Beijing-based doctor Richard St Cyr is fanatical about air quality and protection – and in his latest efforts, he compared a range of 9 common anti-pollution masks using sophisticated testing equipment in the comfort of 3M's Beijing testing lab.

His results? It's all about the fit, baby simply put, if a mask doesn't effectively block air from coming in around the edges, no amount of fancy fabric and/or valves in the front is going to do a lot for you.

The top-ranked mask in the fit department in Dr St Cyr's independent testing was the 3M 9332 (pictured above) which commonly retails for around RMB 38 in some locations of expat supermarkets like April Gourmet, as well as online individually and in boxes of 10 for RMB 200 to RMB 300 at and

The 3M 9332 had a "fit factor" that out-performed the other masks tested by a huge margin, and filtered out 99.6% of all the baddies in the air. In fact its fit was so good that Dr St Cyr noted that was slightly difficult to breathe through, which could be a turnoff for those of you planning to use the mask for things like bike riding or exercise.

The even better news is that the 3M 9501, which retails for a mere RMB 6, did almost as good a job: earning a 97.5% efficiency rating in Dr St Cyr's test.

One caveat: what fits one face does not necessarily fit them all. Dr St Cyr suggests a simple "seal test": "cup your hands on each side of the mask and breathe in quickly. Your mask should cave in a bit from the negative pressure; if it doesn’t, the seal isn’t tight and you need to adjust."

Below is a quick snapshot of his results, ranked ... for a full analysis, read Dr St Cyr's full report on his blog here.

The results (click on image for full results)

Images: and My Health Beijing

Visit the original source and full text: the Beijinger Blog