Air pollution and breast cancer
A new study in the journal Environmental Health Perspectives has found that, in the city where I live – Montreal, there seems to be a correlation between higher incidences of breast cancer in post-menopausal women and increases in local air pollution, specifically ambient concentrations of nitrogen dioxide which is a component of traffic-related pollution.
Post-menopausal 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. As reported by CBC News, the researchers “found around a 30 per cent increase in the risk of breast cancer for every increase of five parts per billion of this tracer gas, nitrogen dioxide,” said Goldberg, who is a clinical epidemiologist and professor of medicine at McGill.
This doesn’t sound like an awfully large increase to me – 5 parts per billion – but the study does not say how much exposure to exhaust would be considered dangerous. Nitrogen dioxide in itself doesn’t cause cancer; however, its presence is associated with other pollutants from vehicle emissions, some of which are known carcinogens.
None of this is entirely surprising as previous studies have also shown possible links between cancer and air pollution. [And if you think about it, doesn’t it just make sense? After all, we know with certainty that smoking causes cancer. Why would excessive exposure to toxic fumes somehow be different?] What is surprising is that we continue to cling to our fossil fuel-obsessed culture despite mounting evidence of the toll it is taking on our health and the environment. Montreal is not even a particularly bad case in terms of big cities with traffic congestion problems. Just imagine the toll that pollution must be taking on public health in places such as Beijing and Mexico City.