EVALUATION OF AN EXPOSURE SETUP FOR STUDYING EFFECTS OF DIESEL EXHAUST IN HUMANS

Diesel exhaust is a common air pollutant and work exposure has been re ported to cause discomfort and affect lung function. The aim of this s tudy was to develop an experimental setup which would allow investigat ion of acute effects on symptoms and lung function in humans exposed t o diluted diesel exhaust. Diluted diesel exhaust was fed from an idlin g lorry through heated tubes into an exposure chamber. During evaluati ons of the setup we found the size and the shape of the exhaust partic les to appear unchanged during the transport from the tail pipe to the exposure chamber. The composition of the diesel exhaust expressed as the ratios CO/NO, total hydrocarbons/NO, particles/NO, NO2/NO, and for maldehyde/NO were almost constant at different dilutions. The concentr ations of NO2 and particles in the exposure chamber showed no obvious gradients. New steady state concentrations in the exposure chamber wer e obtained within 5-7 min. In a separate experiment eight healthy nons moking subjects were exposed to diluted exhaust at a median steady sta te concentration of 1.6 ppm NO2 for the duration of 1 h in the exposur e chamber. All subjects experienced unpleasant smell, eye irritation, and nasal irritation. Throat irritation, headache, dizziness, nausea, tiredness, and coughing were experienced by some subjects. Lung functi on was not found to be affected during the exposure. The experimental setup was found to be appropriate for creating different predetermined steady state concentrations in the exposure chamber of diluted exhaus t from a continuously idling vehicle. The acute symptoms reported by t he subjects were relatively similar to what patients reported at diffe rent workplaces.