from the Journal of Environmental Health Perspectives February, 1996

WHILE LEAD IS THE MAJOR ENVIRONMENTAL HAZARD TO CHILDREN IN much of the United States, air pollution may pose an even greater threat to children in urban areas. Children are more vulnerable to air pollution in part because lungs continue to develop throughout childhood, adding new alveoli until about age 20. Damage from air pollution can impede lung development and may lead to chronic lung disease later in life, according to the ALA's 1995 report Danger Zones: Ozone Air Pollution and Our Children.

CHILDREN'S EXPOSURES TO AIR POLLUTION ARE LIKELY TO BE MUCH greater than adults' for several reasons. Due to their higher metabolic rates, children need more oxygen and therefore breathe more air--twice as much air per pound of body weight compared to adults. In addition, children often play outside on warm, sunny afternoons, which is when ozone levels peak. Children also breathe air closer to the ground, where respirable particles settle, and can be so much more active that they breathe air pollutants deeper into their lungs than adults.

THE OZONE AND PARTICULATE AIR POLLUTION THAT CHILDREN BREATHE COMES PRIMARILY FROM MOTOR VEHICLES. OZONE CAN DAMAGE THE CELLS that line the respiratory tract, making airways narrower and causing wheezing, chest pain, bronchitis, and asthma. These effects are greater in children because their airways are narrower than those of adults. Ozone can also decrease resistance to respiratory infection, make airways more sensitive to airborne allergens, and act synergistically with airborne acidity to damage deep lung tissues, according to the 1993 American Academy of Pediatrics' report Ambient Air Pollution: Respiratory Hazards to Children. While the federal standard for ozone is 120 parts per billion averaged over an hour, wheezing and other symptoms can occur at exposures to lower levels over longer periods of time, according to the ALA.

BESIDES DIESEL VEHICLE AND CAR EXHAUST, SOURCES OF PARTICULATE air pollution include wood fires and factory and utility smokestacks. Particulate air pollution comprises solid and liquid particles less than 10 microns in diameter. Particles this small can be inhaled deep into the lungs, causing wheezing and coughing, and triggering asthma attacks, and are also associated with pleurisy and pneumonia. Symptoms can occur below the federal standard of 150 micrograms per cubic meter, according to Landrigan.

While there have been no direct studies of the effects of air pollution on children, AUTOPSIES OF 100 LOS ANGELES CHILDREN WHO DIED FOR UNRELATED REASONS IN 1990 REVEALED THAT MORE THAN 80% HAD SUBCLINICAL LUNG DAMAGE, says spokesman Jerry Martin of the California Air Resources Board. "We're pretty certain that the only thing they had in common was living in polluted air," he says. This pilot study led to an ongoing, long-term study to determine the effects on developing lung tissues of growing up in polluted air.

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