Research Reports

In a follow-up study to previous research, Dr. Mercer and colleagues at Duke University exposed three groups of rats continuously for six weeks to 2 or 6 ppm nitric oxide (NO) or to filtered air to learn more about the toxicity of NO so as to compare it with two other important oxidants, ozone and nitrogen dioxide (NO₂). At the end of the exposure period he used an electron microscope to measure the number of holes in the alveolar septa and to observe other structural changes, such as in the surface area and the number and type of other abnormalities in the alveolar septa.

Dr. Navidi and colleagues at the University of Southern California discussed the development of three sophisticated statistical methods that would improve the estimates of the health effects of air pollution obtained from epidemiologic studies. First, they took a standard case-crossover design and introduced a bidirectional element where control data were obtained both before and after the health event of interest.

Dr. Arey and colleagues of the University of California, Riverside, examined the genotoxic potential of two PAHs (naphthalene and phenanthrene) that are common air pollutants, and a subset of their atmospheric transformation products. The investigators evaluated the genotoxicity of these compounds using a variety of human cell lines with a range of metabolic capabilities. They examined the ability of these compounds to produce small-scale (damage to genes) and large-scale (damage to chromosomes) genetic damage.

Ozone, a common outdoor air pollutant, is a highly reactive gas and a major component of smog. A public health concern is that prolonged exposure to ozone might damage the airways and contribute to the development of noncancerous respiratory diseases. To examine this issue, the Health Effects Institute collaborated with the NTP to provide HEI-funded investigators access to animals that underwent the same rigorously controlled ozone exposure and quality assurance processes along with the animals used for NTP studies. One of the NTP/HEI investigator groups, Dr.