Acute respiratory symptoms in patients with chronic obstructive pulmonary disease and in other subjects living near a coal-fired plant.

Daily symptom rates in patients with chronic obstructive pulmonary disease and in other subjects with presumed high sensitivity to air pollution who lived near a coal-fired plant were compared with 24-hr ambient air concentrations of nitrogen dioxide, sulfur dioxide, soot, and suspended particles as well as with emissions from the plant. The mean concentrations of each of the pollutants during the 4-month study period were below 30 micrograms/m3, and no single 24-hr concentration exceeded 100 micrograms/m3. There were no consistent associations between plant emissions and pollutant levels or between these two variables and daily symptom rates. The results indicate that the coal-fired plant was not of major importance for the occurrence of acute respiratory symptoms in the surrounding population.