Inhalation toxicology of diesel exhaust particles

Our present knowledge of the health effects of diesel exhaust particles can be summarized as follows: 1. Diesel exhaust particles are very small in size and consist of a carbonaceous core with a myriad of adsorbed hydrocarbon compounds that are readily extracted with organic solvents. 2. The particle extracts are cytotoxic and mutagenic in in vitro bacterial and mammalian cell cultures. 3. The particle extracts area carcinogenic when painted on mouse skin along with a suitable promoter. 4. Inhaled particles readily deposit in the respiratory tract, a portion is rapidly cleared and a substantial portion is retained for long periods of time (over 100 days) in the lung. 5. Adsorbed hydrocarbon compounds slowly dissociate from the particles in biological media and presumably in the lung. 6. Detoxification mechanisms act on the hydrocarbon compounds released from the particles to minimize effects in in vitro systems and presumably in vivo.