A groundbreaking new study has found that long-term improvements in air quality are associated with better respiratory function in children during critical growth years.
The study, published on Wednesday in The New England Journal of Medicine, looked at lung development in children ages 11 to 15 in Southern California over the course of the last two decades as air pollution controls significantly improved air quality. It is the first time that researchers have shown that better air quality leads to the direct improvement of lung development in children.
The University of Southern California Children’s Health Study measured lung development in thousands of adolescent children in communities across the Los Angeles area since 1993. The project found large gains for the children studied from 2007 to 2011, compared to children of the same age in the same communities from 1994–98 and 1997–2001.
By adjusting for age, gender, ethnicity, height, respiratory illness, and other variations, the study provides strong evidence that improved air quality by itself brings health benefits.
“We saw pretty substantial improvements in lung function development in our most recent cohort of children,” said lead author W. James Gauderman, professor of preventive medicine at the Keck School of Medicine of USC. “It’s strange to be reporting positive numbers instead of negative numbers after 20 years.”
Gauderman is used to reporting negative numbers. Previously reported results from his data had provided evidence for the harmful impacts associated with lung development for children in areas with heavy air pollution, as well as showing that children living near busy roads have a higher risk of developing asthma.
Now, the long-term data is showing positive impacts as air quality improved. Specifically, the combined exposure of nitrogen dioxide (NO2) and particulate matter of diameter under 2.5 microns (PM2.5) fell approximately 40 percent over the course of the study. As pollutants dropped, lung growth improved more than 10 percent, according to the long-term data. The percentage of children in the study with abnormally low lung function at age 15 dropped from nearly eight percent for the 1994–98 cohort to 6.3 percent in 1997–2001 and to just 3.6 percent for children followed between 2007 and 2011.
“It certainly supports the efforts that have been made over 40 years to improve air quality,” Gauderman told Reuters Health. “We would expect improvements in other urban centers to produce similar improvements in children’s health.”
The study’s results are especially timely as the Obama Administration and the Environmental Protection Agency struggle to update ground-level ozone standards and implement the Clean Power Plan, which would reduce both conventional air pollution and greenhouse gas emissions from existing and modified power plants. Reductions in greenhouse gases have been shown to in turn reduce conventional air pollutants, according to the EPA.
With the final version of the power plant rule expected to be released later this year, the fossil fuel industry and its political allies are lining up to blockade the government’s effort to limit power plants’ carbon emissions by 30 percent by 2030. Republican leaders have already pledged to strip the EPA of its regulatory power and roll back the rules. Meanwhile, at least a dozen states have filed a lawsuit seeking to invalidate the regulations.
The EPA estimates that the new ozone regulations would prevent 320,000 to 960,000 asthma attacks in children by 2025, and would prevent anywhere from 330,000 to one million missed school days. The proposed plan to tighten its National Ambient Air Quality Standards (NAAQS) for ground-level ozone to between 65 parts per million (ppm) and 70 ppm, down from 75 ppm, is currently under public review. The Agency will issue a final decision by October 1, 2015.
Ozone, a major part of smog, forms in the atmosphere when emissions of nitrogen oxides and volatile organic compounds from cars, trucks, buses, industries, and power plants “cook” in the sun.
The proposed ozone rule has received industry pushback in states across the country, which argue that the costs to improve air quality will cause an undue financial burden. The EPA estimates that meeting the standards will yield significant nationwide health benefits valued at $6.4 to $13 billion annually in 2025 for a standard of 70 ppb, and $19 to $38 billion annually in 2025 for a standard of 65 ppb. Those estimations exclude California, which would have more time to meet the regulations.
“These gains really aren’t fixed,” said senior report author Frank Gilliland, the Hastings Professor of preventive medicine at the Keck School of Medicine. “We have to maintain the same sort of level of effort to keep the levels of air pollution down. Just because we’ve succeeded now doesn’t mean that without continued effort we’re going to succeed in the future.”