Zifang Zhu in The New York Times: The Air We Breathe

The worst effects of the wildfires are the direct ones: the deaths, the loss of homes and the destruction of natural habitat. But the secondary pollution effects — from the smoke that is clogging the air — are not minor.  Long-term exposure to the tiny particles in polluted air increases the risk of asthma, lung disorders, heart attacks and strokes. But even short-term exposure can lead to more respiratory problems, says Yifang Zhu, a professor at the U.C.L.A. Fielding School of Public Health and Institute of the Environment and Sustainability.