Identifying inequalities in air pollution levels across population groups can help address
environmental justice concerns. We were interested in assessing these inequalities across
major urban areas in Australia. We used a land-use regression model to predict ambient
nitrogen dioxide (NO2) levels and sought the best socio-economic and population predictor
variables. We used a generalised least squares model that accounted for spatial correlation
in NO2 levels to examine the associations between the variables. We found that the best
model included the index of economic resources (IER) score as a non-linear variable and
the percentage of non-Indigenous persons as a linear variable. NO2 levels decreased with
increasing IER scores (higher scores indicate less disadvantage) in almost all major urban
areas, and NO2 also decreased slightly as the percentage of non-Indigenous persons
increased. However, the magnitude of differences in NO2 levels was small and may not
translate into substantive differences in health.