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CONTROLLED EXPOSURES OF HEALTHY AND ASTHMATIC VOLUNTEERS TO CONCENTRATED AMBIENT PARTICLES IN METROPOLITAN LOS ANGELES
Impact/Purpose:
Ambient particulate matter (PM) is a complex mixture of particles suspended in the air. The size, chemical composition, and other physical and biological properties of these particles vary with location and time. Although the characteristics of PM vary in different places, epidemiologic studies in many diverse locations have reported that short-term increases in levels of PM are associated with short-term increases in illness and death. These studies have raised several critical questions, including: (1) What are the characteristics—especially size and chemical composition—of particles that may cause harmful human health effects? (2) What biologic mechanisms may explain the reported epidemiologic associations? and (3) Which groups of people are particularly sensitive to the effects of PM?
Preliminary studies have indicated that nonhuman species exposed to CAPs showed certain changes in electrocardiogram (ECG) readings and differences in cell counts of peripheral blood leukocyte subsets. The relevance of these findings to humans was not clear, however. Therefore, the objective of the investigators for this research is to use a technology designed to concentrate ambient particles (CAPs) and expose human volunteers to CAPs using a controlled laboratory protocol. They hypothesized that CAPs exposure would cause cardiopulmonary effects, mediated by local and systemic inflammation, and that responses to CAPs would differ among individuals depending on their health status.
Description:
Investigators expect to use a Harvard ambient particle concentrator to assess the effects of exposure to concentrated ambient particles (CAPs) on healthy and asthmatic people. 12 healthy individuals and 12 individuals with mild asthma will be exposed to either filtered air or CAPs. Gong and colleagues anticipate that their research will reveal that CAPs exposure would cause cardiopulmonary effects, mediated by local and systemic inflammation, and that responses to CAPs would differ among individuals depending on their health status.