Residential mobility and air pollution inequalities : describing income disparities in lifelong air pollution exposure

This paper examines individuals’ differential exposure to air pollution by income, measured as equalised disposable income. We link administrative data on residential location to fine-grained measures of ambient particulate pollution (PM2.5). Exposures are unequal due to spatial sorting between and within urban areas. Relying on the Oaxaca-Blinder decomposition method, we show that the bottom 10% of equalized disposable income is overexposed within urban areas, as they are located in the most polluted municipalities. We then conduct a counterfactual exercise to evaluate the role of mobility in sustaining inequalities of exposure. We provide evidence that inequalities are partially maintained by mobility within urban areas, whereby individuals in the top 10% move to less polluted municipalities in their urban area. We also show that among mobilities occurring around different life events, mobilities at childbirth has contributed the most to widening income inequalities of exposure to PM2.5 since 1999.