DuPre NC, et al. - In the Nurses' Health Study (NHS) and NHSII (two US-based prospective cohort studies), researchers studied breast cancer survival in relation to particulate matter (PM) exposures. Cases were examined in detail with respect to medical history, lifestyle factors, and causes of death. A total of 8,936 women with stage I-III breast cancer were followed through June 2014. Spatio-temporal models were used to estimate residential PM. For 10 μg/m³ increases in post-diagnosis PM, the estimation of hazard ratios (HR) of breast cancer specific-mortality and all-cause mortality was carried out using Cox regression. A total of 1,211 breast cancer specific deaths were reported. Findings revealed no association of PM with breast cancer specific mortality. PM was found to be related to modest increases in all-cause mortality. Among those with stage I breast cancer, a higher breast cancer mortality was observed in association with higher PM2.5, even after adjustment.