State submits report on sulfur dioxide compliance in North Carolina


North Carolina has taken a series of steps to meet the more stringent sulfur dioxide standard that the federal government adopted in 2010 and maintain its full compliance with federal air quality standards, state environmental officials said today.

William G. Ross Jr., acting secretary for the state Department of Environmental Quality, outlined the steps that North Carolina has taken to comply with the sulfur dioxide, or SO2, standard in a letter to the U.S. Environmental Protection Agency. SO2, one of the first major air pollutants designated under the federal Clean Air Act, is harmful to breathe, damages vegetation, and contributes to haze and acid rain.

 “North Carolina has made tremendous strides toward improving air quality across the state over the past 15 years,” Ross said. “Through the Clean Smokestacks Act and other actions, we have achieved full compliance with federal standards for ozone, fine particles and other air pollutants. We will continue that progress in dealing with sulfur dioxide.”

Ross’ letter outlines the steps that North Carolina has taken to comply with the SO2 standard since 2010. Those steps include:

  • Demonstrating through computer modeling analyses that SO2 emissions from four major electric power plants are not causing violations of the air quality standard in surrounding areas. The plants include Duke Energy’s Mayo facility in Person County, Belews Creek in Stokes County, Marshall in Catawba County, and Allen in Gaston County.
  • Installing air quality monitors near four facilities, with compliance to be determined based on measured levels of SO2. These facilities include PCS Phosphate in Beaufort County, Evergreen Packaging in Haywood County, and Duke Energy’s Asheville plant in Buncombe County and Roxboro plant in Person County. The state Division of Air Quality has submitted monitoring data showing that air quality near the PCS Phosphate plant is complying with the standard and should be designated as attainment. Monitoring near the other three facilities began on Jan. 1, 2017, and the state needs three years of data to determine whether nearby air quality is meeting the standard.
  • Continuing to operate a network of five regional SO2 monitors in Durham, Forsyth, Mecklenburg, New Hanover and Wake counties. Long-term monitoring data from all of these sites show that air quality in these areas is complying with the SO2 standard.

In addition to these steps, North Carolina previously installed an air quality monitor for SO2 in Brunswick County due to concerns about potential impacts on air quality from the CPI facility in Southport. DAQ has issued a revised air permit with a more restrictive SO2 emissions limit for the CPI plant.

Under the Clean Smokestacks Act, North Carolina has reduced emissions from the state’s coal-fired power plants by more than 85 percent since the early 1980s. Additional state and federal measures have substantially reduced emissions from other industry as well as cars and trucks. More information about air quality issues in North Carolina can be found at the state Division of Air Quality’s website,

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