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Relationship between chemical composition and pulmonary toxicity of source-specific ambient particulate matter
Citation:
Cho, S., W. P. Linak, C. J. King, J. K. MCGEE, Q. T. KRANTZ, AND M. I. GILMOUR. Relationship between chemical composition and pulmonary toxicity of source-specific ambient particulate matter. Presented at International Congress on Combustion By-Products and Their Health effects, RTP, NC, May 31 - June 03, 2009.
Impact/Purpose:
In this study, the pulmonary toxicity potential of combustion and ambient PM were investigated using data from animal studies at the US EPA.
Description:
Epidemiological studies have reported incidence of cardio-pulmonary disease associated with increase in particulate matter (PM) exposure. In this study, the pulmonary toxicity potential of combustion and ambient PM were investigated using data from animal studies at the US EPA. Specifically, diesel exhaust particles (DEP) with low and high elemental carbon (EC), coal-fly ash (CFA) with varied carbon and inorganic content, and ambient PM collected at various sites in the US were tested. Pulmonary toxicity was evaluated by fold-increases, compared to saline control for levels of neutrophils, interleukin-6, and total protein in bronchoalveolar lavage fluid. Principal component analysis and multiple linear regression analyses were used to determine the association between particle constituents and toxic potential. Ultrafine CFA and DEP, comprising large amounts of EC notably increased neutrophils, while DEP with lower EC content had much less to no effect. For the ambient PM, the first factor, comprising inorganics, sulfates, ammonium, and non-ICP-identifiable components (probably minerals) was significantly associated with increases in all pulmonary endpoints. Within this factor, inorganics and the unidentified fraction had a positive association with all endpoints, while sulfates and ammonium were negatively associated. The second factor, including sodium and chlorine was significantly associated only with interleukin-6 negatively. Low EC content in ambient PM had a non-significant association with all endpoints. We conclude that for combustion PM, EC is a driving factor for pulmonary toxicity, while in the chemically more complex ambient PM, the effects are associated with many other chemical constituents. (This abstract does not reflect EPA policy.)