What’s in the air in our homes?

Abstract

Most people spend as much as 90% of their time indoors. And about 70% of that time is spent at home (J. Exposure Sci. Environ. Epidemiol. 2001, DOI: 10.1038/sj.jea.7500165). Yet we know little about the air that we breathe indoors, especially in our own dwellings. Atmospheric chemists have spent decades upon decades focused on understanding the quality of outdoor air. But given the lopsided ratio of time humans spend indoors versus outdoors, some of these researchers are shifting their attention. They want to use the tools they’ve developed for monitoring outdoor air and start making the same sorts of measurements inside. They are finding that indoor emissions come from many sources—stoves, cleaning products, furnishings, and even people. And the chemicals they’re detecting aren’t always inert. Compounds in indoor air can react with one another and with oxidants to form new molecules. These compounds deposit on particles in the air or