Research Reports

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.

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. Assessing the risk of adverse health effects from such exposures is difficult because only limited data are available on the actual ozone concentrations that people experience. Under the HEI ozone sampler program, three studies were designed to advance the development and testing of personal ozone samplers. The studies were conducted by Dr. Hackney and colleagues at Rancho Los Amigos Medical Center (Part I), Dr. Koutrakis and colleagues at the Harvard School of Public Health (Part II), and Dr. Yanagisawa from the Harvard School of Public Health (Part III). 

Both environmental and genetic factors are believed to contribute to the multistage process that results in carcinogenesis. Therefore, determining the health risks associated with exposure to known and suspected carcinogenic chemicals is essential for informed decision-making by regulatory agencies. Dr. Roger W. Giese and colleagues at Northeastern University developed sensitive and specific techniques for measuring polycyclic aromatic hydrocarbon (PAH)-DNA adducts, a class of DNA adducts associated with exposure to constituents of diesel emissions and other combustion products.

Devices have been developed to reduce particle emissions from vehicles with diesel engines, such as a trap that filters the particles from the exhaust. Periodically, the trap is cleaned (regenerated) by electric heating, thereby burning the particles before they can clog the trap. There is concern that potentially harmful chemicals associated with the particles may be emitted from the trap during normal use and regeneration. Dr.

Carbon monoxide is a ubiquitous air pollutant. It is found in cigarette smoke and emissions from motor vehicles, industrial processes, and poorly ventilated combustion sources. Dr. Penn and his colleagues at New York University Medical Center sought to determine whether chronic exposure to ambient levels of carbon monoxide is also a risk factor for developing atherosclerosis because this disease is the leading contributor to deaths by heart attack and stroke in the United States.

Nitropyrenes, which form during diesel fuel combustion, cause mutations and are carcinogenic in some animals. Dr. Veronica Maher and colleagues at Michigan State University studied the effect of nitropyrene-DNA adducts on gene mutation. The investigators exposed a specific gene, in culture, to each of two nitropyrene derivatives. They then (1) compared the number of adducts formed by each derivative, (2) analyzed the chemical structure of the adducts, and (3) determined in which region of the DNA the adducts formed.

Dr. George Jakab and associates the Johns Hopkins University School of Public Health examined the effects of inhaled formaldehyde, an airway irritant that is part of motor vehicle emissions, on alveolar macrophages. The investigators exposed mice to varying levels of formaldehyde alone or to formaldehyde mixed with carbon black particles. Carbon black particles were chosen because of their similarity to combustion derived particles. Different alveolar macrophage functions were evaluated using two assays.

Dr. Klein-Szanto and colleagues at the Fox Chase Cancer Center employed a novel exposure system to explore the capacity of formaldehyde to cause cancerous changes in human epithelial cells. Formaldehyde is classified as a toxic air pollutant and is emitted in exhaust of motor vehicles, but whether or not formaldehyde is injurious to human health is controversial. The investigators obtained autopsy samples from human infant airways and from adult nasal tissue.