A carefully conducted study of 2,120 children in southern California has found dramatically better lung function in the children as air quality has improved.Over a 13-year period, the children with poor lung capacity and lung health fell by half as levels of nitrogen dioxide and particulate matter dropped. The gains were seen both in youngsters who had asthma and in those who did not.
The Chief author of the study is Dr. James Gauderman of the Department of Preventive Medicine at the University of Southern California in Los Angeles. It is published in the New England Journal of Medicine, complements research showing that childhood lung function deteriorates and the risk of asthma rises as pollution levels rise.
Gauderman and his colleagues examined the long-term effects in children by studying three groups during three time periods between 1994 and 2011. Typically, the children entered the study around age 11 and were followed for four years, a period when the lungs are developing rapidly. All lived in the Los Angeles area, a region of the U.S. known for air pollution problems, which have been abating as a result of strict state controls.
“We looked at the proportion of children whose lung function was below 80 percent of normal. That’s a cutoff a physician will often use to flag a person for a possible issue with their lungs,” Gauderman said. While 7.9 percent of children fell into that category in 1998, the proportion had dropped to 3.6 percent by 2011.
During the study years, the air improved “dramatically,” Gauderman’s team writes in their report. For example, in 1994-1997, each cubic meter of air in one of the most-polluted communities, Mira Loma, had 31.5 micrograms of small particles called PM2.5 that penetrate deep into the lungs. By 2007-2010, Mira Loma averaged 17.8 micrograms of PM2.5 per cubic meter of air, a 43 percent decline.
Average lung capacity increased by 91.4 milliliters for every decrease of 14.1 parts per billion in nitrogen dioxide. It rose by 65.5 ml for each decrease of 8.7 micrograms per cubic meter of particle pollution. Significant changes were not linked to ozone levels, but levels of that pollutant have not declined as dramatically over time.
California has stricter pollution controls than the U.S. as a whole.
Jeffrey Newman represents whistleblowers.
