Spatial Decomposition of Socioeconomic Inequalities in PM2.5 Exposure Across Europe

Despite discernible improvements in ambient air quality across the European Union in recent years, income-based inequalities in exposure to fine particulate matter (PM_2.5) have remained remarkably persistent. Populations residing in the most socioeconomically disadvantaged regions continue to experience disproportionately higher PM_2.5 concentrations compared to those in the wealthiest areas. However, the spatial scales at which these disparities are generated and the structural mechanisms sustaining them remain insufficiently understood.

This study quantifies the PM_2.5 exposure gap between the lowest and highest socioeconomic strata across Europe and decomposes this disparity across its constituent spatial scales. The analysis integrates satellite-derived annual mean PM_2.5 concentrations from the Atmospheric Composition Analysis Group (V6.GL.02), high-resolution population distributions from the Global Human Settlement Layer (GHS-POP), and settlement typologies from the GHS Settlement Model (GHS-SMOD). These are combined with gridded GDP per capita adjusted for Purchasing Power Parity (PPP) to stratify the European population into socioeconomic quintiles. Europe-wide exposure disparities are then systematically partitioned using a sequential spatial decomposition framework.

This approach isolates three fundamental components of total inequality: (1) inter-country economic disparities, (2) the urban–rural divide, and (3) intra-urban socioeconomic segregation. By disentangling these spatial scales, the study identifies whether observed inequalities primarily arise from regional contrasts across Europe or from localized patterns of urban structure and socioeconomic segregation.

Quantitative results for the 2013–2022 period indicate that regional differences are the dominant contributor to PM_2.5 exposure inequality across Europe. Mean concentrations in Southern Europe exceed those in Northern Europe by approximately 9 µgm^-3 on avarage, while the lowest socioeconomic quintile experiences PM_2.5 levels about 15–20% higher than the highest quintile. Urban–rural contrasts are comparatively smaller, on the order of 1–2 µgm^-3.

The findings highlight the necessity of aligning air quality and equity-oriented policies with the spatial scales at which pollution-related inequalities are produced, providing a robust atmospheric science–based foundation for scale-appropriate policy design.