Inequality in the Distribution of Air Pollution Attributable Mortality Within Canadian Cities.

Recent studies have identified inequality in the distribution of air pollution attributable health impacts, but to our knowledge this has not been examined in Canadian cities. We evaluated the extent and sources of inequality in air pollution attributable mortality at the census tract (CT) level in seven of Canada's largest cities. We first regressed fine particulate matter (PM2.5) and nitrogen dioxide (NO2) attributable mortality against the neighborhood (CT) level prevalence of age 65 and older, low income, low educational attainment, and identification as an Indigenous (First Nations, Métis, Inuit) or Black person, accounting for spatial autocorrelation. We next examined the distribution of baseline mortality rates, PM2.5 and NO2 concentrations, and attributable mortality by neighborhood (CT) level prevalence of these characteristics, calculating the concentration index, Atkinson index, and Gini coefficient. Finally, we conducted a counterfactual analysis of the impact of reducing baseline mortality rates and air pollution concentrations on inequality in air pollution attributable mortality. Regression results indicated that CTs with a higher prevalence of low income and Indigenous identity had significantly higher air pollution attributable mortality. Concentration index, Atkinson index, and Gini coefficient values revealed different degrees of inequality among the cities. Counterfactual analysis indicated that inequality in air pollution attributable mortality tended to be driven more by baseline mortality inequalities than exposure inequalities. Reducing inequality in air pollution attributable mortality requires reducing disparities in both baseline mortality and air pollution exposure. Plain Language Summary: Is air pollution attributable mortality equally distributed within cities? What population characteristics drive inequalities? Does the degree of inequality differ between cities? To what extent are inequalities in air pollution attributable mortality driven by exposure inequalities versus baseline mortality inequalities? In this study of seven Canadian cities, we found that neighborhoods with a higher prevalence of low income and Indigenous identity had significantly higher air pollution attributable mortality. However, there were different degrees of inequality among the cities. Inequality in air pollution attributable mortality tended to be driven more by baseline mortality inequalities than exposure inequalities. Key Points: Census tracts with a higher prevalence of low income and Indigenous identity had significantly higher air pollution attributable mortalityThe magnitude of inequality differed among seven Canadian citiesInequality in air pollution attributable mortality tended to be driven more by baseline mortality inequalities than exposure inequalities [ABSTRACT FROM AUTHOR]