In New York City, for all its wonders, it's not uncommon still to hear the childless pronounce that they "could never imagine raising kids in the city." Turns out they might have a good reason for that. Although kids who grow up in cities have a certain worldliness about them, raising urban kids does have its drawbacks, like impaired cognitive function from exposure to air pollution.

To be fair, the latest study that documented this problem centered on Mexico City, a place as polluted as they come. Of the 30 children studied, the ones who grew up in the city were less adept at tasks involving complex reasoning, knowledge integration, verbal memory, and working memory. Those who grew up in Polotitlán, a rural community nearby, did better. The researchers saw physiological brain differences as well.

The scariest aspect of this research is that scientists are finding similarities between these pollution-connected brain problems and the brain abnormalities of Alzheimer's. It's been clear for a long time that pollution causes health problems, but there's growing evidence that seemingly unrelated problems—cancer, obesity, now Alzheimer's—could have their origins in dirty air, too.

See: