Living in a clean environmentis required for a child's healthy growth. Highlighting this point, new research says exposure to air pollution can harm a child's brain.

Outdoor air pollution changed volumes of white matter in brain, the area of brain responsible for cognitive function and left early markers of alzheimer's, researchers said.

White matter, which makes up half of human brain, helps to focus, learn, solve problems and balance the body while walking. According to experts from the Gillings School of Global Public Health in US, white matter plays a crucial role in brain's health and "conditions that impact white matter can lead to significant cognitive impairment and increase the risk of long-term neurological problems."

In the new study, a team of researchers from University of California looked at 40 published studies from different countries including US, Mexico, Europe and Australia. The data provided measurements of outdoor air pollution and its outcome on children's brains from birth to 18 years.

Some studies measured brain differences by usingmethods like MRI scans, while others measured it by testing changes in chemical compounds important for brain health or by analyzing tumors in brain.

Both living near a highly polluted area or even at places that met local air pollution standards were associated with differences in children's brains.

"A lot of these studies include children in places with air pollutant levels that are well below limits set by U.S. or European regulations," co-first author Anna Parenteau from UC Davis, said in a statement.

To reconfirm their findings the research team conducted experiments on animals and received similar results.

"A lot of researchers working on brain development, whether it's autism, Alzheimer's or something else, really discounted for a long time the environmental factors," Director of Air Quality Research Centerat UC Davis, Anthony Wexler, said. "They argued that it's genetic or some other factor other than exposure to air pollution. That's changed a lot recently because of all this research literature."

Concerned by the findings, researchers recommended parents to take some precautionary measures to protect their children from outdoor air pollution and install air filters a home and schools.

"We listed air purifiers as one of the policy recommendations, and that is something that could be subsidized or provided in schools and other places where children spend a lot of time,"Camelia Hostinar, an associate professor of psychology and the study's corresponding author, explained. "These can be quite effective."

Findings of the study have been published in Developmental Cognitive Neuroscience.

Similarly, another team of researchers from the Barcelona Institute for Global Health (ISGlobal)recently foundthat early exposure to air pollution affected development of white matter in brains.

According to UNICEF, apart from brain damage, air pollution also poses severe health risks to children. It is responsible for nearly 26 percent of newborn deaths across the world and causes respiratory infections that is responsible for 15 percent of deaths under age five.