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FAQ: How Can I Keep Indoor Air Clean During Wildfires?

Because getting out of town isn't always an option... especially these days!

When there is heavy smoke outside, one of the best things you can do is get out of the smoke. If you can’t leave the area until air quality gets better, this often means staying indoors. There are a few things you can do keep your indoor air as clean as possible. 
  • Keep your windows and doors tightly closed. Use towels to block air flow if smoke is coming in through gaps in window or door frames. 
  • Set air to recirculate on your heating, ventilation, and cooling (HVAC) system or window air conditioner if possible. 
  • Use high efficiency particulate air (HEPA) filters. These can be portable filters or can be installed in HVAC systems. 
  • Build your own air purifying filter by attaching a 20”x20” furnace filter to a 20” box fan. Follow the instructions in this DIY air filter instruction sheet or in this DIY air filter video, available in English, Spanish and Korean, from the Washington Dept. of Ecology. Never leave a DIY filter unattended or run it at night, as a filter can strain the fan motor and could cause it to overheat or catch fire.
  • Track current air quality on the fire and air quality map or by downloading the free OregonAir app for Android or iPhone.
If you don’t have an air filter, fine particles can creep into your home over time. Watch for times of day when the smoke clears. During those times, open your doors and windows to “air out” your home. That way, you’ll start with cleaner air if the smoke returns.

Reducing other sources of indoor smoke and dust will also help keep your air cleaner. If you don’t enjoy vacuuming, there’s good news! It’s best to avoid vacuuming during heavy smoke. Vacuuming can stir up dust. You can also improve air quality indoors by not vaping or smoking, not lighting candles, and not using gas, propane, or wood-burning stoves.

Keeping the air inside your car clean is also important when you need to run errands or travel. The best thing to do is avoid driving in smoky areas. If you need to drive when it’s smoky, there are things you can do to avoid smoke. Keep windows rolled up and vents closed. Set the air conditioning on “re-circulate” to avoid bringing smoke into your car.