High levels of particulate air pollution associated with increased breast cancer incidence

Monday, September 11, 2023

NIH researchers combined historical air quality data with breast cancer data from large U.S. study

Researchers at the National Institutes of Health found that living in an area with high levels of particulate air pollution was associated with an increased incidence of breast cancer. The study, published in the Journal of the National Cancer Institute, is one of the largest studies to date looking at the relationship between outdoor air pollution, specifically fine particulate matter, and breast cancer incidence. The research was done by scientists at the National Institute of Environmental Health Sciences (NIEHS) and the National Cancer Institute (NCI), both part of NIH.

The researchers saw that the largest increases in breast cancer incidence was among women who on average had higher particulate matter levels (PM_2.5) near their home prior to enrolling in the study, compared to those who lived in areas with lower levels of PM_2.5. Particulate matter is a mixture of solid particles and liquid droplets found in the air. It comes from numerous sources, such as motor vehicle exhaust, combustion processes (e.g., oil, coal), wood smoke/vegetation burning, and industrial emissions. The particulate matter pollution measured in this study was 2.5 microns in diameter or smaller (PM_2.5), meaning the particles are small enough to be inhaled deep into the lungs. The Environmental Protection Agency has a website known as Air Now where residents can enter their zip code and get the air quality information, including PM2.5 levels, for their area.

“We observed an 8 percent increase in breast cancer incidence for living in areas with higher PM_2.5exposure. Although this is a relatively modest increase, these findings are significant given that air pollution is a ubiquitous exposure that impacts almost everyone,” said Alexandra White, Ph.D., lead author and head of the Environment and Cancer Epidemiology Group at NIEHS. “These findings add to a growing body of literature suggesting that air pollution is related to breast cancer.”