Inequality in exposure to air pollutants: A new perspective.

In research and policy design we mainly use a 'population weighted average concentrations' perspective to study changes in air quality, to evaluate if past policies have been effective, or to assess the impact of future air quality plans. This angle is useful and informative, but sometimes masks other important patterns. In this paper we propose to add, to the existing population weighted average point of view, a new indicator that brings to the fore the 'inequalities' in exposure. This inequality indicator is based on the Gini coefficient, usually applied in Economics and here considered to evaluate if exposure to air pollutants is equally distributed among population. A case study for this new indicator is then proposed, to assess the evolution of exposure to air pollutants in Europe from 2000 to 2018, in terms of both average exposure and inequality levels. The results show that using only average exposure metrics can mask other interesting patterns, and confirm the benefits of including this alternative perspective into the analysis.