The Environmental Protection Agency (EPA) on Sept. 7 issued its final update to the agency’s Cross-State Air Pollution Rule (CSAPR) that is designed to help protect communities in the East from smog-forming pollution that crosses state lines.
The updated Cross-State standard should help states meet the 2008 air quality standards for smog, or ozone, EPA said in a news release.
CSAPR, which was finalized in 2011, was designed to help states meet the 1997 ozone standards.
EPA’s approach in the 2011 rule has now been affirmed by the Supreme Court and EPA is applying this same approach to the 2008 ozone air quality standards to help states address transported ozone pollution under the strengthened standards.
The final CSAPR Update reflects stakeholder input and more than 15,000 comments received during the public comment process for the proposal, a public hearing, and a July 2015 Notice of Data Availability (NODA). The rule also responds to the July 2015 decision of the Court of Appeals for the D.C. Circuit, addressing the court’s concerns regarding ozone season NOx emissions budgets for 11 states.
North Carolina not included in final update
North Carolina is not included in the final CSAPR Update because modeling for the final rule indicates that the state is not linked to any downwind nonattainment or maintenance receptors, according to an EPA summary of key changes.
EPA also refined its methodology for establishing emission budgets to better reflect power sector NOx reduction potential by using historical data in combination with projections of potential NOx emission rate improvements in each state.
The EPA revised its assumption of the reasonably achievable NOx rate for units with the emission control selective catalytic reduction (SCR), moving from an emission rate of 0.075 lbs/mmBtu in the proposed rule to 0.10 lbs/mmBtu in the final rule.
The CSAPR Update identifies cuts in NOx emissions in 22 states that contribute significantly to downwind ozone air quality problems and can be achieved using already installed, proven and cost-effective control technologies and other readily available approaches at affected sources.
The cuts in NOx emissions under the final rule will lead to significant improvements in air quality starting in the 2017 ozone season, which runs from May through September, EPA said.
EPA estimates that in 2017 this rule and other changes already underway in the power sector will help cut ozone season NOx emissions by 80,000 tons—a 20% reduction from 2015 levels.
Under the Clean Air Act “good neighbor” provision, states develop state implementation plans while EPA plays a backstop role by issuing federal implementation plans (FIPs) if a state fails to submit an approvable plan. The Sept. 7 action provides the FIP, and a partial remedy, for all 22 affected states under EPA’s backstop obligation.