This is your brain on … air pollution?

Lay summary by Rachel Shaffer

We all know that air pollution affects lung health, but did you know that air pollution may also have an impact on the developing brain? A new study from the University of Pittsburgh adds further evidence to a growing body of scientific literature that links early life air pollution exposure to autism spectrum disorder (ASD).

The incidence of ASDs has been increasing in recent years, and approximately 1 in 68 children in the United States is now diagnosed with this developmental brain disorder. The causes of ASDs are unknown, but environmental exposures — including traffic-related air pollution — are thought to play a role. Of the many components of traffic-related air pollution, small particles known as particulate matter 2.5 or “PM 2.5” (named for their size) may be especially problematic.

In this study, researchers set out to explore the association between ASD and exposure to PM 2.5 during pre-pregnancy, pregnancy, and early life time periods. They focused their investigation on 6 counties in the Pittsburgh area.

Using existing air monitoring data and specialized statistical and extrapolation techniques, the research team developed estimates of PM 2.5 levels for the 6 counties over the multi-year study period. Then, based on location of each family during pre-pregnancy, pregnancy, and post-pregnancy, they estimated the PM 2.5 exposures for each child during different critical periods of development. Overall, they observed an increased risk of ASD from cumulative exposure to PM 2.5 beginning at three months before pregnancy through year two, as well as from exposure to PM 2.5 during year two alone.

While the specific biological mechanism is not yet known, this additional evidence of the association between PM 2.5 and ASD further emphasizes the need for stronger laws and regulations to decrease air pollution. While air quality has improved significantly in recent years, there are still numerous communities that are exposed to dangerous pollution that may result in lifelong health consequences.

For further information

Read the Environmental Research original research article which this summary is based on Fine particulate matter and the risk of autism spectrum disorder (July 2015).

Visit the profile of the research ambassador, Rachel Shaffer, who wrote this summary.

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