RALEIGH, NC (NEWS RELEASE) – State environmental officials have recommended that the Environmental Protection Agency postpone designating the Wilmington area as non-attainment or not in compliance with the new federal air quality standard for sulfur dioxide, or SO2.
Measurements by the N.C. Division of Air Quality, or DAQ, show that the New Hanover County monitor does not meet the more stringent SO2 standard that the EPA adopted in June 2010. States were required to submit recommendations by today for the boundaries of SO2 attainment and non-attainment areas, or those areas not meeting the standard.
The N.C. Department of Environment and Natural Resources recommended that the EPA defer its designation of a non-attainment area for New Hanover County due to the closure of several large sources of SO2 in the area and the resulting drop in measured SO2 levels. Southern States Chemical and WASTEC have shut down their facilities near the monitor, and Progress Energy plans to convert its nearby Sutton plant from coal to natural gas by early 2014. The New Hanover County monitor has measured no SO2 values above the new standard so far in 2011.
“I request that the USEPA consider deferring a nonattainment designation for this area until after 2012,” Dee Freeman, secretary of the N.C. Department of Environment and Natural Resources, stated in a June 2 letter to the EPA. “…It is possible for the Wilmington monitor to attain the 1-hour SO2 standard by the end of 2012.”
If the EPA will not agree to postpone the non-attainment decision for Wilmington, the state environmental agency has recommended that the federal agency designate the northwestern corner of New Hanover County, bounded by the Cape Fear and Northeast Cape Fear rivers and the Pender County line. Non-attainment areas are regions officially designated by the EPA as not meeting air quality standards, and the state must develop plans for bringing such areas back into compliance. Industries that emit SO2 may face more stringent requirements in non-attainment areas.
Sulfur dioxide is one of six criteria or major pollutants specified in the federal Clean Air Act. It is a pungent gas that is unhealthy to breathe, can damage vegetation and materials such as buildings, and contributes to the formation of haze, particle pollution and acid precipitation. High levels of SO2 can cause or worsen respiratory ailments such as asthma, bronchitis and emphysema and aggravate existing heart disease. Populations most affected include children, the elderly and other sensitive groups.
In June 2010, the EPA adopted a more stringent SO2 standard of 75 parts per billion (ppb) averaged over one hour. Previously, there were three SO2 standards: 500 ppb averaged over 3 hours, 140 ppb averaged over 24 hours, and 30 ppb averaged over a year.
Compliance with the federal SO2 standard is determined by a formula based on a three-year average of the 99th percentile of the daily maximum one-hour concentrations. Under that formula, the design value for the air monitor located in New Hanover County is 110 ppb.
More information can be found at this page on the DAQ website: http://www.ncair.org/planning/so2/SO2.shtml.