EXPERIMENTAL EVALUATION OF THE EFFECT OF FILTRATION OF DIESEL EXHAUST BY BIOLOGIC EXPOSURE INDICATORS

The airway resistance, compliance of the respiratory system, transfer factor, and alveolar volume of 33 healthy rabbits were studied before and after exposure to diluted diesel exhaust generated in an experimental motor. Three diesel fuels and two particle traps were tested. Subsequent to the post-exposure lung function measurements, the animals were sacrificed and the lungs were processed for morphologic examination. The concentrations of particles, nitrogen dioxide, and formaldehyde were measured. The inflammatory airway changes were most pronounced in animals exposed to exhaust from standard fuel. Small changes were identified in animals exposed to exhaust filtered through the catalytic trap as well or exposed to unfiltered exhaust from fuels intended for densely built-up areas. Increase in compliance of the respiratory system was associated with the concentration of soot particles and formaldehyde. Compliance decreased significantly in animals exposed to exhaust from standard fuel filtered through the particle traps and increased almost significantly in animals exposed to unfiltered exhaust from the same fuel. (C) 1995 Wiley-Liss, Inc.