As climate change drives more frequent and intense wildfires across North America, the health risks of wildfire smoke are becoming impossible to ignore. Wildfire smoke can travel thousands of miles, bringing a hazardous mixture of pollutants including fine particulate matter (PM2.5), carbon monoxide, nitrogen oxides and volatile organic compounds, to people nationwide. Repeated exposure to these tiny particles that can travel deep into the lungs has been proven to trigger inflammation, worsen existing lung conditions, and contribute to permanent damage to lung function and overall respiratory health.
To truly understand the devastating effects wildfire smoke can have on someone’s health and well-being, we spoke with a doctor and a patient with chronic lung disease about their experience dealing with the increase in wildfires.
Understanding the Harms of Wildfire Smoke
Breathing any amount of wildfire smoke is bad for your health, no matter how healthy you may be. “Inhaling smoke can really affect the immune system of the lungs, making them more susceptible to infection,” Erika Moseson, MD, an ICU doctor and wildfire expert, explained. “I think that’s why we recognize that really no one's immune from the potential health impacts. For example, we know that flu season, even months after a big wildfire event, is going to be more severe and have worse outcomes in an area where smoke has lingered.”
For individuals with chronic lung disease, wildfire smoke presents an even bigger threat. Bonnie, who has lived for over a decade with Alpha-1 Antitrypsin (Alpha-1) and has received a single lung transplant, says she can feel the air pollution the moment she steps outside. “I was visiting Indiana and the air quality (from the smoke) was so bad that I was struggling to breathe just walking from the hotel to the car,” she said. “Once I got in the car, we made sure the vents were closed and the fan was recirculating clean air properly, and that helped a lot. But I wasn’t able to go outdoors and do what I planned. I had to just wait in the car because the smoke was just too much for me.”
Extensive studies into the dangers of particle pollution (PM2.5), a main component of wildfire smoke, show it is extremely toxic to the heart and lungs. Exposure to PM2.5 can lead to premature death in people with chronic heart or lung disease, heart attacks, irregular heartbeat, aggravated asthma, decreased lung function, cardiovascular symptoms, and increased respiratory symptoms, including airway irritation, coughing and difficulty breathing. And though separating long-term data related to wildfire smoke exposure versus long-term data related to other PM2.5 exposure can be tricky, Dr. Moseson believes the dangers of both are clear. “There are a few studies that looked at populations that have been exposed [to wildfire smoke] a few years later and they consistently see decreased lung function and an increased risk of developing lung disease down the road.”
Preventing Smoke Exposure
Because wildfire smoke can cause long-term lung damage, prevention is the best way to keep your lungs healthy. “I have a double whammy, lung disease and a lung transplant, so I want to do everything I can to protect myself and my good lung because it was a gift and I don’t take it for granted,” Bonnie said.
The best way to do this is to monitor the air quality in your area by consulting the air quality index (AQI). An AQI value under 50 is considered safe for everyone to spend time outdoors without posing a risk to their health. But as the AQI increases, so does the health risk, especially for those with lung disease. “I really encourage people to get to know the air quality index and get to know where their health is. They should also consider who in their family might be most vulnerable, and how they can protect them.” Dr. Moseson said.
Bonnie has an alert set on her phone, so she knows when she needs to limit her time outdoors. “I change my behavior if I am in a place with bad air quality. So, I might not go for an outdoor walk, I’ll go to the gym or do something inside instead,” she said.
Actually, no one should exercise outdoors when the air quality is unhealthy. “You want to inhale as little smoke as possible, which means using protective gear and not overexerting yourself. Avoid taking huge deep breaths where you're pulling in a lot of toxins and particulate matter,” Dr. Moseson suggested. “Which is why we recommend that people don’t exercise or exert themselves too much during this time, because then they get an increased dose of the particles.
Other prevention tips Bonnie and Dr. Moseson suggest are:
- Keep all windows and doors closed and run the central air conditioning on the recirculate setting. If you don’t have air conditioning, consider visiting a library, mall or other indoor place where air conditioning is available.
- When driving, make sure all windows and vents are closed, and you are using the recirculating setting on your air conditioning. “That is helpful for me and sometimes people don’t realize that they are driving with the vents open,” Bonnie said.
- If you have one, continuously run a HEPA air cleaner in your bedroom or whichever room you spend the most time in. Be sure to change the filter in your air cleaner regularly. Your HEPA air cleaner should not generate ozone (or have an ionizer setting).
- Limit indoor pollutants as much as possible. This includes never smoking or vaping indoors, but it also includes many other indoor air pollutants like aerosol cleaners, fragrances, hobbies with strong chemicals and more. “I love scented candles, but I avoid burning them indoors, especially during a bad air day. And I try not to use the gas stove during this time either, I normally suggest trying to stick to using your microwave, if possible,” said Bonnie.
- If it is difficult to maintain clean air in your entire house, create a clean room.
Learn more about wildfires and how to protect yourself on our website.
Blog last updated: August 20, 2026
