Bai L, et al. - In order to determine if chronic exposure to ambient fine particulate matter (PM_2.5), nitrogen dioxide (NO₂), ozone (O₃), and redox-weighted average of NO₂ and O₃ (O_x) is related to incident lung and breast cancer, researchers performed this population-based cohort study. The Ontario Population Health and Environment Cohort (ONPHEC), which includes all long-term residents aged 35–85 years who lived in Ontario, Canada, 2001–2015, was used for this study. They ascertained incident lung and breast cancers using the Ontario Cancer Registry. The analysis suggested no associations of O₃ or O_x with lung cancer and indicated sublinear shape relationships of PM_2.5 and NO₂ with lung cancer. No compelling evidence was identified linking air pollution to breast cancer.