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CONCENTRATED COARSE AIR PARTICLE EXPOSURE PRODUCES MILD TOXICOLOGICAL EFFECTS IN HEALTHY VOLUNTEERS
Citation:
GRAFF, D., R. B. DEVLIN, Y. T. HUANG, AND A. J. GHIO. CONCENTRATED COARSE AIR PARTICLE EXPOSURE PRODUCES MILD TOXICOLOGICAL EFFECTS IN HEALTHY VOLUNTEERS. Presented at American Thoracic Society Annual Meeting, San Diego, CA, May 19 - 24, 2006.
Description:
Epidemiological studies have shown that the adverse health effects of ambient particulate matter (PM) exposure to be in general more strongly associated with "fine" PM (<2.5 µM) originating from combustion processes than for "coarse" PM (>2.5 µM) from wind-blown dust, mechanical processes, and biogenic components. The toxicological potential of coarse PM is a major issue in many parts of the Western United States as wind-blown dust can contribute significantly to ambient PM concentrations and can bring some areas out of attainment of the EPA PM standard. To evaluate the health effects of coarse PM exposure we exposed 14 healthy, young volunteers to concentrated coarse air particles (CAPS) and filtered air (FA) for two hours on two separate occasions. We assessed markers of systemic inflammation, coagulation factors, pulmonary function, and heart rate variability (HRV) at baseline, immediately after exposure, and approximately 20 hours after exposure. In addition, subjects underwent bronchoscopy with lavage approximately 20 hours after each exposure to determine effects on airway inflammation. Coarse CAPS exposure (mean ± SD = 89.0 ± 49.5 µM3) increased the percentage of neutrophils in the lower airway from 1 to 2% compared to FA but had no effect on upper airway inflammatory markers or pulmonary function. Coarse CAPS also decreased resting HRV (SDNN) 20 hours post exposure. When all subjects were included in the analysis, we saw no effects on vascular endpoints. However, those receiving <125ug of inspired PM had increased prothrombin and fibrinogen at 20 hours, while those receiving >125ug had decreased tissue plasminogen activator, demonstrating some effect on blood coagulation. In conclusion, healthy subjects exposed to PM exhibit mild systemic and pulmonary effects. This abstract does not necessarily represent EPA policy.