In 2008 EPA revised the 8-hour ozone National Ambient Air Quality Standard (NAAQS) from 0.08 part per million (ppm) to 0.075 ppm. The Baton Rouge area, consisting of five parishes (Ascension, East Baton Rouge, Iberville, Livingston, and West Baton Rouge), was designated nonattainment for the 2008 ozone NAAQS. In 2016 EPA approved a State Implementation Plan (SIP) revision to provide for maintenance of the NAAQS in the area (maintenance plan) and redesignated the area to attainment (81 FR 95051, December 27, 2016). Among the air pollution controls included in the maintenance plan was the continued use of low RVP gasoline in the area.
On January 31, 2018, Louisiana submitted a SIP revision making changes to the maintenance plan for the Baton Rouge area. This revision demonstrates that the relaxation of the 7.8 psi federal RVP requirement would have no impact on maintaining the 2008 8-hour NAAQS. Louisiana’s analysis utilized EPA’s 2014 Motor Vehicle Emissions Simulator (MOVES2014a) emission modeling system to project revised on-road and non-road mobile source emission inventories for the 2011 base year and future years 2022 and 2027.
The maintenance plan creates Motor Vehicle Emissions Budgets (MVEBs) for criteria pollutants and/or their precursors to address pollution from cars and trucks. The MVEB is the amount of emissions allowed in the SIP for on-road motor vehicles; it establishes an emissions ceiling for the regional transportation network. The previously approved Maintenance Plan established MVEBs for the Baton Rouge area for the years 2022 and 2027. Using the MOVES2014a model and evaluating the 9.0 psi RVP scenarios in 2022 and 2027, the average daily on-road NOx and VOC tons per day (tpd) emissions are less than the previously approved budgets.
The EPA is proposing to approve a revision to the Louisiana SIP that would modify the Baton Rouge area maintenance plan for the 2008 8-hour ozone NAAQS which demonstrates that relaxing the federal RVP requirements for gasoline in the Baton Rouge area would not interfere with the area’s maintenance of the 2008 8-hour ozone NAAQS or any applicable requirement of the CAA. EPA is also proposing to approve the 2022 and 2027 MVEBs included in this maintenance plan revision. The relaxation of the federal RVP requirements for gasoline in the Baton Rouge area will be addressed in a separate rulemaking.
Click here for a link to the Federal Register notice.
On April 19, 1987, EPA determined that gasoline nationwide was becoming increasingly volatile, causing an increase in evaporative emissions from gasoline-powered vehicles and equipment. Under CAA section 211(c), EPA promulgated regulations on March 22, 1989 that set maximum limits for the RVP of gasoline sold during the regulatory control periods that were established on a state-by-state basis in the final rule. On June 11, 1990, EPA promulgated more stringent volatility controls establishing maximum RVP standards of 9.0 pounds per square inch (psi) or 7.8 psi (depending on the state, the month, and the area’s initial ozone attainment designation with respect to the 1-hour ozone NAAQS).
The December 12, 1991, Phase II rulemaking explains that EPA believes that relaxation of an applicable RVP standard is best accomplished in conjunction with the redesignation process. In order for an ozone nonattainment area to be redesignated as an attainment area, section 107(d)(3) of the Act requires the state to make a showing, pursuant to section 175A of the Act, that the area is capable of maintaining attainment for the ozone NAAQS for ten years after redesignation. Depending on the area’s circumstances, this maintenance plan will either demonstrate that the area is capable of maintaining attainment for ten years without the more stringent volatility standard or that the more stringent volatility standard may be necessary for the area to maintain its attainment with the ozone NAAQS. Therefore, in the context of a request for redesignation, EPA will not relax the volatility standard unless the state requests a relaxation and the maintenance plan demonstrates, to the satisfaction of EPA, that the area will maintain attainment for ten years without the need for the more stringent volatility standard.
Section 211(h)(l) of the CAA requires the EPA to set a maximum gasoline RVP standard of 9.0 psi during the summer ozone season, June 1- September 15. The lower RVP requirement is intended to reduce evaporative emissions of VOC, which are precursors of ozone. This section requires EPA to establish more stringent RVP standards in nonattainment areas “as the Administrator finds necessary to generally achieve comparable evaporative emissions in nonattainment areas, taking into consideration the enforceability of such standards, the need of an area for emission control, and economic factors.” Furthermore, §21l(h)(2) provides the Administrator may impose a RVP requirement lower than 9.0 pounds per square inch (psi) in any area formerly an ozone nonattainment area, which has been redesignated as an attainment area.”