Air pollution poses the greatest environmental risk to health in Europe. Fine particulate matter (PM2.5) causes more premature deaths in Europe than any other ambient air pollutant. Despite improving trends in air pollution for both the richest and poorest regions of the EU during 2007-2020, inequalities remained with levels of PM2.5 concentrations consistently higher by around one third in the poorest regions. This lack of progress in reducing air pollution exposure disparities seems to indicate that we are not progressing in reducing these important environmental inequalities.

Air pollution poses the greatest environmental risk to health in Europe . Fine particulate matter with a diameter of 2.5μm or less (PM2.5) is the ambient air pollutant associated with the highest number of premature deaths , with no thresholds below which exposure is considered safe in terms of the impacts on health . PM2.5 exposure also demonstrates to be a reliable indicator of risk associated with air pollution in general and in different environments . Monitoring PM2.5 levels is therefore useful for exploring income-related inequalities in the distribution of health impacts of air pollution and more broadly of environmental risks.

This indicator explores these inequalities by comparing the exposure to air pollution by fine particulate matter experienced by the population living in the poorest regions of the EU with that in the richest regions. The analysis uses population-weighted concentrations of PM2.5 in the 20% NUTS3 regions (i.e. in small regions like a prefecture) of the EU with the least per capita income (in terms of purchasing power) and in the 20% NUTS3 regions with the highest per capita income. Exposure at NUTS3 is an imperfect proxy for actual inequalities in air pollution exposure. Most likely, within a city the inequalities can be much higher than between NUTS3 regions, depending on the local situation (proximity to main roads, industry, etc.). However, while we have data on exposure to fine particles at a very fine scale (down to a 1 by 1km cell grid), we do not have Europe-wide data on GDP at a level smaller than NUTS3. Therefore, NUTS3 is the smallest scale at which we can calculate the indicator as currently defined.

Between 2007 and 2020, air quality, measured as population-weighted concentrations of PM2.5, improved in both the least disadvantaged (i.e. richest) and the most disadvantaged (i.e. poorest) quintiles of the EU-27’s NUTS3 regions (figure 1). However, regions in the richest quintile had lower PM2.5 levels to begin with (around 15µg/m3 in 2007) than those in the poorest quintile (19.5µg/m3 in 2007).

In an environmentally equal Europe, poverty and pollution would not be correlated. PM2.5 concentrations have decreased at relatively similar rates in regions in the richest quintile (3.15% average year-to-year decrease between 2007 and 2020) and in the poorest quintile (2.77% average year-to-year decrease in the same period), with no statistically significant difference in the trends. However, despite improving trends in air pollution in both the richest and the poorest regions over the 2007-2020 period, inequalities remained with levels of PM2.5 being consistently higher by around one third in the poorest regions (figure 2).

The indicator, defined as the ratio of population weighted concentration of PM2.5 in EU NUTS3 regions in the most and in the least deprived quintiles remained relatively stable from 2007 to 2020 (see supporting information) and well above 1.0. This indicates that so far there has been no progress with reducing environmental inequalities in the EU, at least when it comes to air pollution.

Some of the most highly polluted NUTS3 regions spatially coincide with the poorest regions in the eastern part of Europe, although there are pockets of highly polluted NUTS3 regions elsewhere in Europe with both high and low purchasing power per capita. However, almost no NUTS3 regions in the quintile with the highest purchasing power per capita are in the quintile with the most pollution.

In terms of what the future trend could be for this indicator, the absence of disaggregated projections at the NUTS3 level for both PM2.5 concentrations and purchasing power makes evidence-based predictions challenging. While there are national level projections in PM2.5 emissions and concentrations (i.e. including cross-border transfers) by country stemming from the third clean air outlook, these cannot be readily used to derive NUTS3-level extrapolations, nor would it be reasonable to assume that NUTS3 GDP levels will remain constant. Thus, no reasonable prediction can be given for this indicator based on existing evidence. The past trend indicates, however, that so far there has been no real progress in reducing the environmental inequalities associated with air pollution. On that basis it therefore seems unlikely that the EU will make significant progress in reducing environmental inequalities, at least those related to air pollution.