Girls play on a soccer field near a complex operated by Duke Energy in Wilmington, N.C., on Wednesday, Feb. 19, 2014. Randall Hill / AP

Regulations designed to reduce air pollution in North Carolina have led not just to cleaner air but to fewer deaths from lung diseases, according to a new study report released Monday.

Researchers at Duke University reviewed 17 years of state air quality data and death records, and found a distinct correlation between the start of stricter pollution rules in 2002 and a marked decline in the number of people perishing from emphysema, asthma and pneumonia. The report was published in the International Journal of COPD.

The evidence pointing to the consequences of air pollution rules likely applies globally, the study’s head author said, adding that it puts into perspective the reason for tougher air quality rules: human health.

“If you ask people, ‘Should we improve air quality?’ it’s hard to get an handle on that,” said Kim Lyerly, a professor of surgery at Duke and the report’s senior author.

“But improving health and reducing deaths – it’s hard to argue that that’s not an important end point.”

North Carolina’s Clean Smokestacks Act of 2002 put in place stricter rules for cars, trucks and coal-burning power plants, reducing levels of harmful gases such as carbon monoxide, sulfur dioxide, nitrogen dioxide and ozone, as well as particulate matter. Carbon monoxide saw the steepest fall.

Meanwhile, between 1980 and 2010, emphysema deaths per 100,000 people went from 12 to about seven; asthma deaths fell from a 1990 peak of about five down to about two, and fatal cases of pneumonia dropped from a high that year of 90 to 60 in 2010.

"This research tends to show that environmental policies work, if the goal of those policies is not only to improve the environment, but also to improve health," Lyerly said.

Frank Holleman, a senior attorney with the Southern Environmental Law Center, hailed the Clean Smokestacks Act of 2002 as the reason for the lower death rates.

“The air in North and South Carolina has become clearer and cleaner as a result of national clean air standards and as a result of North Carolina’s Clean Smokestacks Act,” Holleman said.

“Fewer people are dying from lung disease and fewer people are suffering from aggravated asthma and lung diseases,” he said. The study factored in the effects of cigarette smoking.

Although North Carolina has made significant progress in cleaning up its air, Holleman said the state also faces a sobering challenge in dealing with water pollution that is also related to the burning of fossil fuels.

North Carolina tripped into a harsh spotlight in February, when tens of thousands of gallons of toxic coal ash spilled from a defunct power plant on the Dan River. The leak coated the waterway for 70 miles.

Duke Energy, which was responsible for the coal ash pond that leaked, and the North Carolina Department of Environment and Natural Resources (NCDENR) have both been served subpoenas by federal prosecutors investigating the spill, as environmental groups allege too much coziness between the regulator and the energy company, the nation’s largest.

Holleman said that the state's leaky coal ash ponds can threaten human health, just like air pollutants, and that the state needs to start using renewable energy sources such as solar and wind.

“We need to clean up the legacy of dangerous, dirty, leaking coal ash lagoons, which take pollutants that were removed from the air and transfer them to our rivers, drinking water supplies, and lakes,” he said.

As for officials responsible for public health, Lyerly said he hopes they will take his group’s research into account.

“Policy makers have a tough job,” Lyerly said. “We think this study is important because it contributes to their knowledge and we hope they will consider this kind of data when they make policy decisions.”