Autism May Be Caused by Air Pollution — Specifically, Car Exhaust, New Study Says

A new study says that air pollution — specifically, the kind caused by car exhaust — may be a significant cause of rising rates of autism in children.

Exposure to nitric oxide (NO)— which is produced when fuel is burned — while a mother is pregnant, or in the early months of life, may pose a “significant risk” of a child developing Autism Spectrum Disorder (ASD), according to a study published Nov. 12 in in the journal Brain Medicine.

“ ‘NO’ is a common air pollutant produced mainly by vehicle emissions and the combustion of fossil and industrial fuels. Exposure to NO and its derivative NO2 during pregnancy and early childhood can disrupt normal brain development,” the study’s authors wrote. 

“The timing of its exposure is crucial. Exposure to these pollutants during pregnancy and early postnatal development poses a significant risk of ASD since these periods are essential for brain development.”

The study pointed out that “individuals with a genetic predisposition to ASD may be more vulnerable to the harmful effects of NO exposure.” 

The study also looked at other air pollutants, like ozone, fine particles, and other emissions, and found that together, these environmental toxins increase the risk of autism.

“Benzene is a volatile organic compound commonly found in vehicle emissions, industrial processes, and tobacco smoke. Maternal exposure to NO2 and benzene during pregnancy can also increase the risk of ASD,” the study authors wrote.

The way it works, the authors found, is that the environmental toxins cause inflammation, and “prolonged neuroinflammation triggered by NO exposure has been shown to influence the activity of brain regions involved in social and cognitive functions, which are commonly impaired in ASD.”

As the study authors explained, “air pollution exposure during pregnancy can activate the mother’s immune system, leading to inflammation and altered fetal brain development. Elevated concentrations of inflammation-related cytokines in maternal serum in utero and children during their early life are associated with worse neurodevelopmental outcomes.”

The American Lung Association’s State of the Air report found that nearly 40% of Americans live in places with “unhealthy levels of air pollution.”

According to the most recent data from the U.S. Centers for Disease Control, 1 in 36 children have been diagnosed with ASD — an increase from 1 in 44 just two years prior.

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