In a first, a study has established link between PM 2.5 and mammographic breast density, a strong and independent risk factor for breast cancer. The study also found inverse associations between ozone (O3) and mammographic breast density. In medical terminology, breast density is a reflection of relative amounts of epithelial, stromal and fat tissue in breasts.
Published recently in Breast Cancer Research, the study was conducted to fill the knowledge gap on the link between air pollution and breast density. The authors say that this is the largest and the only study to examine the link between breast density and PM2.5 or O3.
— source downtoearth.org.in