While ambient air toxics can penetrate into homes, offices, and cars, many chemicals, classified as air toxics under the Clean Air Act, are also emitted directly into the indoor air from consumer and cleaning products and building materials. Carpet, paint, and air deodorizers may all release chemicals into the indoor environment. Even taking a hot shower, washing dishes or clothes in hot water, may release chemicals, such as chloroform. In addition, some emissions near a person's face can contribute significant concentrations to personal exposure, while contributing a negligible amount to ambient concentrations. Wearing recently dry-cleaned clothing is an example.
Smoking is another example.
Smoking accounts for the largest percentage of personal exposure to benzene, yet the activity of smoking releases little benzene into the surrounding air. Thus, when the contribution of outdoor sources is minimal compared to indoor sources or the air immediately surrounding an individual, ambient air emissions are not a good indicator of personal exposure. It is therefore important to determine indoor air concentrations, the sources of those concentrations and the relative contribution from outdoor, indoor and personal sources in determining what people are really exposed to in their daily lives. Several studies have been carried out to assess the relationship among outdoor, indoor, and personal air to determine the sources of the exposure to air toxics. The major purpose of the TEAM study was to measure the personal exposures to select chemicals in urban populations in several U.S. cities.