A Retrospective Investigation of PM10 in Ambient Air and Cardiopulmonary Hospital Admissions in Allegheny County, Pennsylvania: 1995-2000

Objective: Air quality in Allegheny County, Pennsylvania has improved over the last decade and we investigated whether the lower concentrations of fine particulate matter (PM10) are still associated with adverse health outcomes.

Methods: Daily cardiopulmonary hospital admissions in elderly residents of Allegheny County and countywide average PM10 measures were available from 1995 through 2000. Using generalized additive models (GAM), a Poisson regression model was fit to the number of daily admissions using predictor variables: lags of PM10, daily temperature and humidity, day of the week, and time.

Results: Our findings suggest that there is a positive association of PM10 with hospital admissions, and the effect is related to current day PM10 levels.

Conclusions: Even at the lower levels of ambient air pollution as measured by PM10, there is still a suggestion of an adverse health effect in the elderly.

Clinical significance: Some hospital admissions for cardiopulmonary disease might be attributed to recent elevated ambient PM10 levels. Physicians should be aware of the environmental conditions when evaluating and treating their patients. These conditions might be the underlying trigger of events leading to the patient’s hospitalization.

Keywords: generalized additive models; PM10; Poison regression; air pollution; hospital admissions; elderly

Department of Biostatistics, Graduate School of Public Health, University of Pittsburgh, Pennsylvania 15261, USA.