Health effects of sulfur-related environmental air pollution: The pulmonary surfactant system is not disturbed by exposure to acidic sulfate and neutral sulfite aerosols

The goal of this study was to assess the impact of long-term exposure to en vironmental sulfur-related aerosols on the biochemical and biophysical prop erties of lung surfactant. Eight Beagle dogs were housed under clean air co nditions for 450 days, followed by an exposure period of 400 days to 0.36 m g/m(3) of sulfite (16.5 h/d) and to 5.66 mg/m(3) of sulfate (6 h/d) equival ent to a pulmonary hydrogen burden of 15 mu mol/m(3). Other dogs kept in cl ean air for the whole study period were additional controls. Serial broncho alveolar lavages (BALs) were analyzed for total phospholipid concentration, content and ratio of a surfactant-rich large aggregate (LA) fraction and a small aggregate (SA) fraction, in vitro surface area cycling of LAs into S As as a measure of alveolar extracellular pulmonary surfactant aggregate me tabolism, and surface activity of native and lipid-extracted LA. No signifi cant changes over time and no differences between the clean air period and the exposure period were observed. Thus, long-term environmental exposure o f dogs to the sulfur-related air pollution tested does not lead to alterati ons in the amount, extracellular metabolism, or surface-active properties o f pulmonary surfactant.