Systematic review links outdoor air pollution to differences in children's brains

Outdoor air pollution from power plants, fires, and automobiles continues to worsen human, animal, and environmental health around the world. New research shows that even pollution levels below government air quality standards are associated with differences in children's brains.

A research team from the University of California, Davis systematically analyzed data from 40 studies. Empirical researchthe majority of which found that outdoor air pollution is associated with brain differences in children. These differences include white matter volume, which is associated with cognitive function, connectivity throughout the brain, and even early markers of Alzheimer's disease.

Research “Air Purification: A” systematic review Mobilizing research on air pollution and childhood brain outcomes policy change,” was published This month Developmental cognitive neuroscience.

“We see differences in brain outcomes between children with high and low levels of pollution exposure,” said Camelia Hostiner, associate professor of psychology and corresponding author of the study.

Children and teens are especially vulnerable to the effects of air pollution because their brains and bodies are still developing. They tend to spend more time outdoors, and their bodies absorb more pollutants relative to their weight than adults, researchers say.

Outdoor air pollution and brain development

The study examined 40 published, peer-reviewed studies that included measurements of outdoor air pollution and its effects on the brain in children of various ages, from newborns to 18-year-old adults. The majority of studies were from the United States, Mexico, and Europe, with one each from Asia and Australia.

Studies vary widely in how they measure brain differences. Some used advanced scanning techniques such as magnetic resonance imaging and MRI. Some have tested for changes in compounds that help brain function and health. Some studies have looked at tumors of the brain or central nervous system.

A Mexico City study comparing children from highly polluted and low-pollution areas found significant differences in brain structure.

Each study included air pollution measurements associated with the child's address and neighborhood, and found that children's brains differed in places with high air pollution levels and in places that met local air pollution standards. It was shown that this was observed.

“Many of these studies have included children in locations with air pollutant levels well below the limits set by U.S. and European regulations,” said Dr. Anna Parenteau. student in psychology at the University of California, Davis, and co-first author of the study.

outdoor air pollution

Sources of outdoor air pollution include coal-fired power plants, wildfires, and many other sources near where people live. The researchers say this systematic review is unique because most other reviews focus on how air pollution affects adults and animals.

“You can't necessarily extrapolate the results of a study to adults and assume it's the same for children,” said Johnna Swartz, associate professor of human ecology and co-author of the study. he said. “We also need to look further into different developmental windows, as they may be very important in how air pollution affects these brain outcomes. ”

to establish causal relationship Between outdoor air pollution and brain differences, the research team focused on studies using animals. That study showed that pollution causes many of the same outcomes identified in the studies in this review, including markers of Alzheimer's disease.

“Many researchers working on brain development, whether it's autism, Alzheimer's disease, or other diseases, have ignored this problem for a long time. environmental factors“They argued that it was a genetic factor or something other than exposure to air pollution,'' said Anthony Wechsler, a professor and director of the Center for Air Quality Research at the University of California, Davis. The situation has changed significantly in recent years, thanks to a growing body of research literature. ”

reduce damage

This systematic review suggests steps for both parents and policy makers to protect children from outdoor air pollution, for example by installing air filters in homes and schools near highways.

“I mentioned air purifiers as one of them.” policy recommendations“And that's something that can be subsidized and provided in schools and other places where kids spend a lot of their time,” Hostiner said, adding, “These can be very effective. There is.”

Researchers can also incorporate air pollution measurements into studies related to brain health and other health outcomes.

“Anyone who collects data from human participants brain “We can easily add questions to assess exposure to air pollution, such as capturing address, including outcomes and cardiovascular outcomes,” said doctoral student in psychology and first co-author of the study. said one Sally Han.