Wildfire smoke leaves harmful gases in floors and walls. Research shows air purifiers don't stop it — but here's how to clean up

Delphine Farmer is a professor of chemistry at Colorado State University.

When wildfire smoke turns the air brown and hazy, you might think about heading indoors with the windows closed, running an air purifier or even wearing a mask. These are all good strategies to reduce exposure to the particles in wildfire smoke, but smoky air is also filled with potentially harmful gases. Those gases can get into buildings and remain in the walls and floors for weeks.