Document ID: EPA-HQ-OAR-2021-0742-0013
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2022-04-13T04:00Z

179B Guidance
December 1, 2020

Finalizing the 179B guidance as drafted has serious economic implications for the Northern Wasatch Front nonattainment area in Utah which may not be able to meet the requirements of the Clean Air Act.

 Did OMB ask that changes be made to the guidance before issuing it?
 Did OMB ask that the statements be removed regarding the international contribution relative to the domestic contribution to local ozone?
 Did OMB ask that statements referring to not doing a demonstration or only doing a retrospective demonstration for a Marginal ozone nonattainment area be removed?
 Does the guidance fall under the newly promulgated 40 CFR Part 2 Subpart D "Guidance Procedures"?
 In light of the Guidance Procedures rule, how does EPA view these inconsistencies with the Clean Air Act text which has only the "but for" test?
 Does EPA plan to issue the guidance?  Will it be issued with or without changes to the draft?
 If EPA plans to issue it, in what time frame?

In accordance with the "Guidance Procedures" rule, 179B guidance should not set up hurdles outside the statutory text of the Clean Air Act.  Changes requested to the guidance:
 Remove two statements on Page 39 of the draft discussing modeling:
 "The range of results should demonstrate that international anthropogenic sources were large contributors relative to U.S. contributions on exceedance days."   
 "When results show that international contributions are larger on exceedance days and meaningfully larger than domestic contributions, the weight of evidence will be more compelling."   
            
 Remove/change the following items regarding demonstrations for Marginal ozone nonattainment areas:
 Page 12 of the draft guidance: "The air agency is not required to develop an attainment demonstration for an O3 nonattainment area classified as Marginal, and therefore EPA does not expect to receive section 179B(a) prospective demonstrations for such areas."  
 Two boxes from the flow sheet in section 4.2.3 of the guidance, the second and third boxes on the top row, "Is the area an ozone nonattainment area classified as Marginal?" and "STOP:  A Marginal ozone area does not need to submit an attainment plan, and therefore a section 179B(a) demonstration would not be necessary."  Instead, have the flow sheet go directly from the first box "An area has been designated as nonattainment for a NAAQS" to the box immediately below it, "Can the area attain the standard by the attainment date based on . . . ."  
Preliminary modeling done by Ramboll at the request of the Utah Petroleum Association shows that 10 ppb of local ozone originates from international anthropogenic emissions.  
 The portion of locally generated anthropogenic ozone in this area is less than 20% of the total, with much coming from motor vehicles. 
 Ozone precursor emissions have already been reduced by 37% through the PM2.5 State Implementation Plan, with controls costing approximately $100 million in the Salt Lake City airshed alone.  Despite these controls, ambient ozone concentrations have not reduced.  Further controls are not anticipated to improve ozone levels but may stifle economic recovery.  
 Without reliance on the 179B provisions, the Wasatch Front area may not be able to meet Clean Air Act requirements; no amount of emission reductions from controllable sources will reduce ozone enough to attain the current standard.  Thus, the guidance on use of 179B provisions should provide as much flexibility as possible and not impose extra hurdles not supported by the statutory text.