[Ground level ozone] is responsible for a number of respiratory illnesses, ranging from coughs to bronchitis and emphysema. It also damages crops. Fires increase ozone levels by releasing nitrogen oxides, which form ozone when exposed to sunlight.
Gabriele Pfister of the US National Center for Atmospheric Research and colleagues focused on fires in
"Ozone can hit unhealthy levels even in places where people don't see smoke," says Pfister. "Wildfires are expected to worsen in the future, especially as our climate grows warmer. But we are only now beginning to understand their potential impacts on people and ecosystems – not only nearby but also potentially far downwind." The findings are likely to call into question suggested policies of letting natural wildfires burn themselves out instead of attempting to fight them. Those who advocate "let them burn" policies say wildfires are a natural ecosystem process.Universal Studios fire, 2008, shot by pinguino k, Wikimedia Commons via Flickr, under Creative Commons Attribution 2.0 License