ABSTRACT
Passive sampling devices (PSDs) have been used extensively over the past decade by industrial hygienists to assess the effects of respiratory exposures to hazardous pollutants on workers. Only recently, however, has the United States Environmental Protection Agency (EPA) become interested in personal exposure monitoring to support the ambient air quality standards set under the Clean Air Act. Since ambient air levels of most pollutants are several orders of magnitude lower than those normally found in the workplace, more sensitive monitoring systems are required. These systems are generally not portable and are usually located at fixed, outdoor sites. Such fixed-site monitoring may not accurately reflect the average daily exposure of the general populace to air pollutants. This is particularly true in the United States where the average person spends an estimated 90 percent of the time indoors. 1
