According to a study published in today's issue of the New England Journal of Medicine, Americans are living longer than they were 20 years ago thanks to cleaner air. USA Today reported that the study, which included 51 US metro areas and more than 200 countries, linked a reduction of small particles in the air to a five-month increase in longevity. Cities that cleaned up their air and added the most years to their citizens' life spans? Pittsburgh and Buffalo, where people added more than 3 years to their life expectancies. And that's just from increasing outdoor air quality. Think of what could happen if Americans bettered their indoor air quality? Find out how to detox your home easily.