Asthmatic children react to "moderate" pollution
Wednesday, October 08, 2003
By Maggie Fox, Reuters
WASHINGTON — Children with severe asthma start suffering from symptoms even
at what are now considered to be acceptable levels of air pollution, U.S.
researchers reported Tuesday.
Ozone, created by traffic, industry, and oil refining, among other
processes, is the prime offender, the researchers write in this week's
issue of the Journal of the American Medical Association.
A study of 271 children with asthma living in Connecticut and Massachusetts
showed those with the worst asthma started to suffer from shortness of
breath, coughing, and chest tightness at "good" air quality levels, as
designated by the Environmental Protection Agency.
"It should be of concern to parents of children with active asthma," said
Janneane Gent, an epidemiologist at Yale University who led the study.
Her team followed the 271 asthmatic children, all under age 12, over the
summer of 2001. It was a moderate year for air pollution in the region, she
said in a telephone interview.
Yet on at least half the days, the children with severe asthma — defined as
needing daily use of medication such as pills or an inhaler — suffered
increased symptoms. These days were linked with higher ozone levels.
"Studies of children with asthma living in regions with levels of pollution
within or near compliance with EPA air quality standards (120 parts per
billion over a one-hour average ... for ozone) significantly enhances the
risk of respiratory symptoms, asthma medication use, and reduced lung
function," they wrote.
"An ozone concentration of 63.3 ppb or higher, measured as the maximum
eight-hour average on the same day as the reported symptom, was associated
with a 30 percent increase in chest tightness," they wrote.
If ozone levels reached 52 ppb on the day before, more kids reported a
tight feeling in the chest, cough, and trouble breathing.
"We found an immediate, same-day effect of ozone on wheeze, chest
tightness, and shortness of breath," they wrote.
Gent said that on half the days that summer, the ozone levels were above 55
parts per billion.
"When the air quality index says that the air is good, that means levels of
ozone in the air are anywhere between 0 and 60 parts per billion," she
said. "When it is 'moderate' it is between 60 and 120 parts per billion. It
really is at that point that parents of asthmatic children would be well
advised to keep their children indoors and make sure they have a low level
Gent said she was not in a position to advise the EPA to tighten pollution
standards but added, "We've provided some more information that those who
are in the business of setting policy can refer to."
In a commentary, George Thurston of the New York University School of
Medicine and Dr. David Bates of the University of British Columbia in
"Of the many triggers of asthma in the environment, air pollution is one of
the few that can be legislated and regulated," they wrote.
"Patients and parents of children with asthma should be aware of the ozone
alert forecast, which is widely publicized in news reports and listed in
the United States on the Internet (available at:
Patients with asthma should stay indoors on
high-pollution days," they added.
It is not just urban children who may be affected. On Monday, a team at the
University of California Irvine found that levels of pollution, including
ozone, were much higher than expected across a swathe of Oklahoma and Texas
where oil refineries and drilling are located.
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