Another study has found a link between air pollution and the risk of developing autism, the World Economic Forum reported last month.
The study of children in Shanghai found that exposure to fine particulate pollution, or PM2.5, correlated with a 78% increase in diagnoses of autism spectrum disorder (ASD). The evidence from the recent study, which monitored the children across a nine-year period, backs up findings from previous research.
A 2014 study of 116,430 pregnant women in the US concluded that increased exposure to PM2.5 during the third trimester doubled the risk of children developing ASD.
With a diameter of less than 2.5 micrometers, PM2.5 — which are “commonly found in industrial flue gases, vehicle exhaust and coal fire fumes” — are easily able to reach tissue deep in the lungs and move on to the bloodstream, where they can travel to organ tissues throughout the body.
The US is one of many countries experiencing a sharp increase in ASD diagnoses, from one in 150 children in 2000 to one in 68 in 2010. While some have put the rise down to greater autism awareness, the link to airborne pollution might offer another explanation.
Although the causes of autism are not yet fully understood and remain the subject of research, the role of genetics has long been recognized.
With each study linking ASD to air pollution, there is greater potential for future regulation of the particulates in question, which currently fall under little oversight:
Of the three particulate categories covered in the Shanghai study – PM1, PM2.5 and PM10 – PM1 are the smallest and most likely to enter the bloodstream through the lungs.
Unfortunately they are also one of the most common and least regulated types of particulate pollution under current international rules.