Children Inhale Higher Percentage Of Pollution

by David L. Williamson,
University of North Carolina at Chapel Hill

The study may help explain recent research suggesting that children are more susceptible than adults to illnesses caused by breathing polluted air, researchers say. Chronic coughing, bronchitis and asthma are among health problems worsened by dirty air.

"We believe this work is important because it supports observations by others about children being affected by particulate air pollution," said Dr. William D. Bennett, research associate professor of medicine at the University of North Carolina at Chapel Hill School of Medicine's Center for Environmental Medicine and Lung Biology.

"Certainly it doesn't tell the whole story of why children tend to get sick this way, but it is likely a key part of the story. Other factors, for example, are that children are outside more often and exercise more than adults."

A report on the findings appeared in the September issue of Inhalation Toxicology. Dr. Kirby L. Zeman, research associate at the center, was co-author.

Bennett and Zeman compared results for healthy children between ages 7 and 14, adolescents, and adults who inhaled tiny amounts of harmless carnauba wax particle. Using sophisticated laser technology, researchers then measured how much of the particles remained in volunteers' lungs.

They found that while older adolescents and adults inhaled and retained more particles because of their larger lungs, younger volunteers retained about 35 percent more simulated "pollution" per unit of lung surface area.

"These results may prove useful in determining age-relative risks associated with inhaling air pollutants," Bennett said. "We now plan to extend our studies to exercising volunteers. That's because we also found children seemed to be much more sensitive to changes in the volume of air breathed in terms of the amount of particles they retain."

Non-toxic carnauba wax particles are a food additive derived from a Brazilian palm known as "the tree of life." Besides coating candy and pills, it is used as a car finish and leather preservative.