Wildfire Smoke & Indoor Air: Protection Guide

Wildfire Smoke & Indoor Air Protection

When wildfire smoke turns skies orange hundreds of miles from the fire, indoor air quality becomes a health emergency — especially for children, elderly, and asthma patients.

Monitor Air Quality

• Check AirNow.gov daily during smoke events
• AQI 101–150: sensitive groups limit outdoor activity
• AQI 151+: everyone stay indoors
• AQI 301+: hazardous — seal home, run HEPA filters

See also: When Will Smoke Clear?

Seal Your Home

1. Close all windows and doors
2. Tape gaps around leaky windows if needed
3. Set HVAC to recirculate — disable fresh air intake
4. Replace HVAC filters with MERV-13 or higher before fire season

Create a Clean Room

• Choose one bedroom with few windows
• Run a HEPA air purifier on high 24/7 during smoke events
• Sleep in this room when AQI exceeds 150

Mask Guidance

• N95 or KN95 masks filter PM2.5 smoke particles outdoors
• Cloth and surgical masks do not protect against smoke
• Replace masks when breathing becomes difficult or after heavy use

When to Evacuate

Leave immediately if authorities issue evacuation orders — smoke plus fire proximity is life-threatening.

Wildfire Evacuation Checklist →

After Smoke Clears

• Replace HVAC filters
• Wet-wipe surfaces before vacuuming (dry vacuuming stirs particles)
• Watch for symptoms: coughing, chest tightness, eye irritation — seek medical care if severe

Monitor official evacuation orders via NOAA and local emergency services.

Updated August 2026

Wildfire season is no longer a maybe—it's a when. Last year's tips about taping windows and using a HEPA purifier still work, but this season brings better data, stricter mask guidance, and a stronger push to prepare before the smoke arrives. Here's what's different and what to do now.

What changed: Generic advice often says "just stay indoors," but that misses two realities. First, indoor air can be just as polluted if you don't create a clean room. Second, not all masks are equal—loose-fitting KN95s allow smoke particles to sneak in around the edges. Public health agencies now recommend fit-tested N95s or elastomerics, and the EPA's Fire and Smoke Map has made hyper-local air quality data the new standard.

This season's checklist:

1. Set up a clean room before the smoke hits. Choose the smallest room with fewest windows and doors. Seal gaps with painter's tape or window film, and place a HEPA purifier rated for at least two-thirds of the room's square footage (check the Smoke CADR). Pre-test your purifier now, not when you're under an evacuation alert. If you're in Western Canada or Australia, check your local health authority for clean air shelter locations—many recreation centers now offer filtered rooms.

2. Upgrade to a fit-tested N95 or elastomeric for outdoor chores. That's what CAL FIRE and EPA recommend for anyone doing more than a quick dash from car to store. KN95s are a backup, not a first choice. Do the "inhale test" each time: the mask should suck in, not leak around your nose or chin. If you have a beard, consider a loose-fitting PAPR or at least plan to shave for a tight seal.

3. Watch the Fire and Smoke Map, not just the city AQI. A sensor a few blocks away might show PM2.5 at 200 while the city forecast says "moderate." In the U.S., use AirNow; in Australia, check your state's AirWatch page; in Canada, use FireWork or provincial air quality portals. Make your decisions based on the closest sensor, especially during active smoke events.

4. Don't let your HVAC be the bottleneck. Many residential systems can't handle MERV-13 filters—they slow airflow and strain the blower. Instead, use a MERV-11 in your system and add a portable HEPA to your clean room. If you do run MERV-13, ask an HVAC tech about a pressure-points kit. And replace your filter more often during smoke season.

Maintenance reminder: If you're reusing an N95 from last season, check the straps and nose foam—they degrade in hot cars. After each smoky day, wipe down the respirator and let it air out. Once the smoke clears, replace the filter and wash any window tape residue with mild soap.

Need the full picture? Start with our Wildfire Smoke & Indoor Air guide, then grab our Wildfire Evacuation Checklist so you're ready if the smoke turns into an order to leave.