In contrast, we find substantial disparity arising from regional pollution gradients combined with the high inter-municipal racial segregation in the Bay Area . On average, the white population is exposed to lower NO, NO2, and UFP than other groups, with a median exposure 16% to 27% below the total-population median, while medians for the Black and Hispanic populations are higher by 8% to 30% depending on pollutant (Fig ; SI Appendix Table ). The spatial detail provided by our method reveals nuance in disparity patterns beyond differences in medians. Figure illustrates the weighting of each racial/ethnic group within total-population exposure deciles. Overall, the white population is strongly overrepresented in the lowest deciles of the concentration distributions. The Asian population is overrepresented at the extremes, with the high end driven by the previously mentioned communities in Downtown Oakland and the SF Financial District, and the low end driven by the Richmond and Sunset Districts. The Black and Hispanic populations are strongly underrepresented at the low end and concentrated towards the higher deciles, giving rise to higher average exposures for those groups. Apart from distinctly higher ranges of NO2 and UFP exposure among Black and Hispanic populations, the range of exposures within racial/ethnic groups tends to be large compared with the range among groups. This finding holds especially for the Asian population (Fig ), which is bimodally distributed between some of the cleanest (coastal) and most polluted (downtown) areas. Within our study domain, the national IEG model also predicts lowest mean exposure for the white population and highest for the Black population, with moderately higher exposure for the Hispanic/Latino population (SI Appendix, Fig ). However, due to the narrower band of exposure estimates, IEG modeled disparity differs from observations. The IEG model predicts a similar magnitude of exposure disparity between the population median and medians for those of Black and Hispanic/Latino descent, but a smaller difference for the white population, and does not show a disproportionate share of people of Asian descent in the highest exposure categories. Thus, modeled disparity may miss an important dimension of racial/ethnic exposure disparity.