MILWAUKEE (news agencies) — The eerie glow of an orange sun through thick wildfire smoke might be unnerving, but the biggest risk from the haze is something much harder to see.
Tiny particles in the air can cause a range of short-term and chronic health issues, experts say.
Wildfire smoke can settle over cities for days — like the recent blanket over parts of the U.S. from burning fires in Canada, which has created hazardous air for millions of people across multiple states.
Health officials advise people to stay indoors — and to take steps to keep the air in your home clean.
If you have central air conditioning, it should clean the air in your home.
Make sure filters are replaced on schedule and are of the highest level of filtration your system can handle. Filters rated MERV 13 or higher are ideal. Set the air to recirculate and close any vents that pull air from outside if you can. The University of Oregon’s Center for Wildfire Smoke Research and Practice recommends running the system’s fan through the entire smoke event, not just when cooling.
If you buy a portable air filter, look for a HEPA air filter or one that says it traps small particles of pollution. Ensure it does not generate ozone, another harmful air pollutant.
If you can only afford one portable air filter, use it to create a “clean room” in your house where you can spend most of your time.
“The basic message is that something is better than nothing,” said Amy Kalkbrenner, an environmental epidemiologist at the University of Wisconsin-Milwaukee.
There’s good evidence that DIY filters made by duct-taping furnace air filters to a box fan work.
They’re simple, relatively affordable and scientists at the Environmental Protection Agency have found they are just as good at removing fine particles of pollution from the air as a small commercial air purifier.
“The good news is they really work,” said Kalkbrenner.
All you need to have to make one is: four 20-by-20-inch (50.8-by-50.8-centimeters) furnace air filters rated MERV 13 or higher, a box fan, cardboard and duct tape. The EPA’s website shows how you can modify the design to only use one or two filters. The fan should blow out, and the arrows on the filters should point in. Make sure everything is taped up air-tight.
Many window air conditioners, mini-split heat exchangers and portable air conditioners don’t have the filters needed to remove fine pollution particles. But heat can also be dangerous.
“When smoke and heat occur together, the impacts on your health are even greater than when they occur by themselves,” said Jess Downey, a researcher at the University of Oregon’s Center for Wildfire Smoke Research and Practice
