The overall goal of the national multicenter (Elizabeth, NJ, Houston, TX, and Los Angeles County, CA) RIOPA study is to establish a scientific foundation for effective, timely, public health intervention strategies. Outdoor, indoor, and personal exposures of adults and children to PM will be measured and evaluated by mass, elemental, chemical, and source apportionment analyses in the other research cores. Non-smoking asthmatic and non-asthmatic adults and their children will be included. Monitoring will occur continuously ("real time") for 48 hours during each of two seasons. Harvard impacter samplers (PM2.5 and elemental analysis for metals) and MSP sampling heads (PM2.5 and organic vapors) will be used to characterize the interdependency of absolute levels and variations in outdoor and indoor microenvironment PM concentrations. Monitoring will also include carbonyl and volatile organic compounds with active and passive samplers. Time-activity patterns will be assessed from subjects' diaries; standard instructions and examples of entries will be developed. PM2.5 and air toxics data will be compared with historical data from EPA/ARB outdoor PM and air toxics monitoring networks, respectively, for later use in REHEX.

This ten-year longitudinal study is focused on the potential associations between ambient air pollution and respiratory health in children. The objectives are to document the respiratory growth of study participants, to assess whether ambient pollutants play a role in respiratory health, and to identify which pollutants are responsible for any observed effects. Ambient air quality is being monitored in each of twelve communities by centrally located regional stations, which also collect standard meteorological data. Gaseous pollutants are monitored continuously, while ambient particle concentration and size are determined by a number of approaches. Additional exposure assessment is occurring because of the establishment of the Particle Center, including more extensive particle size number, surface area, and volume distribution measurements.

This project involved human exposure modeling to assess the change in benzene exposure between 1989 and 1997 in the California South Coast Air Basin using the Regional Human Exposure (REHEX) model. The model, developed by Lurmann and Winer in 1989, is a stochastic model that utilizes available data on air quality (both indoor and outdoor), personal mobility, time activity and demographics. The model was the basis for the first comprehensive assessment of the health and economic benefits of meeting state and federal air quality standards for ozone and PM-10 in the South Coast Air Basin. Recent efforts include extending REHEX to the assessment of exposure of the Southern California population to environmental benzene, evaluation of indoor and in-vehicle microenvironments, benzene exposure due to passive smoking, gasoline stations, and underground parking garages.