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Estimating Air-Manganese Exposures in Two Ohio Towns
Citation:
Colledge, M., J. Wagner, V. Gocheva, C. Beseler, R. Bowler, AND D. Lobdell. Estimating Air-Manganese Exposures in Two Ohio Towns. Presented at International Society for Environmental Epidemiology, Seattle, WA, August 24 - 28, 2014.
Impact/Purpose:
The purpose of this study was to create an exposure metric for air manganese exposure in an epidemiologic study. The exposure modeling conducted in this study may be applicable to other communities where emissions data may not be available.
Description:
Manganese (Mn), a nutrient required for normal metabolic function, is also a persistent air pollutant and a known neurotoxin at high concentrations. Elevated exposures can result in a number of motor and cognitive deficits. Quantifying chronic personal exposures in residential populations studied by environmental epidemiologists can be time-consuming and expensive. We developed an approach for quantifying chronic exposures for two towns (Marietta and East Liverpool, Ohio) with elevated air Mn concentrations (air-Mn) related to ambient emissions from industrial processes. This was accomplished through the use of measured and modeled data in the communities studied. A novel approach was developed because one of the facilities lacked emissions data for the purposes of modeling. A unit emission rate was assumed over the surface area of both source facilities, and offsite concentrations at receptor residences and air monitoring sites were estimated with the American Meteorological Society/Environmental Protection Agency Regulatory Model (AERMOD). Ratios of all modeled receptor points were created, and a long-running air monitor was identified as a reference location. All ratios were normalized to the reference location. Long-term averages at all residential receptor points were calculated using modeled ratios and data from the reference monitoring location. Modeled five-year average air-Mn exposures ranged from 0.03-1.61 µg/m3 in Marietta and 0.01-6.32 µg/m3 in East Liverpool. Air-Mn monitoring for total suspended particulate (TSP) ranged from 0.01-1.50 µg/m3 in Marietta and 0.01-6.80 µg/m3 in East Liverpool. Our approach can be used for other studies where the relationship between exposure and health outcomes is being evaluated and where at least some air monitoring data are available, even in the absence of source emissions data. This abstract does not necessarily reflect ATSDR or EPA policy.