Controlled Exposures of Healthy and Asthmatic Volunteers to Concentrated Ambient Particles in Metropolitan Los Angeles

Dr. Henry Gong Jr and his colleagues at the Los Amigos Research and Education Institute used 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 were exposed to either filtered air or CAPs with a maximum exposure level of 200 µg/m³ for two hours while exercising intermittently on a stationary bicycle. Gong and colleagues 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. The investigators evaluated pulmonary function and cardiac electro-physiologic and blood parameters at multiple time points before, during, and after exposure to CAPs or air.