Protecting Yourself from Wildfire Smoke
California is facing increasingly catastrophic wildfire seasons. Wildfire smoke – a complex mixture of air pollutants – is unhealthy to breathe and can be especially dangerous for children, the elderly, pregnant women and people with heart or respiratory conditions. These sensitive groups are advised to limit outdoor activities, especially when the Air Quality Index (AQI) reaches levels considered ‘Unhealthy for Sensitive Groups’ or above. Even healthy people may experience symptoms in smoky conditions or after exposure. Pets also can be affected by unhealthy air and should be brought indoors, if possible.
Smoke Ready California
California has experienced some of the most destructive wildfire seasons in recent years. Large wildfires often produce intense smoke that can pose serious health risks. There are several steps you can take now to keep your family safe before and during wildfire season.
Air Quality Guide for Particle Pollution
- For near real-time updates on air quality and smoke near you, visit the AirNow Fire and Smoke Map or the U.S. Forest Service Wildland Fire Air Quality Response Program
- For mobile devices, access air quality information for more than 150 California locations using BreatheWell
- Check with your local air district for the latest information specific to your community
Wildfires produce a range of harmful air pollutants, from known cancer-causing substances to tiny particles that can aggravate existing health problems and increase the risk of heart attack or stroke. Particulate matter (PM) is the principal pollutant of concern from wildfire smoke for the relatively short-term exposures (hours to weeks) typically experienced by the public. Particles from smoke tend to be very small (with diameters of 2.5 micrometers and smaller). They are small enough to get deep into the lungs and the tiniest, ultrafine particles can pass directly into the bloodstream. The association between PM2.5 and heart and lung health effects is well documented in scientific literature.
Larger and more frequent and intense wildfires are a growing public health problem, contributing to reduced air quality for people living near or downwind of fire. Health problems related to wildfire smoke exposure can be as mild as eye and respiratory tract irritation and as serious as worsening of heart and lung disease, including asthma, and even premature death.
While cloth face coverings offer protection against COVID-19 virus spread, they do not provide protection against smoke particles. People who must be outdoors for long periods, in areas with heavy smoke, or where ash is disturbed, may want to wear a NIOSH-certified N95 respirator mask. Those with existing respiratory, lung or heart conditions should limit their exposure by staying indoors. Since wearing a respirator can make it harder to breathe, those with lung or heart conditions should check with their doctor before using one.
NIOSH-certified N95 respirators were not widely available during the COVID-19 pandemic. This may continue to be the case in some areas as manufacturers continue to increase supply. In areas where N95 respirators are available, make sure they are NIOSH-approved. Choose a size and model that fits your face and has no gaps. Test it by doing a seal check to make sure it fits.
- CDPH: Face Coverings Q&A – COVID-19 guidance from California (as of June 2021)
- CDPH: Get the Most out of Masking – A breakdown of the different types of masks and when to use them (as of June 2021)
- Cal/OSHA: List of vendors for employers seeking NIOSH-certified N95 respirators
- CDC: NIOSH-Approved Particulate Filtering Facepiece Respirators
Protecting Yourself from Smoke
Stay Indoors and Keep Indoor Air Clean
The best way to prevent breathing harmful particles in wildfire smoke is to stay indoors.
- When air quality reaches dangerous levels due to wildfire smoke, the most effective way to reduce exposure and avoid the ill effects of smoke is to stay indoors with windows and doors closed.
- If you have a central ducted air conditioning and heating system, be sure to set the system to “on” to ensure air is being filtered constantly, rather than “auto,” which runs the system intermittently.*
- If your system brings fresh air into the home, close the fresh-air intake so that it operates in in recirculation mode to prevent outdoor smoke from getting inside.
- Install a high-efficiency filter (MERV 13 rating or higher) with a MERV rating as high as your system can handle, based on the manufacturer’s recommendation.
- Consider using a CARB-certified air cleaner which can greatly reduce indoor particle levels to further reduce impacts from smoke.
- Do not run swamp coolers or whole house fans.
- Avoid activities that increase indoor pollution, such as burning candles, using gas stoves and vacuuming.
*In the event of a Flex Alert – a call for consumers to voluntarily conserve electricity when there is a predicted shortage of energy supply, often during heat waves which coincide with wildfire season – follow all guidance from California ISO.
If you do not have a central ducted air conditioning and heating system, or if you cannot afford a CARB-certified air cleaner, there are some other steps you can take to protect yourself and your family.
Contact your local Air Pollution Control District or local governing body (city council, county board of supervisors, etc.) to see if a designated clean air center is open in your community. This could be a recreation center, library, school gymnasium or other indoor facility equipped with proper ventilation and air conditioning that is open to the public during smoke events.
Construct a temporary box fan air filter. These devices should be used with extreme caution, and only if other air cleaning options are unavailable. Only use box fans manufactured in or after 2012 – these fans will have a fused plug, which will prevent electrical fires if the device is knocked over. Attach a high-efficiency air filter (MERV 13 rating or higher) to the back of the fan using duct tape or a bungee cord, with the arrow printed on the filter pointing toward the fan (in the same direction as the airflow). Close all windows and doors when the box fan filter is being used. Change the air filter when it gets dirty. Never leave the device unattended.
Avoid outdoor activities
- People should avoid exercising outdoors during smoky conditions. Exposure and the resulting health effects depend on the amount of time spent outside, level of exertion, level of air pollution, and possible existing health conditions.
- Consider eliminating outdoor activities altogether when the AQI reaches unhealthy levels.
- Officials may call for an evacuation in emergency situations or when the AQI reaches the hazardous level. Always follow evacuation orders. In the event of an evacuation, make sure to operate your vehicle with the windows rolled up and the air conditioner set to recirculate.
Interviews with CARB experts on the following topics are available for attribution, use and download.
- Wildfire Smoke Health Risks
- Protecting Yourself from Wildfire Smoke
- Accessing Local Air Quality Information
- Air Quality Index
- Air Pollution Monitoring
To request graphics for download contact CARB's Office of Communications.
- CAL FIRE: Ready for Wildfire
- CalEPA: Fire Response and Recovery
- Cal/OSHA: Worker Safety and Health in Wildfire Regions
- CDPH: Wildfires
- California Smoke Blog
- U.S. EPA: Wildfire Smoke Guide for Public Officials
- U.S. EPA: Smoke Ready Toolbox
- U.S.F.S. Wildland Fire Air Quality Response Program: Smoke Forecast Outlooks
- CDC: Wildfire Smoke and COVID-19