What to know about bad air caused by wildfires and how to protect yourself

By — Caleigh Wells, Associated Press Caleigh Wells, Associated Press Leave your feedback Share Copy URL https://www.pbs.org/newshour/health/what-to-know-about-bad-air-caused-by-wildfires-and-how-to-protect-yourself Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter What to know about bad air caused by wildfires and how to protect yourself Health Jul 17, 2026 11:28 AM EDT When wildfires burn, smoke can travel long distances and degrade air quality far away, posing risks to those breathing it. Fires burning in one state can make the air worse several states away, and wildfires in Canada can send smoke into U.S. cities. READ MORE: As wildfire smoke makes air unhealthy from Midwest to East Coast, officials say stay inside Here's what to know about taking precautions against poor air quality due to wildfires. Grow your mind Subscribe to our Science Newsletter to explore the wide worlds of science, health and technology. What counts as bad air? The Environmental Protection Agency's Air Quality Index converts all pollutant levels into a single number. The lower the number, the better. Anything below 50 is classified as "healthy." Fifty to 100 is "moderate," while 100 to 150 is unhealthy for "sensitive groups," and anything above 150 is bad for everyone. READ MORE: Wildfire smoke may be worse for brain health than other air pollution, dementia research finds Sensitive groups include people with asthma, lung disease or chronic obstructive pulmonary disease, said Dr. Sanjay Sethi, chief of the division of pulmonary, critical care and sleep medicine at the University at Buffalo medical school. "If you have heart or lung problems, then you've got to be definitely more careful," Sethi said. "I would either avoid going outside or wear an N95 or at least a dust mask." Is my air unhealthy? Sometimes the air is bad enough to see or smell the smoke. Even if you don't see the pollution, it can be unhealthy to breathe. The EPA maintains a website with up-to-date, regional air quality information. PurpleAir, a company that sells air quality sensors and publishes real-time air quality data, has a citizen scientist air quality monitoring network with a more granular map of street-by-street air quality readings. WATCH: How massive wildfires in the West spread harmful particles across North America The best way to get indoor air quality readings is to buy a monitor, said Joseph Allen, director of Harvard University's Healthy Buildings Program. "You can find these low-cost, indoor air quality monitors just about everywhere online now. They don't cost all that much anymore," he said. What if I have to go outside? For most people, going outside for just a short time won't have a negative long-term impact, said Sethi. Wearing an N95 mask, which became common during the coronavirus pandemic, will help filter out the pollution. WATCH: Wildfire smoke is hazardous even hundreds of miles away. Here's how to protect your health "N95 is going to get