Source-to-dose modeling of long-term population exposures to co-occurring reactive and inert air pollutants
P.G. Georgopoulos1, S. Isukapalli1, S.W. Wang1, N. Lahoti1, Y.C. Yang1, J. Burke2, H. Özkaynak2, J. Ching2, T. Pierce2
1Environmental and Occupational Health Sciences Institute, UMDNJ - R.W. Johnson Medical School and Rutgers University; 2National Exposure Research Laboratory (NERL), USEPA
A novel source-to-dose modeling study of long-term (seasonal to annual) population exposures to co-occurring fine Particulate Matter (PM2.5) and reactive air pollutants (e.g., ozone and formaldehyde) is presented for the urban Philadelphia, PA, and Camden, NJ areas. This study employs the new integrated and mechanistically consistent source-to-dose modeling framework of MENTOR/SHEDS-1A [Modeling ENvironment for TOtal Risk studies (MENTOR) using the Stochastic Human Exposure and Dose Simulation (SHEDS) approach in a “One Atmosphere” (1A) setting] to quantify inhalation exposure and dose for individuals and/or populations due to co-occurring air pollutants. MENTOR/SHEDS-1A characterizes cumulative exposures to co-occurring air pollutants by taking into account their physical and chemical interactions, and calculates exposure and dose profiles, while providing the ability to focus on mechanism relevant time scales and subpopulations of interest. This is achieved by combining information on: demographic characteristics of the population under study, outdoor concentration distributions, indoor/outdoor air exchange rates, indoor sources, time-activity diaries, and biologically based dosimetry. The MENTOR/SHEDS-1A application in the present study consists of following four steps: (1) calculation of ambient outdoor concentrations using emission-based multiscale photochemical modeling, (2) spatiotemporal interpolation for developing census-tract level outdoor concentration fields, (3) calculation of microenvironmental concentrations that match activity patterns of the individuals in the population of each census tract in the study area, and (4) population-based dosimetry modeling that accounts for activity and physiological variability. Special focus has been on susceptible population groups such as the children and the elderly.
This work had been funded in part by the US Environmental Protection Agency under Cooperative Agreement # EPAR-827033 to the Environmental and Occupational Health Sciences Institute (EOHSI). The viewpoints expressed here are the responsibility of the authors and do not necessarily reflect the views of the USEPA or its contractors.