The project was conducted to provide an improved estimate of nationwide annual person hours of exposure to non-reactive mobile source pollutants. National population estimates by hour of the day were developed using the population activity files for six neighborhood types from the EPA NAAQS Exposure Model (NEM) for CO, with the addition of three mobile source microenvironments (street canyons, tunnels and parking garages). The NEM neighborhood populations together with the mobile source microenvironment populations constitute a complete hour-by-hour assignment of the nationwide population to a set of location types. Mobile source pollutant concentrations for the six NEM neighborhoods were derived from 1981 CO monitor data contained in the EPA SAROAD data base. Mobile source pollutant concentrations for the three mobile source microenvironments were derived for data in the literature. A computer program was written to combine the population and pollutant concentration distributions by hour of the day to produce an annual person hours of exposure distribution of mobile source pollutants. If the mobile source emission rate of a pollutant is known, the information in the report can be used to determine the person hours of exposure to various concentrations of that pollutant.

"EPA/460/3-85/002." "March 1985." "Contract No. 68-03-3162 Work Assignment 6." Microfiche.