Exposure Model Development and Applications

STI scientists developed the Regional Human Exposure (REHEX) model for estimation of total air pollution exposures, including those occurring indoors, outdoors, and in vehicles, and those associated with special activities. The model provides a useful framework in which to combine spatially resolved population data and ambient air quality data with human time-activity data, building ventilation rates, indoor source strengths, and in-vehicle exposures. Versions of the model have been designed for application to the general population and special cohorts. The REHEX model has been used to assess the benefits of ozone, PM, and benzene air quality improvements in large metropolitan areas such as Los Angeles, San Francisco, and Houston. A Monte Carlo version of the model has been used extensively in the Southern California Children's Health Study. STI offers services to apply existing models and to refine models for specific purposes, such as taking advantage of special data sets.