Particulate Matter

Dr. Laskin and her colleagues at the Environmental and Occupational Health Sciences Institute at Rutgers University tested the hypothesis that oxidants in ambient air, such as hydrogen peroxide, may be transported by fine particulate matter into the lungs and thus contribute to lung tissue injury. The investigators used ammonium sulfate particles because of their prevalence in the ambient air of the eastern United States and their reportedly low toxicity in animals and humans.

Stephen Holgate and his colleagues at the University of Southampton proposed that inflammatory changes in lung fluids and blood from humans exposed to PM were related to the chemical composition of the particles. He obtained samples from two human studies in which participants were exposed to diesel exhaust and concentrated ambient particles (CAPs). At a Swedish laboratory 25 healthy and 12 asthmatic participants were exposed to diesel exhaust or filtered air on separate days. At a US laboratory, 12 healthy participants were exposed to filtered air and 30 different healthy participants were exposed to a range of CAPs concentrations. All participants underwent bronchoscopy to obtain lung tissues and fluids to analyze inflammatory markers, including numbers of specific white blood cells, expression of activation markers, and levels of cytokines in addition to analysis of lung function, lung fluids, and blood.

Communication 10 contains proceedings of a workshop held in Baltimore, MD, December 4–6 2002. The workshop sought to address the search for a "Diesel Signature": Do We Have a Diesel Signature? Where Do We Go From Here? Communication 10 includes a workshop summary and reports from speakers on: Health Studies of Diesel Particulate Matter; Future Trends of Diesel Emissions; Diesel and Gasoline Particle Characteristics; Approaches to Particle Characterization; Diesel Source Signature Studies; Emissions and Air Quality Studies; Data Analysis Approaches.

Dr. Aust and her colleagues at Utah State University and Ford Motor company hypothesized that transition metals (metals that can participate in possibly toxic oxidative reactions) associated with particulate matter are released within lung epithelial cells and catalyze the formation of reactive oxygen species. The investigators focused their study on coal fly ash that was produced in the laboratory and separated into four size fractions.