Associations between respiratory illness and PM10 air pollution.

In this study, the association between daily morbidity and respirable particulate pollution (i.e., particles with a mass median aerodynamic diameter of < or = 10 microns [PM10]) was evaluated in the general population of Anchorage, Alaska. Using insurance claims data for state employees and their dependents who lived in Anchorage, Alaska, the authors determined the number of medical visits for asthma, bronchitis, and upper respiratory infections. The number of visits were related to the level of particulate pollution in ambient air measured at air-monitoring sites. This study was conducted during a 3-y period, which included several weeks of higher-level particulate pollution that resulted from a volcanic eruption (i.e., August 1992). The particulate pollution was measured by the Anderson head sampler (24-h accumulation). The medical visits of the population at risk were also tallied daily. To help confirm whether PM10 exposure was a risk factor in the exacerbation of asthma, we used a regression analysis to regress daily asthma visits on PM10 pollution levels, controlling for seasonal variability. A significant positive association between morbidity and PM10 pollution was observed. The strongest association was with concurrent-day PM10 levels. The relative risk of morbidity was higher with respect to PM10 pollution during warmer days.