Disparities in ambient air pollution exposure among the U.S. population amid climate change

Air pollution and climate change remain critical environmental challenges. Using integrated modeling (global change analysis model [GCAM] and TM5-FASST), we assess future U.S. ambient air pollution (PM_2.5 and O₃) and exposure disparities under climate mitigation scenarios. Nationally, annual mean O₃ declines from 58.3 ppbv in 2010 to 47.3-54.1 ppbv by 2050, and PM_2.5 decreases from 6.5 μgm to -3 to 4.6-5.7 μgm^-3 depending on scenario. Regional differences persist, with elevated O₃ along the West Coast, Northeast, and Great Lakes, and PM_2.5 hotspots above 12 μgm^-3 in the eastern U.S. Sensitivity analysis shows socioeconomic pathways drive >90% of early-term pollutant reduction variance, but their contribution declines to about 70% by mid-century. Disparities narrow between white and Black communities but widen between white and Asian groups, reflecting urban exposure patterns. These results highlight the importance of both emission targets and structural socioeconomic choices in shaping future air quality and underscore the need for targeted equity-focused interventions.