As the first fleet of gas-guzzling motor vehicles began rolling off the factory floor and onto city streets, the smokey clouds of exhaust left in their wake must have smelled a bit like progress. But a century later, with an estimated 750 million cars in the world today, the devastating human toll of traffic pollution is becoming clearer in the smog -- and it just stinks.
Although researchers have already documented the harmful impact of air pollution on cardiovascular and reproductive health, a new study suggests that exposure to traffic fumes is linked to one of the most pressing health issues of our day: the spike in autism rates.
According to Heather E. Volk, PhD, MPH, of the University of Southern California Keck School of Medicine, pregnant women exposed to high levels of traffic pollution were twice as likely to give birth to a child that would present the developmental disorder. Furthermore, children exposed to the highest levels of pollution were shown to be three times more likely to be diagnosed with autism.
In 2011, Volk's team reported a higher risk of autism for children whose families lived within about 1,000 feet of a freeway. For the new study, she looked at data from 279 children with autism and a comparison group of 245 children without it.
At the time they started, the children were ages 2 to 5 years. Volk used the mothers' addresses to estimate exposure to pollution during each trimester of pregnancy and during the child's first year of life. They used information from the EPA and did traffic modeling to figure out how much traffic-related air pollution was at each location. They also looked at exposure to particulate matter and nitrogen dioxide.
"Children exposed to higher levels of traffic-related pollutants during pregnancy or during the first year of life were at increased risk of autism compared to children exposed to the lowest level," says Volt.
The researcher is quick to note that although an association has been found, it is too soon to claim a cause and effect relationship. Nevertheless, as other environmental factors are more closely examined to pin down those that contribute to autism, little doubt remains that air pollution from vehicle emissions is harmful to the health of both our planet and those that reside upon it.
Sadly, the consequences of such, forewarned as a looming sceptor for future generations, just might be impacting the lives and well-being of those born today.