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Background. Air pollution contains numerous carcinogens and endocrine disruptors which may be relevant for breast cancer risk. Previous research on air pollution and breast cancer risk has predominately been conducted in white women; however, Black women may have higher exposure to air pollution. Methods. Using land-use regression models, we estimated annual average ambient levels of particulate matter < 2.5 µm (PM_2.5), nitrogen dioxide (NO₂) and ozone (O₃) at the 1995 residence of 41,325 participants in the Black Women’s Health Study who resided in 56 metropolitan areas across the United States. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for an interquartile range (IQR) increase in each pollutant. We evaluated whether the association varied by menopausal status at diagnosis, invasiveness, and estrogen receptor (ER) status of the tumor and by geographic region of residence. Results. With follow-up through 2015 (mean=18.3 years), 2,216 incident cases of breast cancer were confirmed. Higher exposure to PM_2.5, NO₂, or O₃ was not significantly associated with breast cancer risk overall or by ER status. However, an IQR increase in NO₂ (10 ppb) was associated with a higher risk of premenopausal breast cancer (N=571, HR=1.15, 95% CI: 1.02-1.31). For the association between PM_2.5 and invasive breast cancer, we observed significant modification by geographic region (p for heterogeneity=0.02). Among women living in the Midwest, but not other geographic regions, an IQR increase in PM_2.5 (2.87 µg/m³), was associated with a higher risk of invasive breast cancer (HR=1.27, 95% CI: 1.04-1.55). Conclusions. These results support the hypothesis that higher exposure to specific air pollutants may be a risk factor for breast cancer among Black women, particularly for premenopausal women and women living in the Midwest.