COVID-19 and Wildfire Smoke
This wildfire season will again be especially challenging with the ongoing COVID-19 pandemic. There is concern about health impacts of wildfire smoke overlapping with COVID-19 because both impact respiratory and immune systems. Local COVID-19 restrictions may limit how we can reduce our exposure to wildfire smoke.
For public health and air quality officials: Guidance for wildfire smoke and COVID-19 during the 2021 wildfire season (PDF)
Outdoor smoke contains very small particles and gases, including carbon monoxide. These particles can get into your eyes and lungs where they can cause health problems. Main sources of outdoor smoke in Washington:
- Wood stoves, pellet stoves, and fireplaces
- Agricultural burning
- Prescribed fires (used to manage forests)
Frequently Asked Questions
- What health problems can smoke cause?
COVID-19: Both wildfire smoke and COVID-19 impact your respiratory and immune systems, and early evidence suggests experiencing both can lead to worse health impacts. If you have COVID-19, breathing in wildfire smoke may make your symptoms worse. Wildfire smoke can make you more susceptible to respiratory infections, likely including COVID-19. Some symptoms such as cough, sore throat, and difficulty breathing, are common to both wildfire smoke exposure and COVID-19. Experiencing both the COVID-19 pandemic and bad wildfire smoke may also be harmful to mental health.
Exposure to smoke from fires can cause several health problems that range from minor to severe. Some symptoms include:
- Eye, nose, and throat irritation (burning eyes and runny nose).
- Headache and coughing.
- Wheezing and shortness of breath.
- Aggravation of existing lung, heart and circulatory conditions, including asthma and angina.
- Mental health concerns and psychological stress.
- Who is especially sensitive to smoke?
COVID-19: Some of those especially sensitive to smoke are also those most at risk for COVID-19. People with, or recovering from, COVID-19 may be more at risk for more severe health effects from wildfire smoke exposure because of compromised lung and heart function.
Inhaling smoke is not good for anyone, even healthy people. Most people are likely to have minor symptoms. Several groups of people, especially those with pre-existing heart and lung conditions, are more at-risk for severe health impacts. People most likely to have health problems from breathing smoke include:
- People with lung diseases such as asthma or chronic obstructive pulmonary disease (COPD), including bronchitis and emphysema.
- People with respiratory infections, such as pneumonia, acute bronchitis, bronchiolitis, colds, or flu.
- People with existing heart or circulatory problems, such as dysrhythmias, congestive heart failure, coronary artery disease, and angina.
- People with a prior history of heart attack or stroke.
- People with diabetes because they are more likely to have an undiagnosed cardiovascular disease.
- Infants and children under 18 because their lungs and airways are still developing and they breathe more air per pound of body weight than adults.
- Older adults (over age 65) because they are more likely to have unrecognized heart or lung diseases.
- Pregnant women because both the mother and fetus are at increased risk of health effects.
- People who smoke because they are more likely to already have lower lung function and lung diseases.
- People with low socioeconomic status because they are more likely to have higher exposures and less likely to have access to healthcare.
- How can I find out about the current air quality?
- How can I tell if smoke is affecting my family?
COVID-19: Some respiratory symptoms, including cough, sore throat, and difficulty breathing, are common to both wildfire smoke exposure and COVID-19.
- Smoke can cause coughing, scratchy throat, irritated sinuses, shortness of breath, chest pain, headaches, stinging eyes, and runny nose.
- If you have heart or lung disease, smoke might make your symptoms worse.
- People who have heart disease might experience chest pain, a rapid or irregular heartbeat, shortness of breath, and fatigue.
- If you have a pre-existing respiratory condition such as asthma, COPD (including chronic bronchitis and emphysema), or allergies, smoke may worsen symptoms (inability to breathe normally, cough with or without mucus, chest discomfort, wheezing, and shortness of breath).
- When smoke levels are high, even healthy people can have symptoms or health problems.
Contact your health care provider if you have heart or lung problems when around smoke. Dial 911 for emergency assistance if symptoms are serious.
COVID-19: Seek medical attention when experiencing severe symptoms, such as chest pain or difficulty breathing, during wildfire smoke events. If you have a fever, cough, or shortness of breath, it is best to treat it like it could be COVID-19. Protect others by staying home. If you are concerned about your health, call your health care provider to discuss COVID-19 testing and other possible reasons for your illness.
- What can I do to protect myself and my family from outdoor smoke?
COVID-19: The best way to protect you and your family when the smoke levels rise is to stay indoors and keep the indoor air as clean as possible by closing windows and doors and taking steps to filter your indoor air. Depending on local COVID-19 restrictions, it might not be safe or as easy to go to public spaces to seek cleaner and cooler indoor air away from home. Check in advance to see if these places are open and be prepared for lower capacity, to physically distance, or wear a cloth face covering. Being vaccinated for COVID-19 can keep you safe if seeking shelter elsewhere.
Increasing ventilation by opening your windows for outside air can help reduce the spread of COVID-19. When outside air needs to be reduced because of high levels of smoke, increase filtration of indoor air and bring in outside air when air quality improves. Improving the air filtration in your home can help reduce both exposure to smoke and the spread of COVID-19, but filtration alone is not enough to protect you from COVID-19. See question 8 for information on how to filter indoor air. Follow current public health recommendations for COVID-19 and get a vaccine.
If you decide to leave the area and visit friends or relatives to get away from smoke, consider COVID-19 restrictions in the county you are traveling to and with the people you are visiting, including vaccination status. This is particularly important if either they or you are more sensitive to COVID-19. Get a COVID-19 vaccine to be able to safely reduce exposure to smoke together with friends or neighbors, and follow local guidance on indoor gatherings.
- Stay updated on current and forecasted air quality. See question 3 above for more resources.
- Avoid physical exertion outdoors if smoke is in the air.
- If you have asthma or other lung diseases, make sure you follow your doctor's directions about taking your medicines and follow your asthma management plan. Call your health care provider if your symptoms worsen.
- Stay indoors and keep indoor air as clean as possible. Take the following steps when indoors during smoke events:
- Keep windows and doors closed. Track the air quality and open your windows for fresh air when the air quality improves. Pay attention to the heat indoors and follow guidance in question 6 below if it's too hot.
- Improve the filtration in your home. Three options are described in question 8 below.
- Run an air conditioner, set it to recirculate and close the fresh-air intake. Make sure to change the filter as the manufacturer recommends. It may get dirty faster when smoke is prolonged or at high levels.
- Don't add to indoor pollution.
- Avoid using candles, incense, sprays, fireplaces, or gas stoves.
- Avoid diffusing essential oils.
- Don't broil or fry food or smoke cigarettes indoors.
- Avoid vacuuming unless your vacuum has a HEPA filter, because vacuuming stirs up particles already inside your home.
- Consider leaving the area if the air quality is poor and it's not possible to keep the indoor air clean, especially if you or those you are caring for are having health problems or are in a sensitive group. See section above for who is especially sensitive to smoke.
For more information about keeping indoor air free of smoke, see EPA's Indoor Air Filtration Factsheet (PDF).
- What if I don't have air conditioning and it's hot indoors?
COVID-19: It might not be safe or as easy to go to public spaces to seek cleaner and cooler indoor air away from home this year. With the crowding of people at these settings, there is an increased risk of COVID-19. Check in advance to see if these places are open and be prepared for lower capacity, to physically distance, or wear a cloth face covering. If you decide to leave the area and visit friends or relatives to get cooler, consider COVID-19 restrictions in the county you are traveling to and with the people you are visiting, including vaccination status. This is especially important if either they or you are more sensitive to COVID-19. Get a COVID-19 vaccine to be able to safely stay cool together with friends or neighbors, and follow local guidance on indoor gatherings.
Without an air conditioner or a central cooling system, it can be challenging to manage indoor temperatures while keeping out smoke. Heat-related illness can occur quickly and be life threatening, so it's important to know the signs and prevent overheating. If it's hot indoors during poor air quality, these steps can help you stay cooler:
- Reduce the heat indoors: close curtains or shades during the day, use your stove and oven less, and use portable fans.
- Cool off by taking a cool bath or shower. Use ice packs or put your feet in cool water.
- Stay hydrated, especially with water. Avoid sugary or alcoholic drinks since these can be dehydrating.
- Go to an indoor place that is cooler—even if only for a few hours. Try to choose a place with cleaner air.
- Track the air quality and open your windows when the air quality improves and outdoor temperatures are cooler than inside.
- If it's still too hot and the outside air quality is poor: open windows when outdoor temperatures are cooler than inside and take steps to filter indoor air (see question 8).
- For more information about preventing heat-related illness, follow our hot weather safety guidance or CDC's Tips for Preventing Heat-Related Illness.
- Should I use a face mask when there is outdoor smoke?
COVID-19: Face masks are not the best option to reduce exposure to smoke. While the supply and availability of N95 and other NIOSH-approved respirators has improved, the market can be unpredictable, and if they are in short supply in your area, they should be reserved for those required to wear them for work. NIOSH-approved respirators may be available in smaller quantities in local hardware stores for purchase but be mindful of purchasing respirators in bulk. N95 respirators with exhalation valves can provide protection from wildfire smoke, but they are less effective in preventing the spread of COVID-19. KN95 masks or other masks that are approved in other countries may not provide the same protection as those that are NIOSH approved because they are not regulated in the United States. If using a KN95 mask, look for ones that meet requirements similar to NIOSH-approved respirators. Cloth face coverings and surgical masks generally do not provide much protection from breathing in the fine particles in wildfire smoke. If you have to go outside, using the best mask available and wearing it properly can be a helpful option for some people and a limited time. Follow local COVID-19 guidance on face coverings.
Face masks are not your best option to reduce exposure—it is better to stay indoors and filter indoor air to keep it clean. If you cannot leave the smoky area or find other ways to reduce your exposure or you must be outside, certain types of face masks can provide some protection. NIOSH-approved N95 or N100 respirator masks filter out fine particles but not hazardous gases (such as carbon monoxide). These masks can be found at many hardware and home repair stores and pharmacies. It's important to take necessary steps to wear it correctly to achieve a proper fit and seal to provide protection. If worn improperly, it may not provide as much protection. Face masks also do not work for everyone.
Masks will provide less protection for people with beards and facial hear because they do not seal as well to the face.
Masks are not always designed infants or small children, and there are concerns about their use for children, including fit.
Anyone with lung disease, heart disease, or who is chronically ill should consult a health care provider before using a mask. Wearing a mask makes it more difficult to breathe, which may worsen existing medical conditions.
- More information: Wildfire Smoke and Face Masks Fact Sheet (PDF)
Watch this video on how to properly use an N95 respirator.
- How can I improve filtration in my home to reduce smoke levels?
Covid-19: While ventilation and filtration can help reduce the risk of COVID-19, these alone are not enough to protect you from spread of the virus. Follow other best practices to reduce the spread of COVID-19 and get a vaccine.
Filtration of air in your home will improve the indoor air quality and reduce your exposure to smoke during wildfire smoke events. Three options are described below. There are different technical considerations, equipment, and supplies with each of these options. Buy necessary materials before wildfire season as supplies will sell quickly once wildfire smoke hits.
1. If you have a heating, ventilation, and/or air conditioning (HVAC) system, this can be the best way to reduce fine particles from wildfire smoke throughout your home, rather than a single room.
- Consult your HVAC manual or consult with an HVAC professional before making improvements.
- Increase the filtration in your home HVAC system to a MERV 13 rated filter or the highest rated filter your system will handle. Select a filter with the deepest pleat your system can accommodate to prevent excess strain on the system. The filter must fit tightly.
- Set the system fan to recirculate and a continuous running fan mode, such as “on” instead of “auto.”
- Close the fresh air intake while there is poor outside air.
- Change the filter when dirty or as indicated by the manufacturer's instructions or an HVAC professional.
2. Portable air cleaners with HEPA filters can improve indoor air quality by removing particulates from smoke. HEPA air cleaners with charcoal filters can also remove some harmful gases from indoor air. Consider using portable air cleaners in the room where you spend most of your time, which is often a bedroom, with the windows and doors closed.
Select a portable air cleaner with a true HEPA filter. Beware that some portable air cleaners claim to have “HEPA like” filters.
Select one that is rated for the size of the room where you plan to use it. The clean air delivery rate (CADR) is a rating given to the portable air cleaner based on its fan speed and filter efficiency. The smoke CADR should be equal to the square footage of the intended room of use.
Consider the noise rating, as some can be quite loud. Choosing a portable air cleaner with a CADR for a larger size room and running it at a lower setting will reduce the noise.
Do not use ozone generators, personal air purifiers electrostatic precipitators, or ionizers that produce ozone. Ozone is a respiratory irritant that can aggravate asthma and other lung diseases. Check that it has been certified to not produce little or no ozone through the California Certified Air Cleaning Devices portal.
Place the portable air cleaner in a room where you spend time, with the windows and doors closed. When starting up the portable air cleaner, or if you choose to change the room where you use the portable air cleaner, be aware that it will take some time for the fine particles to decline.
Change the filter when dirty or as indicated by manufacturer's instructions.
- For more information, see California Air Resources Board Air Cleaner Information for Consumers and List of CARB-Certified Air Cleaning Devices.
3. Making your own box fan filter can be a less expensive option to filter air and improve indoor air quality in a single room. When building your own box fan filter, it is important to understand their limitations and the potential risk. Box fans are not designed to operate with a filter attached, and there is limited research on their effectiveness, safety, and operation.
- Select a standard box fan and a filter with a MERV 13 rating of the same dimensions.
Use a box fan with multiple speed settings and a safety fuse.
It's helpful to select a fan where the control settings and power cord are located on the exterior rim of the fan so that they are accessible after the filter has been attached.
- There are different designs to consider, such as the filter is attached by bungee cord, the filter is screwed on by brackets, or two filters that attach to create a triangle shape. A design with multiple filters can reduce the burden on the fan motor.
- WA Department of Ecology's video on how to make your own clean air fan
- Puget Sound Clean Air Agency's info on DIY air filters
- Colville Tribes Air Quality Program box fan filter a DIY users guide
- BC Centre for Disease Control's factsheet on Home-made Box Fan Air Filter
- Place the constructed DIY box fan filter in a room where plan to spend most of your time with and where it is at least a foot away from a wall, furniture, or other objects so that the air flow of the fan is not blocked.
- Keep windows and doors closed.
When starting up the DIY box fan filter, or you choose to change the room where you use the portable air cleaner, be aware that it will take some time for the fine particles to decline.
Do not run the fan on high speed.
Do not run unattended and monitor for overheating to reduce the risk of fire.
Change the filter when dirty.
- Should I exercise when it's smoky?
Exercise is very important for health. When you exercise your air intake is increased, which means inhaling more pollution when the air quality is bad. Exercise indoors, but if your indoor air is smoky, keep activities light.
People have a wide range of responses to smoke at low and high levels, and it is important to pay attention to your own symptoms and adjust your activities as needed. As general guidance, if you are sensitive to smoke, you should limit your activities when air quality is in the Unhealthy for Sensitive Groups category. People with asthma and lung and heart conditions may be very sensitive to poor air quality and may start to have symptoms when air quality is in the Moderate category and they should consider reducing indoor and outdoor activities.
- What should I do if I have to drive when it's smoky?
Avoid driving, when possible. If you must drive, keep the windows closed. Use the air conditioner and set filtration to recirculate. Most vehicles can recirculate the inside air which will help keep the smoky air out, however carbon dioxide levels can build up and cause sleepiness. You may have to shift from recirculating air to drawing in fresh air periodically. Maintain your car intake filters. Smoke can also impact visibility.
- What can schools do to protect students during smoky conditions?
- Department of Ecology Resources
- Wildfire smoke information
- Burn bans
- Washington Air Monitoring Network (current and forecast air quality conditions)
- Washington clean air agencies
- Wood stoves
- Outdoor and residential burning
- Agricultural burning
- Report illegal burning
- Burning alternatives
- Additional Resources
- Mobile Phone Apps
- COVID-19 and Wildfire Smoke Resources