Background Scant data quantify associations between economic and racial/ethnic spatial polarization and individual’s exposure to pollution. Methods We linked data on the socioeconomic position (SEP) of 1757 urban working class white, black, and Latino adults (age 25–64; Boston, MA: 2003–2004; 2008–2010) to: (1) spatiotemporal model-based estimates of cumulative black carbon exposure at their exact residential address, and (2) their census tract values for the Index of Concentration at the Extremes (ICE) for SEP and race/ethnicity. Results ICE measures, but not individual- and household-SEP, remained independently associated with black carbon exposure. Conclusions The ICE may be useful for environmental health research.