Stronger emission controls in North Carolina may have saved lives by reducing deaths from respiratory illness, according to an academic study published Monday.
During the past few decades, the state has tightened its air quality standards through adherence to federal legislation such as the Clean Air Act and the state’s 2002 Clean Smokestacks Act. The state’s success in reducing air pollution may explain a substantial decline in deaths from the respiratory illnesses asthma and emphysema during corresponding periods, reported Duke University scientists in the International Journal of COPD on Monday.
The release of the study comes as state lawmakers are considering legislation this week that eliminates some of the state’s air-quality stations, part of the framework for measuring pollution across the state.
“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 public health,” said the study’s lead author, Dr. H. Kim Lyerly from Duke University.
State and Environmental Protection Agency air quality measurements and public health records from 1993-2010 allowed researchers to connect improved air quality to reduced death rates from asthma and emphysema. In their analysis, scientists correlated death rates and exposure to levels of nitrogen dioxide, sulfur dioxide, airborne particulate matter and other pollutants. Researchers factored out the effects of age or smoking history in determining changes in subjects’ health.
The research established that the improvements in health coincided with the reduction in pollution. But researchers said the data could not conclusively show the reduction in pollution caused the health improvements because there are other potentially influential factors – such as medical history or allergies – they did not account for in their analysis.
Sheila Holman, the director of the Division of Air Quality at the N.C. Department of Environment and Nature Resources, documented the decline in emissions and improvement to air quality since the passage of the Clean Smokestacks Act. She partnered with Duke researchers on the project and believes the improvements to air quality have improved health.
“Here was some evidence that we did have an impact on the public health of North Carolina,” Holman said.
Scientists also explored whether overall medical advances could explain the decline in death rates in North Carolina but concluded that it was unlikely. Death rates in the state fluctuated along with seasonal concentrations of pollutants within a year, a time frame too short for medical advances to have an effect. Unlike the changes in mortality seen in North Carolina, deaths from respiratory illness at the national level remained relatively constant from 1999-2010, according to National Vital Statistics System records.
Duke, DENR collaborate
Partnerships across multiple disciplines at Duke University and the state DENR made the study possible.
“There was a great opportunity to bridge the gap in information by bringing together environmental data and health-related data, something that hadn’t been done before,” Lyerly said.
Few studies are able to evaluate the health consequences of chronic air pollution over a long period, mostly because consistent long-term records of such factors are seldom kept. Duke researchers capitalized on existing health and environmental data. They used records from both state and federal EPA air-quality devices. And they gathered public-health information from the Vital Statistics National Center for Health Statistics, the Centers for Disease Control and Prevention, and other databases.
The study was supported with funding from Fred and Alice Stanback to the cancer and environment program of the Nicholas School of the Environment-Duke Cancer Center.
“Our study leverages these collected data in a way that it can contribute to the dialogue on whether pollution controls are effective in improving public health,” Lyerly said.
Bill would remove monitors
The presence of devices that measure air quality has created ongoing discussion in this year’s session of the General Assembly.
Senate Bill 734 – sponsored by Republican Sens. Trudy Wade, Brent Jackson and Andrew C. Brock – would change long-term air quality monitoring in the state. The bill passed the Senate on May 29 and has been referred to two House committees. It would require the state DENR to request removal of any air monitors not required by federal regulations in its next report to the EPA.
The bill does not threaten the department’s ability to install temporary air monitors for targeted investigations. The House has sent its own environmental bill to the Senate that does not include a provision to remove monitoring stations.
Currently, 56 air quality monitoring sites scattered across the state house devices to measure pollutants. Each device costs approximately $12,540 per year to operate, with additional costs for maintenance and data management, according to the DENR.
Costs, benefits weighed
Health care costs from respiratory illness in North Carolina may outweigh the cost to improve air quality. In addition to increasing death rates evaluated in this study, air pollution can trigger asthma attacks, according to the CDC. Asthma cost the U.S. $56 billion in direct and indirect costs in 2007, the CDC reported in May 2011.
Duke Energy estimates it costs citizens roughly $250 million per year to meet emissions standards after the Clean Smokestacks Act took effect.
The energy company and the state have worked together to dramatically reduce emissions of carbon monoxide, nitrogen dioxide, sulfur dioxide and particulate matter. Sulfur dioxide emissions have dropped 92 percent since 2005 in North Carolina and South Carolina, and half of the aging coal plants in North Carolina have shut down.
“It has been a very successful process. It is a great example of private industry working with the state to bring environmental benefits to citizens,” said Jeff Brooks, a Duke spokesman.
Lyerly will continue to research the health consequences of air pollution by refocusing his analysis to the county level.
“Now we have some opportunities to make more accurate equations of the pros and cons of policies that improve air quality.”