MicroTrac is a model developed by EPA that uses GPS data to estimate time of day and duration that people spend in different microenvironments, such as indoors and outdoors at home, work, school, and inside vehicles. Using MicroTrac can improve exposure assessments for health studies by helping air pollution scientists determine location and physical activity of study participants prior to adverse health effects.

• MicroTrac Factsheet (PDF)(1 pg, 86 K)