- The Environmental Protection Agency (EPA) has proposed issuing non-attainment designations for 12 U.S. counties and declared another 23 unclassifiable under the sulfur dioxide provisions of the National Ambient Air Quality Standard (NAAQS), SNL Energy reports. A total of 31 counties subject to review were recommended the designation unclassifiable, which would put them in attainment with the standard.
- Under the Clean Air Act, the EPA is required to set air quality standards for carbon monoxide, nitrogen oxides, lead, sulfur dioxide, particulates and ground level ozone — common pollutants resulting from burning coal for electricity and other sources like transportation. EPA must review the standards every five years, and court order compelled the agency to finalize this round of sulfur dioxide designations under the NAAQS by July after a challenge from the Sierra Club.
- Under NAAQS, the agency must release proposed designations 120 days before finalization and include a comment period, according to SNL. Two final rounds of designations will be released in 2017 and 2020.
In 2010, the EPA updated SO2 standards under the NAAQS, setting the one-hour standard at 75 parts per billion, a tighter target welcomed by many environmentalists. The standard was based on research that showed even brief exposure to relatively low concentrations of SO2, a common coal pollutant, can trigger respiratory problems, especially for at-risk populations, SNL reports.
This round of designations includes areas with new violations of SO2 standards set in 2010, as well as areas with existing power plants that were in non-attainment with the standard and were not retired by March 2015. EPA previously identified 68 plants not in attainment of the standard.
Unclassifiable designations indicate that EPA determined the available data for a county is not sufficient to assess if it is meeting NAAQS standards. In that case, SNL reports, any areas with sources of SO2 pollution that exceed 2,000 tons per year will have to provide the agency with air quality data starting in Jan. 2017.
Including the previously-identified plants, more than 66 GW of generation are on the list, and Energy Future Holdings, Xcel, Dynegy and NRG Energy all have multiple plants on the list, SNL notes.
Luminant Energy, a Texas generator and Energy Future Holdings subsidiary, has three plants on the non-attainment list. It issued a statement calling into question the EPA's methods for measuring pollution, saying they "are based on computer modeling funded by environmental groups,” according to the Dallas Morning News.
State environmental regulators in Texas had similar concerns, the paper noted. The state has 12 plants on the list, the most of any state.
“The TCEQ’s position is that designations should be based on monitoring – not modeling,” said Texas Department of Environmental Quality spokeswoman Andrea Morrow. “There are no areas in Texas monitoring an exceedance of the [standards]. Our assessment is different from EPA’s because our assessment was based on monitoring and EPA’s was based on modeling supplied by a third party.”