How Strong Is the Connection Between Autism & Air Pollution?

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Researchers have found that children with autism are more likely to suffer from respiratory problems, due to the association between air pollution and asthma. How could this be addressed?

The “autism risk calculator” is a tool that helps people to determine the likelihood of an individual being diagnosed with autism. The higher the score, the more likely it is that they will be diagnosed with autism.


There is a link between prenatal air pollution exposure and autism. Although further research is needed, air pollution is presently thought to be a risk factor for autism. 

Air Pollution as an Autism Risk Factor

The severity of the link between autism and air pollution is a hot topic of debate, particularly when it comes to the link between prenatal exposure to ambient air pollution and the risk of autistic spectrum disorder.

Researchers writing in the journal Current Environmental Health Reports say that a decade of research has found consistent links between different types of air pollution, as well as place of residence and socioeconomic status, and autism spectrum disorder, to the point where pollution is lumped in with “other potential causal risk factors for ASD.”

Two research stand out in particular. One study, published in the journal Environment International, studied the development of a large sample of children in Shanghai from birth to three years old (124 children with autism and 1,240 neurotypical children). Exposure to fine particles emitted by automotive exhaust, industrial pollutants, and other types of outdoor air pollution raised the chance of developing autistic spectrum disorder by up to 78 percent, according to researchers. 

While the origins of autism are complex and unknown, it is well established that environmental variables have a role in the risk of ASD developing in utero, according to one of the study’s authors. 

The hypothesis behind this is that young children’s growing brains are more sensitive to pollutants in their settings and atmospheres when they are still in gestation or infancy. The existence of hazardous exposures has been shown to have an influence on the immune system and brain function in a large body of studies. 

The ramifications of the link are enormous. According to the World Health Organization, inhaling dirty air kills up to 4.2 million people every year. In nations with weak environmental standards and heavily populated metropolitan areas, such as India and China, such pollutants contribute to high rates of sickness and early mortality. 

Small Exposures & Delayed Learning

Even in nations with stricter environmental controls, such as Australia, air pollution caused by industrial outputs and the use of fossil fuels is responsible for 3,000 early deaths per year. 

According to Science Alert, an associate professor at Monash University’s School of Public Health and Preventative Medicine said that no quantity of air pollution is safe, and that “even very minute concentrations of fine particulate matter” may have a role in the development of delayed learning. 

The smaller the airborne particles, the more likely they are to reach the circulation via the lungs, according to a Shanghai research.

A Real Link Between Autism & Air Pollution

Another research, this one published in JAMA Pediatrics, suggested that an increase in autism incidence might be linked to motor traffic pollution. Researchers looked at 132,256 births in Vancouver, Canada, and discovered a relationship between prenatal exposure to traffic pollution and a diagnosis of autism in childhood. 

A third research, published in Environmental Epidemiology, looked at 15,000 Danish babies born between 1989 and 2013. The research showed a relationship between early-life exposure to hazardous chemicals and a later diagnosis of autism spectrum condition. 

In all instances, experts stressed that further study was required to fully understand the nature of the link between autism and air pollution. The sheer amount of studies — all of which is in considerable agreement — “suggests that the association is true,” according to an associate professor and environmental epidemiologist at the University of Wisconsin, Milwaukee, who was not involved in either study.

She stated that although it is vital not to generate unnecessary worry, it is also critical to inform young and expectant families that pollution from vehicles and trucks may represent a risk for the development of autism.

Micropollutants & Fetal Development

While high levels of pollution exposure have been linked to early fetal mortality in pregnancies that do not survive, low-level pollution exposures may have a more subtle influence on brain development. This might be one of the elements that contribute to the onset of autism, particularly if other factors like genetics are present. 

Despite rising rates of autism diagnoses, Vancouver and Denmark are noted for their relatively pristine air quality. According to a scientist at Simon Fraser University in Vancouver, British Columbia, air quality has altered so much throughout the globe that even under more favorable situations, there are enough micropollutants in the air to influence fetal development.

Shipping & Pesticides

Although traffic is often considered as the primary source of pollution linked to autism, it is not the only one. Sulfur dioxide, which might be emitted by the shipping sector, was also connected to autism, according to the Danish researchers. In 2018, the American Journal of Psychiatry released the findings of a research that linked a mother’s exposure to pesticides to autism.

Scientists advise governments to put schools and other childcare facilities away from congested roads and traffic regions to lessen the danger of autistic spectrum disorder developing as a result of long-term interaction between pregnant women and young children. 

This investigation will not provide any evidence that “pollution causes autism.” This is largely due to the fact that no study can ever intentionally expose children or pregnant women to pollution, but it is also due to the fact that autism’s multiple causes and risk factors are still unknown. While there is no conclusive proof that autism causes air pollution, one researcher said that “together, we have enough [evidence].”

How Wildfire Smoke Might Affect Autism Development

While pollution from automobiles and industry is often identified as a risk factor in the development of autism spectrum disorder, other natural types of air pollution, such as smoke from wildfires, may also play a role. According to experts at the University of Washington, the air quality in Seattle during the summer wildfires was comparable to that seen in areas with low air quality indices owing to industrial and traffic emissions.

These scientists performed animal studies and discovered that exposure to diesel exhaust during development might result in minor alterations in the cerebral cortex’s structure. People with autism spectrum disorder have these abnormalities in their brains as well.

The research discovered that babies who were exposed to nitric oxide (one of the pollutants) before birth had a slight increase in autism diagnosis.

The researchers thought that their findings contributed to worries that air pollution is a “possible etiological (contributing to the formation of a medical disease) factor for developmental and neurodegenerative illnesses,” as they wrote in the journal Brain, Behavior, and Immunity.

According to the findings, pollution causes neuroinflammation and reduces the synthesis of a protein that triggers a signaling pathway required for correct cell placement in the brain. Both of these occurrences are common in autism spectrum disorders.

Pregnancy and Exposure

Children whose mothers were exposed to high levels of fine particulate pollution late in their pregnancies were twice as likely to develop autism spectrum disorder as children whose mothers were not exposed to such pollution and breathed cleaner air, according to Harvard School of Public Health researchers.

The danger grew when the amount of fine particles generated by industrial smokestacks, cars, and fires was increased.

The hypothesis that there is a relationship between a pregnant woman’s environmental and atmospheric health and the risk of autism has also been validated by previous studies. Specifically, if a pregnant woman lived near a motorway during her third trimester, her child’s chance of autism doubled.

However, there was no link between autism and fine particle pollution exposure before to pregnancy, throughout pregnancy, or after the child was delivered. The danger window appears to be limited to the third trimester.

Despite the fact that the rate of autism diagnoses has increased dramatically (from 1 in 150 children in 2000 to 1 in 68 children in 2010, according to the American Psychological Association), the question of whether this is due to increased autism incidence or simply increased awareness of the disability continues to be debated.

Despite this ambiguity, the sharp rise in occurrence has prompted academics to investigate environmental factors. While there is a hereditary component to autism, the rapid increase in numbers cannot be explained only by genetic causes.

Despite this, epidemiologists agree that an expecting mother’s exposure to air pollution increases the risk of her kid developing autism.

How to Evaluate the Air Quality in Your Neighborhood

If you’re worried that the air quality in your neighborhood is contaminated enough to put your family’s health at danger, check out the Globe Air Quality Index Project, a nonprofit organization whose stated mission is to provide information on air quality in major cities across the world. Many local news organizations and weather stations also report on the current state of air quality in their localities. There are also a variety of smartphone applications that can provide you with a localized assessment of the air quality index.

You may also discuss environmental issues with your doctor or pediatrician. Wearing a mask or going to a different region if feasible might help mitigate the impacts of pollution from highways. The capacity (or lack thereof) to relocate or travel to get away from motorways and industrial regions is closely connected to socioeconomic levels, according to the Environmental Health journal. This is not always a possibility for women and families with lesser incomes.


There is a connection between autism and air pollution. There is no research that has been done on this topic yet, but there are some studies that have shown the correlation. Reference: how common is autism.

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