It's already quite clear that air pollution is very bad for us: It's bad for our hearts, for our lungs, it causes cancer, triggers asthma, etc. It's estimated to cause about 7 million deaths per year, more than malaria and AIDS combined. In fact, it's so bad that the World Health Organization now puts air pollution in the same category as tobacco smoke, UV radiation and plutonium!
But if all that wasn't enough to convince us all to take this problem seriously, a new study published in the Annals of Neurology provides evidence that air pollution can cause damage to the brain directly (not just indirectly, through inflammation of the vascular system).
“Particles in the ambient air are an environmental neurotoxin to the aging brain.”Researchers followed 1,403 women from a study done in the 1990s, and then saw the participants again in the mid-2000s to examine their brains with MRI scans. They then used the participant's histories to determine their approximate exposure to air pollution over the years using recorded air quality data from monitoring sites where the patients lived.
They found that: "Each increase of 3.49 micrograms per cubic centimeter cumulative exposure to pollutants was associated with a 6.23 cubic centimeter decrease in white matter, the equivalent of one to two years of brain aging," and this seemed to be independent of other things. "The association remained after adjusting for many variables, including age, smoking, physical activity, blood pressure, body mass index, education and income."