Long-Term Exposure to Fine-Particle Air Pollution Increases Breast Cancer Risk
Women who work and live in places with high levels of fine-particle air pollution are more likely to develop breast cancer than women who live in less polluted areas.
The research was presented on Oct. 24, 2023 at the European Society for Medical Oncology (ESMO) Congress 2023.
What is fine-particle air pollution?
Also called fine particulate matter air pollution, fine-particle air pollution is made up of tiny pieces of solids or liquids that are in the air. The particles often include pieces of:
dust
dirt
soot
smoke
The particles in the air are grouped according to size: coarse, fine, and ultrafine.
Coarse particles are 2.5 microns (or micrometers) to 10 microns in diameter – about one to four thousandths of an inch – and are called PM10. They include dust, pollen, and mold.
Fine particles are 2.5 microns or smaller in diameter and are called PM2.5. They can be particles from burning things like liquid fuels, coal, or wood; organic compounds, like the compounds in paint that you smell; or tiny pieces of metal.
Ultrafine particles are smaller than 0.1 microns in diameter and are small enough to pass through lung tissue and into the bloodstream. Most particles in cigarette smoke are ultrafine.
The different-sized particles have different effects on people. In many cases, you can cough or sneeze out some coarse particles. But it’s very difficult for your body to get rid of fine and ultrafine particles. They can get trapped in the lungs and move into other parts of the body.
About the study
A number of international organizations classify air pollution as a carcinogen. Still, there has not been much research to look for links between air pollution and breast cancer.
This French study compared home and workplace exposure to air pollution from 1990 to 2011 in 2,419 women diagnosed with breast cancer and 2,984 women without breast cancer.
The women were matched on a number of factors:
where they lived
where they worked
age
menopausal status
the date when they joined the study, for women without breast cancer, or the date when they were diagnosed, for women with breast cancer
The researchers estimated annual pollution levels of fine- and coarse-particle air pollution levels from information on land use, including types of industry, agriculture, and housing in an area. They then calculated each woman’s average exposure level to air pollution during the 21-year study period.
The results showed that the risk of breast cancer increased by 28% when women’s exposure to fine-particle air pollution increased by 10 µg/m3 (micrograms per square meter) or 0.01 ppm (parts per million). This increase in particle concentration is roughly equal to the difference in fine-particle air pollution between urban and rural areas in Europe.
This difference was statistically significant, which means that it was likely due to the differences in air pollution exposure rather than just because of chance.
Women who were exposed to high levels of coarse-particle air pollution had a 9% increase in breast cancer risk. This difference wasn’t statistically significant.
“Our data showed a statistically significant association between long-term exposure to fine-particle air pollution, at home and at work, and risk of breast cancer,” Béatrice Fervers, MD, PhD, head of the Department of Prevention Cancer Environment at the Léon Bérard Comprehensive Cancer Centre, in Lyon, France, said in a statement. “This contrasts with previous research which looked only at fine-particle exposure where women were living, and showed small or no effects on breast cancer risk.”
Charles Swanton, FRS, FMedSci, of the Francis Crick Institute, in London, UK, who has conducted research that suggested how fine particles may cause lung cancer to develop in non-smokers, stressed the importance of the new findings with breast cancer.
“These very small particles can penetrate deep into the lung and get into the bloodstream from where they are absorbed into breast and other tissues,” he explained in a statement.
“There is already evidence that air pollutants can change the architecture of the breast,” he continued. “It will be important to test if pollutants allow cells in breast tissue with pre-existing mutations to expand and drive tumor promotion possibly through inflammatory processes, similar to our observations in non-smokers with lung cancer. It is very concerning that small pollutant particles in the air and microplastic particles of similar size are getting into the environment when we don’t yet understand their potential to promote cancer. There is an urgent need to set up laboratory studies to investigate the effects of these small air pollutant particles on the latency, grade, aggression, and progression of breast tumors.”
What this means for you
An increase in wildfires around the world, as well as exhaust from motor vehicles and particles from mining operations and agriculture, all contribute to poor air quality in many areas.
Unhealthy air quality can be scary, but air quality indexes can tell you about the air quality in your area and help you stay safe.
In the United States, the AirNow website allows you to put in your ZIP code, city, or state to see the air quality around you. In Europe, the European Air Quality Index website allows you to select your country and see all the air quality stations there. The IQAir website is an international air quality site that allows you to look at air quality on a world map. It also lists the cities with the best and worst air quality.
When the air quality is bad:
Limit the time you spend outside to less than 30 minutes, and reduce the intensity of any outdoor activities you’re doing. So instead of running for 25 minutes, walk instead.
If you must be outside, consider wearing a well-fitted N95 or KN95 mask. Since the COVID-19 pandemic, these masks are available at many stores and online.
Keep your indoor air healthy by keeping your windows and doors closed. If you run an air conditioner, run it on the recirculate setting. You also may want to use an air cleaner with a HEPA (high-efficiency particulate air) filter.
— Last updated on March 1, 2025 at 10:52 PM