As fires blanket growing swathes of the West, scientists are beginning to understand more about how their smoke affects the transmission and severity of COVID-19 and other illnesses, and how it differs from that of other types of air pollution.

As fires blanket growing swathes of the West, scientists are beginning to understand more about how their smoke affects the transmission and severity of COVID-19 and other illnesses, and how it differs from that of other types of air pollution.