After staying in Beijing for nearly four years, I’ve learned to look for good bargains, so when I came across this do-it-yourself purifier post I could feel my sense of cheapness being called upon (despite the fact that the picture looks like a broken air conditioning unit).
The post on Tumblr by particlecounting, who just started blogging about a week ago, claims that you can make an effective indoor air purifier simply by taking a flat front motor run fan and strapping a HEPA filter (purchasable from Taobao for RMB 58) for a total of just RMB 166 (as opposed to the RMB 11,000 or so you’d pay for a high-end filter).
The author, a self-professed "nerd" who says he is a 2012-2013 Fulbright Scholar based in Beijing and a PhD student in cultural psychology at the University of Virginia, gives a step-by-step guide on how to make your own, accompanied by pictures.
In a subsequent post
, the author also documents a series of tests he conducted to study the effectiveness of his DIY purifier. He conducted a particle count of the air inside the room before switching the purifier on and used the US Embassy’s AQI
to correlate with his particle counter and tested the air for eight hours in his bedroom with the windows and doors closed. He also took into account variables like someone entering and leaving the room which might cause a gust of wind to blow into the room.
The author compares the effectiveness of the DIY with a state of the art purifier based on data collected
blogger and Beijing United Family Hospital
Doctor Richard St. Cyr, who calculated his air quality reductions on the air outside as opposed to the inside air, which the author believes is a better approach (he later updated the post by noting Dr. Richard conducted his tests with the doors closed for one hour).
In the end he acknowledges that variables like room size (his room is 6.5m smaller than Dr Richard’s) make the comparisons imperfect but concludes that his DIY filter is "roughly comparable to an expensive filter at far lower cost."
Photo courtesy of farm7 via Flickr