Researchers looked at children in Shanghai from birth to three years and found that exposure to fine particles from vehicle exhausts, industrial emissions and other sources of outdoor pollution increased the risk of developing autism spectrum disorder by up to 78%.
“The causes of autism are complex and not fully understood, but environmental factors are increasingly recognized in addition to genetic and other factors,” Associate Professor Yuming Guo, from Monash University in Australia, said in a news release.
“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 [autism], but further research is needed to explore the associations between air pollution and mental health more broadly.”
Guo said global air pollution is rapidly becoming worse and there is no safe level of exposure. Air pollution is estimated to cause up to 4.2 million deaths every year globally, according to the World Health Organization.
“The serious health effects of air pollution are well-documented, suggesting there is no safe level of exposure. Even exposure to very small amounts of fine particulate matter have been linked to preterm births, delayed learning, and a range of serious health conditions, including heart disease,” Yuming said.
About the study
The study, published today in Environment International, included 124 children with autism spectrum disorder (ASD) and 1,240 healthy children in stages over a nine-year period, examining the association between air pollution and ASD.
It is said to be the first to examine the effects of long-term exposure of air pollution on ASD during the early life of children in a developing country, adding to previous studies that have already linked prenatal air pollution exposure to ASD in children.
The study examined the health effects of three types of particulate matter (PM1, PM2.5, PM10) — fine airborne particles that are the byproducts of emissions from factories, vehicular pollution, construction activities and road dust. The smaller the airborne particles, the more capable they are of penetrating the lungs and entering the bloodstream causing a range of serious health conditions.
“Despite the fact that smaller particles are more harmful, there is no global standard or policy for PM1 air pollution,” Yuming noted