Neighborhood Air Quality, Respiratory Health, and Vulnerable Populations in Compact and Sprawled Regions

Problem: Recently, public health researchers have argued that infill development and sprawl reduction may improve respiratory outcomes for urban residents, largely by reducing vehicle travel and its attendant mobile-source emissions. But infill can also increase the number of residents exposed to poor air quality within central cities. Aside from emissions studies, planners have little information on the connections between urban form, ambient pollutant levels, and human exposures or how infill changes these. Purpose: We examined neighborhood exposures in 80 metropolitan areas in the United States to address whether neighborhood-level air quality outcomes are better in compact regions than in sprawled regions. Methods: We used multilevel regression models to find the empirical relationship between a measure of regional urban form and neighborhood air quality outcomes. Results and conclusions: Ozone concentrations are significantly lower in compact regions, but ozone exposures in neighborhoods are higher in compact regions. Fine particulate concentrations do not correlate significantly with regional compactness, but fine particulate exposures in neighborhoods are also higher in compact regions. Exposures to both ozone and fine particulates are also higher in neighborhoods with high proportions of African Americans, Asian ethnic minorities, and poor households. Takeaway for practice: Compact development and infill do not solve air quality problems in all regions or for all residents of a given region. Planners should take differences in neighborhood air quality and human exposure into account when planning for new compact developments rather than just focusing on emissions reductions. Research support: This project was supported by a grant from the ShenAir Institute at James Madison University and by the National Oceanographic and Atmospheric Administration.