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Identifying the Sources Contributing to PM Exceedances in Ostrava, Czech Republic, Using Passive Aerosol Sampling Coupled with Computer-Controlled Microscopy
Willis, R., L. Cernikovsky, T. Conner, J. Novak, H. Placa, B. Krejei, I. Nikolova, E. Chalupniekova, AND R. Williams. Identifying the Sources Contributing to PM Exceedances in Ostrava, Czech Republic, Using Passive Aerosol Sampling Coupled with Computer-Controlled Microscopy. Presented at Dust 2014 International Conference on Atmospheric Dust, Castellaneta Marina, ITALY, June 01 - 06, 2014.
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA 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.
The Czech Hydrometeorological Institute (CHMI) in collaboration with the U.S. Environmental Protection Agency conducted a multi-pollutant source apportionment study in 2012 to quantify the impact of regional as well as local sources on air quality in the Ostrava metropolitan area. Samples were analyzed for inorganic species (XRF), PAHs, organic and elemental carbon and pollutant gases for seven-week periods during the summer of 2012 and the late fall/early winter of 2012 at three monitoring locations: an industrial suburban site typically downwind of a major industrial facility; a residential area typically upwind of the same industrial facility, and a background suburban residential area. In addition, passive aerosol samplers (Wagner and Leith, 2013) were deployed at the three ambient monitoring sites for three successive two-week periods during both the summer and late fall/winter campaigns.This presentation discusses the use of passive aerosol sampling coupled with computer-controlled scanning electron microscopy (CCSEM) to enhance understanding of PM sources in the Ostrava study and to assist in the interpretation and confirmation of PMF modeling results. In addition to ambient sampling, passive samplers were deployed near suspected PM sources in order to develop quasi-source signatures for the following sources: blast furnace, sintering plant, steel works, coke plant, mobile sources, and home heating. Samples of bulk slag dust generated in steelmaking were also collected. Samples were analyzed by CCSEM coupled with energy-dispersive X-ray spectrometry (EDS) to yield the size, composition and morphology of individual particles. Analysis of the source samples yielded an atlas of source-related particle types that was used to directly assess the impact of different sources at the ambient monitoring sites as well as to help interpret source-related factors generated by PMF (positive matrix factorization) modeling. Carbonaceous aerosols prove particularly challenging to apportion because they are generated by multiple sources (home heating, coke ovens, mobile sources, biogenic pollens/spores). CCSEM results obtained at the three monitoring sites show significant spatial variability in PM concentrations and relative source contributions.