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Novel Approaches for Estimating Human Exposure to Air Pollutants
Citation:
WATKINS, T. H., L. BAXTER, H. A. OZKAYNAK, V. ISAKOV, AND D. MOBLEY. Novel Approaches for Estimating Human Exposure to Air Pollutants. Chapter 122, Douw G. Steyn & Silvia Trini Castelli (ed.), Air Pollution Modeling and its Application, XXI. Springer Netherlands, , Netherlands, Series C:741 - 745, (2011).
Impact/Purpose:
The National Exposure Research Laboratory′s (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA′s mission to protect human health and the environment. HEASD′s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA′s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Numerous health studies have used measurements from a few central-site ambient monitors to characterize air pollution exposures. Relying on solely on central-site ambient monitors does not account for the spatial-heterogeneity of ambient air pollution patterns, the temporal variability in ambient concentrations, nor the influence of infiltration and indoor sources. Central-site monitoring becomes even more problematic for certain air pollutants that exhibit significant spatial-heterogeneity. Improving characterization of air pollution exposures involves novel approaches to estimating ambient concentrations, a better understanding of the personal-ambient relationship, and personal exposure modeling. Estimates of ambient concentrations and human exposure estimates have been enhanced by utilizing both measurements and modeling tools. Statistical interpolation techniques and passive monitoring methods can provide additional spatial resolution in ambient concentration estimates. In addition, spatiotemporal models, which integrate GIS data and other factors, such as meteorology, have also been developed to produce more resolved estimates of ambient concentrations. Hybrid modeling approaches, which integrate regional scale models with local scale dispersion models, provide new alternatives for characterizing ambient oncentrations. Estimating actual personal exposures requires an understanding of factors that impact personal-ambient relationship. Publically available data on housing characteristics (e.g., age and size of home) and commuting patterns can be utilized to understand these personal-ambient relationships. In addition, personal exposure modelling approaches are being developed, such as the Stochastic Human Exposure and Dose Simulation (SHEDS) model, which provides estimates of population exposures, and the Exposure Model for Individuals (EMI), which provide individual specific estimates of exposure. Many of these exposure characterization approaches are currently being applied and evaluated in epidemiological investigations. This paper describes the novel exposure assessment approaches discussed above and will briefly present results from the application of these tools. In addition, the paper will discuss ongoing and future applications of these approaches to evaluate their use in health studies.