Smoke From Fires

Outdoor smoke contains very small particles and gases. 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?

Exposure to smoke from fires can cause or worsen several health problems that range from minor to severe. When smoke is present, the worst symptoms more often occur in people with chronic conditions, though everyone 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 conditions, particularly 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 and in the week after.

Who is especially sensitive to smoke?

Inhaling smoke is not good for anyone. Everyone should take steps to reduce exposure and monitor symptoms during and following smoke events. Most often when people are exposed to lower levels of smoke, they have minor symptoms like sore throats and headaches. As the smoke levels increase, especially for sensitive groups, the impacts can worsen and become severe. Many people are at increased risk of severe health impacts. This includes:

  • People with lung diseases, such as asthma or chronic obstructive pulmonary disease (COPD), including chronic bronchitis, and emphysema.
  • People with current or recent respiratory infections, such as COVID-19, 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.
  • People 18 and younger because their lungs and airways are still developing, and they breathe more air per pound of body weight than adults.
  • People older than 65 because they are more likely to have unrecognized heart or lung diseases.
  • Pregnant people because both the pregnant person 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 people 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 health care 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?
  • 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. See “Should I exercise when it's smoky?” below.
  • 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 and a 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, or air fresheners.
      • Avoid broiling or frying food, and limit use of gas or propane stoves or ovens.
      • Avoid smoking or vaping indoors.
      • Avoid sweeping or vacuuming unless your vacuum has a HEPA filter, because vacuuming and sweeping stir up particles.
      • Set HVAC to recirculate mode or close the outdoor/fresh air intake.
      • Avoid using gas or propane furnaces or heaters.
    • Create a cleaner air room. Watch a video and learn how to create a clean room, EPA
    • During long-term smoke events, take advantage of periods of improved air quality, such as during rain or shifts in wind, to open windows and the fresh air intake on your HVAC system.
  • 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. (See “Should I use a respirator when there is outdoor smoke?” below).
  • If you have asthma or other lung diseases, follow your health care provider’s advice and asthma action plan, if you have one.
What if I don't have air conditioning and it's hot indoors?

It can be a challenge to keep smoke out when it’s hot, especially without an air conditioner or central cooling system. Pay attention to rising temperatures, as heat-related illness can occur quickly and can be life threatening. If it's hot indoors during poor air quality, these steps can help you stay cool:

  • Close windows and curtains or shades during the day and use portable fans.
  • Minimize use of your stove and oven during the hottest parts of the day.
  • Cool off by taking a cool bath or shower. Be mindful of extreme temperature changes, which can cause life-threatening issues.
  • 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. For updated information on cooling centers in your community, visit Washington 2-1-1.
  • Track the air quality (See “How can I find out about the current air quality?” above) 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?” below). An open window is most effective when a door or additional window can be opened to provide a cross draft.
  • For more information, see the handout Cooling Indoor Spaces Without Air Conditioning (PDF)
  • To check your area's current and forecasted heat risk and find suggestion precautions, see CDC's HeatRisk

For information about preventing heat-related illness, follow DOH's hot weather safety guidance or CDC's Preventing Heat-Related Illness.

Should I use a mask when there is outdoor smoke?

When you have no other way to avoid wildfire smoke, certain types of masks can provide some protection. N95 masks filter out most fine particles in smoke 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 them correctly to achieve a proper fit and seal to provide protection. If worn improperly, they may not provide as much protection. 

Masks also do not work for everyone: masks will provide less protection for people with beards and facial hair because they do not seal as well to the face. N95 masks do not come in suitable sizes for very young children and have not been tested for broad use in children. Effective use requires proper selection, size, and fit. See Western States PEHSU guidance (PDF) on mask use by children. Wearing a mask 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 mask. More information on proper use and fit: Wildfire Smoke and Face Masks Fact Sheet (PDF). See NIOSH's Personal Protective Equipment for the Public.


In indoor spaces where you do not have the ability to keep windows closed or filter indoor air, wearing an N95 mask 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 mask.

How can I improve filtration in my home to reduce smoke levels?

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. For more information, see EPA's What is a MERV rating?
  • Set the system fan to recirculate and the continuous running fan mode, “on” instead of “auto.”
  • If you do not have a MERV 13 filter, close the fresh air intake to keep smoke out during a smoke event. Reopen it when air quality improves (See “How can I find out about the current air quality?” above). 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 particles from smoke in a single room or designated space. HEPA air cleaners that include carbon filters can also remove some harmful gases from indoor air.

Choose a portable air cleaner that is:

  1. Filter only – no ionic, ozone, or UV technologies.
  2. A real HEPA filter.
  3. The right size for your room.
  4. Not too loud.

For more information see: Selection and Use of Portable Air Cleaners to Protect Workers, NIEHS and Guide to Air Cleaners in the Home, EPA.  

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 with fans from 2012 or later, 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 2012 or newer standard 20” x 20” box fan and 20” x 20” MERV 13 filters. The number of MERV 13 filters you need depends on the design that you select (see below).
  • What to look for in a box fan:
    • Look for a fan 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.
  • Ways to attach the filter to the fan: you can use a bungee cord, use clamps, screw the filter to the fan using brackets, or use tape.
  • There are different designs to consider that use different numbers of filters. The simplest design is to attach a single filter to the fan. 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 where you plan to spend most of your time and where you can keep windows and doors closed. It will be more effective in smaller rooms and where interior doorways to other rooms can be closed.
    • 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 increases, which means inhaling more pollution when the air quality is bad. During smoke events, exercise indoors, but if your indoor air is smoky, keep activities light. 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 or worse.

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. It’s also important to remember that even if you feel ok during the activity, smoke exposure can still harm your health, and you may have symptoms hours or days later. 

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. We recommend they take steps to reduce exposure at that level.

Your pet should also avoid outdoor exercise during periods of poor air quality. Take pets outside for brief bathroom breaks only.  

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, but 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 parents and schools do to protect children and students during smoky conditions?

Children and youth are more sensitive to health effects from breathing in smoke because they breathe in more air than adults for their body weight. This increases their total dose of air pollution. The respiratory system also develops until about age 21. Children and youth with health conditions (including asthma and other lung diseases, heart disease, and diabetes) have a higher risk of emergency department visits and hospitalizations compared to children without health conditions. Children and youth may also be at risk for declines in academic performance, neurodevelopmental problems, and chronic conditions in adulthood from air pollution exposure.



Find additional technical guidance and risk communication resources for public health, air quality, and other officials in the Wildfire Smoke Partner Toolkit.

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 and physical health are both extremely important.

  • Social connection is key. Identify someone you can ask for help and someone else who may need your help. Check in with loved ones and neighbors 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.
  • Spend time with your pets and play games indoors to get them some exercise as well.
  • Read more about Coping with the Stress of Wildfire Smoke (PDF) from the EPA, CDC, and others.
What should I do to keep my pets and livestock healthy when it’s smoky?

Smoke can affect animals’ health too. Animals with cardiovascular or respiratory disease are at increased risk from smoke and should be watched during periods of poor air quality. Look for the following signs of possible smoke irritation in animals. If your animals are experiencing any of these signs, contact your veterinarian. 

  • Coughing or gagging.
  • Difficulty breathing, including open mouth breathing and increased noise when breathing or increased breathing rate.
  • Eye irritation or redness and excessive watering.
  • Nasal discharge.
  • Fatigue or weakness.
  • Disorientation or stumbling.
  • Reduced appetite and/or thirst.

For pets:

  • Keep them indoors as much as possible and avoid outdoor exercise. Keep outdoor bathroom breaks short.
  • Spend time with them indoors and play games with them to keep them mentally and physically active. 
  • Pet birds are particularly sensitive to smoke and poor air quality and should avoid any outdoor exposure. 

For more information, see Protect Your Pets from Wildfire Smoke, EPA (PDF).

For livestock: 

  • Limit their exercise and have plenty of fresh water always available, located near their feed or hay.
  • Consider soaking hay to reduce inhalation of dust particles that might further irritate the airways.
  • Limit dust exposure by feeding low-dust or dust-free feeds and sprinkling or misting the livestock holding area.
  • Livestock may need several weeks to recover after a poor air quality event. Talk to your veterinarian about how to best monitor your animals and when to return to exercise, handling, moving, or transporting them. 

For more information, see Protect Your Large Animals and Livestock from Wildfire Smoke (PDF).

Smoke from Fires Information in Other Languages


Department of Ecology Resources
Additional Resources