Mitigating the health impacts of wildfire smoke


Last year, Californians endured one of the worst fire seasons in recent history. Homes were lost, people were evacuated and the vast majority of the Bay Area population was advised to stay indoors for weeks to avoid toxic levels of air pollution.

As we adjust to California’s “fire season,” HealthySteps to Wellness spoke with Mary Prunicki, Director of Air Pollution and Health Research at Stanford University School of Medicine and Lucile Packard Children’s Hospital, to gain insights on staying safe, healthy, and sane in the event of a wildfire. 

Climate change is expected to cause more extreme weather conditions in general. As climate change progresses, we can expect more wildfires, especially in dry regions like the Bay Area. 

There are many ways we can combat the effects of climate change, like paying close attention to Spare the Air days, which provide behavioral guidelines for preventing wildfires and preserving air quality. 

However, it is important to be realistic about the risk of wildfires and to be prepared and protected in the event of a wildfire near you.

Some populations are more vulnerable to health effects after exposure to wildfire smoke. Vulnerable populations include:

  • People with pre-existing conditions: Research has shown that people with pre-existing conditions (especially respiratory conditions) are more likely to end up in the emergency room or the hospital due to health complications from wildfire smoke.1 If you have asthma, you’re more likely to have an asthma attack when the air quality is poor, so always be prepared with your inhaler in the event of a wildfire. People with chronic obstructive pulmonary disorder (COPD) and other respiratory infections are more prone to cardiac events (like stroke, arrhythmia, or cardiac arrest) when breathing in high levels of smoke. For these people in particular, it is important to take precautions and limit smoke exposure whenever possible. 
  • People over age 65: Studies have shown that those over the age of 65 are more likely to experience cardiac health conditions, like heart attacks and arrhythmias in the event of a wildfire.2
  • Pregnant people: For pregnant people, smoke exposure can impact fetal development. In general, pregnant people are considered a vulnerable population and should be extra cautious in the event of a wildfire.
  • Infants and young children: Youth aged zero to four years are more likely to experience respiratory conditions during a wildfire because of the small size of their airways.  
  • Individuals who spend a lot of time outdoors: Those who spend a lot of time outdoors, like people experiencing homelessness, farmworkers and essential construction workers face an increased health risk during fire season.
  • People recovering from COVID-19: Another vulnerable population that we know less about are those who are recovering from COVID-19. There is a lot of research being done on that front, but current evidence shows that coronavirus alters the immune response and can lead to long-term respiratory issues, so those who are recovering from COVID should take special care in the event of a wildfire.  
  1. Filter your home air. If you have a centralized air system (and if your system can handle it), get an air filter with a 13 or higher rating. These are finer filters that will keep larger particle pollutants out of your home. Be sure to replace it regularly to keep your filter functioning effectively. 
  2. Consider investing in an air purifier. The purifier you purchase should correlate with the size of the room you’re purifying. If you’re not able to keep your entire house purified, consider having a “clean air room” where you can spend most of your time or at least where you sleep. 
  3. Block open airways. You can use basic household materials to block drafty doors and windows to prevent extra airflow into your home.
  4. Stock up on essentials. Stay stocked with medications, food items and other everyday essentials so you can minimize outside air exposure during a wildfire.
  5. Be prepared for evacuation. If there’s any chance that you’re in a high-risk fire zone, have a backpack with some non-perishable food items, water, a mask and critical medications for every member of the family, so you can grab-and-go in the event of an evacuation.
  6. Protect your outdoor space. Take care to ensure your own home doesn’t contribute to the spread of a wildfire. Some examples include thinning vegetation around your property and keeping combustible materials (like a grill) away from your home. Learn more about avoiding wildfire damage.
  7. Protect yourself while driving. When you ride in a car, keep the windows up and put the air on to recirculate to avoid taking in extra smoke contaminants from outside. 

If you need to go outdoors during a wildfire, try to time your activity for when the air quality is not so bad. is a great source for real-time air quality reports and forecasting. If you or your kids are cooped up for a long time and need to get outside, try to time the outdoor activity for when the air quality is better. It is recommended to restrain from intense physical activity outside, because the deep breathing that occurs with more vigorous exercise increases exposure to air pollutants. 

If you need to venture outdoors while the air quality is poor, wearing an N95 mask can help keep you protected from harmful air pollutants. The N95 mask must have a strong seal in order to be protective, so be sure to secure your mask firmly. Most masks, aside from N95 masks, do not provide adequate protection against the air particles and remnants from a fire. 

Most wildfires occur during the hottest points of the year. While centralized air conditioning systems can filter out air pollutants, most window units don’t have a filter that’s adequate to filter out remnants from a wildfire. Keeping the windows closed and the airways secured can help preserve your respiratory health during a fire, but it can also put you at risk for things like heat exhaustion if you are not using an air conditioner. If a wildfire occurs during a heat wave, you will have to make the decision that’s best for you. It is really up to you and your medical provider to determine what is the best choice for your overall health.

There was a study in Canada that looked at the rates of ambulance calls during a wildfire and they found that within two hours of a community experiencing wildfire smoke, there was a dramatic increase in respiratory distress calls, meaning the impact can be quick.3  There was a study in California showing that when people are exposed to wildfire smoke there’s an increase in sudden cardiac deaths.4 Caring for your health during a wildfire is something to take seriously, and the sooner the better.

If there is smoke exposure and you’re experiencing any type of symptoms, it’s always advantageous to ask your medical care team if they want to do any type of preventive check-in with you. For example, if you think you might be heading towards an asthma exacerbation, it’s much better to seek care beforehand and get on the proper medications to prevent a full-blown asthma attack. 

Being in a wildfire is going to be stressful. On top of that, fire season can lead to more isolation, which can increase the risk for mental health conditions. There are studies that show an association between poor air quality and increased risk of mental health conditions, independent of other factors.5 Worrying about things like your house burning down or the safety of your family does not help. 

Try your best to minimize the impact of being isolated — this is one factor that we can control that we know makes a difference. Be proactive about seeking mental health support if you need it. Also, try your best to keep the air quality clear in your home, so you feel you have a safe place to rest.

If you’re continually exposed to smoke (for example, when we look at the long-term health effects of retired firefighters) we see an increased risk of certain types of cancers and a decreased life expectancy. Where the research falls short is understanding how prolonged smoke exposure from wildfires affects the general population. What we know more about at this time is the immediate effects of smoke exposure on the more vulnerable populations. The long-term health consequences for healthy individuals is still being determined.

Preparation and education are key.

Although wildfires pose a health risk to those living in the Bay Area and other fire-prone zones, you can mitigate your risk by staying educated and prepared in the event of a wildfire. Share what you know with your family and friends, and do what you can to protect yourself and your community, since we are all in this together.



August 2021