You may see some people here in the Bay Area wearing surgical face masks to protect themselves against pollutants in the air, and face masks are widely used in Asia.
There are different types of such masks, including industry standard and highly-tested disposable masks which might cost three or four dollars each, but often in many countries.
Richard Peltier with the University of Massachusetts led a study of reusable cloth masks and found that many don't really protect people from pollution.
"Air pollution's a very toxic exposure that we have. It kills between six and seven million people per year, but it's kind of one of those hidden things that people don't think about. And, whenever they take a simple preventative measure like wearing a face mask, assuming they're going to be protected, they're really not getting all the facts," Peltier said.
Peltier says it is necessary to educate people on the effectiveness of cloth masks, which really have not been widely studied.
"It does require a lot of effort on our part as public health officials to educate people, to say that even if you're wearing a cloth mask, it may be somewhat protective, but it's certainly not eliminating your exposure, and you're still at risk," Peltier said.
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