An Ecological Study of Airport-Related Exposures and Population Health Outcomes in King County, Washington

Abstract

Background: Public Health – Seattle and King County (PHSKC) is currently assessing community health outcomes at varying radii from the Sea-Tac airport to help give context to airport-related exposures. This study aims to supplement those analyses by exploring exposure distributions and associations with community health outcomes through an alternative set of methods using a cross-sectional, ecological approach and only publicly available data. Methods & Analysis: Aircraft activity and air and noise pollution exposure profiles were estimated for local communities. Exposure distributions were compared between race and ethnicity-defined groups on Lorenz-type curves and through difference-in-means tests. Additionally, ordinary least squares regression was used to evaluate area-level associations between aircraft activity, air and noise pollution exposures, and cause-specific mortality rates such as heart disease-related deaths. Results: The exposure analyses provided strong evidence for different levels of exposures between race/ethnicity-defined subgroups in King County. Non-Hispanic White populations had higher distributions in lower exposure tracts and higher socioeconomic status (SES) tracts. Hispanic/Latinx and American Indian and Alaska Native (AIAN) populations had higher mean exposures and lower mean neighborhood SES score than the county as a whole. Black and Native Hawaiian Pacific Islander (NHPI) populations were consitently more distributed in higher exposure tracts. The regression analysis did not provide strong evidence for an association between the six health outcomes of interest and the three primary exposures. This part of the analysis was limited by sample size, data limitations, and severe multicollinearity. Conclusion: This study of King County adds to local documentations of environmental exposures, especially among NHPI and AIAN communities with smaller local populations. While this study could not draw definitive conclusions about associations between local airport exposures and health outcomes, the results may still be helpful alongside the results from the PHSKC analyses to piece together what is happening locally. Future work on this same local issue would benefit from more recent and more granular data and multi-level methods that can incorporate data at different geographic scales.