How to protect yourself from the bad air caused by wildfires

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.

Here’s what to know about taking precautions against poor air quality due to wildfires.

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.

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.”

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.

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.

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.

“N95 is going to get rid of 90-95% of the particles,” said Jennifer Stowell, a research scientist at Boston University’s Center for Climate and Health. “If you have access to a mask that has a respirator-type attachment to it, then that’s the very best.”

If you must be outside and you experience symptoms, experts say you should head indoors or elsewhere with better air quality. Even if you are healthy, it’s good to take precautions.

“If you start wheezing, which is like this whistling sound of the chest, or if you’re feeling short of breath, that’s definitely more concerning,” Sethi said.

Close the windows and turn on the air conditioner, if you have one, setting it to circulate the indoor air. Use blankets to cover cracks that allow outside air into your home, such as under doors.

Finally, swapping the air conditioner's filter for a MERV 13 filter can help, but ensure it's installed correctly.

“If you happen to have access to an air purifier, even if it’s just a room air purifier, try to keep it running and in the room that you’re doing most of your activities in,” said Stowell.

Wells is a former reporter for The Associated Press.

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Boats maneuver the East River near the Brooklyn Bridge as smoke from wildfires blankets the sky Thursday, July 16, 2026, in New York. (AP Photo/Alyssa Goodman)

A plumes of smoke from the Camp Fire hang in the air over Moose Lake as multiple wildfires burn in Minnesota's Boundary Waters Canoe Area Wilderness, Tuesday, July 14, 2026. (Anthony Souffle/Minnesota Star Tribune via AP)

Willy Vosburgh, owner of Vosburgh's Custom Cabin Rentals on Moose Lake, uses a tow boat to evacuate canoeists from the Boundary Waters Canoe Area Wilderness after multiple wildfires burning there prompted its closure and evacuation Tuesday, July 14, 2026 in Ely, Minn. (Anthony Souffle/Minnesota Star Tribune via AP)

A woman wearing a mask crosses the street in Toronto as wildfire smoke fills the city, on Wednesday, July 15, 2026. (Laura Proctor/The Canadian Press via AP)

PALU, Indonesia (AP) — Rescuers were continuing to search on Thursday for 24 people missing after a passenger boat sank off Indonesia, authorities said.

At least one person is known to have died after the KM Nurul Salsa experienced engine failure and sank about 43 nautical miles (79 kilometers) from its destination port in the Selayar Islands, in South Sulawesi Province, on Wednesday.

Rescuers located 49 survivors and are searching for 24 missing passengers, according to Muhammad Arif Anwar, head of the Makassar Search and Rescue Office.

“The challenge is the weather, with waves 2 meters to 2.5 meters high at the search site. The winds are also strong. That’s the main challenge,” Anwar said.

The search operation involves personnel from the Indonesian National Armed Forces, National Police, fishermen and residents.

The Nurul Salsa was carrying 74 passengers and crew, as well as copra, cattle and motorcycles, when it departed Jampea Island on Wednesday morning, authorities have said.

Passenger boats are a common form of transportation in Indonesia, an archipelago with more than 17,000 islands. Lax safety standards and problems with overcrowding frequently result in accidents.

Associated Press journalist Edna Tarigan in Jakarta contributed to this report.

In this photo made from video released by Makassar Search and Rescue Office on Thursday, July 16, 2026, rescuers scan the horizon as they search for victims after a passenger boat sank in the waters near Selayar Island in South Sulawesi, Indonesia. (Makassar SAR Office via AP)