Simulated Downwind Coal Combustion Emissions For Laboratory Inhalation Exposure Atmospheres

Exposure atmospheres for rodent inhalation toxicology studies were generated to enable the evaluation of biological responses to a simulated downwind coal combustion atmosphere. A composition representing a single test case of emissions components as they may exist tens to hundreds of miles from a coal-fired power plant was developed. The particulate matter (PM) was 99% sulfate (partially neutralized) and 1% ash. Sulfate was present in equimolar concentrations to sulfur dioxide (SO2). Gaseous nitrogen species included nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitric acid (HNO3). At the high-exposure level, the gaseous species target concentrations were 0.2 ppm SO2, 0.6 ppm NO, 0.3 ppm NO2, and 0.1 ppm HNO3. The test atmosphere was produced by combining effluent from a laboratory coal combustor with sulfate generated through an evaporation-condensation generator. These atmospheres were used to conduct inhalation toxicology studies that have been previously reported.