The findings, published in a US medical journal, link an increased risk of autism with traffic pollution.
While it's early days, the new work backs earlier studies in the same field.
Correspondent: Martin Cuddihy
Speaker: Dr Heather Volk, University of Southern California
MARTIN CUDDIHY: Autism is a neural development disorder. Sufferers have problems with social interactions, communication and often display repetitive behaviours.
It's thought both genetic and environmental factors contribute to its origins. This US study addressed the external factors by focussing on pollution.
It used the addresses of mothers in California to estimate their exposure while pregnant and in the first year of a child's life.
Lead researcher from the University of Southern California, Dr Heather Volk, found children living near places with high traffic pollution are as much as three times more likely to develop autism.
HEATHER VOLK: Our study found that children exposed to high levels of air pollution - both from traffic and regional particulate matter, as well as nitrogen dioxide - were at increased risk for autism.
MARTIN CUDDIHY: Were you surprised by your findings?
HEATHER VOLK: These findings really are consistent with our earlier work looking at roadway proximity and autism risk. So in that vein our findings here really make sense and are somewhat in line too with the previous associations looking at air pollution and autism.
MARTIN CUDDIHY: The environment of almost 300 children with autism was assessed, along with a control group of 245.
The paper says more work is needed, in particular as to whether pollutants might trigger some effects.
It admits that lifestyle, nutrition and other factors like second-hand smoke could be distorting the results.
How conclusive is the link between environmental pollutants and developing autism?
HEATHER VOLK: So I would say that more research really needs to be done regarding environmental pollution and are types of air pollution in particular an autism risk. Several other studies have been published which indicate an association using different data bases in the United States and our own work, which additionally looked at roadway proximity - how near or far an individual lived from a highway.
So while there is a growing body of research which seems to suggest this association is present, we need to do more research to replicate these findings.
MARTIN CUDDIHY: The study also says the findings have big public health implications because "air pollution exposure is common, and may have lasting neurological effects".
What sort of levels of pollution would you consider to be a risk?
HEATHER VOLK: Um, well, you know that's sort of a... that's a tough question to answer. You know, in our study these children exposed to the highest quartile or increasing pollution levels. That will, of course vary based on the pollutant mix in any given location, what those risks will be.
MARTIN CUDDIHY: Don't panic yet?
HEATHER VOLK: Don't panic yet. We need to do more research to really understand when exposure might be important, if there are particular pollutants that are important and as always, replication really is needed.
MARTIN CUDDIHY: The study is being released today in the Archives of General Psychiatry journal.