Studies Record Effects of Pollutants on Children’s Asthma, Chronic Diseases Among Adults

Children's risk of being diagnosed with asthma increases the closer they live to freeways, according to a study University of Southern California researchers released on Tuesday, the Los Angeles Times reports. The findings, which are scheduled to appear in the November issue of the journal Epidemiology, add to the evidence that air pollution contributes to the development of asthma.

Researchers followed 208 children living in 10 cities in Southern California, including 31 children, or 15%, already diagnosed with asthma. Air samplers were installed outside of the children's homes to measure nitrogen dioxide -- produced by vehicle pollutants -- for two-week periods in the summer and fall of 2000. Researchers measured the distance between each home and freeways and then counted how many vehicles traveled within 164 yards of the homes.

The study found that children with higher levels of nitrogen dioxide near their home were more likely to have asthma. Researchers also found that children who lived a quarter of a mile from a freeway had an 89% higher risk of asthma than children living about one mile from a freeway. In addition, the risk of asthma increased by 83% for each increase of 5.7 parts per billion of nitrogen dioxide, according to the study.

Researchers could not determine that nitrogen dioxide is causing asthma but found that air pollution from freeways had a greater influence on nitrogen dioxide levels than pollution from smaller roads.

Lead author James Gauderman, a USC associate professor of preventive medicine, said the study shows that not every child living near a freeway gets asthma. He said, "The message is probably more general, in terms of thinking about not planning [housing] tracts or schools close to a major freeway" (Schoch, Los Angeles Times, 9/21).

Los Angeles City Council member Jan Perry called the study a wake-up call to planners, the Long Beach Press-Telegram reports. Perry, also a member of the South Coast Air Quality Management District, said, "Family housing should not be encouraged next to freeways" (Cavanaugh, Long Beach Press-Telegram, 9/19).

A different team of USC researchers concluded that polluted air "may be causing three times the number of premature deaths than previously estimated," the Fresno Bee reports.

Researchers took pollution readings from Los Angeles-area sites and tracked the relationship between fine particles, called PM 2.5, and the health of residents.

The results indicated that ozone, a main ingredient of smog, had no significant ties to early deaths. However, the researchers found deaths increased by as much as 17% for each increase of 10 micrograms per cubic meter of PM 2.5 particles. Deaths from heart disease rose by as much as 39% and more lung cancer deaths also occurred, researchers found.

Michael Jerrett, lead researcher and USC associate professor of preventive medicine, said, "The picture that's evolving now is one that suggests air pollution is a much bigger and more significant threat to public health than we previously thought" (Anderson, Fresno Bee, 9/21).