Health effects of subchronic inhalation exposure to simulated downwind coal combustion emissions

Context: There have been no animal studies of the health effects of repeated inhalation of mixtures representing downwind pollution from coal combustion. Environmental exposures typically follow atmospheric processing and mixing with pollutants from other sources.Objective: This was the fourth study by the National Environmental Respiratory Center to create a database for responses of animal models to combustion-derived pollutant mixtures, to identify causal pollutants—regardless of source.Methods: F344 and SHR rats and A/J, C57BL/6, and BALB/c mice were exposed 6 h/day 7 days/week for 1 week to 6 months to three concentrations of a mixture simulating key components of “downwind” coal combustion emissions, to the highest concentration filtered to remove particulate matter (PM), or to clean air. Emissions from low-sulfur subbituminous coal were modified to create a mixture recommended by an expert workshop. Sulfur dioxide, nitrogen oxides, and PM were the dominant components. Nonanimal-derived PM mass conc...