A smoky haze obscures the Space Needle and downtown Seattle in 2018. Wildfires in the West are churning out waves of unhealthy smoke that scientists say will sweep across the continent to cause a spike in premature deaths as climate change makes the blazes worse.
(AP file photo/Elaine Thompson)
In this Nov. 16, 2018, file photo, the Golden Gate Bridge is obscured by smoke and haze from wildfires in this view from Fort Baker near Sausalito, Calif. Tens of millions of people in the Western U.S. face a growing health risk due to wildfires as more intense and frequent blazes churn out greater volumes of lung-damaging smoke, according to research scientists at NASA and several major universities. (AP Photo/Eric Risberg, File)
In this Thursday, June 6, 2019, photo, Sarah Montoya plays with her twins Farallon, left, and Nicasio, center, at their home in San Francisco. During last year's deadly Camp Fire, which killed 85 people and destroyed 14,000 homes, smoke from the blaze inundated a San Francisco neighborhood roughly 170 miles away where Montoya lives with her husband, Trevor McNeil, and their three children. All three children have respiratory problems suspected to be asthma. But when the smoke from the Camp Fire filled the air for two weeks, the family was unable to find child-sized face masks to protect them or an air filter to clear the air in their house. (AP Photo/Eric Risberg)