No wonder there are so many stupid people in the world. Researchers recently found that air pollution exposure before birth lowers IQ scores in childhood, providing substantial evidence that smog may harm brain development.

So next time you see someone turn the wrong way onto a one way street or try to iron a shirt they are currently wearing, don’t give them a hard time. Just think that maybe they grew up a block too close to the nuclear power plant or the oil refinery.

The results are in a study of 249 children of New York City women who wore backpack air monitors for 48 hours during the last few months of pregnancy. They lived in mostly low-income neighborhoods in northern Manhattan and the South Bronx. They had varying levels of exposure to typical kinds of urban air pollution, mostly from car, bus and truck exhaust.

At age 5, before starting school, the children were given IQ tests. Those exposed to the most pollution before birth scored on average four to five points lower than children with less exposure.

That may not seem like a very big difference, but it’s big enough that it could affect children’s performance in school, said Frederica Perera, the study’s lead author and director of the Columbia Center for Children’s Environmental Health.

Read more at askmen.com