Cleaner air really benefits human health, as new research from the University of Southern California links cleaner air to significantly fewer respiratory symptoms in children over a two-decade period.
The researchers behind the study said that the latest findings support previous results from a landmark University of Southern California Children's Health Study showing that children's lungs grew stronger over the past 20 years as air quality improved in the Los Angeles Basin.
After examining rates of bronchitic symptoms in children, researchers found that kids showed fewer signs of respiratory disease as pollution levels dropped.
To understand how air quality influences bronchitic symptoms, lead researcher Kiros Berhane, a professor of preventative medicine Keck School of Medicine of University of Southern California, and his team examined data from children in eight California communities. The team defined respiratory symptoms as experiencing daily cough, congestion or phlegm for at least three consecutive months that's not related to a cold or inflammation of the mucous membranes.
"This is one of the few times that we have been able to report good news, and this is very likely a direct result of the science-based policies that have been put in place," Berhane said. "The message that clean air leads to better health in children should be taken seriously because it has implications for how we live and how productive we become."
The latest study involved 4,602 children as they aged from five to 18. Researchers collected answers from questionnaires about children's health and air quality samples from different communities.
The study revealed that air pollution reduction was linked to a significant reduction in bronchitic symptoms in healthy kids and kids suffering from asthma. The researchers said that the findings held true, even accounting for factors like age, gender, ethnicity, secondhand tobacco smoke and presence of cockroaches in living places.
"It is important to note that while reductions in bronchitic symptoms were larger in children with asthma, they were still substantial and significant in children without asthma as well -- indicating that all children have benefited from the improvement in air quality over the past 20 years," Berhane said.
"Because of the wide variations in ambient pollution levels among the eight California communities we analyzed, these findings are applicable to other parts of the United States and maybe other parts of the world as well," he added.
The findings were published in the April 12 issue of the Journal of the American Medical Association.
