Wildfire Smoke Chokes US: How to Guard Your Home

Wildfire smoke from fires burning in Canada has created hazardous air quality conditions across wide swaths of the United States, affecting areas from North Dakota to New York and as far south as Maryland. The primary concern is PM2.5, a type of fine particulate pollution that can easily enter the lungs when inhaled, posing health risks even from distant fires.

Indoor air quality experts recommend a multi-pronged approach to mitigate smoke exposure. Key strategies include keeping windows closed, turning off outdoor air supplies to HVAC systems, and using high-efficiency filters (MERV 11 or higher) in central air systems, allowing the fan to run continuously for air cleaning. Portable HEPA air purifiers should be run on high settings.

Additional advice involves minimizing the use of exhaust fans, which can draw in outdoor air. For those with window air conditioning units, ensuring filters are properly installed and running the unit with the fan on high can help circulate air and remove particles. In situations where commercial filters are unavailable, DIY air cleaners, such as a Corsi-Rosenthal box, can be constructed.

If smoke continues to cause discomfort, such as coughing or throat irritation, wearing a high-quality mask, like an N95, is advised, particularly if venturing outdoors or engaging in heavy exertion. The overarching goal is to maintain indoor air quality by keeping outdoor pollutants out and effectively cleaning the air within homes.