We’re working to keep N.C. air clean

Sheila Holman
Sheila Holman

From Sheila Holman, Director, N.C. Division of Air Quality:

The July 2 editorial, “An about-face on air quality,” understated the accomplishments of North Carolina’s Division of Air Quality and did not provide the proper context to understand why its monitoring of North Carolina’s air quality is evolving.

After years of reducing pollution in North Carolina, our air quality and protection of the environment have improved markedly. In fact, North Carolinians are breathing cleaner air today than any time in decades. Taking this success into account as we plan for new federal requirements is responsible policy. More is not always better.

Pollution levels have by design been declining year after year. We use the latest scientific data to determine the design of an appropriate air monitoring plan. Those data come from criteria pollutant monitors, which are used by the Environmental Protection Agency (EPA) to determine compliance with federal health based standards.

Due to miscommunication between the Observer's editorial board and a DENR spokesperson, the editorial said the number of air monitors would be reduced by more than half. North Carolina’s program operates instruments to monitor the air for compliance with federal standards as well as track weather and other information not required by federal regulations. The Division of Air Quality has proposed to decrease the number of monitors we operate by about 17 percent, or 19. Those reductions would be made in areas where we are confident that air quality standards will continue to be met. We identified the monitors that could be removed only after analyzing scientific data that justifies their reduction. We will remain a leader in the Southeast in ambient monitoring even with the proposed reduction, as Virginia and South Carolina would still operate fewer monitors than North Carolina.

North Carolina’s historical policy was to operate more monitors than required by the EPA to better define the counties that needed more stringent regulation to meet a national health standard. But the EPA has since included counties in the enhanced regulatory group even when a county’s monitor showed compliance.

The ambient levels of other air pollutants that are regulated on an hourly basis, including sulfur dioxide, are impacted by individual nearby sources. During the past year, the EPA and some special interest groups settled a lawsuit that defined how short-term sulfur dioxide levels will be estimated in the future. In part, the March 2 settlement allows the use of computer models that have been shown to inaccurately predict one-hour concentrations. The use of these inaccurate models will be imposed wherever sulfur dioxide ambient monitors are not in place. We are readying to install 10 to 30 new sulfur dioxide monitors to avoid expending unnecessary resources based on inaccurate modeling data.

Our regional air quality is steadily improving and environmental regulation is at an all-time high. North Carolina understands that its finite resources will be better spent on the implementation of new sulfur dioxide requirements rather than maintaining monitors that do not impact our compliance with the federal health based standards. This shift from quantity to quality rooted in scientific-based monitoring will advance how we measure sulfur dioxide and further improve the health of our air quality.