New Research Shows Air Pollution Can Reduce Children’s Lung Function
Children who live in polluted communities are five times more likely
to have clinically low lung function less than 80 percent of the
lung function expected for their age. New data from the Children's
Health Study suggests that pollutants from vehicle emissions and
fossil fuels hinder lung development and limit breathing capacity
for a lifetime.
The study was funded by the National Institute of Environmental
Health Sciences (NIEHS), one of the National Institutes of Health,
the California Air Resources Board and the Hastings Foundation.
The results of the study, conducted by researchers at the University
of Southern California Keck School of Medicine, are published in
this week's issue of the New England Journal of Medicine.
"This is the longest study ever conducted on air pollution
and children's health," said Dr. Kenneth Olden, director of
NIEHS. "It shows that current levels of air pollution have
adverse effects on lung development in children between the ages
of 10 and 18."
Each year, pulmonary function data were collected from 1,759 children
as they progressed from 4th grade to 12th grade. The researchers
also tracked levels of air pollutants like nitrogen dioxide, acid
vapor, elemental carbon, and particulate matter in the 12 Southern
California communities where the children lived. The study encompassed
some of the most polluted areas in the greater Los Angeles basin,
as well as several less-polluted communities outside the Los Angeles
Over the eight year period, researchers found that children living
in the most polluted communities had significant reductions in their
"forced expiratory volume" the volume of air that can
be exhaled after taking a deep breath as compared to children
living in communities with cleaner air.
In healthy people, lungs grow to full capacity during the teenage
years, but typically stop growing at age 18. Then, lung capacity
gradually declines. Adults begin to lose lung function by 1 percent
each year after age 20.
"Lung development in teenagers determines their breathing
capacity and health for the rest of their lives," said John
Peters, M.D., Hastings Professor of Preventive Medicine at the Keck
School of Medicine. "The potential long-term effects of reduced
lung function are alarming. It's second only to smoking as a risk
factor for mortality. As lung function decreases, the risk of respiratory
disease and heart attacks increases."
Deficits in lung function are associated with other short- and
long-term effects. "If children or young adults with low lung
function were to have a cold, they might have more severe lung symptoms,
or wheezing," says W. James Gauderman, Ph.D., associate professor
of preventive medicine at the Keck School and lead author on the
study. "They may have a longer disease course, while children
with better lung function may weather it much better."
Researchers are unsure how air pollution may retard lung development.
Gauderman believes chronic inflammation may play a role, with air
pollutants irritating small airways on a daily basis. Scientists
also suspect that air pollutants might dampen the growth of alveoli,
tiny air sacs in the lungs.
The research team will continue to follow the study participants
into their early 20s, when their lungs will be fully mature. They
want to find out whether the participants will experience respiratory
symptoms, and if those who moved away from a polluted environment
will show some improvement in lung function.
This research is part of the larger Children's Health Study, an
ongoing study that was started in 1993. The study is the longest
ever undertaken on the association between air pollution and children's