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 team of researchers at the University of California, Davis systematically analyzed 40 empirical studies, most of which found that outdoor air pollution was associated with differences in children’s brains. These differences include white matter volume, which is associated with cognitive function, connectivity throughout the brain, and even early markers of Alzheimer’s disease.
The study, “Cleaning the Air: A Systematic Review of Research on Air Pollution and Child Brain Consequences to Mobilize Policy Change,” was published this month in the journal Developmental Cognitive Neuroscience.
“We see differences in brain outcomes between children with high levels of pollution exposure and children with low levels of pollution exposure,” said Camelia, associate professor of psychology and corresponding author of the study. Hostiner said.
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 methods 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 as 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 says. “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 a causal link between outdoor air pollution and brain differences, the research team turned to experimental 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, such as autism and Alzheimer’s disease, have long ignored environmental factors,” said Anthony Wechsler, professor and director of the Center for Air Quality Research at the University of California, Davis. “It was,” he says. “They argued that it was either genetic or something other than exposure to air pollution. Thanks to research literature like this, things have changed a lot recently.”
reduce damage
In this systematic review, both parents and policy makers suggested measures to protect children from outdoor air pollution, for example by installing air filters in homes and schools near highways.
“We mentioned air purifiers as one of our policy recommendations, something that could be subsidized or provided in schools and other places where children spend a lot of time. ,” Hostiner said. “These are very effective.”
Researchers can also incorporate air pollution measurements into studies related to brain health and other health outcomes.
“Anyone who collects brain outcomes, cardiovascular outcomes, or other data from human participants can easily add questions to assess exposure to air pollution, such as capturing address. ” said Dr. Sally Han. student in psychology and first co-author of the study.
