Guidance from the EPA to Reduce Exposure to Wildfire Smoke Inside the Home

According to the EPA, smoke from wildfires in the United States can adversely affect indoor air quality and put people’s health at risk from exposure to particulate matter and other pollutants. During a wildfire, smoke can make the outdoor air unhealthy to breathe, and local officials may advise you to stay indoors during a smoke event. However, some of the smoke from outdoors can enter the home and reduce indoor air quality. Exposure to fine particles, a major component of wildfire smoke, can cause respiratory symptoms and aggravate chronic heart and lung diseases.

Wildfire smoke could impact your indoor air quality (IAQ) differently depending on the proximity of the fire and the density of the smoke. If you are close to a wildfire, the fire itself, as well as heavy smoke and ash, can pose serious, immediate risks to your safety and health. You and your family should be prepared to evacuate immediately if told to do so.

When wildfires create smoky conditions, there are things you can do, indoors and out, to reduce your family’s exposure to smoke. Reducing exposure to smoke is important for everyone’s health — especially children, older adults, and people with heart or lung disease.

If local officials advise you to stay indoors, there are many actions you can take within your home to reduce smoke exposure, such as setting up a clean room.

A clean room is a room that is set up to keep levels of smoke and other particles as low as possible during wildfire smoke events. See below for steps to creating an effective clean room:

1. Choose a room. It should be big enough to fit everyone in your household and comfortable to spend time in. A bedroom with an attached bathroom, for example, is a good choice because you can close it off from the rest of the house and keep the door closed for long periods of time.
2. Prevent smoke from entering the room. Close all windows and doors in the room, but don’t do anything that makes it hard to get out. If there is an exhaust fan or range hood in the clean room space, only use it for short periods.
3. Stay cool. Run fans, window air conditioners, or central air conditioning. If your HVAC system or window air conditioner has a fresh air option (meaning it pulls in air from the outside), turn it off, close the intake, or set the system to recirculate mode. Avoid using an evaporative cooler or portable air conditioner with a single hose in smoky conditions unless there is a heat emergency. Using these devices can result in more smoke being brought inside.
4. Filter the air in the room. Use a portable air cleaner that is the right size for the room. Run the portable air cleaner continuously on the highest fan setting if you can. Pick one that does not produce ozone. If you have central HVAC, you can also install a high-efficiency filter (MERV 13 or higher) in the system. Run the system’s fan as often as possible to get the most out of the filter.
5. Avoid activities that create smoke or other particles indoors, and dust or mop surfaces in the clean room with a damp cloth as needed to keep settled particles from getting back into the air.
6. Spend as much time as possible in the clean room to get the most benefit from it. Avoid exercising while in the clean room to help reduce exposure to any particles that may enter the room. When the air quality improves, even temporarily, air out the clean room by opening windows or open the fresh air intake on your HVAC system to freshen the air.