Research Reports

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.

Dr. Schlesinger and colleagues at the New York University School of Medicine used a well-established animal model of airway hyperresponsiveness (a heightened tendency of the bronchial airways to constrict) and allergic asthma to determine whether ozone can induce airway hyperresponsiveness or exacerbate existing airway hyperresponsiveness. Male and female guinea pigs were exposed to ozone concentrations comparable to levels to which humans are exposed during periods of ozone pollution.

This report describes two studies that measured emissions in roadway tunnels. Dr. Alan Gertler and colleagues at the Desert Research Institute studied particulate matter emissions in the Tuscarora Mountain Tunnel located on the Pennsylvania Turnpike. Dr Daniel Grosjean and colleague at DGA, Inc studied carbonyl emissions in the Tuscarora Mountain Tunnel and in the Caldecott Tunnel in California. The unique environment in tunnel studies allows the investigators to measure emission rates averaged over many vehicles, to determine the physical and chemical character of emissions under ambient conditions, and in some instances to compare current emissions with past emissions at the same location. Both groups of investigators also measured emissions at times when the proportions of gasoline engine vehicles and diesel engine vehicles differed, allowing them to estimate the differences between emissions from the two sources.