American
and Chinese researchers have found that shutting down an old, dirty, coal-fired
power plant can reduce pollution and significantly improve cognitive
development — the ability to think — in young children. VOA's Art Chimes has
details on a new study of how children can benefit from cleaner air.
Children's
developing nervous systems make them especially sensitive to toxic pollutants.
"This
study compares children who were exposed in utero to pollution from coal-fired
power plants with children who were not so exposed, and it demonstrates the
benefits of closing the plant on children's development measured at age
two," said Frederica Perera of Columbia University. She led the research
team, which took advantage of a decision by Chinese officials to close down a
power plant in the city of Tongliang, in Chongqing Municipality.
"This
power plant was shut down because the Chinese government had ordered the
closure of old, small, polluting power plants that burned coals, and this one
was on the list."
The
facility was a major source of chemicals called polycyclic aromatic
hydrocarbons (PAHs). Earlier research has identified PAHs as toxic materials
that can cause a variety of developmental defects in young children.
To
evaluate the impact of PAHs, the researchers compared two groups of children.
One group was born in 2002, before the power plant closed; the second group was
born in 2005, after it shut down.
Most
studies that look at the effects of pollution use indirect measures of how much
pollution people are exposed to — such as where they live or where they work.
Perera says this study was able to use a more direct measure of exposure.
"We
collected umbilical cord blood from babies at birth, and we analyzed the levels
of the chemicals, the PAHs, that we were concerned about. And this is a kind of
marker or fingerprint of exposure at the individual level."
When
the babies were two years old they were evaluated using a standard test of
child development, the Gesell Developmental Schedules. And the group born after
the coal-burning plant shut down scored higher, particularly in a measure of
motor skills.
Perera
says she and her university- and hospital-based Chinese colleagues took steps
to account for other factors that might explain the change in cognitive
development.
"And
those did include things like socioeconomic status of the mother and her
education, levels of lead; we also measured those in the blood. And second-hand
tobacco smoke exposure," she said "We wanted to be sure that what we
were seeing was, in effect, attributable to the PAHs and not to some unmeasured
factors."
Perera
says previous studies demonstrated that the pollutants could be harmful. But
the researchers here were able clearly demonstrate the benefits of reducing
pollution with compelling before-and-after data.
"This
study was unique in that it allowed us to show the benefits of removing such a
polluting source and to demonstrate that the children in the second group
actually fared better in terms of developmental tests, particularly in the area
of motor function," she said.
China
has been closing older, dirtier coal-burning power plants. But with oil prices
in record territory, coal remains a dominant fuel for generating electricity
around the world. The newest, high-tech plants do have pollution controls, but
many older ones remain in operation.
As
the demand for electricity continues to increase, Dr. Frederica Perera says her
research sounds a note of caution ... and, at the same time, demonstrates the
benefits of cutting emissions from existing facilities.
"These
findings do have relevance for environmental health and energy policy worldwide
since these are pollutants that are extremely widespread from fossil fuel
burning, particularly from coal, so they are a positive message both for China
and the rest of the world."
Frederica Perera's paper appeared this week in Environmental Health Perspectives. The journal is published by the U.S. National Institute of Environmental Health Sciences.
