SO2 Average Values for 2013-2015 in NC Counties

In 2010, EPA revised the sulfur dioxide (SO₂) standard to a 1-hour standard at a level of 75 parts per billion (ppb). To determine if the standard is met, a continuous 3-year average concentration is calculated from daily measurements and compared to the requirements of the standard.

The table below shows the 3-year average SO₂ concentrations for the 5 highest reported values by county for 2013-2015.

SO₂ levels in North Carolina are low, ranging from 2.7 percent to 42.7 percent of the standard. These values are higher than the previous 3-year period.

Additionally, for many years, SO₂ has been measured at several sites across the state on a rotating basis. This monitoring is conducted at five sites operated for 12 months every 3 years.   For these sites we do not have continuous 3-year averages.  The overall monitoring conducted at those sites show no exceedances of the standard.