Smoke From Fires

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. The main sources of outdoor smoke in Washington are:

  • Wildfires
  • 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 Considerations: Both wildfire smoke and COVID-19 impact your respiratory and immune system, and increasing 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 dry cough, sore throat, and difficulty breathing, are common to both wildfire smoke exposure and COVID-19. Experiencing both the COVID-19 pandemic and long periods of wildfire smoke can impact mental and behavioral health.

Exposure to smoke from fires can cause several health problems that range from minor to severe. The worst symptoms more often occur in people with pre-existing conditions. When smoke levels are high, even healthy people can have symptoms or health problems. Some symptoms include:

  • Eye, nose, and throat irritation (burning eyes and runny nose)
  • Fatigue
  • Headache and coughing
  • Wheezing and shortness of breath
  • Aggravation of existing especially heart and lung diseases, with symptoms like asthma attacks, chest pain, or irregular heartbeat
  • Mental health concerns and psychological stress

Seek medical attention when experiencing severe symptoms, such as chest pain or difficulty breathing, during wildfire smoke events.

COVID-19 Considerations: 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.

Who is especially sensitive to smoke?

COVID-19 Considerations: 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. There are groups of people with increased risk for sever health impacts, such as hospitalization or death, including:

  • 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, congestive heart failure, or coronary artery disease.
  • 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.
  • Outdoor workers because they often spend more time outside and are exposed to smoke longer.
  • People of color and tribal and indigenous populations because of institutional and structural discrimination that often put these populations in challenging life circumstances and unhealthy environments.
  • People with low income because they are more likely to have higher exposures and are less likely to have access to healthcare or to be able to afford interventions to reduce exposure.
How can I find out about the current air quality?
What can I do to protect myself and my family from outdoor smoke?

COVID-19 Considerations: The best way to protect you and your family from smoke 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 recommendations, it might not be as 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 the possibility of capacity limitations, physical distancing, and/or mask requirements. Being vaccinated for COVID-19 can help protect you and your family from getting seriously sick if you are seeking shelter elsewhere.

Increasing ventilation by opening your windows for outside air can help reduce the spread of COVID-19. When it’s smoky outside,  increase filtration of indoor air, and bring in outside air when air quality improves. Increased filtration is part of reducing transmission of COVID-19 and can help protect you from both smoke and COVID-19. Follow other steps to reduce exposure to each hazard, such as masking if there is someone sick in your household.  

If you decide to leave the area and visit friends or relatives to get away from smoke, consider vaccination status and whether you or the people you are visiting are more sensitive to COVID-19.

  • Stay updated on current and forecasted air quality. See “How can I find out about the current air quality?” above for more resources.
  • Limit duration and intensity of outdoor physical activity.
  • Stay indoors with cleaner indoor air.
    • Close windows and doors’ unless it is too hot to maintain safe temperatures. See “What if I don’t have air conditioning and it’s hot indoors?” below.
    • Filter indoor air through an HVAC system, HEPA portable air cleaner, or DIY box fan filter (See “How can I improve filtration in my home to reduce smoke levels?” below). Don’t add to indoor pollution. This is always good practice, but especially when it’s smoky.
      • Avoid burning candles incense, and wood in fireplaces.
      • Avoid using sprays, diffused essential oils, and fireplaces.
      • Avoid broiling or frying food and limit use of gas stoves.
  • Avoid smoking indoors.
  • Avoid vacuuming unless your vacuum has a HEPA filter, because vacuuming stirs up particle Set air conditioning to recirculate.
  • If unable to maintain cleaner air at home, go elsewhere for cleaner air such as a friend’s place, public space, or unimpacted area.
  • If you must be outside for a limited duration, consider wearing a properly fitted NIOSH-approved particulate respirator, such as an N95 mask. (SeeShould I use a respirator when there is outdoor smoke?” below).
  • If you have asthma or other lung diseases, follow your healthcare provider’s advice and asthma action plan if you have one.
What if I don't have air conditioning and it's hot indoors?

COVID-19 Considerations: It might not be safe or as easy to go to public spaces to seek cleaner and cooler indoor air away from home . 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 the possibility of capacity limitations, physical distancing, and/or mask requirements. If you decide to leave the area and visit friends or relatives to get cooler, consider vaccination status and whether you or the people you’re visiting are more sensitive to COVID-19. 

Without an air conditioner or a central cooling system, it can be challenging to keep cool inside while keeping windows closed to keep smoke out . Pay attention to heat, as heat-related illness can occur quickly and be life threatening. If it's hot indoors during poor air quality, these steps can help you stay cooler:

  • Close curtains or shades during the day, and use portable fans.
  • Use your stove less often.
  • Cool off by taking a cool bath or shower. Use ice packs or put your feet in cool water. Apply wet rags on the back of your neck or mist yourself with water while sitting near a fan.
  • 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.
  • Only open windows when it is cooler outside than inside, and, if possible, take steps to filter indoor air (See “How can I improve filtration in my home to reduce smoke levels?” above).
  • For more information about preventing heat-related illness, follow DOH's hot weather safety guidance or CDC's Tips for Preventing Heat-Related Illness.
Should I use a respirator when there is outdoor smoke?

COVID-19 Considerations: Going indoors where there is cleaner air is usually the best option for reducing exposure to smoke, but respirators can be helpful in some situations. The supply and availability of N95 and other NIOSH-approved respirators has improved. N95 respirators with exhalation valves can protect you from wildfire smoke and  COVID-19. However, if you have COVID-19, an N95 respirator with a valve may not protect others as well as an N95 without a valve. Cover the valve to protect others. 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, surgical masks, and masks with filter inserts generally do not provide much protection from breathing in the fine particles in smoke.

Respirators 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, find other ways to reduce your exposure. or you must be outside, certain types of respirators can provide some protection. N95 or other NIOSH-approved respirators filter out fine particles but not hazardous gases (such as carbon monoxide). These respirators 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. Respirators also do not work for everyone.

  • Respirators will provide less protection for people with beards and facial hair because they do not seal as well to the face.
  • Respirators are not always designed for infants or small children, and there are concerns about their use for children, including fit.
  • Wearing a respirator makes it more difficult to breathe. Anyone with lung disease, heart disease, or who is chronically ill should consult a health care provider before using a respirator.
  • More information: Wildfire Smoke and Face Masks Fact Sheet (PDF).

In indoor spaces where you do not have the ability to keep windows closed or filter indoor air, wearing an N95 respirator for short durations could be helpful if outdoor smoke levels are high. Examples of these spaces could include public transportation and commercial or public buildings.

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 Consideration: Increased filtration is part of reducing transmission of COVID-19 and can help protect you from both smoke and COVID-19. Follow other steps to reduce exposure to each hazard, such as masking if there is someone sick in your household.  

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, use a filter rated for particle removal.  This will  reduce fine particles from wildfire smoke throughout your home.

  • 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, “on” instead of “auto.”
  • Close the fresh air intake to keep smoke out.
  • Change the filter when dirty or as indicated by the manufacturer's instructions or an HVAC professional. This will be needed more often during long periods of smoke.

2. HEPA portable air cleaners can improve indoor air quality by removing particulates from smoke in a single room or designated space. HEPA air cleaners that include charcoal filters can also remove some harmful gases from indoor air.

  • 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 or space 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, electrostatic precipitators and ionizers, or negative ion air purifiers because they can produce harmful by-products.. Ozone is a respiratory irritant that can aggravate asthma and other lung diseases. Check that it has been certified to produce little or no ozone (less than 5 ppb 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 the 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 or designated space. When building your own box fan filter, it is important to understand its limitations. While testing by UL in collaboration with EPA found no safety concerns, box fans are not designed to operate with a filter attached, and effectiveness varies with the design and supplies selected. EPA does not recommend them as a permanent alternative to products of known performance, like commercially available HEPA portable air cleaners.

  • Select a standard box fan and a filter with a MERV 13 rating of the same dimensions.
  • Select a 2012 or newer standard 20” x 20” box fan and the number of MERV 13 filters of the same size for the design that you select.
    • Look for one with a UL or ETL safety marking. Newer models have added safety features.
    • Box fans built before 2012 may pose a fire risk. If you use an older model fan, do not leave it unattended or use while sleeping.
    • 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.
  • Follow the box fan manufacturer’s instructions, including:
    • Do not leave children unattended when in use.
    • Do not use an extension cord.
  • Place the constructed DIY box fan filter in a room you plan to spend most of your time in and where you can keep windows and doors closed. It will be more effective in smaller rooms.
    • Position the filter  at least a foot away from walls, furniture, or other objects so the air flow of the fan is not blocked.
    • Do not operate in a window.
    • Puget Sound Clean Air Agency found that it takes at least 10 to 15 minutes to clean a smaller room (15’ x 15’).
  • Keep windows and doors closed.
  • Change the filter when dirty. This may be more often during smoke events.

For more information about keeping indoor air free of smoke, see EPA's Indoor Air Filtration Factsheet (PDF).

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.

Some people are especially sensitive to lower levels of smoke and may start to have symptoms when air quality is in the Moderate category, such as people with asthma and lung and heart conditions. It's recommended they take steps to reduce exposure.

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, and you may need to adjust as you would during other weather hazards to drive safely.

What can schools do to protect children students during smoky conditions?
Can smoke impact my mental health?
  • Long periods of wildfire smoke can impact mental and behavioral health. Wildfire smoke and disasters impact our daily routine, including limiting the time we spend outside and changing activities. There may be feelings of isolation from staying inside or sadness from the lack of sunshine. Smoke is also a direct threat to health and safety.
  • Protecting mental health and physical health are both extremely important.
    • Social connection is key. Identify someone you can ask for help and one person who may need your help. Check in with loved ones throughout a wildfire smoke episode.
    • Spend time with loved ones in areas of the home that have cleaner air or go to a public space with cleaner air together.
    • Build DIY box fan filters together
    • Get some light exercise indoors.
    • Follow other tips to take care of your emotional health.