The Centerfor Biological Diversity intends to sue the U.S. EPA for allegedly failing to reviewand revise federal air quality standards for sulfur oxides and nitrogen dioxide,which are pollutants that can be released from power plants.
The environmentalgroup, in a letter of intent released April 27, said the EPA failed to review airquality criteria for sulfur oxides, or SOx, and the primary National Ambient AirQuality Standards for sulfur dioxide, or SO2, and the NAAQS for nitrogen oxide,or NOx. The EPA regulates SO2 under the NAAQS rather than the wider category ofcompounds grouped as SOx.
Currently,the primary SO2 standard is 75 parts/billion and the secondary is 0.5 parts/million;the NO2 primary standard is 100 ppb and the secondary standard is 53 ppb.
The letterof intent warns that the group will bring a lawsuit against the EPA after 60 daysfor failing to revise the standards in line with the Clean Air Act. The EPA is requiredunder the statute to revise the NAAQS every five years. Both the NOx and SO2 standardswere last issued in 2010. The agency reviewed both standards in 2012 and ultimatelydeclined to change them.
The Centerfor Biological Diversity alleged that the actual scientific reviews conducted tobuild the 2010 SOx standards were conducted in 2008. Therefore, the EPA should havereleased a new SOx standard by June 22, 2015.
As forNOx, the EPA completed an integrated science assessment in January, which demonstratedthat the health impacts of the pollutant are worse than what the EPA was previouslyaware of in setting the 2010 standard. "This new science, however, providesno protection to the American public until EPA uses the science to revise the NAAQS,"the letter read.