Hugh Pickens DOT Com writes "Emily Sohn reports at Discovery Magazine that high levels of air pollution in Beijing, where levels of pollution have spiked above 750 micrograms per cubic meter, have caused a run on face masks as people look for ways to protect themselves from the smog. The capital is on its sixth day of an 'orange' smog alert — the second-highest on the scale — with the air tasting gritty and visibility down to a few hundred meters. But experts say that under the hazards they're facing, the masks are unlikely to help much. In fact, images of masked citizens navigating the streets of Beijing highlight the false confidence that people put in face masks in all sorts of situations, including flu outbreaks and operating rooms. For a step up in protection, consumers can buy a category of mask known technically as N95 respirators, which are generally available at hardware stores. N95 facemasks are often used in industrial workplace situations to protect against things like lead dust and welding fumes, and they are certified by the National Institute for Occupational Safety and Health to trap 95 percent of particles sent through them in testing situations. But in order to work N95 respirators need to be professionally fitted to each person's individual face (PDF) to make sure there is a tight seal with no leaks. If they truly fit right, they are uncomfortable to wear."