Respiratory Hospital Admissions Associated with PM₁₀ Pollution in Utah, Salt Lake, and Cache Valleys

Abstract

This study assessed the association between respiratory hospital admissions and PM₁₀ pollution in Utah, Salt Lake, and Cache valleys during April 1985 through March 1989. Utah and Salt Lake valleys had high levels of PM₁₀ pollution that violated both the annual and 24-h standards issued by the Environmental Protection Agency (EPA). Much lower PM₁₀ levels occurred in the Cache Valley. Utah Valley experienced the intermittent operation of its primary source of PM₁₀ pollution: an integrated steel mill. Bronchitis and asthma admissions for preschool-age children were approximately twice as frequent in Utah Valley when the steel mill was operating versus when it was not. Similar differences were not observed in Salt Lake or Cache valleys. Even though Cache Valley had higher smoking rates and lower temperatures in winter than did Utah Valley, per capita bronchitis and asthma admissions for all ages were approximately twice as high in Utah Valley. During the period when the steel mill was closed, differences in per capita admissions between Utah and Cache valleys narrowed considerably. Regression analysis also demonstrated a statistical association between respiratory hospital admissions and PM₁₀ pollution. The results suggest that PM₁₀ pollution plays a role in the incidence and severity of respiratory disease.