California Wildfires and the Health Risks of Smoke Exposure: What You Need to Know in 2025
As the Palisades, Woodley, Easton, and Hurst wildfires devastate Los Angeles County, displacing over 100,000 residents, the potential health impacts of the smoke may not be an immediate concern for many. However, in addition to the direct threat posed by the fires, the air pollution caused by wildfire smoke—billowing clouds of ash and smoke drifting across the region—can significantly affect health. Experts warn that inhaling toxic particulate matter released by wildfires is linked to a range of respiratory and cardiovascular issues. Taking preventative and protective measures to limit exposure to wildfire smoke can help mitigate some of these health risks.
Consistent evidence shows that breathing large amounts of particulate matter from smoke can cause irritation of our mucous membranes (in our nose, sinuses, throat and lungs). It can exacerbate underlying conditions, such as asthma, heart disease, COPD, and emphysema. For those in areas where air quality is severely impacted, the risk of exacerbating these conditions is high. Unfortunately, prolonged exposure to dense wildfire smoke is associated with other health events.
The Health Toll of Wildfire Smoke
Recent studies, including one from the University of California San Francisco, underscore the significant health risks posed by wildfire smoke. The research reveals that people exposed to heavy wildfire smoke are at a heightened short-term risk for serious health issues like heart failure, stroke, and ischemic heart disease (Wettstein et al., 2018). Even more concerning, the study found that during heavy smoke days, emergency room visits for heart attacks surged by 42%, especially among older adults.
The link between wildfire smoke and cardiovascular events is thought to stem from the inflammation triggered when tiny particles from smoke are inhaled. These particles can irritate the lungs and lead to systemic inflammation, which in turn may trigger heart problems. Inhalation of wildfire smoke doesn't just affect the lungs. It can have far-reaching effects on the heart and blood vessels, especially for vulnerable populations such as the elderly and those with preexisting conditions. This is why taking steps to reduce your exposure to air pollution and particulate matter is important.
Protect Yourself from the Smoke
Given the ongoing wildfire crisis in the Los Angeles area, taking measures to protect your health from harmful smoke exposure is important. While some of these proactive steps require resources that may not be accessible to everyone, they help reduce the risks associated with wildfire pollution. (I have also included some low-cost alternatives.) Here are some ideas as to how to prevent excessive or prolonged exposure to smoke, protect your health, and promote well-being:
Stay Indoors with Air Filtration
Photo: Image of air purifier
Close all windows and outside doors to keep smoke from entering. For an added layer of protection, consider using weatherstripping products like high-density foam or caulking to seal gaps around windows or doors. Although it may not be as effective, for a quick and low-cost fix, you can also try lining a leaky windowsill with a towel (or two).
Clean the air indoors. Consider using a non-ozone producing HEPA air purifier. If you have a central HVAC system, upgrading your filter to one that is rated MERV 13 or greater can help trap harmful particulate matter. There is also a relatively inexpensive yet effective do-it-yourself version of a room filter comprised of a box fan, duct tape, and an air filter (with thanks to the Mariposa County Health and Human Services Agency).
If you have air conditioning or heat, check that it is set to recirculate so you are not bringing smoke inside.
Create a “clean room” - a designated space with an air purifier, where you and/or your family (and pets) can spend most of your time. The smaller the room, the easier it will be for your air purifier to clean the air. Make sure the windows are properly sealed. Ideally, this would also be the room that you (and possibly your pets) are spending the most amount of your time. Take into consideration:
· square footage of the room
· the air purifier’s capacity to clean that area
· where you spend the most amount of time
Monitor Air Quality and Limit Outdoor Activities (if air quality is poor)
Before venturing outdoors, check the air quality index (AQI) to determine whether it’s safe to go outside. The following are helpful sites that provide real-time air quality data:
Image of Los Angeles, January 9, 2025 from Purpleair
· If the air quality is poor, try to limit outdoor activities, especially strenuous exercise. If possible, time your outdoor activities for when the air quality is better.
Image of protective gear
· When you go outside, consider wearing a properly fitted mask that offers protection from wildfire smoke, specifically an N95 or better. The hierarchy of recommended masks start with N95, then N100, P100 (P designation is resistant to oil) and P100+ organic vapor (the prior masks only capture particles, not gas-phase toxins. If you’re on the frontline as a responder, this is what you will want to wear). Note that people with certain heart or lung conditions, it is always best to consult your health care practitioner about prolonged use of a mask.
· Avoid strenuous activity outdoors (if possible).
Minimize Indoor Air Pollution
Consider taking efforts to avoid creating additional sources of particulate matter indoors:
Don’t burn incense, candles, cigarettes or cigars.
Postpone that big cooking project on your gas stove unless your kitchen is well-ventilated with a range hood.
Replace the filter on your vacuum cleaner if you must vacuum.
Additional tips and tricks:
Applying plastic over windows can add another layer of protection against smoke, especially if you notice any air leaks around your windows. Insulating film window kits are available at many hardware stores and online. Glad Press N’ Seal wrap and painter’s tape is a quick fix that can be used to cover windows in “clean rooms.” This, paired with air purifiers, can lead to a dramatic reduction of smoke in the clean rooms.
Also, check the airflow by your fireplace. Make sure the damper is closed. If you’re going for absolutely minimal particulate matter, then consider sealing off any regular fireplace with the insulating film window kits or Glad Press N’ Seal and painter’s tape.
Final Thoughts
While there’s no easy way to fully eliminate the risks posed by wildfire smoke, taking the right preventive and protective measures can mitigate many of the harmful effects. As a Northern Californian, whose family lost their generational home last year in a fire, my heart goes out to all those affected by the wildfires in California.
May you be safe,
Michelle