A new study shows that exposure to traffic-related air pollution ups the risk of breast cancer.
“We’ve been watching breast cancer rates go up for some time,” says study co-author Dr. Mark Goldberg. “Nobody really knows why, and only about one third of cases are attributable to known risk factors. Since no one had studied the connection between air pollution and breast cancer using detailed air pollution maps, we decided to investigate it.”
Using information on levels of nitrogen dioxide (NO2), a by-product of vehicular traffic, the study’s authors created “maps” of air pollution in different parts of Montreal over 10 years. Next, they charted the home addresses of women diagnosed with breast cancer.
“Across Montreal, levels of NO2 varied between 5 ppb to over 30 ppb,” notes Dr. Goldberg. “We found that risk increased by about 25% with every increase of NO2 of five parts per billion. Another way of saying this is that women living in the areas with the highest levels of pollution were almost twice as likely to develop breast cancer as those living in the least polluted areas.”
Environmental Health Perspectives – October 6, 2010;Epub.