Breathe Naturally - October 2, 2023

Advanced Air Filters for Wildfire Defense: Guard Against Smoke and Ash


As wildfires become more frequent and intense across many regions, dealing with wildfire smoke is becoming an unfortunate reality. Exposure to wildfire smoke can irritate eyes and throat, trigger headaches and breathing issues, exacerbate chronic conditions like asthma or heart disease, and even lead to emergency room visits and hospitalizations.

Key Takeways:

  • Use high-quality air filters like carbon activated filters to remove wildfire smoke and ash
  • Keep windows and doors closed to prevent smoke from entering, and seal any gaps
  • Consider using portable air cleaners with HEPA filters to supplement central air filtration
  • Monitor local air quality reports and take action when air pollution reaches unhealthy levels
  • Create positive pressure by using fans to keep outdoor smoke out
  • Stay aware of health symptoms related to smoke exposure like asthma attacks

During active wildfires, smoke and ash can enter homes through windows, doors, vents and tiny cracks. Fortunately, there are steps you can take to protect your indoor air quality when wildfires are burning in your area. Maintaining clean air is important for health and comfort when smoke lingers for days or weeks.

Upgrading Home Air Filters

One of the best defenses against wildfire smoke is ensuring your home's heating/cooling system (HVAC) can effectively filter extra-fine particles found in wildfire smoke and ash using high-quality air filters. Standard 1-inch filters found in most homes do an insufficient job of removing dangerous fine particulate matter.


Premium high-MERV filters made of densely-woven materials like Breathe Naturally's extra-thick carbon activated filters are excellent at capturing airborne particles down to 0.3 microns. This includes most of the microscopic ash and smoke particles that make wildfire smoke so hazardous. High-efficiency filters also reduce common allergens like pollen and dust.

Carbon activated air filters go even further to actively purify the air using highly porous carbon that absorbs and traps some gaseous pollutants in smoke. This is an advantage over mechanical filtration alone in filters without activated carbon. The premium carbon layer in Breathe Naturally filters absorbs irritating volatile organic compounds (VOCs) and odors from wildfire smoke.

When exposure to smoke will be prolonged, it's wise to invest in the best possible air filters for your home's HVAC system. Poor quality filters allow fine particles through and quickly become overloaded, reducing system airflow. An annual replacement is generally recommended.

Using Portable Air Cleaners and Purifiers

While central air filtration protects indoor air overall, portable air purifiers with HEPA filters provide supplemental localized filtration in rooms where you spend the most time. HEPA (High Efficiency Particulate Air) filters remove 99.97% of particles down to 0.3 microns. This includes most of the fine particulate pollution that makes wildfire smoke dangerous.

When using portable air cleaners for wildfire smoke, choose larger models that can filter a room's entire volume in 30 minutes or less. This "air changes per hour" rating reflects filtration power. Place portable units where smoke could enter and where family members spend time, such as bedrooms. Close the doors and windows in these rooms while running air purifiers to focus their capabilities. Loud high-power settings may be necessary to clean smoke-filled air after sufficient filtration, use low settings for general room air purification.


Protect Indoor Air Quality

Along with using high-quality filters in home HVAC systems and supplemental portable air cleaners, it is important to prevent smoke from entering your home as much as possible. Here are tips to maintain clean indoor air quality when smoke pollution is high:

  • Keep all windows and doors tightly closed. Seal gaps under and around doors with towels or weather stripping if needed. Close exterior vents that could allow smoke inside, such as crawl space vents.
  • Only use "recirculate" mode on climate control systems so that outdoor air is not brought inside. If your system lacks this control, consider turning it off during very smokey conditions. Avoid using "fan only" mode or whole house fans that bring in lots of outdoor air.
  • Stop vented appliances like gas stoves, wood stoves and furnaces which could draw in outdoor polluted air. Avoid activities that generate additional fine particles like frying foods, spraying chemicals, vacuuming, or lighting candles. Consider using bathroom and kitchen exhaust fans sparingly.
  • Follow local air quality reports and take additional protective action when the Air Quality Index (AQI) reaches very unhealthy levels. This may mean staying indoors in a filtered space, wearing an N95 respirator mask outdoors, or leaving the area until conditions improve.

Create Positive Pressure

A useful tactic is to create positive indoor air pressure that keeps smoke from entering by using fans in cleaner rooms facing outdoors with sealed windows. The outward airflow makes it difficult for contaminated outdoor air to flow inside. Place a folded damp towel at the base of doors leading to these rooms to block smoke, while allowing cleaner air to flow under the door. Monitor indoor air quality with an accurate particle counter to determine where the cleanest rooms exist.

Monitor Health When Exposed to Smoke

Be vigilant about health symptoms potentially related to wildfire smoke exposure. These include irritated eyes, runny nose, cough, scratchy throat, headaches, fatigue and difficulty breathing. Smoke can exacerbate asthma, COPD and cardiovascular conditions which requires prompt medical attention.

Infants, children, pregnant women, seniors and those with chronic conditions need to take extra precautions since they are most vulnerable to smoke. It's also wise to have several days of medications available in case evacuation becomes necessary. Pay attention to local guidance about when cleaner air shelters are available during hazardous smoke pollution.

While dealing with wildfires and their smoke is stressful, taking proactive steps allows residents to stay healthier indoors. Advanced home air filtration, portable air cleaners, tightly sealed buildings, health vigilance and cooperation with authorities can provide the best protection during wildfire emergencies. Maintaining clean indoor air quality reduces health impacts when wildfires threaten communities.



CDC Guidance on Wildfire Smoke
EPA Indoor Air Filtration for Wildfires
AQI Basics