It’s estimated that 1 out of 68 children will develop a disorder on the autism spectrum–disorders of which we are not certain of the cause, have no cure for, and are occurring more and more frequently (in 2012 that statistic was 1 out of 88). Autism is a disability that has begun to touch more and more people in my life, so I decided to investigate what research was being done on the causes. Theories as to the cause of autism range from genetic to environmental to a combination of the two, but recent studies are reporting a correlation between air pollution to the development of autism during childhood. A study done by researcher Amy Kalkbrenner examined addresses of pregnant women who would later go on to have children with autism and compared them to records of air pollution in their area at specific weeks of their pregnancy. She observed that women in their third trimester of pregnancy were more likely to go on and have children with autism if they were living in areas with high levels of pollution as opposed to their fresh air counterparts. The study provides a piece of evidence to the hypothesis, but the actual pollution particulates/chemicals in the women were not specifically measured or identified (which would make an interesting study given a large sample size and long period of time), so to say “air pollution in general causes autism” is both premature and inadequate answer to the question of what causes autism.

While the study is observational and only one correlation (and certainly not causation) to the idea that air pollution causes autism, another (experimental) inquiry was done to attempt to answer the same question. Researchers from the University of Rochester Medical Center exposed mice to levels of air pollution typical to mid-sized US cities at rush hour two weeks after birth (for four hours each day for two four-day periods). Examining the brains 24 hours after the last exposure, they found that excessive inflammation caused damage to the brain cells and prevented the lateral ventricles from developing properly. They also investigated the effects 40 days and 270 days after, and found that the stunted development was in fact permanent, and the mice in all three groups had elevated levels of glutamate (an observation seen in humans with autism). While this study doesn’t prove that pollution causes autism any more than the latter does, it does provide some empirical insight into the effects pollution has on the developing brain. It’s enough to have a future pregnant me slightly concerned–but more conclusive studies would need to be done for me to camp out in the countryside for nine months.