PM2.5-induced changes in cardiac function of hypertensive rats depend on wind direction and specific sources in Steubenville, Ohio

Abstract

Background: Increases in particulate matter less than 2.5 µm (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.