Can Air Pollution Cause Asthma in Kids? How About Autism?

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(Getty Images/Thinkstock)
(Getty Images/Thinkstock)

We all know air pollution is not great for your health, but two new studies this week stressed just how bad it can be for children, infants and the developing fetus. Exposure to air pollution at a young age, these studies showed, can lead to an array of long-lasting health problems, including asthma and autism.

It's not just that polluted air can, say, trigger asthma attacks. Now, researchers are finding that exposure to air pollution may actually cause some diseases.

“We’re discovering some of the long-term effects of this air pollution: things like lung development in kids,” said Georges Benjamin, executive director of the American Public Health Association.

A study led by UCSF found that African American and Latino infants living in communities with high automobile exhaust are more likely to develop childhood asthma than those living with less pollution. This is significant because minority communities are more likely to live near congested roadways.

In California, African Americans and multi-racial people have some of the highest rates of asthma, according to the CDC. But rigorous scientific studies that examine just how the lungs of minority children develop when swamped with car exhaust have been rare.


In this new study, researchers followed more than 4,000 African American and Latino children in the Bay Area and other cities in the United States and Puerto Rico. It’s one of the largest studies of its kind.

They found that exposure to higher levels of nitrogen dioxide -- a pollutant found in automobile exhaust -- put healthy infants at a greater risk of developing asthma later in life.

This was despite the fact that the average amount of nitrogen dioxide infants were exposed to was almost 3 times lower than the limit set by the Environmental Protection Agency.

“We found an association even though all of these children were exposed to what the EPA would consider to be an acceptable level of air pollution,” said Katherine Nishimura, a UCSF researcher and lead author on the study.

Nishimura tracked pollution exposure for infants within their first years of life. This is a time when children’s lungs and immune system are developing, she said.

Even though factors other than pollution may also increase the risk of developing asthma -- like obesity, stress, and a family history -- the team’s results raise questions about whether the national standards for nitrogen dioxide are strong enough.

The problem hits home in California. This year, California cities dominated the top ten most air polluted cities in the nation, according to the American Lung Association's State of the Air report.

“The state has this golden reputation of being so far out in front in everything,” said Paul Cort, attorney at Earthjustice, a San Francisco-based environmental advocacy group that has pushed for tighter air pollution standards. “And yet we still have two of the most polluted air basins in the country.”

Stronger evidence that pollutants increase risk of autism

Other research out this week links air pollution to autism. Those findings suggest that public health officials might want to look at strengthening regulations for more than just nitrogen dioxide.

Diesel particulates and metals like lead, manganese, and mercury that are found in polluted air have been shown to disrupt brain development in babies in the womb.

Scientists from Harvard's School of Public Health found that pregnant women who were exposed to high levels of air pollution were up to two times more likely to have a child with autism when compared to pregnant women who lived in low pollution areas.

In the study, air pollution came from a variety of sources including automobiles, power plants, factories, incinerators and businesses. And greater levels of diesel, mercury, lead, manganese, methylene chloride, and a combination of metals found in the air were linked to higher rates of autism.

“New studies should begin the process of measuring metals and other pollutants in the blood of pregnant women or newborn children to provide stronger evidence that specific pollutants increase risk of autism,” Marc Weisskopf, a public health professor at Harvard and an author of the study said in a press release. “A better understanding of this can help to develop interventions to reduce pregnant women’s exposure.”

The researchers looked at more than 22,000 women who had children with and without autism. This was the first large national study to examine the effects of air pollution on pregnancy and autism, the authors said.

“Clearly the underserved communities are very affected,” said Benjamin. “Many times these [factories and] plants are put into communities where the land is fundamentally cheap.”

But air pollution has rarely been monitored in these communities, hindering advocates’ abilities to fully grasp and tackle the issue, said Cort. “These communities should be informed of what they’re breathing,” he said.

Advocates hope that the flood of research on the effects of air pollution on children will bolster a case for tighter air pollution and car emission standards in the future.