Diesel Exhaust

Research Report 138, Health Effects of Real-World Exposure to Diesel Exhaust in Persons with Asthma, is one part of HEI's larger program on the role of particles in exacerbating asthma and other allergic diseases. This report describes a study to evaluate how inhaling air with a high concentration of diesel exhaust from vehicular traffic while walking on a busy street in Central London might affect people who had either mild or moderate asthma. Dr.

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.

A Special Report of the Institute's Diesel Epidemiology Working Group. The Diesel Epidemiology Working Group was formed in the fall of 2000 to (1) review reports from 6 diesel feasibility studies funded by HEI to provide information on potential study populations and on exposure assessment methods; and (2) consider the results of the feasibility studies and other ongoing research in order to develop a new research agenda to seek better information for quantitative risk assessment of lung cancer and other chronic diseases that may result from exposure to diesel exhaust. The 6 feasibility studies described in this report were funded by HEI to provide insight about whether a new retrospective or prospective epidemiologic study could provide data to improve estimates of cancer risk from exposure to diesel exhaust, and about whether new methods of exposure analysis would allow us to reevaluate older epidemiologic studies.