# Phoenix Ozone Nonattainment Area, Clean Air Act Section 182(f) Exemption Petition > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/fr%3A94-27018 ## Record - **Collection:** Federal Register - **Document type:** Uncategorized Document - **Published:** November 1, 1994 ## Text ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [AZ34-1-6418; FRL-5100-3] Phoenix Ozone Nonattainment Area, Clean Air Act Section 182(f) Exemption Petition AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of proposed rulemaking (NPRM). ----------------------------------------------------------------------- SUMMARY: The EPA is proposing to approve a petition submitted by the Arizona Department of Environmental Quality (ADEQ) requesting that the EPA grant an exemption for the Phoenix ozone nonattainment area (Phoenix Area) from the requirement to implement oxides of nitrogen (NOX) Reasonably Available Control Technology (RACT). In accordance with the requirements of the Clean Air Act, as amended in 1990 (the Act or CAA), the Phoenix area may be exempted from the NOX reduction requirements where the Administrator determines that net air quality benefits are greater in the absence of NOX reductions from the sources concerned or that additional NOX reductions would not contribute to attainment of the national ambient air quality standard (NAAQS) for ozone. The ADEQ petition uses the Urban Airshed Model (UAM) to demonstrate that additional NOX reductions in the Phoenix Area would not contribute to attainment of the ozone NAAQS. The EPA is proposing to exempt the Phoenix Area from the requirement to implement NOX RACT and the applicable NOX general and transportation conformity requirements. The EPA is proposing approval of this action under provisions of the CAA regarding plan requirements for nonattainment areas. DATES: Comments on this proposed action must be received in writing on or before December 1, 1994. ADDRESSES: Comments may be mailed to: Daniel A. Meer, Chief, Rulemaking Section (A-5-3), Air and Toxics Division, U.S. Environmental Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA 94105. Copies of the exemption petition are available for public inspection at EPA's Region 9 office during normal business hours. Copies of the submitted petition may be obtained from the following locations: Rulemaking Section (A-5-3), Air and Toxics Division, U.S. Environmental Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA 94105. Arizona Department of Environmental Quality, 3033 North Central Avenue, Phoenix Arizona 85012. Maricopa County Air Pollution Control District, 2406 S. 24th Street, suite E214, Phoenix, Arizona 85034. FOR FURTHER INFORMATION CONTACT: Wendy Colombo, Rulemaking Section (A- 5-3), or Scott Bohning, Air Quality Section (A-2-4), Air and Toxics Division, U.S. Environmental Protection Agency, Region IX, 75 Hawthorne Street, San Francisco, CA 94105 Telephone: (415) 744-1202; (415) 744- 1293. SUPPLEMENTARY INFORMATION: Background On November 15, 1990, the Clean Air Act Amendments of 1990 were enacted. Public Law 101-549, 104 Stat. 2399, codified at 42 U.S.C. 7401-7671q. The air quality planning requirements for the reduction of NOX emissions are set out in section 182(f) of the CAA. On November 25, 1992, EPA published a NPRM (57 FR 55620) entitled, ``State Implementation Plans; Nitrogen Oxides Supplement to the General Preamble; Clean Air Act Amendments of 1990 Implementation of Title I; Proposed Rule,'' (the NOX Supplement) which describes the requirements of section 182(f). The November 25, 1992, notice should be referred to for further information on the NOX requirements and is incorporated into this document by reference. Section 182(f) of the Act requires States to apply the same requirements to major stationary sources of NOX (``major'' as defined in section 302 and section 182(c), (d), and (e)) as are applied to major stationary sources of volatile organic compounds (VOCs). These requirements are RACT and New Source Review (NSR) for major stationary sources in certain ozone nonattainment areas. The RACT requirements for major stationary sources of VOCs are contained in section 182(b)(2), while the NSR requirements are contained in section 182(a)(2)(C) and other provisions of section 182. Section 182(b)(2) requires submittal of RACT rules for major stationary sources of VOC emissions (not covered by a pre-enactment control technologies guidelines (CTG) document or a post-enactment CTG document) by November 15, 1992. There were no NOX CTGs issued before enactment, and EPA has not issued a CTG document for any NOX sources since enactment of the CAA. Section 182(a)(2)(C) requires submittal of NSR rules incorporating the new preconstruction permitting requirements for new or modified sources. The RACT and NSR rules were required to be submitted by November 15, 1992. The Phoenix area is classified as a moderate1 nonattainment area for ozone; therefore this area is subject to the RACT and NSR requirements cited above and the November 15, 1992 deadline.2 On April 13, 1994, the State of Arizona submitted a petition to the EPA requesting that the Phoenix area be exempted from the requirement to implement NOX RACT measures pursuant to section 182(f) of the CAA. The exemption request is based on UAM modeling conducted in accordance with EPA guidelines. --------------------------------------------------------------------------- \1\ The Maricopa County ozone nonattainment area was redesignated nonattainment and was classified by operation of law pursuant to sections 107(d) and 181(a) upon the date of enactment of the CAA. See 55 FR 56694 (November 6, 1991). \2\ The State of Arizona was issued a finding of nonsubmittal for the section 182(f) NOX RACT requirements on April 21, 1993, and subsequently submitted a commitment on April 23, 1993 to adopt and submit the NOX RACT rules. The commitment was submitted as an interim measure to satisfy the NOX RACT requirements, and proposed that the Maricopa County Bureau of Air Pollution Control (MCBAPC) would develop the NOX RACT rules for submittal in January 1994. The rules were to be developed at the same time that the Maricopa Association of Governments (MAG) was conducting UAM for the 1994 attainment demonstration requirements. If the UAM modeling showed that NOX reductions would not contribute to attainment of the ozone standard, then Arizona would petition for a section 182(f) exemption from the NOX RACT requirements. --------------------------------------------------------------------------- General Criteria--Section 182(f) Exemption Requests The NOX RACT petition was submitted in accordance with the EPA guidance document entitled, Guideline for Determining the Applicability of Nitrogen Oxides Requirements Under Section 182(f) issued on December 16, 1993 (exemption guidance). In addition to the exemption guidance, EPA's NOX exemption policy is contained in two memoranda\3\ providing that under section 182(f)(1)(A), an exemption from the NOX requirements may be granted for nonattainment areas outside the ozone transport region (OTR) if EPA determines that additional reductions of NOX would not contribute to attainment of the NAAQS for those areas. EPA's approval of monitoring-based NOX exemptions are granted on a contingent basis and last for only as long as the area's monitoring data continue to demonstrate attainment. As described below, EPA's approval of modeling-based NOX exemptions are also granted on a contingent basis. --------------------------------------------------------------------------- \3\Michael H. Shapiro, Acting Assistant Administrator for Air and Radiation, dated September 17, 1993, entitled ``State Implementation Plan (SIP) Requirements for Areas Submitting Requests for Redesignation to Attainment of the Ozone and Carbon Monoxide (CO) National Ambient Air Quality Standards (NAAQS) on or after November 15, 1992'', and a subsequent revision to this memorandum from John S. Seitz, Director of EPA's Office of Air Quality Planning and Standards, issued on May 27, 1994, entitled, ``Section 182(f) Nitrogen Oxides (NOX) Exemptions--Revised Process and Criteria''. --------------------------------------------------------------------------- EPA's conformity rules4, 5 also reference the section 182(f) exemption process as a means for exempting affected areas from NOX conformity requirements.6 Therefore, ozone nonattainment areas that are granted areawide section 182(f) exemptions under this approach will also be exempt from the NOX general and transportation conformity requirements. --------------------------------------------------------------------------- \4\``Criteria and Procedures for Determining Conformity to State or Federal Implementation Plans or Transportation Plans, Programs, and Projects Funded or Approved under Title 23 U.S.C. of the Federal Transit Act'', November 24, 1993 (58 FR 62188). 5``Determining Conformity of General Federal Actions to State or Federal Implementation Plans; Final Rule'', November 30, 1993 (58 FR 63214). \6\The section 182(f) exemption is explicitly referred to and is described in similar language in 40 CFR 51.394(b)(3)(i), the ``Applicability'' section of the transportation conformity rule, and in the preamble (see 58 FR 62197, November 24, 1993). The language is repeated in the provisions of the rule regarding the motor vehicle emissions budget test [section 51.428(a)(1)(ii)] and the ``build/no-build'' test [sections 51.436(e), 51.438(e)], although section 182(f) of the Act is not specifically mentioned. In the general conformity rule, the section 182(f) NOX exemption is referred to in section 51.852 (definition of ``Precursors of a criteria pollutant'') and is discussed in the preamble (see 58 FR 63240, November 30, 1993). --------------------------------------------------------------------------- The EPA first provided guidance on NOX exemptions in the NOX Supplement. The guidance states that EPA would rescind a NOX exemption in cases where NOX reductions were later found to be beneficial to an area's ability to attain and maintain the ozone NAAQS. That is, a modeling-based exemption would last for only as long as the areas's modeling continues to demonstrate attainment without NOX reductions from major stationary sources. If EPA later determines that NOX reductions are beneficial based on new photochemical grid modeling in an area initially exempted, the area would be removed from exempt status and would be required to implement the NOX requirements, except to the extent modeling shows that the NOX reductions are excess reductions.7 A determination that the NOX exemption no longer applies would mean that the NOX general and transportation conformity provisions would again be applicable (see 58 FR 63214; 58 FR 62188; 59 FR 31238) to the affected area. The NOX requirements would also re-apply, although some reasonable time period after the EPA determination may be provided for sources to meet the RACT limits. EPA expects this time period to be as expeditious as practicable, taking into account any current and applicable State or Federal regulations. --------------------------------------------------------------------------- \7\Section 182(f)(2) states that the application of the new NOX requirements may be limited to the extent necessary to avoid excess reductions of NOX as determined by applying tests similar to the net air quality benefits test, the contribute to attainment test, and the net ozone air quality benefits test. --------------------------------------------------------------------------- The subsequent modeling analyses alluded to above need not be limited to the purpose of demonstrating attainment in the 1994 SIP revisions. For example, future modeling might also be initiated to resolve issues related to transport of ozone and ozone precursors into downwind nonattainment areas. State or local officials might want to consider a strategy that phases in NOX reductions only after certain VOC reductions are implemented. As improved emission inventories and ambient data become available, planning officials may choose to remodel. In addition, alternative control strategy scenarios might be considered in subsequent modeling analyses in order to improve the cost-effectiveness of the attainment plan. EPA's exemption guidance provides that pursuant to the requirements of section 110(a)(2), States should consider evidence, such as photochemical grid modeling, which shows that granting the NOX exemption would interfere with attainment or maintenance in downwind areas. The State of Arizona has not yet implemented NOX RACT, and at the time of this notice, EPA has not received evidence from the Phoenix Area or any downwind areas that shows that granting the NOX exemption for the Phoenix Area would interfere with attainment or maintenance in downwind areas. Exemption Modeling Requirements The policy documents cited above which contain guidance on the petition requirements state that the modeling performed for the petition should follow the Guideline on Regulatory Application of the Urban Airshed Model, EPA-450/91-013, July 1991, (UAM guideline). The UAM guideline describes procedures for the appropriate use of UAM, such as for attainment demonstrations required of all ozone nonattainment areas. Section 182(f) of the CAA recognizes that although VOC and NOX emissions are both precursors to ozone, in certain circumstances the reduction of NOX emissions can actually increase ozone concentrations. This occurs because two competing groups of chemical reactions are affected by NOX. NOX emissions reduction reduces one of the basic materials needed for ozone production, but it also enhances the formation of hydrocarbon radicals, thus increasing another basic ozone ingredient. Which effect dominates, if any, depends on the ratio of VOC to NOX in the atmosphere, temperature, and other factors. The atmosphere is said to be ``NOX-limited'' if NOX reductions decrease peak ozone concentrations, and ``VOC- limited'' if NOX reductions increase peak ozone concentrations. UAM can simulate ozone photochemistry to determine the effects of VOC and NOX emission reductions on ozone. Therefore, if these simulations demonstrate that NOX emission reductions are of no benefit or are counter-productive, then an exemption under section 182(f) would apply. The NOX exemption guidance sets forth two possible tests for showing that NOX emission reductions are of no benefit or are counter-productive to ozone attainment for areas outside the OTR. The petition must show that one or both of these tests is/are passed. (i) Net air quality benefit: Show that the required NOX reductions from the potential exempted sources are counter-productive for overall air quality, primarily considering the modeled effect on the number of ozone NAAQS exceedances. Also considered are welfare, visibility, toxic pollutants, the effect on secondary PM10 formation, etc. This must include UAM modeling reflecting an area's submitted ozone attainment demonstration, with adopted control measures. (ii) Contribute to attainment: This test uses UAM modeling to show that substantial reductions of VOC emissions result in lower ozone levels than substantial reductions of NOX emissions AND combined reductions of VOC and NOX emissions.8 The maximum one-hour ozone concentrations from these three scenarios are then compared. These three UAM simulations need not be tied to an actual attainment demonstration9, but the modeled ``NOX reductions should be as source-specific as possible, rather than across-the-board'' (p.27), and should reflect ``baseline'' NOx reductions that are expected to occur without the exemption. --------------------------------------------------------------------------- \8\``Substantial VOC reduction'' means that required to show attainment, and ``substantial NOx reduction'' means a similar percentage reduction. \9\If an exemption is being requested for only certain NOX sources, then the chosen test is to determine whether just the ``excess emission reductions'' from these sources would be counter- productive; in this case, the test must be tied to an actual submitted attainment demonstration. The UAM guideline describes procedures for applying UAM, such as choosing ozone episodes and the geographical domain to model, setting emissions and meteorological inputs, setting boundary conditions to the model, and evaluating the model's performance. The reliance of the NOX exemption guidance on the UAM guideline is intended to ensure that the model is used in a scientifically appropriate manner. Portions of the UAM guideline that are specific to SIP attainment demonstrations may not always be applicable to modeling used specifically for NOX exemptions. Description of Submitted Petition The petition submitted by the ADEQ first briefly describes the methodology used. Then, citing UAM modeling results of simulations required for the chosen exemption test (the contribute to attainment test), it concludes that the test is passed. In an appendix (Exhibits 1-4), the petition notes revisions to the emission inventory input made after the cited Addenda to the MAG 1993 Ozone Plan for the Maricopa County Area was prepared, and includes descriptions and graphs of UAM modeling performance indicators and concentration results cited in the main text. The contribute to attainment test applied in the petition requires a showing that substantial reductions of VOC yield a lower ozone peak than do reductions of NOX, and of both VOC and NOX. In order to make the modeling as source-specific as possible (required by the exemption guidance), UAM simulations were also performed to examine the effects of possible NOX RACT reductions at specific NOX sources in the Maricopa County nonattainment area. The ozone episodes chosen for modeling were the August 9-10, 1992 episode, which is the base case modeling described in Exhibit 2 (of the petition) in an abbreviated form, and the June 13-14, 1993 episode. The petition notes that there is only a single meteorological regime associated with ozone NAAQS violations in Phoenix, due to stable weather patterns, its ``island'' location which isolates the area from other urban complexes, and its generally even distribution in size and location of NOX emissions throughout the area. The reduction levels chosen for the three 1996 modeled scenarios for each simulation are as follows: Episode 1 (1) A 20% VOC reduction, and a 0% NOX reduction; (2) a 0% VOC reduction, and a 60% NOX reduction; and (3) a 40% reduction of both VOC and NOX. The results of these reduction simulations are described and illustrated in Exhibit 1 of the petition. The ozone peaks are 11.9 parts per hundred million (pphm), 16.5 pphm, and 12.8 pphm, respectively. Since the 11.9 pphm value, corresponding to the VOC-only reduction, is the lowest, the test is passed. Also noted for this scenario is the lowest area covered by high ozone concentrations. Episode 2 (1) A 20% VOC reduction, and a 0% NOX reduction; (2) a 0% VOC reduction, and a 20% NOX reduction; and (3) a 20% reduction of both VOC and NOX. The results of these reduction simulations are described and illustrated in attachment 1 of the Technical Support Document (TSD). The ozone peaks are 11.1 pphm, 14.6 pphm, and 13.0 pphm, respectively. Since the 11.1 pphm value, corresponding to the VOC-only reduction, is the lowest, this test is also passed. The petition also describes modeling of 1996 emissions (including adopted and committed control measures), with and without RACT applied to specific NOX sources (this modeling is explained in attachment 1 of the TSD). Exhibit 1 of the petition states that the total NOX reductions from potential NOX RACT measures for the August episode is 50.6% of the large point source emissions, or 5.4% of the total NOX emissions for the second day of the ozone episode (August 10). These yielded a 0.1 pphm ozone increase. For the June episode, with a 52.5% reduction in elevated point source NOX emissions and a 6.9% reduction in total NOX emissions, the results showed no impact on the maximum simulated concentration. As referred to above, a more detailed discussion of the petition can be found in the Technical Support Document, dated October 1994. Evaluation of Submitted Petition The petition correctly utilizes an appropriate test from the NOX exemption guidance. The ``contribute to attainment'' test is available to nonattainment areas outside an OTR, and need not be tied to an adopted and submitted attainment demonstration. The single meteorological regime and the August 9-10, 1992 and June 13-14, 1993 ozone episodes used in the three required reduction scenarios are described in the modeling protocol used for the Phoenix Area's ozone attainment demonstration due November 15, 1994. For attainment demonstrations, the UAM guideline requires an area with a single regime to model three episodes of that meteorological type. The intent in requiring that the UAM guideline be followed is to ensure that the UAM is utilized in a scientifically appropriate manner and to ensure that multiple meteorological regimes are addressed, if necessary. However, in cases where an area is using intensive data from a field study, a minimum of two episodes is acceptable. This is appropriate where a field study is conducted that provides more comprehensive data for the modeling analysis. The field study was conducted during the summer of 1992 and provided more air quality and meteorological data than is routinely available. Since 1996 is the required attainment year for a moderate ozone nonattainment area, the 1996 year is appropriate for use in the analysis using UAM simulations. The NOX and VOC reduction levels used in the test were ``substantial'' within the meaning of the exemption guidance, and provide a reasonable basis for comparisons of their effect on ozone. The additional simulations of NOX RACT reductions at specific sources meet the exemption guidance requirement that the test be as source-specific as possible, and further substantiate the conclusion that implementation of NOX RACT for major stationary sources would not contribute to attainment. EPA Proposed Action This action proposes to exempt the Phoenix ozone nonattainment area from implementing the NOX RACT requirements and the general and transportation conformity regulations for NOX. It is based on UAM modeling for two episodes in the Phoenix area which demonstrate that NOX reductions do not contribute to attainment. The final action on this proposal will serve as a final determination that the finding of nonsubmittal for the NOX RACT requirements has been corrected and that on the effective date of the final action on this proposal, any Federal Implementation Plan (FIP) clock is stopped. Nothing in this action should be construed as permitting or allowing or establishing a precedent for any future implementation plan. Each request for a section 182(f) exemption shall be considered separately in light of specific technical, economic, and environmental factors and in relation to relevant statutory and regulatory requirements. Regulatory Process The Office of Management and Budget has exempted this regulatory action from Executive Order 12866 review. Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA must prepare a regulatory flexibility analysis assessing the impact of any proposed or final rule on small entities. 5 U.S.C. 603 and 604. Alternatively, EPA may certify that the rule will not have a significant impact on a substantial number of small entities. Small entities include small businesses, small not-for-profit enterprises and government entities with jurisdiction over population of less than 50,000. This exemption action does not create any new requirements, but allows suspension of the indicated requirements for the life of the exemption. Therefore, because the proposed approval does not impose any new requirements, I certify that it does not have a significant impact on any small entities affected. Moreover, due to the nature of the Federal-state relationship under the CAA, preparation of a regulatory flexibility analysis would constitute Federal inquiry into the economic reasonableness of state action. The CAA forbids EPA to base its actions concerning SIPs on such grounds. Union Electric Co. v. U.S. E.P.A., 427 U.S. 246, 256-66 (S. Ct. 1976); 42 U.S.C. 7410 (a)(2). Under section 307(b)(1) of the CAA, petitions for judicial review of this action must be filed in the United States Court of Appeals for the appropriate circuit by December 1, 1994. Filing a petition for reconsideration by the Administrator of this rule does not affect the finality of this rule for the purposes of judicial review nor does it extend the time within which a petition for judicial review may be filed, and shall not postpone the effectiveness of such a rule. This action may not be challenged later in proceedings to enforce its requirements. Section 307(b)(2). List of Subjects in 40 CFR Part 52 Environmental protection, Air pollution control, Hydrocarbons, Intergovernmental relations, Nitrogen dioxide, Ozone, Reporting and recordkeeping requirements, Volatile organic compounds. Dated: October 25, 1994. Carol M. Browner, Administrator. Part 52, chapter I, title 40 of the Code of Federal Regulations is proposed to be amended as follows: PART 52--[AMENDED] 1. The authority citation for part 52 continues to read as follows: Authority: 42 U.S.C. 7401-7671q. Subpart D--Arizona 2. Subpart D is proposed to be amended by adding Sec. 52.235 to read as follows: Sec. 52.235 Control strategy for ozone: Oxides of nitrogen. EPA is approving an exemption request submitted by the State of Arizona on April 13, 1994 for the Maricopa County ozone nonattainment area from the NOX RACT requirements contained in section 182(f) of the Clean Air Act. This approval exempts the area from implementing reasonably available control technology (RACT) for major stationary sources of nitrogen oxides (NOX) and the NOX related requirements of general and transportation conformity regulations. The exemption is based on Urban Airshed Modeling as would last for only as long as the area's modeling continues to demonstrate attainment without NOX reductions from major stationary sources. [FR Doc. 94-27018 Filed 10-31-94; 8:45 am] BILLING CODE 6560-50-P --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-27018. Public record. Not legal advice.