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The wildfires across California have killed more than 50 people and destroyed thousands of homes. Many more people are still missing. And even beyond the fire zone, Californians are feeling the effects of these fires. Smoke is blowing into the Los Angeles Basin, the Central Valley and the San Francisco Bay Area. Public health officials say people should avoid exercising outside and should wear protective masks outdoors. From member station KQED in San Francisco, Raquel Maria Dillon has more.
RAQUEL MARIA DILLON, BYLINE: Children are especially vulnerable to wildfire smoke because their lungs are still developing and they play hard.
UNIDENTIFIED CHILD: One, two, three, four, five, six, seven, eight, nine, 10.
DILLON: At Marshall Elementary in San Francisco's Mission District, the smoky air means recess is canceled for the rest of the week. Teacher Greg Arias says his kindergartners are bouncing off the walls.
GREG ARIAS: They haven't been outside. They have all this energy, and it's tough on them.
DILLON: It's probably tough on him, too. The winds that fanned the Camp Fire north of Sacramento haven't let up, and the current weather pattern is pushing smoke out through the Golden Gate. This air is unhealthy. Doctors are recommending filtering respirator masks made for dusty construction work rated N-95 or better.
TINA ROTOLO: Yeah. All the N-95s are higher. Yep, that's correct.
UNIDENTIFIED CUSTOMER: So this one will last a little longer, right?
ROTOLO: Yeah, this one's reusable.
DILLON: At Cole Hardware store in the North Beach neighborhood, Tina Rotolo says they've sold thousands of masks since the smoke hit on Friday.
ROTOLO: We bought as many as they would sell us - 800, 700, 500 at a time.
DILLON: While masks are helpful, pulmonologist Dr. John Balmes says they may give a false sense of security.
JOHN BALMES: They work, but they have to be properly fitted. They have to make a good seal around the nose and mouth kind of like a snorkel mask.
DILLON: But they don't fit on children or people with beards. Smoke is unhealthy because of what's in it - particulate matter and carcinogenic compounds. How bad it is for you has a lot to do with how close you are to the source and how much you breathe. Balmes says wildfire smoke is like diesel exhaust and cigarette smoke.
BALMES: And so wildfire smoke is basically the same stuff, but it's different. Sitting right next to a fire - that's a different level of exposure than us being several-hundred miles downwind from the Camp Fire.
DILLON: Wildfire smoke also contains other stuff - plastics, paint, metals, even pesticides - from the homes, businesses and vehicles that burned. Tony Wexler, director of the Air Quality Research Center at UC Davis, says these extended mega-fire smoke events have health officials rethinking their advice to the public.
TONY WEXLER: We've always had wildfires in California. We've always had - we've had various levels of devastation. But in my experience, it hasn't been one after the other for, you know, basically years at a time here. This is a whole new game.
DILLON: Wexler says this new game of millions of people exposed to heavy smoke over days, weeks and even months has adverse health implications, and he says that's a concrete and immediate effect of climate change. For NPR News, I'm Raquel Maria Dillon in San Francisco. Transcript provided by NPR, Copyright NPR.