How to keep the air inside your home clean during wildfires - AP News

What the report says

The Associated Press reports that health experts are urging people affected by wildfire smoke to remain indoors and take specific steps to reduce fine-particle pollution inside their homes. The guidance comes as smoke from Canadian wildfires has spread hazardous air across parts of the United States, creating unhealthy conditions for millions. AP notes that the most dangerous components of smoke are tiny particles that can contribute to short-term symptoms and longer-term health problems.

For homes with central air conditioning, AP says residents should use the highest-rated filter their system can safely support, ideally MERV 13 or above, and keep air circulating indoors rather than drawing from outside. The University of Oregon’s Center for Wildfire Smoke Research and Practice recommends running the system fan throughout a smoke event. Portable air cleaners should use HEPA filtration or be designed to capture small pollution particles, and should not produce ozone.

AP also highlights evidence that low-cost do-it-yourself air cleaners, made with furnace filters attached to a box fan, can meaningfully reduce indoor particle levels. The Environmental Protection Agency has found such devices can perform comparably to small commercial purifiers for fine-particle removal when assembled properly. Experts say a single purifier can be used to create one cleaner room where household members spend most of their time.

The report adds that window and portable air conditioners often do not filter smoke particles well, so sealing units and pairing cooling with filtration is important, especially when heat and smoke occur together. Residents are also advised to block drafts, avoid indoor burning such as candles or gas stove use when smoke is heavy, and seek medical help for severe breathing distress.