How to protect yourself from wildfire smoke

Fine particles are the main danger in smoke

Smoke is a mix of gases and fine particles. The EPA says the particles are the biggest health threat. They get into your eyes and lungs and can cause burning eyes, a runny nose and illnesses such as bronchitis. They can also worsen heart and lung disease, and they're linked to early deaths in people with those conditions.

If you're healthy, the EPA says you're usually not at major risk from a short spell of smoke. It still advises avoiding it when you can. The people at greater risk are children, older adults, pregnant people, people with heart or lung disease, and people who get more exposure, like outdoor workers.

Check your air on the AirNow Fire and Smoke Map, which adds corrected readings from thousands of air sensors to the official monitors. Our AQI guide explains the colors.

Keep the smoke out of your house

• Keep windows and doors closed.
• If your central system has a fresh air intake, close it or set it to recirculate.
• Close the outdoor air damper on a window air conditioner. If it won't close, the EPA says don't use that unit.
• Use a single-hose portable air conditioner sparingly. It can pull in smoky air from elsewhere in the house.
• If you have an evaporative (swamp) cooler you can reach safely, cover its outside intakes with 4-inch MERV 13 furnace filters. Otherwise use it sparingly.
• When the air outside gets better, even for a while, open up and air out the house.

Don't add smoke of your own. The EPA lists candles, incense, gas, propane and wood stoves, aerosol sprays, smoking, vaping, frying or broiling food, and vacuuming without a HEPA filter.

Filter the air in one clean room

Pick a room big enough for your household, ideally a bedroom with its own bathroom so the door can stay shut. Run a portable air cleaner in it on its highest speed as much as you can. Choose one that doesn't make ozone, such as a model on the California Air Resources Board's certified list. Our air purifier guide covers sizing.

With central air, use a MERV 13 filter and set the fan to "On" (HVAC guide). If you can't get or afford a purifier, a box fan with a furnace filter is a stopgap.

During heavy smoke, replace filters more often than the package says.

Outdoors, only a fitted respirator helps

The EPA says the most effective step is limiting your time outside. Skip mowing, running and other hard exercise.

If you have to be out for a long time, wear a NIOSH-approved N95 or P100 respirator. Look for "NIOSH" and "N95" or "P100" printed on it. The EPA's fit rules:

• Choose one with 2 straps that go around your head. Ear-loop masks don't seal.
• Put one strap above your ears and one below.
• It should cover your nose and go under your chin with no gaps. Do the seal check on the package.
• A good seal isn't possible with facial hair.
• Throw it away when it gets dirty or harder to breathe through.

Cloth masks, surgical masks, one-strap dust masks and bandanas (wet or dry) give little or no protection from smoke.

A respirator can make breathing harder and raise the risk of heat illness. If you have heart or lung problems or are pregnant, the EPA says to ask your doctor first.

Children and pets need extra care

Children's lungs are still developing, so the EPA says they're especially at risk. Keep them indoors in the clean room. NIOSH respirators don't come in sizes for young children. Children under 2 should not wear one. Some older children may fit an adult small, so check the fit and watch that they wear it right. For recess, sports and what schools do at each AQI level, see Kids, school and bad air.

Smoke can irritate pets' eyes and airways too. The EPA's smoke guide says to cut their time in smoky areas, keep the indoor air clean, give them plenty of water and limit their activity. Watch animals with heart or lung disease closely. Call a vet if a pet is coughing or having trouble breathing.

In the car, close the windows and recirculate

The EPA says to close the windows and run the air conditioner on recirculate. Slow down when smoke cuts visibility.

Know when to leave

If officials tell you to evacuate, go. When a fire is very close, the EPA says it can be nearly impossible to keep dense smoke out of a home.

Farther away, leave or find other shelter if you can't stay cool, the power goes out, or too much smoke gets in. The EPA suggests friends or family outside the smoke, a public cleaner air shelter, or a large air-conditioned building with good filtration, such as a mall. If you have heart or lung disease, are an older adult, or have children, AirNow suggests talking with your doctor about whether and when to leave. In long, heavy smoke, fine particles can build up indoors even when you can't see them.

Smoke can travel hundreds of miles

In June 2023, smoke from fires in Quebec poured south into the eastern US. NASA reported PM2.5 above 400 µg/m³ in Syracuse, New York, the city's highest since routine measurements began in 1999. New York City's PM2.5 AQI passed 175 on June 6, topping its 2002 record of 167, and June 7 was worse: the EPA's daily county AQI reached 278 in Queens, in the very unhealthy range, and 331 in Philadelphia, in the hazardous range. On the morning of June 8, NASA reported hourly readings in New York City, Philadelphia and Washington, D.C. still in the purple, very unhealthy range. A 2026 study traced the smoke to New York City from fires about 1,000 kilometers (about 600 miles) away.

Distant smoke often stays high in the sky. NASA notes Canadian smoke crosses the Northeast most summers without much notice because it's high up, and the EPA says smoke from thousands of miles away is usually light at ground level. So check the AQI.

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