Global clean air improvements mask socioeconomic inequalities in fine particulate matter health burden

Exposure to fine particulate matter ≤2.5 µm is a major environmental cause of premature mortality, yet the equity of air-quality improvements remains unclear. Using epidemiological modelling and inequality decomposition, we found widening disparities in health impacts from 2000 to 2019, including simultaneous growth in populations living in both low-risk (≤20 deaths/105) and high-risk (>160 deaths/105) regions. Socioeconomic inequalities also worsened: populations living in the lowest socioeconomic decile bore 20.56% of the global mortality burden, compared with only 1.16% in the highest decile. This socioeconomic inequality persisting across 181 countries and 1,831 provinces. Future projections suggest that sustainable development pathways could reduce health burdens, whereas regional rivalry and uneven development may substantially increase mortality rates by 2100. These findings highlight the importance of addressing both environmental and socioeconomic factors in air-quality management. From 2000–2019, global fine particulate matter related mortality burdens grew more unequal, with rising high risk populations and worsening socioeconomic disparities across 181 countries, according to air pollution, epidemic modeling and inequality decomposition.