Protect Yourself and Others - Smoke From Fires

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.

In indoor spaces where you cannot keep windows closed or filter indoor air, wearing an N95 mask for short periods can be helpful if outdoor smoke levels are high. Examples of these indoor spaces include public transportation and commercial or public buildings.

More information on proper use and fit and how to identify if a mask is NIOSH-approved.

• Wildfire Smoke and Face Masks Fact Sheet (PDF)
• NIOSH's Personal Protective Equipment for the Public.

Exercise is very important for health. However, when you exercise, your air intake increases, which means you breathe in more pollution when the air quality is bad. During smoke events, try to exercise indoors. If your indoor air is bad, keep your 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 (Orange, AQI 101-150) or worse. Whether or not you are sensitive, you should watch for symptoms. Everyone should limit activities when air quality is in the Unhealthy (Red) category or worse (AQI 151 or higher). 

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. 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 (Yellow, AQI 51-100), such as people with asthma and lung and heart conditions. If you are especially sensitive to lower levels of smoke, we recommend taking steps to reduce exposure at that level. 

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

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 air inside the car, 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 and seek service when necessary. Smoke can also impact visibility, and you may need to adjust as you would during other weather hazards to drive safely.

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:

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

• Take 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 a cooler indoor place – 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 and open your windows when the air quality improves. It can be helpful to view the “Trend” information for sensors on the EPA Fire and Smoke map for more recent air quality information.
• Only open windows when it is cooler outside than inside. An open window is most effective when a door or additional window can be opened to provide a cross draft. For more information, see Cooling Indoor Spaces Without Air Conditioning (PDF). 
• Take steps to filter indoor air - see below "Improve Air Filtration in My Home".

Filtering the air in your home can improve your indoor air quality and reduce your exposure to smoke. Three filtration options are described below. Keep in mind, there are different considerations and supplies with each of these options. Try to buy any needed materials before wildfire season as supplies will sell quickly once wildfire smoke arrives. Wildfire smoke season typically starts in July or August, but can begin as early as May.

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.
• Use a MERV 13 rated filter or the highest rated filter your system can 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 continuously run on the fan mode. (Make sure your system is set to “on”, not “auto”)
• If you do not have a MERV 13 filter, close the fresh air intake to keep smoke out. Reopen it when air quality improves.
• Remember to replace the filter when dirty or as indicated by the manufacturer's instructions or an HVAC professional. Filter replacements 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 ultraviolet (UV) technologies.
2. A High Efficiency Particulate Air (HEPA) filter.
3. The right size for your room.
4. Not too loud.

For more information see:

• Portable Air Cleaners
• Selection and Use of Portable Air Cleaners to Protect Workers, NIEHS
• Guide to Air Cleaners in the Home, EPA  

3. Making your own box fan filter (also called a DIY box fan filter) can be a less costly option to filter air and improve indoor air quality in a single room or designated space.

• Select a standard 20” x 20” box fan (2012 or newer)
  • What to look for in a box fan:
    • Look for a fan that says UL-listed or ETL-listed under the product details. 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 on the outside rim of the fan so they are accessible after the filter has been attached.
• Attach a 20” x 20” MERV 13 filter to the box fan. If you are using 1 MERV filter, you can use a bungee cord, clamps, tape, or screw the filter to the fan using brackets. See more information here:
  • Watch Ecology's video on how to make your own clean air fan.
• You can also consider using two or more filters. Using multiple filters can reduce the burden on the fan motor. See an example of a DIY Box Fan Filter with 2 filters here:
  • Watch Colville Tribes DIY box fan filter video.
  • BC Centre for Disease Control's factsheet on Home-Made Box Fan Air Filter (PDF).
• See an example of a DIY Box Fan Filter with 4 or 5 MERV filters here:
  • Research on DIY air cleaners to reduce wildfire smoke indoors, US EPA
• Follow the box fan manufacturer’s instructions, including
  • Do not leave children unattended when in use.
  • Do not use an extension cord.
• Place the 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 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.

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.

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

Below are resources to help children learn about smoke from fires and how it affects them. 

• Read the interactive e-book, Sofia’s Story by PEHSU with your kids to help them understand health effects of wildfires.
• Give your kids some crayons and Ready Wrigley Prepares for Wildfires & Smoke Activity Book, CDC (PDF).
• Read or watch the video Why is Coco Red by the EPA with your kids.

Washington Children and Youth Activities Guide (PDF) provides recommendations to protect children and youth from fine particles in smoke (PM2.5).

It can be applied to school, child care, athletic practices and games, before and after school programs, camps, field trips, and other outdoor programming and activities. This guide also has information on outdoor and indoor air quality monitoring, including with low-cost sensors. Follow guidance to reduce smoke inside schools and commercial buildings:

• Improving Ventilation and Indoor Air Quality during Wildfire Smoke Events
• (PDF) Summary Wildfire Smoke Guidance for Closing Schools (PDF)
• Additional technical guidance and risk communication resources for public health, air quality, and other officials is available at Wildfire Smoke Partner Resources.

• 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)

• Limit their exercise and have plenty of fresh water always available near their feed or hay.
• Soak hay to prevent them from breathing in 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).