Air Pollution May Be Linked to Autism Risk in Kids, Study Finds

About one in 36 children in the United States are on theautism spectrum, but scientists still don’t know why some kids’ brains develop differently than neurotypical ones.Now, new research suggests that being exposed to certain types of pollution during key developmental periods in pregnancy and early childhood may be a reason.The scientific review, published in the journalBrain Medicine, found that common air pollutants—like fine particulate matter and nitrogen oxides—can trigger a series of biological events that may contribute toautism spectrum disorder (ASD).This particular review identified several pathways in the body where pollution can potentially impact the developing fetus.Those include things like biological reactions that can have a toxic effect on cells, inflammation in the brain and body, a disruption in the chemical signals between nerve cells, changes to DNA, and disruptions to certain chemicals and chemical reactions in the body.“Exposure to air pollutants is associated with systemic inflammation, which can affect in-utero and early-life brain development,”Stefania Papatheodorou, MD, PhD, associate professor in epidemiology at the Rutgers School of Public Health, told Verywell.Autism Risks Related to Pregnancy and BirthAir pollutioncan also influence the function of blood vessels and blood flow in pregnant people, which can then affect the developing fetus. “Air pollution can also impact the placenta function, which can alter fetal development and growth," Papatheodorou said.The review also found that small particles—especially PM2.5, a mixture of particles in the air that are 2.5 micrometers or less in diameter, and the toxic gas nitric oxide—can cross the placenta and impact fetal brain development.That means air pollution may have a direct impact on the growing fetus, saidKelly Bakulski, PhD, an associate professor of epidemiology at the University of Michigan School of Public Health.This review isn’t the only research to link autism and pollution. A 2019 analysis of 132,256 babies and their mothers’ exposure to pollution during pregnancy found an association between nitric oxide exposure and an ASD diagnosis. However, it didn’t find a link between PM2.5and the condition.A case-control study published in 2020 found that ozone exposure during the third trimester and exposure to PM2.5during the first year of life were both associated with a greater risk of ASD.Air Pollution Particles Can Reach the Placenta, Study FindsWhat This Research Means for Expecting ParentsWhile a growing body of research links air pollution to ASD, there are no definitive causes yet. Limiting your exposure to pollution may reduce the risk that your child has autism, but it also may not. Depending on where you live, it may be very difficult to significantly reduce your exposure to air pollution.Another important thing to note is that while kids with autism have different brain development than their neurotypical peers, it doesn’t mean their brain is “bad” or needs to be fixed.That said, research has found that reducing yourexposure to pollutionmay help support your health in other ways, including lowering the odds of developingheartand respiratory issues.To do so, Papatheodorou recommends checking theAir Quality Index (AQI)daily. “AQI values at or below 100 are generally considered safe,” she said. “If AQI is unsafe, they should stay indoors or minimize outdoor activities as much as possible.”When you do need to venture out on a poor air quality day, Bakulski said that wearing a high-quality, well-fitted mask like an N95 may help. “Masks, such as N95 masks, are highly effective at filtering the particle components of air pollution,” she added.Indoor air quality is also important. Papatheodorou noted that using an air purifier in the home is a good idea. “High-efficiency particulate air (HEPA) filters in air purifiers can reduce the concentration of PM2.5,” she said.A 25-Minute Training Can Help Reduce People’s Autism BiasesWhat This Means For YouIf you’re an expecting parent or are planning on a pregnancy, it’s best not to stress about reducing air pollution exposure for the sole purpose of reducing your child’s autism risk. Scientists don’t yet know what causes autism. If you’d like to limit your exposure for other health reasons, staying indoors when air quality is bad and wearing an N95 mask may help.

About one in 36 children in the United States are on theautism spectrum, but scientists still don’t know why some kids’ brains develop differently than neurotypical ones.Now, new research suggests that being exposed to certain types of pollution during key developmental periods in pregnancy and early childhood may be a reason.

The scientific review, published in the journalBrain Medicine, found that common air pollutants—like fine particulate matter and nitrogen oxides—can trigger a series of biological events that may contribute toautism spectrum disorder (ASD).

This particular review identified several pathways in the body where pollution can potentially impact the developing fetus.

Those include things like biological reactions that can have a toxic effect on cells, inflammation in the brain and body, a disruption in the chemical signals between nerve cells, changes to DNA, and disruptions to certain chemicals and chemical reactions in the body.

“Exposure to air pollutants is associated with systemic inflammation, which can affect in-utero and early-life brain development,”Stefania Papatheodorou, MD, PhD, associate professor in epidemiology at the Rutgers School of Public Health, told Verywell.

Autism Risks Related to Pregnancy and Birth

Air pollutioncan also influence the function of blood vessels and blood flow in pregnant people, which can then affect the developing fetus. “Air pollution can also impact the placenta function, which can alter fetal development and growth," Papatheodorou said.

The review also found that small particles—especially PM2.5, a mixture of particles in the air that are 2.5 micrometers or less in diameter, and the toxic gas nitric oxide—can cross the placenta and impact fetal brain development.

That means air pollution may have a direct impact on the growing fetus, saidKelly Bakulski, PhD, an associate professor of epidemiology at the University of Michigan School of Public Health.

This review isn’t the only research to link autism and pollution. A 2019 analysis of 132,256 babies and their mothers’ exposure to pollution during pregnancy found an association between nitric oxide exposure and an ASD diagnosis. However, it didn’t find a link between PM2.5and the condition.

A case-control study published in 2020 found that ozone exposure during the third trimester and exposure to PM2.5during the first year of life were both associated with a greater risk of ASD.

Air Pollution Particles Can Reach the Placenta, Study Finds

What This Research Means for Expecting Parents

While a growing body of research links air pollution to ASD, there are no definitive causes yet. Limiting your exposure to pollution may reduce the risk that your child has autism, but it also may not. Depending on where you live, it may be very difficult to significantly reduce your exposure to air pollution.

Another important thing to note is that while kids with autism have different brain development than their neurotypical peers, it doesn’t mean their brain is “bad” or needs to be fixed.

That said, research has found that reducing yourexposure to pollutionmay help support your health in other ways, including lowering the odds of developingheartand respiratory issues.

To do so, Papatheodorou recommends checking theAir Quality Index (AQI)daily. “AQI values at or below 100 are generally considered safe,” she said. “If AQI is unsafe, they should stay indoors or minimize outdoor activities as much as possible.”

When you do need to venture out on a poor air quality day, Bakulski said that wearing a high-quality, well-fitted mask like an N95 may help. “Masks, such as N95 masks, are highly effective at filtering the particle components of air pollution,” she added.

Indoor air quality is also important. Papatheodorou noted that using an air purifier in the home is a good idea. “High-efficiency particulate air (HEPA) filters in air purifiers can reduce the concentration of PM2.5,” she said.

A 25-Minute Training Can Help Reduce People’s Autism Biases

What This Means For YouIf you’re an expecting parent or are planning on a pregnancy, it’s best not to stress about reducing air pollution exposure for the sole purpose of reducing your child’s autism risk. Scientists don’t yet know what causes autism. If you’d like to limit your exposure for other health reasons, staying indoors when air quality is bad and wearing an N95 mask may help.

What This Means For You

If you’re an expecting parent or are planning on a pregnancy, it’s best not to stress about reducing air pollution exposure for the sole purpose of reducing your child’s autism risk. Scientists don’t yet know what causes autism. If you’d like to limit your exposure for other health reasons, staying indoors when air quality is bad and wearing an N95 mask may help.

5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Data and statistics on autism spectrum disorder.Ojha SK, Amal H.Air pollution: an emerging risk factor for autism spectrum disorder.Brain Med. Published online November 12, 2024. doi:10.61373/bm024e.0115Pagalan L, Bickford C, Weikum W, et al.Association of prenatal exposure to air pollution with autism spectrum disorder.JAMA Pediatr. 2019;173(1):86-92. doi:10.1001/jamapediatrics.2018.3101McGuinn LA, Windham GC, Kalkbrenner AE, et al.Early life exposure to air pollution and autism spectrum disorder: findings from a multisite case-control study.Epidemiology. 2020;31(1):103-114. doi:10.1097/EDE.0000000000001109World Health Organization.How air pollution is destroying our health.

5 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Centers for Disease Control and Prevention.Data and statistics on autism spectrum disorder.Ojha SK, Amal H.Air pollution: an emerging risk factor for autism spectrum disorder.Brain Med. Published online November 12, 2024. doi:10.61373/bm024e.0115Pagalan L, Bickford C, Weikum W, et al.Association of prenatal exposure to air pollution with autism spectrum disorder.JAMA Pediatr. 2019;173(1):86-92. doi:10.1001/jamapediatrics.2018.3101McGuinn LA, Windham GC, Kalkbrenner AE, et al.Early life exposure to air pollution and autism spectrum disorder: findings from a multisite case-control study.Epidemiology. 2020;31(1):103-114. doi:10.1097/EDE.0000000000001109World Health Organization.How air pollution is destroying our health.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Centers for Disease Control and Prevention.Data and statistics on autism spectrum disorder.Ojha SK, Amal H.Air pollution: an emerging risk factor for autism spectrum disorder.Brain Med. Published online November 12, 2024. doi:10.61373/bm024e.0115Pagalan L, Bickford C, Weikum W, et al.Association of prenatal exposure to air pollution with autism spectrum disorder.JAMA Pediatr. 2019;173(1):86-92. doi:10.1001/jamapediatrics.2018.3101McGuinn LA, Windham GC, Kalkbrenner AE, et al.Early life exposure to air pollution and autism spectrum disorder: findings from a multisite case-control study.Epidemiology. 2020;31(1):103-114. doi:10.1097/EDE.0000000000001109World Health Organization.How air pollution is destroying our health.

Centers for Disease Control and Prevention.Data and statistics on autism spectrum disorder.

Ojha SK, Amal H.Air pollution: an emerging risk factor for autism spectrum disorder.Brain Med. Published online November 12, 2024. doi:10.61373/bm024e.0115

Pagalan L, Bickford C, Weikum W, et al.Association of prenatal exposure to air pollution with autism spectrum disorder.JAMA Pediatr. 2019;173(1):86-92. doi:10.1001/jamapediatrics.2018.3101

McGuinn LA, Windham GC, Kalkbrenner AE, et al.Early life exposure to air pollution and autism spectrum disorder: findings from a multisite case-control study.Epidemiology. 2020;31(1):103-114. doi:10.1097/EDE.0000000000001109

World Health Organization.How air pollution is destroying our health.

Meet Our Medical Expert Board

Share Feedback

Was this page helpful?Thanks for your feedback!What is your feedback?OtherHelpfulReport an ErrorSubmit

Was this page helpful?

Thanks for your feedback!

What is your feedback?OtherHelpfulReport an ErrorSubmit

What is your feedback?