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DETERMINE IF COARSE PM IS OF REGULATORY CONCERN: PHYSIOLOGICAL CHANGES OF ASTHMATICS EXPOSED TO CONCENTRATED CHAPEL HILL AIR PARTICLES
Impact/Purpose:
1. To identify health effects associated with coarse PM, using a combination of panel studies, controlled human exposure studies, animal exposure studies, and in vitro toxicology. 2. To determine if asthmatics are especially susceptible to coarse PM. 3. To characterize the relative potency of coarse PM collected from several different geographical areas, including both rural and urban locations.
Description:
Uncertainty about the effects of coarse PM has led the EPA to propose a dual standard for coarse PM: one for urban areas and one for rural areas. The underlying assumption is that rural PM may be different in chemical composition and toxicity. The OAR has indicated that one of the most important research questions that ORD needs to address in the area of PM is a clear understanding of whether coarse PM causes adverse health effects, and whether the science supports a rural and urban standard for coarse PM. Asthmatics will be recruited and followed for several days. Personal and outside home monitoring will be used to assess exposure to coarse and fine PM, as well as components such as LPS. Holter monitoring will be used to assess changes in heart variability; vascular factors involved in clotting, coagulation, and inflammation will be assessed; respiratory effects will be measured by lung function and induced sputum will be used to assess changes in lung inflammation and injury. Models will then be used to compare daily fluctuations in PM levels with daily fluctuations in biological effects. Healthy volunteers as well as those with asthma will be exposed to concentrated Chapel Hill coarse PM and a number of cardiopulmonary end points assessed. These include heart rate variability; vascular factors involved in clotting, coagulation, acute phase response, and inflammation; and respiratory tract measurements such as lung function, diffusing capacity, inflammation, and lung injury. The results of these studies will be compared with effects seen in volunteers exposed to concentrated fine and ultrafine particles. Coarse particles will be collected from Chapel Hill and other appropriate geographical regions, including both urban and rural areas. Their relative potency will be compared following in vitro exposure to cultured human respiratory tract and endothelial cells. Additionally, mechanisms by which these size fractions cause biological changes will be characterized. To show in vivo relevance of these studies, selected subsets of particles will be instilled into healthy and compromised rodents and cardiopulmonary changes assessed.