Transboundary air pollution and environmental justice: Vancouver and Seattle compared

This paper comparatively analyzes the association between urban neighborhood socioeconomic markers and ambient air pollution in Vancouver and Seattle, the two largest urban regions in the Georgia Basin-Puget Sound (GB-PS) international airshed. Given their similarities and common airshed, Vancouver and Seattle are useful comparators addressing not only whether socioeconomic gradients exist in urban environmental quality but also identifying clues to differences in these gradients between Canadian and American cities. Large air quality sampling campaigns and pollution regression mapping provide the pollution data, in this case nitrogen dioxide—a marker of traffic emissions considered the most important air pollutant for human health in the typical North American city. Pollution data are combined with neighborhood census data for regression and spatial analyses. Median household income is the most consistent correlate of air pollution in both cities, including their most polluted neighborhoods, although neighborhoods marked by immigrant populations do not correlate with high pollution levels in Vancouver as they do in Seattle.