An evaluation of transported pollution and respiratory–related hospital admissions in the state of New York

Abstract

Human exposure to air pollution transported from the Midwest is evaluated in eight New York State (NYS) regions over ten summers (1997 – 2006) for association with respiratory–related hospital admissions. Days when pollution is transported into the Northeastern United States (U.S.) were identified by using back–trajectories from the eight regions. These back–trajectories help identify predominant meteorological patterns associated with “polluted” air parcels (originating in the Midwest where power plant emissions are known to be relatively high) and “clean” air parcels (originating from the North where pollution is known to be relatively low). Ambient ozone concentrations measurements were used to validate the classification of “polluted” and “clean” air parcels. These classifications were then used to define the days of high– versus low–exposure for populations residing within each region. The results of this analysis indicate that the risk of being hospitalized for respiratory–related illness in NYS is greater on those days when air is transported from the Midwest as compared to days when air is transported from the North. Using a refined method to examine air parcels moving through a boundary drawn around high–emitting power plants in the Midwestern U.S. resulted in stronger associations across more regions (significant odds ratios ranging from 1.06 to 1.16 for the entire study time period for six of the eight NYS regions). An assessment of temperature and its impact on the odds ratio calculation in the New York City metropolitan region indicates that temperature alone does not explain the increased association between air pollution and respiratory–related hospital admissions.