are, my guess is this box fan is ~40CFM, giving ~30 minutes between air changes.
For 30 bucks, you can get a 2000+ CFM fan (see above), and put the filter on the intake side rather than the output side.
This would change the air in the room roughly twice a minute, or roughly 60 times faster. There will be some loss of CFM due to static pressure increase, but ...
They also probably want a cheap, washable, electrostatic pre-filter so you aren't wasting the filtrating on easily caught particles.
Otherwise, you are just going to go through this hepa filter really quickly.
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.
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.
The DIY Filter idea is great to have a transitional solution and I applaud the startup for this idea. But a government, a country, a company, or a stakeholder, none of them can make profit and money, when there are no trees to cut, no clean air to breathe, no healthy citizen to employ, no educated class to teach, no unpolluted earth for the seed and no will for change. Then you've created the perfect environment for a colony of sheep that follows a butcher who sells himself as a shepard.
In my experience Beijing's air is really "special". Hot, humid, dusty. Not my favorite environment.
As well, a HEPA filter becomes clogged very rapidly without appropriate prefilter. This means that the pressure drop required increases considerably definitely beyond reach of any household fan.
It might fall short of the official specs, but its difficult to argue with their results.
What kind of prefilter would one need? I'm thinking of DIYing this...
For this one would need to know the exact measurement setup. For real world performance it is important to know the approximate exchange rate of air of the room. The throughput of the fan across the filter must be considerably higher than that.
>What kind of prefilter would one need? I'm thinking of DIYing this...
First of all, you would need a radial fan to overcome the required pressure drop. As for the prefilter, I am from Europe, which has probably different standards than the US, but some overview is provided here: http://www.filtration-engineering.co.uk/air_filter_testing.h... . For my clean room set up I had a EU5 prefilter combined with a EU9 main filter. Afair, laminar flow boxes for dirty environment (i.e. not supposed to be used within a clean room) have EU5 (or the equivalent) prefilters as well.
Seems to be quite effective.
Also, if you're into woodworking, woodgears is probably one of the best, if not the best on the net.
Here is his 3D Pantograph:
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 emailed us saying that some stores stop carrying fans in the winter and that some HEPA manufacturers don’t sell in small orders. We buy in bulk so we can offer a low, flat rate (200RMB) that includes shipping anywhere in Mainland China. By buying with us, you also know that you’re getting HEPAs that we tested personally for effectiveness.
It is amazing how much the air flow is cut down by the filter, though.
Edit: I know the particle counter ($200) is 6 times the price of the air purifier, which can seem ridiculous; but to me it makes much more sense to do that than to buy a $300 air filter and just pray for the best while having no clue at all about what's really going on.
The consumer air purifier market is a mess. There is so much misinformation and fake reviews out there that it's impossible to make a decision.
Each company runs dozens of smear sites against everyone else. All the Amazon reviews look fake. All the companies seem to have something wrong with them. It got to the point that when I was doing me research I just gave up and decided to not buy anything.
Also, what would be a good source for obtaining HEPA or carbon filters in Canada/USA?
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:
However, I don't know of home filters that target gases.
TED presenter Kamal Meattle argues for:
- Areca Palm
- Mother-in-law's Tongue
- Money Plant
As far as I know, there is no practical way of filtering out the other AQI-component pollutants using consumer-level technology. It's possible to filter them: power plant chimneys have devices called "scrubbers" attached that filter out things like SO2 . But I don't think there exists a device you can place in your living room that does so.
How about this? http://i.imgur.com/whD4yWh.png
The fact that people need air filters? Or something about the way these people are doing it?
I really like their website. They're open and honest about not being experts, and about how they do things, and how they want corrections and additional information. They sell you a kit if you want it, but they make no secret about it being really easy to do by yourself.
Instead of solving the problem at the root, everyone takes an every man for himself approach to the problem like the one described by the OP. The government should provide some sort of tax incentive to every building willing to upgrade their heating to something cleaner and should tax the hell out of cars in the city and put that money towards public transportation
FWIW, I lived in Beijing back in 2005/2006 and had a solid smoker's cough after a year. It's truly disgusting how everyone is effectively poisoning each other there.
 Furthermore, the design of the onramps and offramps on the ring roads are such that they cause a cascading locking condition once the level of traffic hits a certain point. When the line to exit a ring road gets long enough, it blocks the on ramp. This causes locking to cascade through the whole city.
Old coal boilers are another problem, and a lot of pollution blows in from the Hebei country side and gets stuck in Beijing without an outlet. All buildings in Beijing are heated by the city, so it's not even the building owner's option to be more efficient. Beijing is slowly switching over to natural gas for heating but the transition will take a couple years to finish.
The AQI right now is down to 50 where it was 340 only a few hours ago. I can only imagine we got some wind to blow out the bad air all of a sudden.
Would this help against lots of smog?