Gasoline Reid Vapor Pressure
Volatility is the property of a liquid fuel that defines its evaporation characteristics. Reid vapor pressure is a common measure of and generic term for gasoline volatility. EPA regulates the RVP of gasoline sold at retail stations during the summer high ozone season (“summer season”) to reduce evaporative emissions of volatile organic compounds from gasoline that are a major contributer to ground-level ozone (i.e., smog) and diminish the effects of ozone-related health problems. (For all regulated parties except retailers and wholesale purchaser-consumers, the summer season is generally May 1 to September 15; for retailers and wholesale purchaser consumers, the summer season is generally June 1 to September 15.)
Under Clean Air Act section 211(h), gasoline RVP may not exceed 9.0 pounds per square inch during the summer season. However, under the CAA, some areas of the country are subject to a more stringent RVP standard of 7.8 psi. (For these areas, there are regulatory provisions that enable EPA to relax the more stringent standard to the 9.0 psi RVP standard.) In either case, the CAA provides a 1.0 psi RVP allowance for gasoline containing 10 percent ethanol. In order to relax the more stringent federal 7.8 psi RVP standard, the state must submit a revision to the area’s attainment demonstration or maintenance plan demonstrating timely attainment or continued attainment of the ozone National Ambient Air Quality Standard with the less stringent 9.0 psi RVP standard in place and that the RVP relaxation complies with the anti-backsliding requirements in CAA section 110(l).
On December 4, 2020, EPA revised and relocated the federal RVP regulations to 40 CFR 1090.215. (See 85 FR 78412 (pdf) (1.5 MB).) The current regulatory text explains that summer gasoline (e.g., gasoline that is sold to consumers from June 1 to September 15) must meet a maximum per-gallon RVP limit of 9.0 psi unless it is required to meet a lower RVP limit. Lower RVP limits apply in areas that are:
- subject to the federal 7.8 psi RVP standard;
- required to sell federal reformulated gasoline;
- required to sell California RFG (i.e., the entire state of California); or
- subject to a state fuel rule in an approved State Implementation Plan that requires an RVP of less than 9.0 psi.
Designations and exact boundaries of the areas that are currently subject to the federal 7.8 psi RVP standard can be found in 40 CFR 1090.215(a)(2) and are described below:
| Area Designation | State | Counties |
|---|---|---|
| Denver-Boulder-Greeley-Ft. Collins-Loveland* | Colorado | Adams Arapahoe, Boulder, Broomfield, Denver, Douglas, Jefferson, Larimer,1 Weld2 |
| Reno | Nevada | Washoe |
| Portland | Oregon | Clackamas (only the Air Quality Maintenance Area), Multnomah (only the Air Quality Maintenance Area), Washington (only the Air Quality Maintenance Area) |
| Salem | Oregon | Marion (only the Salem Area Transportation Study), Polk (only the Salem Area Transportation Study) |
| Beaumont-Port Arthur | Texas | Hardin, Jefferson, Orange |
| Salt Lake City | Utah | Davis, Salt Lake |
1 That portion of Larimer County, CO that lies south of a line described as follows: Beginning at a point on Larimer County’s eastern boundary and Weld County’s western boundary intersected by 40 degrees, 42 minutes, and 47.1 seconds north latitude, proceed west to a point defined by the intersection of 40 degrees, 42 minutes, 47.1 seconds north latitude and 105 degrees, 29 minutes, and 40.0 seconds west longitude, thence proceed south on 105 degrees, 29 minutes, 40.0 seconds west longitude to the intersection with 40 degrees, 33 minutes and 17.4 seconds north latitude, thence proceed west on 40 degrees, 33 minutes, 17.4 seconds north latitude until this line intersects Larimer County’s western boundary and Grand County’s eastern boundary. (Includes part of Rocky Mtn. Nat. Park).
2 That portion of Weld County, CO that lies south of a line described as follows: Beginning at a point on Weld County’s eastern boundary and Logan County’s western boundary intersected by 40 degrees, 42 minutes, 47.1 seconds north latitude, proceed west on 40 degrees, 42 minutes, 47.1 seconds north latitude until this line intersects Weld County’s western boundary and Larimer County’s eastern boundary.
*Beginning with the 2024 summer season, gasoline sold in the Denver area is required to comply with the more stringent federal RFG RVP standard of 7.4 psi. See 40 CFR 1090.215(a)(3).
Below is a summary of the federal fuel volatility regulations at 40 CFR 1090.215:
- For all regulated parties except retailers and wholesale purchaser-consumers, maximum per-gallon standards generally take effect May 1.
- Standards for June 1 to September 15 are maximum per-gallon standards for all regulated parties including retailers and wholesale purchaser-consumers, unless the state has an extended summer ozone season as part of their approved SIP (e.g., Arizona, Eastern Texas, El Paso).
- Gasoline meeting the requirements of 40 CFR 1090.215(b) has a 1.0 psi waiver of applicable RVP standard unless one of the following:
- The state has adopted and enforces a SIP-approved RVP standard that does not provide for the 1.0 psi waiver (e.g., Maine, New York, Texas, and Vermont).
- The state has received EPA's approval to opt-out of the 1.0 psi waiver provision per CAA section 211(h)(5) (i.e., Illinois, Iowa, Minnesota, Missouri, Nebraska, Ohio, South Dakota, Wisconsin). Learn more about states that have opted-out of the 1.0 psi waiver.
- The state uses RFG, which has an RVP standard of 7.4 psi as required by 40 CFR 1090.215(a)(3). Additional information about RFG, including a list of RFG areas and their geographic boundaries, can be found in 40 CFR 1090.285 and on the Reformulated Gasoline page.
- Alaska, Hawaii, and U.S. territories are exempted from federal volatility regulations.
Notes on Federal and State RVP Standards:
- In states that have received a waiver under CAA 211(c)(4)(C) to adopt a state fuel program more stringent than federal requirements into their approved SIP, the state fuel program may define a volatility level and compliance date for refiners and/or terminals different than the compliance date for retailers. For more information on SIP-approved state fuel regulations see the State Fuels page. Potentially affected parties should refer to the SIP or contact the state for more information about proper compliance.
- Certain SIP-approved fuel programs do not provide for use of a 1.0 psi ethanol waiver under 40 CFR 1090.215(b). These states include Maine, New York, Texas, and Vermont. The 1.0 psi ethanol waiver is not applicable during the entire volatility control period defined in the SIP (e.g., May 1 - September 15).
EPA has approved relaxation of the summer gasoline RVP standards for a number of states and areas. The following is a list of all actions that EPA has taken since 2014 to either relax the federal 7.8 psi RVP standard or to remove state fuel regulation from the state’s approved SIP:
| State | Area | Action | Federal Register Citation | Publication Date | Effective Date |
|---|---|---|---|---|---|
| North Carolina | Davidson, Davie, Durham, Forsyth, Granville, Guilford, and Wake Counties | Relaxation of federal 7.8 psi RVP standard | 79 FR 29362 (pdf) (260 KB) | May 22, 2014 | May 30, 2014 |
| North Carolina | Mecklenburg and Gaston Counties | Relaxation of federal 7.8 psi RVP standard | 80 FR 49164 (pdf) (231 KB) | August 17, 2015 | October 16, 2015 |
| Florida | Broward, Dade, Duval, Hillsborough, Palm Beach, and Pinellas Counties | Relaxation of federal 7.8 psi RVP standard | 79 FR 29362 (pdf) (260 KB) | May 22, 2014 | May 30, 2014 |
| Alabama | Jefferson and Shelby Counties | Relaxation of federal 7.8 psi RVP standard | 80 FR 38284 (pdf) (212 KB) | July 2, 2015 | July 2, 2015 |
| Georgia | 45-county Atlanta area | Removal of state fuel program | 80 FR 52627 (pdf) (242 KB) | September 1, 2015 | October 1, 2015 |
| Georgia | Cherokee, Clayton, Cobb, Coweta, DeKalb, Douglas, Fayette, Forsyth, Fulton, Gwinnett, Henry, Paulding, and Rockdale Counties | Relaxation of federal 7.8 psi RVP standard | 84 FR 49470 (pdf) (239 KB) | September 20, 2019 | October 21, 2019 |
| Ohio | Butler, Clark, Clermont, Greene, Hamilton, Miami, Montgomery, and Warren Counties | Removal of state 7.8 psi RVP standard | 82 FR 16932 (pdf) (239 KB) | April 7, 2017 | April 7, 2017 |
| Tennessee | Davidson, Rutherford, Sumner, Williamson, and Wilson Counties | Relaxation of federal 7.8 psi RVP standard | 82 FR 26354 (pdf) (217 KB) | June 7, 2017 | June 7, 2017 |
| Tennessee | Shelby County | Relaxation of federal 7.8 psi RVP standard | 82 FR 60675 (pdf) (232 KB) | December 22, 2017 | January 22, 2018 |
| Louisiana | Beauregard, Calcasieu, Jefferson, Lafayette, Lafourche, Orleans, Pointe Coupee, St. Bernard, St. Charles, St. James, and St. Mary Parishes | Relaxation of federal 7.8 psi RVP standard | 82 FR 60886 (pdf) (246 KB) | December 26, 2017 | January 25, 2018 |
| Louisiana | East Baton Rouge, West Baton Rouge, Livingston, Ascension, and Iberville Parishes | Relaxation of federal 7.8 psi RVP standard | 83 FR 53584 (pdf) (215 KB) | October 24, 2018 | November 23, 2018 |
| Pennsylvania | Allegheny, Armstrong, Beaver, Butler, Fayette, Washington, and Westmoreland Counties | Removal of state 7.8 psi RVP standard | 83 FR 65301 (pdf) (215 KB) | December 20, 2018 | January 22, 2019 |
| Pennsylvania | Allegheny County | Removal of state 7.8 psi RVP standard | 84 FR 32076 (pdf) (260 KB) | July 5, 2019 | July 5, 2019 |
| Kansas | Johnson and Wyandotte Counties | Removal of state 7.8 psi RVP standard | 86 FR 14000 (pdf) (224 KB) | March 12, 2021 | April 12, 2021 |
| Missouri | Clay, Jackson, and Platte Counties | Removal of state 7.8 psi RVP standard | 86 FR 14007 (pdf) (230 KB) | March 12, 2021 | April 12, 2021 |
Additional Information:
- Information on EPA’s fuel quality regulations can be found on the Federal Gasoline Regulations page.
- Information on areas where federal RFG is required can be found on the Reformulated Gasoline page.
- Information on areas where a SIP-approved state fuel rule applies can be found on the State Fuels page.