Wildfire smoke has been settling in the American West

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Wildfire smoke is settling across the American West. About a hundred major wildfires are burning mostly on the West Coast, sending dense smoke as far east as the Dakotas. From Idaho, NPR's Kirk Siegler reports that air quality alerts have become a mainstay, along with the extreme heat advisories.

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KIRK SIEGLER, BYLINE: So I'm just stepping out of our office here along the Boise River. And lately, you haven't been able to even see the mountains - not even three miles from here - the dense smoke clinging to these big cottonwood trees in front of me. And pretty much all of July, the temps were in the triple digits.

JAY BREIDENBACH: It's the earliest I've ever seen this much smoke affecting multiple states in the Western United States.

SIEGLER: This is NOAA meteorologist Jay Breidenbach over at the National Interagency Fire Center in Boise, the nation's wildfire command center.

BREIDENBACH: We have so many fires burning that there's not enough atmosphere to have that smoke dissipate and settle out of the atmosphere.

SIEGLER: Close to a million acres of rangeland has now burned in eastern Oregon alone. Then there's California, and the Park Fire near Chico, which has fast become one of that state's largest wildfires ever.

BREIDENBACH: You know, the local smoke problem around that is tremendous, but the impacts go way downwind.

SIEGLER: Indeed, these climate-driven megafires, made worse by prior forest management decisions, aren't exactly the Smokey Bear forest fires of old. This smoke contains cancer-causing benzene and harmful particulates from burnt homes, cars and power lines. Maryum Merchant is a pulmonologist with UCLA Health.

MARYUM MERCHANT: We have recognized that it has now become - wildfire smoke has become a public health crisis.

SIEGLER: Every summer in California, Merchant sees a spike in patients needing treatment for respiratory diseases, and she says it's not just patients with preexisting lung conditions either or the actual wildfire evacuees.

MERCHANT: We are also recognizing the impact is not just confined to patients who are in immediate vicinity to the fire. But people living miles away can also get exposed to the smoke and can also develop increased respiratory symptoms.

SIEGLER: Scientists have only recently started publishing studies of the long-term effects of wildfire smoke. Merchant says there are things we can do to limit harm - run a high-efficiency particulate air filter at home, limit your outdoor time and, when it gets really bad, wear an N95 mask.

Kirk Siegler, NPR News, Boise. Transcript provided by NPR, Copyright NPR.

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