Publications

One major component of urban smog is ozone, a highly reactive gas that forms when emissions from mobile and industrial sources react chemically in the presence of sunlight.  One concern is that prolonged ozone exposure could cause noncancerous lung diseases such as fibrosis and emphysema. The NTP's bioassay project presented a unique opportunity for a collaboration between the HEI and the NTP.

Ozone is a highly reactive gas that is a pervasive air pollutant at ground level. It is a major component of urban smog, forming when emissions from mobile and industrial sources interact with sunlight. The nose is the first line of defense against inhaled pathogens, dusts, and irritant gases; thus, changes induced by ozone in the normal functions of the nose could result in an increased susceptibility to respiratory infections and other diseases. In one of eight studies in the NTP/HEI Collaborative Ozone Project, Drs.

Dr. Mauderly and coworkers exposed F344/N rats to clean air or to one of two levels (2.5 or 6.5 mg of particles/m³ of diesel exhaust or air) of either emissions from a light-duty diesel engine or carbon black particles. The exposures lasted for 16 hours/day, 5 days/week, for 24 months. The carbon black particles were similar to the soot particles in the diesel engine exhaust; however, they contained markedly lower amounts of adsorbed organic compounds.

Ozone is a highly reactive gas that is a pervasive air pollutant at ground level. It is a major component of urban smog, forming when emissions from mobile and industrial sources interact with sunlight. The study of the effects of long-term ozone exposure on lung complex carbohydrates, described in this report, was one of eight laboratory studies supported by the NTP/HEI collaborative agreement. In addition to studying lung and nasal structure and function, investigators studied other constituents of lung connective tissue. Dr.

Ozone is a major outdoor air pollutant and short term inhalation can produce temporary chest discomfort, and transient changes in breathing patterns and lung function. Because a large number of people are exposed to levels of ozone sufficient to cause effects on breathing, it is important to understand the short- and long-term consequences of these exposures for human health. Dr.

Dr. Fennell at the Chemical Industry Institute of Toxicology sought to develop new methods for improving the detection of formaldehyde-DNA adducts in exposed cells and tissues. The investigator treated formaldehyde-DNA adducts with sodium bisulfite, a compound that reacts with these adducts and traps them as stable compounds, and then tested different analytical techniques for separating and detecting the adducts. He exposed pure DNA, cell nuclei, and cells in culture to formaldehyde and treated them with sodium bisulfite under a variety of experimental conditions.

Exposure to polycyclic aromatic hydrocarbons (PAHs) and their nitro-substituted derivatives (nitro-PAHs), products of incomplete combustion, is widespread. This is of concern because individual PAHs and PAH-containing mixtures cause tumors in animals and they are suspected to contribute to human cancer. To asses their carcinogenic potential in humans, biomarkers of PAH exposure that measure the internal dose or the effective dose need to be developed. Dr.

HEI conducted the Environmental Epidemiology Planning Project in order to identify research needs and opportunities in selected areas of environmental epidemiology. Working groups in each selected area prepared documents composed of individually authored papers. The Planning Project documents were originally published in Environmental Health Perspectives (December 1993, Vol. 102).

Human exposure to carbon monoxide can occur from automobile emissions, industrial processes, sidestream or mainstream cigarette smoke, and poorly ventilated appliances such as space heaters and gas stoves. Most researchers consider the major mechanism for the toxicity of carbon monoxide to be its ability to compete with oxygen for binding to hemoglobin, the protein that transports oxygen through the bloodstream and releases it to cells and tissues.

Ozone and nitrogen dioxide are highly reactive oxidant gases that are derived from the combustion of fossil fuels and the atmospheric transformation of these combustion products. A major unanswered question is whether or not exposure to oxidant air pollutants contributes to lung cancer. Dr. Witschi and colleagues at the University of California at Davis examined whether exposure to ozone or nitrogen dioxide enhances the development of tumors induced by the chemical carcinogen diethylnitrosamine (DEN), particularly neuroendocrine tumors, in the respiratory tract of hamsters.

Communication 2 provides information to decision makers on research that is potentially capable of narrowing uncertainties related to the health effects of specific air toxics. This report is based on the Mobile Air Toxics Workshop held in Monterey, CA, December 4–6 1992.

This publications contains two reports by Drs. Jonathan M. Samet, John D. Spengler, and colleagues, who conducted a prospective investigation of 1,205 healthy infants living in homes with gas or electric stoves in Albuquerque, NM. Nitrogen dioxide exposures were carefully estimated from repeated measurements in multiple locations in the subjects' homes throughout the entire 18-month observation period. Respiratory illnesses were monitored prospectively using a surveillance system based on daily parental diaries of respiratory signs and symptoms. Parental reports of illness episodes were validated in a subset of the population by comparison with clinical diagnoses and microbiological testing. Potential confounding factors that influence respiratory infections were reduced by selecting subjects whose parents did not smoke or intend to use day-care services outside the home.