Air pollution: a respiratory hue and cry.

Air pollution: A respiratory hue and cry 

High levels of air pollution may foster respiratory symptoms in otherwise healthy individuals, a new analysis suggests. An even more provocative study indicates that air pollution, at least in Los Angeles, may begin permanently "deranging" the lung's cellular architecture by the time a person reaches age 14.

Environmentalists say both studies underscore the need for stepped-up efforts to bring areas with substandard air quality into compliance with the Clean Air Act. Researchers presented the new findings this week in Arlington, Va., at the annual conference of the Society for Occupational and Environmental Health.

Bart Ostro and his co-workers reexamined data collected 12 years ago in the north-central Los Angeles area, looking for associations between respiratory health and local measurements of air pollutants. The team focused on 320 generally healthy, nonsmoking men and women who had kept daily logs of their respiratory symptoms over a six-month period as part of another study.

A preliminary analysis indicates that runny noses, sinusitis, sore throats, head colds and other upper-respiratory symptoms arose most often on the haziest days or on days with the highest peaks in smog-ozone, reports Ostro, an epidemiologist with the California Department of Health Services in Berkely. The bad smog episodes also coincided with more lower-respiratory symptoms, such as coughs, phlegm, wheezing and chest colds -- but only among participants whose homes lacked air conditioners, which can limit indoor ozone levels. In addition, the researchers uncovered hints that when sulfates reached high levels in the city's air, lower-respiratory symptoms emerged the following day.

Daily one-hour peaks in ozone were high throughout the study period, averaging 0.1 parts per million and sometimes reaching 0.43 ppm -- well above the federal limit on 0.12 ppm. For each 0.1 ppm elevation in peak ozone, participants logged "roughly a 10 percent increase in upper or lower respiratory symptoms, and increases of 30 percent in eye irritation," Ostro reports.

Russell P. Sherwin and his colleagues at the University of Souther California in Los Angeles detected surprising sings of "an ecologic problem at the cell level" in the lungs of 85 Los Angeles residents, aged 14 to 25, who had died in homicides or traffic accidents. The team's detailed cellular assays uncovered chromic bronchitis, inflamed bronchial submucosal glands and microscopic holes -- subtle but "pretty severe" lung damage that would elude detection by most coroners, Sherwin says.

Some of these lung abnormalities probably reflect damage from smoking, drugs and previous respiratory diseases. However, Sherwin says, "we know ozone is involved [too]," because studies have shown that nonhuman primates develop identical lesions when exposed to ozone levels exceeding the federal standard. Parts of Los Angeles exceed the ozone standard "every other day," he notes.

Overall, 98 percent of the young victims showed some form of chronic bronchitis. In 55 percent of the cases, the researchers observed atrophy, or even some outright loss, of submucosal glands. Three-quarters of the youths also suffered centriacinar-region lung disease -- a condition characterized by chronic inflammation, and often structural aberations, in the smallest, terminal "twigs" of the bronchial tree.

Sherwin says such damage indicates that the deceased youths had "certainly [been] heading for a lot of trouble" with emphysema and perhaps early heart attacks. If their lungs turn out to be bellwethers of air pollution's effects on the population at large, "we're all heading for a lot of trouble," he warns.