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Background: Increases in particulate matter less than 2.5 µµm (PM2.5) in ambient air is linked to acute cardiovascular morbidity and mortality. Specific components and potential emission sources of PM2.5 responsible for adverse health effects of cardiovascular function are unclear. Methods: Spontaneously hypertensive rats were implemented with radiotelemeters to record ECG responses during inhalation exposure to concentrated ambient particles (CAPs) for 13 consecutive days in Steubenville, OH. Changes in heart rate (HR) and its variability (HRV) were compared to PM2.5 trace elements in 30-min time frames to capture acute physiological responses with real-time fluctuations in PM2.5 composition. Using positive matrix factorization, six major source factors were identified: (i) coal/secondary, (ii) mobile sources, (iii) metal coating/processing, (iv) iron/steel manufacturing, (v) lead and (vi) incineration. Results: Exposure-related changes in HR and HRV were dependant on winds predominately from either the northeast (NE) or southwest (SW). During SW winds, the metal processing factor was associated with increased HR, whereas factors of incineration, lead and iron/steel with NE winds were associated with decreased HR. Decreased SDNN was dominated during NE winds by the incinerator factor, and with SW winds by the metal factor. Metals and mobile source factors also had minor impacts on decreased SDNN with NE winds. Individual elemental components loaded onto these factors generally showed significant associations, although there were some discrepancies. Conclusions: Acute cardiovascular changes in response to ambient PM2.5 exposure can be attributed to specific PM constituents and sources linked with incineration, metal processing, and iron/steel production. [ABSTRACT FROM AUTHOR]

Abstract: Recent epidemiological and toxicological studies have suggested that short-term elevations of ambient fine particle mass concentrations (aerodynamic diameter <2.5μm, PM2.5) can increase cardiac and pulmonary health risks. Thus, examining temporal variations of chemical changes in ambient PM2.5 that could pose the greatest health risks and identifying its sources is critical so that the most toxic categories can be controlled. In this study we collected detailed air quality data in Steubenville, Ohio in August 2006 with the ultimate goal to evaluate associations between cardiovascular (CV) parameters measured in exposed laboratory animals and the chemical and elemental composition of PM2.5. Current approaches using radiotelemetry to measure CV parameters in conscious laboratory animals are capable of collecting continuous recordings. To provide a robust and analogous dataset that can be better matched with CV responses, we have incorporated a highly time-resolved sampling method to characterize trace elements and thereby obtain more robust input data to determine potential emission sources. We applied positive matrix factorization (PMF) to trace element concentrations from 30-minute ambient PM2.5 samples in Steubenville, Ohio, an area designated as a non-attainment area for the PM2.5 National Ambient Air Quality Standards by the Environmental Protection Agency. The average ambient PM2.5 filter-based mass concentration during the 8-hour summer exposure study period was 26±11μgm−3. Results from PMF indicated that six major factors contributed to the ambient PM2.5 mass during this time: coal combustion/secondary (39±46%), mobile sources (12±14%), metal coating/processing (10±11%), iron and steel manufacturing (5±5%), Pb factor (5±8%), and incineration/smelting (1±3%). The objectives of this paper are (1) to present chemical composition of ambient PM2.5 and its potential emission sources in Steubenville; and (2) to evaluate the PMF modeling results using observed meteorological data. These semi-continuous sampling approaches to determine potential emission sources have significant advantages over similar analyses using samples averaged over 8–24h, and are being utilized by our group to determine associations of PM with acute CV responses from animal inhalation toxicology field studies. [Copyright &y& Elsevier]