07/06/2009 05:12 am ET | Updated May 25, 2011

Indoor Air Pollution: Six Surprising Sources

The most widely quoted statistic about air quality is this: The Environmental Protection Agency estimates that indoor air can be two- to five-times more polluted than the air outdoors. And while the EPA is responsible for cracking down on outdoor pollution -- the smog, ozone and other chemicals that spew from tailpipes and smokestacks -- protecting the air indoors is largely the responsibility of homeowners.