EFFECTS ON SYMPTOMS AND LUNG-FUNCTION IN HUMANS EXPERIMENTALLY EXPOSED TO DIESEL EXHAUST

Objectives-Diesel exhaust is a common air pollutant made up of several gases, hydrocarbons, and particles. An experimental study was carried out which was designed to evaluate if a particle trap on the tail pip e of an idling diesel engine would reduce effects on symptoms and lung function caused by the diesel exhaust, compared with exposure to unfi ltered exhaust. Methods-Twelve healthy non-smoking volunteers (aged 20 -37) were investigated in an exposure chamber for one hour during ligh t work on a bicycle ergometer at 75 W. Each subject underwent three se parate double blind exposures in a randomised sequence: to air and to diesel exhaust with the particle trap at the tail pipe and to unfilter ed diesel exhaust. Symptoms were recorded according to the Borg scale before, every 10 minutes during, and 30 minutes after the exposure. Lu ng function was measured with a computerised whole body plethysmograph . Results-The ceramic wall flow particle trap reduced the number of pa rticles by 46%, whereas other compounds were relatively constant. It w as shown that the most prominent symptoms during exposure to diesel ex haust were irritation of the eyes and nose and an unpleasant smell inc reasing during exposure. Both airway resistance (R(aw)) and specific a irway resistance (SR(aw)) increased significantly during the exposures to diesel exhaust. Despite the 46% reduction in particle numbers by t he trap effects on symptoms and lung function were not significantly a ttenuated. Conclusion-Exposure to diesel exhaust caused symptoms and b ronchoconstriction which were not significantly reduced by a particle trap.