(Reuters Health) - Air quality improvements in southern California are tied to improvements in the respiratory health of children in that area, according to a new study.
While the researchers can't say for sure that cleaner air caused kids' breathing to improve, they believe their findings strongly support that theory.
"I think we can safely say this is one of the clearest pieces of scientific evidence to say reduction of air pollution can lead to improvement in respiratory health for children," said study leader Kiros Berhane, from the University of Southern California (USC) in Los Angeles.
At a teleconference Tuesday, Berhane and his USC colleagues said policies have led to significant reductions in pollution since 1992.
"In recent years we observed air pollution levels were coming down in southern California," said coauthor Dr. Frank Gilliland.
Coauthor Edward Avol noted that billions of dollars have been spent to replace school buses, trucks and other forms of transportation that produced too much pollution.
In eight southern California communities, the research team tracked three groups of children, ages five to 18 - one group from 1993 to 2001, another from 1996 to 2004, and the third from 2003 to 2012.
Altogether there were 4,602 youths, who entered the study at an average age of eight.
In general, decreases in air pollution (nitrogen dioxide, ozone and particulate matter) were tied to reduced odds of breathing problems for children with and without asthma when they were 10 and 15 years old.
The problems included coughing, congestion, phlegm in kids who didn't have a cold or the flu, or bronchitis.
The greatest reduction in breathing problems with improved air quality was seen in children with asthma. Boys, and youths from homes with dogs, also had larger declines in breathing problems, the authors reported in JAMA.
The researchers caution that the study has some limitations. For example, symptom assessment, based on questionnaire responses, was imprecise.
Still, Berhane said the findings are useful.
"They could inform policymakers to show that reductions in pollution can result in public health benefits," he said.
SOURCE: bit.ly/1Ysih5i JAMA, online April 12, 2016.
Support HuffPost
Our 2024 Coverage Needs You
Your Loyalty Means The World To Us
At HuffPost, we believe that everyone needs high-quality journalism, but we understand that not everyone can afford to pay for expensive news subscriptions. That is why we are committed to providing deeply reported, carefully fact-checked news that is freely accessible to everyone.
Whether you come to HuffPost for updates on the 2024 presidential race, hard-hitting investigations into critical issues facing our country today, or trending stories that make you laugh, we appreciate you. The truth is, news costs money to produce, and we are proud that we have never put our stories behind an expensive paywall.
Would you join us to help keep our stories free for all? Your contribution of as little as $2 will go a long way.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
As Americans head to the polls in 2024, the very future of our country is at stake. At HuffPost, we believe that a free press is critical to creating well-informed voters. That's why our journalism is free for everyone, even though other newsrooms retreat behind expensive paywalls.
Our journalists will continue to cover the twists and turns during this historic presidential election. With your help, we'll bring you hard-hitting investigations, well-researched analysis and timely takes you can't find elsewhere. Reporting in this current political climate is a responsibility we do not take lightly, and we thank you for your support.
Contribute as little as $2 to keep our news free for all.
Can't afford to donate? Support HuffPost by creating a free account and log in while you read.
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. Would you consider becoming a regular HuffPost contributor?
Dear HuffPost Reader
Thank you for your past contribution to HuffPost. We are sincerely grateful for readers like you who help us ensure that we can keep our journalism free for everyone.
The stakes are high this year, and our 2024 coverage could use continued support. If circumstances have changed since you last contributed, we hope you’ll consider contributing to HuffPost once more.
Support HuffPostAlready contributed? Log in to hide these messages.