smoke

Smoky skies cast a reddish glow to San Francisco skies when the Northern California wildfires were burning earlier this year. Ray Chavez/MediaNews Group/The Mercury News via Getty Images hide caption

Firefighters struggle Tuesday against the strong wind in an effort to secure nearby houses from bush fires near the town of Nowra in the Australian state of New South Wales. Saeed Khan/AFP via Getty Images hide caption

Outside of risks from the fire's heat — and any health risks related to a long-term power outage — the main health concern in wildfire conditions is smoke, which produces particulate matter that can penetrate deep into the lungs, increasing the risk of respiratory diseases and asthma, as well as heart problems. Anna Maria Barry-Jester/KHN hide caption

Researcher Claire McCarthy, also known as the "queen of dung," sits on a blanket with images of DNA, test tubes and beakers. Heather Kim/NPR hide caption