LOS ANGELES—Slowed lung function growth in adolescents exposed to high levels of particulate pollution may be reversible, a new study suggests.[1]

Edward L. Avol, MS, and colleagues previously reported that lung function growth between ages 10 and 14 years is measurably lower in children living in areas of high ambient air pollution than in those living in areas with cleaner air.[2] “There’s an association with PM10, acids, and NO2, but not ozone,” noted Professor Avol, Associate Research Professor in the Department of Occupational and Environmental Health at University of Southern California, Keck School of Medicine in Los Angeles. He and his colleagues estimated that during a four-year period, children in the most polluted region (compared with those in the least polluted area) would suffer reductions in forced expiratory volume in one second (FEV1) and maximal midexpiratory flow (MMEF) of 3.4% and 5%, respectively. Building on this work by asking if relocating to an area with better or worse air quality influenced growth rate, “we compared movers with stayers,” Professor Avol told RESPIRATORY REVIEWS.

CLEAN AIR BOOSTS GROWTH

Data from 110 children, who were age 10 years in 1994 and who moved before they were age 15, confirmed that growth rates in MMEF and peak expiratory flow rate (PEFR), and to a lesser degree, FEV1, decreased with increasing exposure to particulate matter with a mean diameter of 10 µm (PM10). Compared with these movers, the 1,002 stayers experienced small changes in PM10 exposure. Individuals were categorized based on whether they were originally from a low-, medium-, or high-exposure area.

Among those from low-PM10 communities, each 10-µg/m3 increase in average PM10 exposure was linked to a 54.9-mL/s reduction in annual MMEF growth; those from high-PM10 communities showed a 19.1-mL/s increase in annual MMEF growth for every 10-µg/m3 decrease in community annual PM10 levels. Thus, said Professor Avol, “For a group of kids who move to higher-pollution areas, you see a drop of a few percent in growth rate,” whereas movers to low-PM10 areas show improved growth.

POLLUTION AS HARMFUL AS SMOKING

“What we’re saying is that if one cleaned up the community’s air, it would have had a measurable effect on lung function growth rate on kids in that community,” Professor Avol emphasized. “Your lungs grow until your mid-20s. During this rapid rate of growth is when you can really see this difference—organs tend to be more susceptible,” he explained.

He compared pollution with another respiratory threat: “[In] kids who became active smokers, there’s a decrement in growth rate … on the same order of magnitude.” He concluded, “Ambient air pollution appears to be as important a factor as smoking in affecting annual respiratory function growth in adolescents.... Cleaning up the air is on the same level of priority as preventing smoking in kids.”

—Mimi Zucker, PhD