AAF Recommends Midwest, East Coast Residents and Businesses Upgrade to MERV 13-rated Air Filters in Wildfire-Impacted Regions

Global air filtration leader offers guidance for homes and businesses on protecting indoor air during and after wildfire smoke events, and makes a spokesperson available for interviews

LOUISVILLE, Ky., July 17, 2026 /PRNewswire/ -- As smoke from wildfires burning in Canada and Minnesota spreads across the Midwest, Northeast and Mid-Atlantic this week, exposing an estimated 115 million people to unhealthy air, AAF International, a member of the Daikin Group and global leader in air filtration solutions, urges homeowners and businesses in affected regions to upgrade to MERV 13 rated air filters and to replace filters immediately once smoke clears from their areas.

Air quality alerts are active across the Midwest, New York, Pennsylvania, Massachusetts, Maine, and Washington, D.C., this week, with Pennsylvania issuing a Code Red air quality alert and New York City distributing N95 masks to commuters. Smoke has discolored skies over Boston and parts of Maine, and forecasters expect conditions to persist into the weekend.

"Most home and business owners aren't aware of the need to change filters regularly and how important it is to use the right filter," said Dr. Jon Rajala, Manager of Research & Development, AAF International. "Wildfire particulates, known scientifically as PM2.5, are so small that they cannot be filtered effectively with standard MERV 8-rated HVAC air filtration, which is most commonly used and recommended in homes and businesses during normal air quality conditions."

These hazardous particles can worsen medical conditions like heart disease and asthma, with older people being particularly vulnerable to these effects. Simply upgrading from a MERV 8 to a MERV 13 filter can significantly improve respiratory health and reduce an individual's exposure to PM2.5 particulates by 75%-80%.

"While the health effects of wildfire smoke are often associated with time spent outdoors, homes and businesses in affected regions can accumulate many of the same fine particulates indoors without the right filtration in place," adds Rajala.

In addition, standard filters fill with debris faster than normal during periods of poor air quality, so homes and businesses need to change them more often while the smoke is active and right after it clears.

Why MERV 13 Air Filters
Standard residential filters, typically rated MERV 8, are built to capture larger particles like dust and pet dander and are not rated to capture the fine particulate matter that makes up wildfire smoke. MERV 13 filters capture up to 70 percent of PM2.5. These particles are so small that they can penetrate deep into the lungs and enter the bloodstream. The CDC reports that this level of exposure can worsen asthma, COPD and congestive heart failure, and the EPA identifies children, older adults and people with existing heart or lung conditions as facing the greatest risk.

Research from Harvard's T.H. Chan School of Public Health has also found that the cardiorespiratory effects of wildfire smoke particles can persist for months after a fire has ended, which is a main reason AAF recommends acting on filtration promptly rather than waiting to see if symptoms appear.

Guidance for Homes and Businesses
AAF recommends the following steps for anyone in or downwind of a wildfire smoke event.

• Upgrade to a MERV 13-rated filter for the duration of the smoke event, checking first that your HVAC system can handle the increased airflow resistance.
• Replace filters immediately once the smoke clears from your area, even if the filter is not yet due for its scheduled change.
• Close windows, doors, and fresh air intakes where possible, and run a portable air purifier in commonly used rooms.
• Consider adding a carbon-based filter for lingering smoke odor and volatile organic compounds, which particulate filters alone do not address.
• Treat ash residue or a persistent smoke smell as a sign that your current filter was likely overwhelmed during the event.

Dr. Jon Rajala, Manager of Research & Development of AAF International, who has a chemical engineering background and researched nanofibers and filter media, is available for media interviews on indoor air quality and practical filtration guidance for homeowners, facility managers and Environmental, Health, and Safety professionals in wildfire-affected regions.

For AAF's recommendations for commercial and industrial facilities, read our article on Indoor Air Quality During Wildfire Season. IAQ for Commercial and Industrial Facilities During Wildfire Season. Homeowners can visit this article NAME to learn more.

About AAF
Headquartered in Louisville, Ky., AAF International is the world's largest manufacturer of air filtration solutions, developing and manufacturing a wide variety of solutions that are designed to remove and control airborne particulates and gaseous contaminants in commercial, industrial, cleanroom, transportation and nuclear power applications. Founded in 1921, AAF has grown into an international standard for innovative products that bring clean air to life for billions of people throughout the globe. www.aafintl.com

About the Daikin Group
Daikin Industries, Ltd., a global Fortune 1000 company established in 1924, pioneers high quality, energy efficient heating, cooling, ventilation, air purification and low global-warming-potential (GWP) refrigerant technology that brings people comfort - at home and at work. The world's number one air conditioning company, Daikin operates in 170 countries with approximately 100,000 employees. In the United States, Daikin proudly employs more than 22,000 workers who engineer, design and assemble industry leading products across 25 advanced manufacturing sites. Daikin serves Americans coast-to-coast through its nine Research and Development centers, 400+ distribution points and a nationwide network of local contractors who trust and choose Daikin every day. https://www.daikin.com/corporate

SOURCE AAF International