When policies reduce the overall emissions rate without substantially altering the pattern of where emissions occur, relative disparities in exposure can persist . In this vein, the findings from our retrospective analysis resonate with results of studies that have prospectively modeled the potential future equity impacts associated with specific vehicle policies (e.g., heavyduty truck electrification, zero-emission vehicle adoption). Consistently with those studies, we have found large absolute concentration changes in regions with the highest share of people of color, yet we nonetheless find minimal reduction in the relative disparity for PM2.5 exposure . These results arise because the places with the largest concentration changes over time tend to be the places most impacted by vehicles (Fig. ).