According to a new study, small children exposed to fine particles (PM2.5) from industrial emissions, vehicle exhaust and other outdoor pollution sources have an increased risk of developing autism spectrum disorder (ASD).

Publishing their findings in the journal Environment International, researchers observed children living in Shanghai from birth to three years old — 124 ASD children and 1,240 healthy children.

The researchers observed the children in stages over the course of nine years, investigating the relationship between ASD and air pollution during the first years of life.

"The causes of autism are complex and not fully understood, but environmental factors are increasingly recognized in addition to genetic and other factors," said associate professor Yuming Guo from Monash University's School of Public Health and Preventive Medicine.

"The developing brains of young children are more vulnerable to toxic exposures in the environment and several studies have suggested this could impact brain function and the immune system. These effects could explain the strong link we found between exposure to air pollutants and ASD, but further research is needed to explore the associations between air pollution and mental health more broadly."

For more on the study, go to the journal Environment International.

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