Easy steps to clean up indoor air pollution. By Melinda Wenner Moyer, Redbook Most of us assume that when we walk into our homes, we slam the door on exhaust, secondhand smoke, and other air-pollution ugliness. In your own house, everything is safe and clean. Oh, if only. According to the U.S. Environmental Protection Agency (EPA), levels of about a dozen common chemical pollutants are two to five times higher inside homes than outside of them. Part of the problem is that houses are so much better insulated than they used to be: That's a good thing when it comes to conserving energy, but being more airtight also means that "whatever you emit indoors — whether it's your burnt microwave popcorn, cigarette smoke, or cleaning-product fumes — is going to persist in the indoor environment for longer," says Lynn Hildemann, an environmental engineer and researcher at Stanford University. In light of this, scientists are beginning to suspect that it may be thes...