issues and experts

Prenatal exposure to air pollution linked to increased likelihood of Autism

November 19, 2018

Ian Bryce, Communications and Marketing, 236-880-2187,

Lief Pagalan, Health Sciences, +1 416-822-2371,


One of the largest studies to date on prenatal exposures to air pollutants and Autism Spectrum Disorder (ASD) found an increased incidence of ASD in the children of more heavily exposed women.

“Association of Prenatal Exposure to Air Pollution with Autism Spectrum Disorder” published in JAMA Pediatrics adds to the evidence that air pollution is risk factor for the development of ASD.

SFU Health Sciences researcher Lief Pagalan conducted the population-based birth cohort study in the Metro Vancouver area—an area with relatively low levels of air pollution. Encompassing nearly all births in Metro Vancouver from 2004 through 2009, Pagalan analyzed air pollution data to assess exposure rates over the same period.

The study included exposures to particulate matter, nitrogen dioxide, and nitric oxide. Results found an increased risk of ASD associated with exposure to air pollutants, although not all were statistically significant. The study’s results are consistent to similar studies in the United States, Israel, and Taiwan.

“Our study, which indicates that air pollution is associated with ASD in a city with relatively lower levels of air pollution adds to the growing concern that there may be no safe levels of exposure to air pollution,” says Pagalan. “While the causes of ASD are not yet fully known, this study suggests that reducing exposure to air pollutants in pregnant women could reduce the likelihood of their children developing autism.”

Researchers involved in the study:

  • Lief Pagalan
  • Celeste Bickford
  • Whitney Weikum
  • Bruce Lanphear
  • Michael Brauer
  • Nancy Lanphear
  • Gillian E. Hanley
  • Tim F. Oberlander
  • Meghan Winters

Institutions involved in the study:

  • Faculty of Health Sciences, SFU
  • Centre of Hip Health and Mobility
  • School of Population and Public Health, UBC
  • Department of Pediatrics, UBC
  • Sunny Hill Health Centre for Children, BC Children’s Hospital
  • BC Children’s Hospital Research Institute
  • Department of Obstetrics and Gynaecology, UBC
  • Population Data BC


Study findings and why they matter:
Pregnant women more heavily exposed to air pollution had higher chances of having children with autism spectrum disorder (ASD). This suggests that air pollution plays a role in the development of ASD, although the overall impact was small and other risk factors are also relevant. Avoiding air pollution during pregnancy is not easy because it's all around us and we are all exposed to it to varying degrees. We should view these results as additional evidence of the widespread health impacts of air pollution. More specifically as there is no cure for ASD, prevention of air pollution has the potential to lead to reductions in ASD.

Our study, which indicates that air pollution is associated with ASD in a city with relatively lower levels of air pollution adds to the growing concern that there may be no safe levels of exposure to air pollution.


Why the study was conducted:

The causes of ASD are not yet fully known. They're complex and have many factors, but researchers recognize that genetics and environmental factors both play a role. Research into the environmental factors of ASD is relatively recent, so we wanted to determine if air pollution posed a risk. Identifying environmental risk factors helps identify opportunities for prevention.
Not only did we have access to rich data, enabling us to develop one of the largest studies to date, but we were also able to conduct this study in a city with relatively lower levels of air pollution.


How the study was conducted:

We linked databases recording information on pregnancies with records of all births in Vancouver, Canada, from 2004 to 2009 and medical records of children over the first five years of life. In particular, we identified children diagnosed with ASD. We applied high resolution maps of air pollution, based on detailed measurements, to measure the exposure of mothers during their pregnancies. We were then able to compare whether ASD rates in children were different among lower or more heavily exposed pregnant woman.

About Simon Fraser University:

As Canada's engaged university, SFU is defined by its dynamic integration of innovative education, cutting-edge research and far-reaching community engagement. SFU was founded more than 50 years ago with a mission to be a different kind of university—to bring an interdisciplinary approach to learning, embrace bold initiatives, and engage with communities near and far. Today, SFU is Canada’s leading comprehensive research university and is ranked one of the top universities in the world. With campuses in British Columbia’s three largest cities – Vancouver, Burnaby and Surrey – SFU has eight faculties, delivers almost 150 programs to over 35,000 students, and boasts more than 150,000 alumni in 130 countries around the world.


Simon Fraser University: Engaging Students. Engaging Research. Engaging Communities.