Tiny, toxic particles creep into developing
brains, cause inflammation and may damage brain pathways responsible for
emotion and decisions, researcher finds
Date:
December 13, 2017
Source:
University of Southern California
Summary:
A new study
linking higher levels of air pollution to increased teenage delinquency is a
reminder of the importance of clean air and the need for more foliage in urban
spaces. The study suggests ambient air pollution may increase delinquent
behavior among 9- to 18-year-olds in urban neighborhoods in Greater Los
Angeles. The insidious effects are compounded by poor parent-child
relationships and parental mental and social distress, researchers report.
A new study linking higher levels of air pollution to increased teenage
delinquency is a reminder of the importance of clean air and the need for more
foliage in urban spaces, a Keck School of Medicine of USC researcher said.
Tiny pollution particles called particulate matter 2.5 (PM2.5) — 30 times
smaller than a strand of hair — are extremely harmful to your health,
according to Diana Younan, lead author of the study.
“These tiny, toxic particles creep into your body, affecting your
lungs and your heart,” said Younan, a preventive medicine research
associate at the Keck School of Medicine. “Studies are beginning to show
exposure to various air pollutants also causes inflammation in the brain. PM2.5
is particularly harmful to developing brains because it can damage brain
structure and neural networks and, as our study suggests, influence adolescent
behaviors.”
The study, published on Dec. 13 in the Journal of Abnormal Child
Psychology, suggests that ambient air pollution may increase delinquent
behavior among 9- to 18-year-olds in urban neighborhoods in Greater Los
Angeles. The insidious effects are compounded by poor parent-child
relationships and parental mental and social distress, researchers said.
“Previous studies by others have shown that early exposure to lead
disrupts brain development and increases aggressive behavior and juvenile
delinquency,” Younan said. “It’s possible that growing up in places
with unhealthy levels of small particles outdoors may have similar negative
behavioral outcomes, though more research is needed to confirm this. Both lead
and PM2.5 are environmental factors that we can clean up through a concerted
intervention effort and policy change.”
More than just a lung and heart concern
The study followed 682 children in Greater Los Angeles for nine years
starting when they were 9. Parents completed a child-behavior checklist every
few years and noted if their child had engaged in 13 rule-breaking behaviors,
including lying and cheating, truancy, stealing, vandalism, arson, or substance
abuse. Up to four assessments were recorded per participant.
Researchers used 25 air quality monitors to measure daily air pollution in
Southern California from 2000 to 2014. They computed each participant’s
residential address and used mathematical modeling to estimate the ambient
PM2.5 levels outside each home. About 75 percent of the participants breathed
ambient air pollution that exceeded the federal recommended levels of 12
micrograms per cubic meter. Some areas had nearly double the recommended amount
of these particles.
“It is widely recognized that ambient air pollution is detrimental to
the respiratory and cardiovascular health of young and old alike. But in recent
years, scientists have come to acknowledge the negative impact of air pollution
on human brains and behaviors,” said Jiu-Chiuan Chen, an associate
professor of preventive medicine at the Keck School of Medicine and senior
author of the study.
Environmental scientists and economists have speculated that elevated air
pollution levels could increase criminal activities in communities.
Interestingly, data show that both ambient PM2.5 concentration and crime rates
in Southern California have been on the decline, the study stated. Future
studies need to examine whether that is mere coincidence or if tightened air
regulation might have contributed to the declining crime rates in many
metropolitan areas, the researchers said.
“Poor people, unfortunately, are more likely to live in urban areas in
less than ideal neighborhoods,” Younan said. “Many affordable housing
developments are built near freeways. Living so close to freeways causes health
problems such as asthma and, perhaps, alters teenagers’ brain structures so
that they are more likely to engage in delinquent behavior.”
This one-two hit may increase teenage delinquency
The study identified higher air pollution estimates near freeways and in
neighborhoods with limited greenspace or foliage.
Researchers noticed more delinquent behavior from boys, African-Americans,
adolescents from lower socioeconomic backgrounds and people who lived in
downtrodden neighborhoods with limited greenspace when compared to their
counterparts.
The bad behaviors associated with increased outdoor air pollution levels
were magnified when children did not have good relationships with their
parents, lived with depressed mothers or grew up in homes with higher levels of
parental stress.
“If you live in an area with high air pollution, like near a freeway
or in a neighborhood with little greenery, try to avoid being outside so much
and keep windows closed as much as possible when the ambient PM2.5 levels are
high,” Younan said. “Try to compensate for air pollution by having a
good indoor environment and healthy family dynamics.
“A bad parent-child relationship causes a stressful family
environment, and if this goes on for too long, the teenager could be in a
chronic state of stress. This could wreak havoc on the body, making teens more
vulnerable to the effects of exposure to small particles. Many scientists
suspect PM2.5 causes inflammation in the brain or somehow travels directly into
the brain and messes with neural network connections, resulting in the observed
bad behaviors.”
The data was adjusted for gender, ethnicity, socioeconomic status,
neighborhood socioeconomic characteristics and neighborhood quality.
More foliage and cleaner air needed
Younan and her colleagues at the USC Environmental Health Sciences Center
have collaborated with researchers and engineers from different disciplines at
USC for more than two decades to investigate the insidious effects of air
pollution. They found that air pollution increases obesity, that teenagers in
urban communities with less foliage (such as parks) tend to be more aggressive
and that older women living in areas with PM2.5 levels exceeding the U.S.
Environmental Protection Agency’s standard had nearly double the risk for
dementia when compared to their counterparts.
Story Source:
Materials provided by University of Southern California. Original written by Zen
Vuong. Note: Content may be edited for style and length.
Journal Reference:
1.
Diana Younan,
Catherine Tuvblad, Meredith Franklin, Fred Lurmann, Lianfa Li, Jun Wu, Kiros
Berhane, Laura A. Baker, Jiu-Chiuan Chen. Longitudinal Analysis of Particulate
Air Pollutants and Adolescent Delinquent Behavior in Southern California. Journal
of Abnormal Child Psychology, 2017; DOI: 10.1007/s10802-017-0367-5
