Raging wildfires have caused red skies and foul air along much of the West Coast of the United States and the smoke from the fires is expected to hover in the region through the weekend.

Dr. Afif El-Hasan, a spokesperson for the American Lung Association and an expert in pediatric asthma and lung conditions at Kaiser Permanente in California, said wildfire pollution can leave people more susceptible to flu and COVID-19.