Air pollution is a major threat to
health, and the dangers are particularly acute in low- and
middle-income countries. However, little is known about how
the burden of pollution is spread across the wealth
distribution in these countries. This paper uses new data
providing high-resolution wealth estimates for more than 100
low- and middle-income countries, combined with equally
high-resolution estimates of air pollution, to estimate how
wealth is correlated with ambient air pollution around the
world. The findings show that on average air pollution is
positively correlated with wealth, but the relationship is
highly heterogeneous across countries. The fact that air
pollution and wealth are both disproportionately high in
urban areas, where economic activity is largely
concentrated, appears to drive this relationship. When the
analysis is limited to anthropogenic sources of pollution,
the relationship becomes less heterogeneous and more
systematically positive. The paper also examines the
relationship between pollution exposure and wealth within
large cities around the world. Again, the findings show
substantial heterogeneity across cities. The paper explores
several hypotheses for this heterogeneity but does not find
a single explanation. Economic concentration within cities
appears to explain some of the relationship. Cities with
more concentrated economic opportunity tend to have more
positive correlations between pollution and wealth
