Diesel Exhaust

Nitropyrenes are a class of chemicals found in diesel engine exhaust that can form DNA adducts and are suspected animal carcinogens. Dr. Beland at the University of Arkansas for Medical Sciences examined the relationship between DNA adducts and cancer in laboratory animals treated with 1-nitropyrene, the major nitropyrene present in diesel engine exhaust. The investigator used state-of-the-art techniques to study DNA adducts formed from 1-nitropyrene under different conditions of exposure, with an emphasis on identifying unique adducts that had not been recognized before.

This report describes a study by Drs. Yu and Yoon to mathematically predict the lung burden in rats and humans of diesel exhaust particles (DEP) from automobile emissions. Building on a previously constructed model describing DEP deposition, the present work focused on clearance and retention of DEPs deposited in the lung. The transport rates of each component of DEPs were derived using experimental data and mathematical approximations. The complete model was first developed for rats and then extrapolated to humans of different age groups.

This report describes a study by Dr. Schenker and colleagues to investigate the usefulness of urinary mutagenicity as a biological marker of occupational diesel exhaust exposure. Personal exposure to diesel exhaust over 2 consecutive work shifts was monitored via personal air samplers in 87 railroad workers, with adjustment for first-hand and environmental tobacco smoke exposure. Urine samples collected at the end of shifts were evaluated for mutagenicity and analyzed for any correlation with diesel exhaust exposure.

This report describes a study by Dr. Moon and colleagues to investigate the carcinogenic potential of 1-nitropyrene, a mutagenic constituent of diesel exhaust particles, using a hamster respiratory-carcinogenesis model. Male hamsters were exposed to 1 or 2 mg of 1-nitropyrene via intratracheal administration either once or twice a week for 92 weeks. In order to study activity as a cocarcinogen, 1 or 2 mg of 1-nitropyrene was administered in combination with 0.25 mg of the known environmental carcinogen benzo[α]pyrene once per week for 92 weeks.