Health Effects of Breathing Wildfire Smoke
Even after their flames have been extinguished, wildfires can have lasting health impacts. Lingering airborne particulates from wood smoke can irritate the lungs. They also can aggravate respiratory conditions such as COPD and asthma. However, in the aftermath of wildfires in more developed areas — such as the 2021 Marshall Fire in Colorado and the more recent L.A. fires in California — wood smoke particulates are joined by toxic chemical compounds released by burning construction materials, plastics, car batteries, other household items and more. These compounds can include many chemicals, including metals, asbestos, volatile organic compounds (VOCs), like benzene, polyaromatic hydrocarbons (PAHs) like naphthalene and others.
While these substances can be released during a fire , according to pulmonologist Lisa Maier, MD, they are also a hazard when navigating a wildfire’s aftermath. “Certainly, exposures during a fire are most concerning, especially downwind, although, there’s a significant threat to health, including respiratory health, that can occur after a wildfire,” said Dr. Maier. “These substances can be harmful when inhaled and are likely to stay in the air for a while and or be present in the ash remaining from a fire. And the air quality index does not reflect that.”
What an Air Quality Index Doesn’t Measure
Dr. Maier explained that the Environmental Protection Agency air quality index (AQI) is useful for tracking city air pollution and potential wood smoke particulate released by wildfires in more remote forested regions. However, this tool doesn’t measure the levels of various chemical compounds released by fires affecting residential areas. “The AQI is monitoring the usual criteria pollutants — things like particulates, ozone, carbon monoxide, nitrogen dioxide and sulfur dioxide. It does not measure chemicals or metals from wildfires. And that's going to be the problem. What do we know about lung disease? Gases, fumes and dust irritate the airways and lungs. So, all of these chemicals are likely to have an impact after the fire is gone if they remain aerosolized or are re-aerosolized.”
Complications During Wildfire Cleanup
During the cleanup process after a wildfire, some chemical substances, along with the ash and soot produced by the burn, are going to be deposited among the debris. As workers and residents rummage through these materials, wildfire pollutants can reenter the air. According to Dr. Maier, this risk factor for potential exposure is already well-known among firefighters. However, in large-scale wildfires affecting urban and suburban areas, these dangers could extend to a broader population.
Another complication that may get overlooked is how wildfire pollutants can infiltrate indoor spaces. As these substances are carried by the wind into surrounding areas, they can enter homes and offices. Once inside, they can go undetected. HEPA filters in air purifiers and furnaces are effective at limiting exposure to allergens and particulates from wood smoke. They are not designed to filter out gases and other chemical compounds. This means that both AQI and HEPA filter readings may not paint a complete picture of pollution in the wake of wildfires.
When it comes to assessing the reach of these effects on air quality, according to Dr. Maier, it’s hard to know. “When we had those fires in Alberta, Canada, in 2023, polluted air traveled across the country,” said Dr. Maier. “That was mainly wood fire smoke. But honestly, we don't know everything that was in the air after those fires.”
Given the complexity of wildfires affecting urban and suburban areas, Dr. Maier stresses the importance of prevention, awareness and protection for anyone at risk of exposure, especially those with health conditions.
Symptoms Caused by Wildfire Exposure
With more research confirming the health risks caused by wildfires, it’s crucial to monitor your symptoms in the weeks and even months following a wildfire in your region. If you have preexisting conditions, such as asthma, heart disease or COPD, you may be more at risk for complications.
According to Dr. Maier, the most common symptoms of wildfire exposure are:
- Coughing
- Headaches
- Scratchy or sore throat
- Shortness of breath
- Strange taste in your mouth
Recent research examining the impacts of the Marshall wildfires in Colorado has indicated that symptoms from wildfire exposure near a residential area can persist six months or longer. If you have noticed any of these symptoms after a wildfire, it’s important to talk to your doctor.
Ways to Protect Yourself
The impacts of wildfires can present residents and workers with a number of difficult choices. If you live near a recent wildfire, Dr. Maier recommends staying inside as much as possible. Use a HEPA filter to reduce your exposure to pollution that drifts indoors. While HEPA filters do not provide full protection from all the chemicals released by the fires, they still offer protection from the wood smoke particulates. HEPA filters can be useful, but not everyone can afford them. Fortunately, there are ways to create homemade versions that offer some protection.
If you are involved in the cleanup of a wildfire, Dr. Maier recommends wearing gloves and a respirator mask to reduce inhaling particulates. And if it is possible for you to avoid areas affected by a wildfire altogether, it’s best to do so.
Researching Solutions
Researchers are currently investigating ways to prevent further wildfires and reduce their impact on residential areas. When it comes to understanding the indoor effects of air pollution from wildfires, Dr. Maier and other medical professionals are moving toward a more boots-on-the-ground approach. In recent months, Dr. Maier, along with researcher James Crooks, PhD, began working with the city of Denver on a new Healthy Homes Program to evaluate the impact of reducing air pollution indoors on lower-income families. “When coping with wildfires, rebuilding is important. So is prevention,” said Dr. Maier, “but we also need to look at how specific homes can be affected by indoor air pollution so that we can be better prepared for the future. This is a difficult problem, but working with the communities that are the most vulnerable is an important step.”