A team of researchers from the University of Southern California after monitoring the impact of contaminated air around Los Angles said the improvement of air quality in the areas has led to better health among children.

Findings of the 20-year study were published in The New England Journal of Medicine. The study included more than 2,000 children between the ages of 11 and 15.

Researchers associated with the study informed that the participants of the study lived in four inland cities where wind patterns and topography traps the air pollution, and the coastal city of Long Beach.

Lead author James Gauderman said in a statement that the levels of fine particulates were down by 50% in these areas. He said the nitrogen dioxide levels were also found to be down by one-third.

Gauderman said, "This is an incredible success story, because despite increased traffic and economic activities, the air quality in the Los Angeles region has actually gotten better".

The study clearly shows that cleaner air resulted in lung development. Lung capacity of kids in these areas has also improved tremendously.

Researchers said improvement of lungs and cleaner air will result in fewer breathing problems and heart problems later in life. Better lungs can also help to improve life span of children, they added.

Researcher Frank Gilliland said the improvement in air quality was a result of joint efforts made by local, state and federal regulators. Emissions from cars and other sources were strictly restricted.

Long Beach activist Mark Lopez said efforts to bring down the pollution levels at the ports have paid off, but he still worries what will happen in the future.

He said the increased air quality is equal to improved health, but if people start to deviate from this point they would again move backward when the air quality was poor and had ill effects on health.