Protecting Indoor Air from Wildfire Smoke
August 1, 2022
Wildfires have become more common, more intense and now spread to places not previously considered at risk. Increasingly wildfires are approaching major population centers and impacting air quality for more people than ever before.
The Impact of Wildfire Smoke on Health
According to the Centers for Disease Control and Prevention (CDC), the health effects of breathing particle pollution from wildfire smoke can range from minor (irritation to eyes and lungs) to very serious (exacerbation of asthma, heart failure, death). Certain groups of people—children, older adults, pregnant women and people with conditions like asthma and cardiovascular disease—are considered higher risk when it comes to the impacts of wildfire smoke.
How can we protect our families from smoke inside the home?
When the outside air is clean, opening windows to bring fresh air inside is a great way to improve indoor air quality. But when outdoor air quality is low—or dangerous--due to pollution, allergens or wildfire smoke, opening windows is not a good idea. The EPA’s Office of Radiation and Indoor Air Environments Division lists two primary ways to improve indoor air quality near a wildfire, when ventilating with outdoor air is not an option.
The Role of HVAC Filters
The first way many homes filter indoor air is through a furnace or HVAC filter. In houses and apartments with a central HVAC system, the furnace fan delivers air throughout the home already. Installing a high-quality filter is one simple way to clean the air and reduce the number of harmful particles inside the home. Minimum Efficiency Reporting Values (MERV) is the rating system most commonly used to measure filtration for HVAC filters. Consult with an HVAC specialist or the instruction manual for the HVAC equipment to ensure fit and performance.
While HVAC filters are a great way to filter the air in the home, it is important to note that they only filter air while the furnace or HVAC system is running. Most households do not continuously run their HVAC fans due to cost and energy usage.
Air Purifiers with HEPA Filters
The other primary way to clean the indoor air when outside air is not safe is using a portable air cleaner or air purifier. These are standalone appliances that effectively remove particles from the air with internal filters and can run at a much lower cost than a whole-home HVAC system. They can also be highly effective at reducing particulate matter indoors.
The EPA’s Residential Air Cleaners white paper says “Intervention studies of air cleaners operating in homes have consistently found statistically significant reductions in indoor exposures to indoor PM2.5, PM10, and/or particle number counts with the use of portable air cleaners.” Further, the EPA says that the reduction in particulate matter is most significant with the use of high-energy particulate air filters, or HEPA filters. As a result, studies have shown that the use of portable air cleaners (purifiers) is associated with at least one marker of improved health outcome.
In addition to HEPA filters for particulate matter, other technology exists for reducing unwanted substances from the indoor air. Carbon Filters remove gaseous and odorous compounds, Ultra-Violet or UV Lights help kill or inactivate airborne microbes and germs, and Ionizers attach to and collect other air particles.
Ensuring a Quality Product
With an increase in attention around airborne particles during the early stages of the COVID 19 pandemic, more people purchased air purifiers. As a result, many new air purifier manufacturers entered the market. Some of the new products introduced came with less rigorous performance testing and questionable quality. Experts recommend purchasing an air purifier that has been independently tested for performance. The Association of Home Appliance Manufacturers (AHAM) does testing for several types of home appliances and sets standards for performance and safety.
For more information
The EPA’s Indoor Air Quality, or IAQ website is very helpful resource for citizens and public health officials.
A full list of AHAM certified Air Purifiers with HEPA filters from Guardian Technologies can be found here: