South Coast Air Quality Manage v. EPA , 882 F.3d 1138 ( 2018 )


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  •  United States Court of Appeals
    FOR THE DISTRICT OF COLUMBIA CIRCUIT
    Argued September 14, 2017         Decided February 16, 2018
    No. 15-1115
    SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT,
    PETITIONER
    v.
    ENVIRONMENTAL PROTECTION AGENCY, ET AL.,
    RESPONDENTS
    NATIONAL ENVIRONMENTAL DEVELOPMENT ASSOCIATION'S
    CLEAN AIR PROJECT, ET AL.,
    INTERVENORS
    Consolidated with 15-1123
    On Petitions for Review of a Final Action
    of the Environmental Protection Agency
    Megan E. Lorenz Angarita argued the cause for petitioner
    South Coast Air Quality Management District. With her on the
    briefs were Kurt R. Wiese and Barbara Baird.
    2
    Seth L. Johnson argued the cause for Environmental
    Petitioners. With him on the briefs was David S. Baron.
    Kelvin J. Dowd and Andrew B. Kolesar III were on the
    brief for amicus curiae Ventura County Air Pollution Control
    District in support of petitioner South Coast Air Quality
    Management District.
    Heather E. Gange, Trial Attorney, U.S. Department of
    Justice, argued the cause for respondents. With her on the brief
    was John C. Cruden, Assistant Attorney General at the time the
    brief was filed.
    Seth L. Johnson argued the cause for Environmental
    Movant-Intervenors. With him on the brief was David S.
    Baron.
    Megan E. Lorenz Angarita, Kurt R. Wiese, and Barbara
    Baird were on the brief for amicus curiae South Coast Air
    Quality Management District in support of respondent’s
    opposition to Sierra Club’s argument regarding reasonably
    available control technology in Case No. 15-1123.
    Leslie Sue Ritts was on the brief for intervenor for
    respondent    National     Environmental   Development
    Association's Clean Air Project in support of U.S.
    Environmental Protection Agency.
    Before: GARLAND, Chief Judge, ROGERS, Circuit Judge,
    and SENTELLE, Senior Circuit Judge.
    Opinion for the Court filed by Senior Circuit Judge
    SENTELLE.
    3
    SENTELLE, Senior Circuit Judge: In this consolidated
    proceeding, we consider petitions for review of an
    Environmental Protection Agency (“EPA”) final rule entitled
    “Implementation of the 2008 National Ambient Air Quality
    Standards for Ozone: State Implementation Plan Review
    Requirements,” 80 Fed. Reg. 12,264 (Mar. 6, 2015). In Case
    No. 15-1115, petitioner South Coast Air Quality Management
    District (“South Coast”) contends that the EPA incorrectly
    concluded that precedent of this Court requires emissions
    reductions that demonstrate reasonable further progress all
    come from within the nonattainment area. In Case No. 15-
    1123, petitioners Sierra Club, Conservation Law Foundation,
    Downwinders at Risk, and Physicians for Social Responsibility
    (Los Angeles) (“Environmental Petitioners”) contend that in
    enacting the Final Rule, the EPA acted arbitrarily and
    capriciously in its revocation of 1997 National Ambient Air
    Quality Standards and relaxation of previously applicable
    requirements under the Clean Air Act.
    For the reasons stated below, we deny South Coast’s
    petition for review, and grant in part and deny in part that of
    the Environmental Petitioners.
    I.      BACKGROUND
    A. The Clean Air Act Framework
    The Clean Air Act (“CAA” or “Act”) directs the EPA to
    set National Ambient Air Quality Standards (“NAAQS”) for
    air pollutants “allowing an adequate margin of safety . . .
    requisite to protect the public health.” 42 U.S.C. § 7409(b)(1).
    The CAA also requires the EPA to establish air quality control
    regions and designate them as “attainment” for “any area . . .
    that meets” the NAAQS, “nonattainment” for “any area that
    does not meet” the NAAQS, and “unclassifiable” for “any area
    4
    that cannot be classified on the basis of available information.”
    § 7407(d)(1)(A).
    The EPA must classify each area “designated
    nonattainment for ozone” as “marginal,” “moderate,”
    “serious,” “severe,” or “extreme” based on the degree to which
    the ozone level in the area exceeds the NAAQS. § 7511. “An
    area that exceeds the NAAQS by a greater margin is given
    more time to meet the standard but is subjected to progressively
    more stringent emissions controls for ozone precursors,
    namely, volatile organic compounds (VOCs) and oxides of
    nitrogen (NOx).” Natural Res. Def. Council v. EPA (NRDC
    2009), 
    571 F.3d 1245
    , 1250 (D.C. Cir. 2009).
    The Act places on the states “the primary responsibility for
    assuring air quality” by submitting state implementation plans
    (“SIPs”) that specify how they will achieve and maintain
    compliance with the NAAQS. 42 U.S.C. § 7407(a). States
    must formally adopt SIPs through state notice and comment
    rulemaking and then submit the SIPs to the EPA for approval.
    § 7410(a). For those areas designated as “nonattainment,” SIPs
    must show how the areas will achieve and maintain the relevant
    NAAQS. 
    Id. A nonattainment
    area may be redesignated to attainment if
    the EPA (1) has determined that the area has attained the
    applicable NAAQS; (2) has fully approved the applicable SIP
    under § 7410(k); (3) has determined that the attainment is due
    to permanent and enforceable emissions reductions; (4) has
    fully approved a § 7505a “maintenance plan,” which
    demonstrates that the area will maintain the NAAQS for at least
    10 years after the redesignation, see § 7505a(a); and (5) has
    determined that the state containing the area seeking
    redesignation has met all applicable SIP requirements.
    5
    § 7407(d)(3)(E). Areas redesignated as attainment are referred
    to as “maintenance areas.”
    B. SIPs for Nonattainment Areas
    As is relevant to this case, the Clean Air Act requires SIPs
    for nonattainment areas to include the following provisions:
    1. Reasonable Further Progress
    SIPs for nonattainment areas “shall require reasonable
    further progress.” § 7502(c)(2). “Reasonable further progress”
    is defined as “such annual incremental reductions in emissions
    of the relevant air pollutants as are required by this part or may
    reasonably be required by [the EPA] for the purpose of
    ensuring attainment of the applicable [NAAQS] by the
    applicable date.” § 7501(1). The Clean Air Act requires an
    area in a moderate or greater degree of nonattainment to reduce
    emissions of VOCs by fifteen percent in the first six years after
    November 15, 1990. § 7511a(b)(1)(A). For areas in a serious
    or greater degree of nonattainment, subsequent reductions in
    VOC emissions must average three percent per year over each
    consecutive three-year period until the area reaches attainment.
    § 7511a(c)(2)(B).
    2. Reasonably Available Control
    Technology
    SIPs for ozone nonattainment areas must also “provide for
    the implementation of all reasonably available control
    measures as expeditiously as practicable (including such
    reductions in emissions from existing sources in the area as
    may be obtained through the adoption, at a minimum, of
    reasonably available control technology).” § 7502(c)(1). For
    nonattainment areas classified as moderate and above, SIPs
    6
    must “require the implementation of reasonably available
    control technology” with respect to all major sources of VOCs
    in the area and any sources that emit VOCs in the area that are
    covered by a control technique guideline. § 7511a(b)(2). The
    reasonably available control technology requirement also
    applies to major sources of NOx. § 7511a(f).
    3. New Source Review
    SIPs governing nonattainment areas must require permits
    for the construction of new or modified sources of air pollution.
    §§ 7502(c)(5), 7503, 7410(a)(2)(C). The goal of New Source
    Review is to require permits to ensure that new or modified
    sources will not exacerbate the pollution problem in the
    nonattainment area. § 7503(a)(1)(A), (a)(2), (c). New Source
    permits for major sources of VOCs require the proposed source
    (1) to comply with the lowest achievable emissions rate and
    (2) to obtain pollution offsets representing equal or greater
    reductions of a pollutant at issue in the area. 
    Id. 4. Conformity
    The Act mandates that nonattainment and maintenance
    areas are subject to “conformity requirements,” so that “[n]o
    department, agency, or instrumentality of the Federal
    Government shall engage in, support in any way or provide
    financial assistance for, license or permit, or approve, any
    activity which does not conform to an implementation plan.”
    § 7506(c)(1), (5). Federally funded projects must “conform”
    to SIPs, meaning that the projects will not “cause or contribute
    to any new violation,” “increase the frequency or severity of
    any existing violation,” or “delay timely attainment of any
    standard or any required interim emission reductions or other
    milestones in any area.” § 7506(c)(1)(B). These areas are also
    subject to the more specific transportation conformity
    7
    requirements, whereby federal agencies may not “approve,
    accept or fund any transportation plan, program or project
    unless” it conforms to an applicable SIP. § 7506(c)(2). With
    respect to transportation conformity requirements, the EPA is
    responsible for promulgating, and periodically updating,
    “criteria and procedures for demonstrating and assuring
    conformity in the case of transportation plans, programs, and
    projects.” § 7506(c)(4)(B).
    5. Contingency Measures
    SIPs must include contingency measures that take effect
    automatically “if the area fails to make reasonable further
    progress, or to attain the [NAAQS] by the attainment date.”
    §§ 7502(c)(9), 7511a(c)(9).
    C. Anti-Backsliding Measures for Revoked NAAQS
    The Clean Air Act requires the EPA to “complete a
    thorough review” of each NAAQS every five years and “make
    such revisions . . . and promulgate such new standards as may
    be appropriate.” § 7409(d)(1). In promulgating new standards,
    if the EPA relaxes a NAAQS, it shall promulgate anti-
    backsliding measures for all areas that have not attained that
    standard as of the date of the relaxation. § 7502(e). The anti-
    backsliding measures “shall provide for controls which are not
    less stringent than the controls applicable to areas designated
    nonattainment before such relaxation.” 
    Id. D. Ozone
    NAAQS
    In 1979, the EPA promulgated the first ozone NAAQS
    based on a one-hour average concentration of 0.12 parts per
    million (ppm). Revisions to the NAAQS for Photochemical
    Oxidants, 44 Fed. Reg. 8202, 8202 (Feb. 8, 1979). In 1997,
    8
    after determining that the one-hour NAAQS was inadequate to
    protect public health, the EPA promulgated a new NAAQS
    based on an eight-hour average of 0.08 ppm. NAAQS for
    Ozone, 62 Fed. Reg. 38,856, 38,858 (July 18, 1997). Although
    the EPA replaced the one-hour NAAQS with an eight-hour
    NAAQS, it determined that it would continue to enforce the
    one-hour NAAQS until “an area has attained air quality that
    meets the 1-hour standard.” Implementation of Revised Air
    Quality Standards for Ozone and Particulate Matter, 62 Fed.
    Reg. 38,421, 38,424 (July 18, 1997). In a 2004 rule, the EPA
    revoked the one-hour NAAQS effective June 15, 2005. Final
    Rule to Implement the 8-Hour Ozone NAAQS—Phase 1, 69
    Fed. Reg. 23,951, 23,951 (Apr. 30, 2004). This Court held that
    the EPA has the “authority to revoke the one-hour standard so
    long as adequate anti-backsliding provisions are introduced.”
    South Coast Air Quality Mgmt. Dist. v. EPA, 
    472 F.3d 882
    , 899
    (D.C. Cir. 2006), clarified on denial of reh’g, 
    489 F.3d 1245
    (D.C. Cir. 2007).
    In 2008, the EPA determined that the 1997 NAAQS was
    inadequate to protect public health. The EPA therefore
    promulgated a new NAAQS of 0.075 ppm of ozone averaged
    over eight hours. NAAQS for Ozone, 73 Fed. Reg. 16,436,
    16,436 (Mar. 27, 2008). “The 2008 ozone NAAQS retains the
    same general form and averaging time as the 0.08 ppm
    NAAQS set in 1997, but is set at a more stringent level.”
    Implementation of the 2008 NAAQS for Ozone: State
    Implementation Plan Requirements, 80 Fed. Reg. 12,264,
    12,265 (Mar. 6, 2015).
    E. The Final Rule
    On March 6, 2015, the EPA finalized a rule that “revises
    existing regulations and guidance as appropriate to aid in the
    implementation of the 2008 ozone NAAQS.” 80 Fed. Reg. at
    9
    12,265. As part of the Final Rule, the EPA revoked the 1997
    NAAQS “for all purposes and establish[ed] anti-backsliding
    requirements for areas that remain designated nonattainment
    for the revoked NAAQS.” 
    Id. II. STANDARD
    OF REVIEW
    We will not set aside EPA action under the Clean Air Act
    unless we determine that such action is “arbitrary, capricious,
    an abuse of discretion, or otherwise not in accordance with
    law.” 42 U.S.C. § 7607(d)(9)(A). The EPA’s interpretation of
    the Clean Air Act is reviewed under the familiar two-step
    framework of Chevron U.S.A., Inc. v. Natural Resources
    Defense Council, Inc., 
    467 U.S. 837
    (1984), whereby we first
    look to the statute’s language to determine if Congress has
    “directly spoken to the precise question at issue.” 
    Id. at 842.
    If Congress has directly spoken to the precise question, then we
    must “give effect to the unambiguously expressed intent of
    Congress.” 
    Id. at 843.
    If, however, “the statute is silent or
    ambiguous with respect to the specific issue,” we defer to the
    EPA’s interpretation of the Act so long as it “is based on a
    permissible construction of the statute.” 
    Id. Under those
    standards, we review in turn the cross-
    petitions of South Coast and the Environmental Petitioners.
    III. SOUTH COAST’S PETITION
    We begin with the simpler of the two petitions, that of
    South Coast. South Coast petitions this Court to invalidate the
    EPA’s interpretation of the CAA in the Final Rule that “states
    may not take credit for VOC or NOx reductions occurring from
    sources outside the nonattainment area for purposes of meeting
    the 15 percent [rate-of-progress] and 3 percent [reasonable
    further progress] requirements.” 80 Fed. Reg. at 12,273. South
    10
    Coast argues that the EPA was not required to interpret “in the
    area” in the context of the reasonable further progress
    requirement to mean “in the nonattainment area.” See 42
    U.S.C. § 7511a(b)(1)(B). In promulgating the Final Rule, the
    EPA explained that in light of this Court’s decision in NRDC
    
    2009, 571 F.3d at 1256
    , “there is no legal basis” for “allowing
    states to credit reductions achieved at sources outside the
    nonattainment area.” 80 Fed. Reg. at 12,273. South Coast
    counters that our decision in NRDC 2009 does not mandate the
    EPA’s interpretation. Instead, South Coast contends that
    because downwind nonattainment areas are impacted by
    emissions from upwind areas, the EPA could reasonably
    interpret “in the area” in the context of the reasonable further
    progress requirement to mean the “transport couple area”—“a
    larger area consisting of the nonattainment area in question
    plus the upwind area from which emission reductions would be
    obtained.”
    The text here is unambiguous. The Clean Air Act requires
    nonattainment areas that are classified as moderate or above to
    plan for “reasonable further progress” measured from “baseline
    emissions,” which are defined as “the total amount of actual
    VOC or NOx emissions from all anthropogenic sources in the
    area during the” baseline year. 42 U.S.C. § 7511a(b)(1)(A),
    (b)(1)(B), (c)(2)(B), (d), (e). These statutory provisions refer
    to only one area, “the area.” Further, the term appears in a
    section entitled “Moderate Areas,” not a greater area.
    § 7511a(b); see also § 7511(c)(1).
    South Coast contends that limiting the phrase “in the area”
    to nonattainment areas would produce absurd results.
    According to South Coast, it may be impossible for certain
    areas to achieve the necessary emissions reductions. Where the
    purpose of the Clean Air Act is served by interpreting “in the
    11
    area” to mean “transport couple area,” South Coast argues that
    the statutory language is ambiguous.
    However, the Clean Air Act provides for an alternative to
    reducing emissions of pollutants by fixed percentages.
    § 7511a(b)(1)(A)(ii), (c)(2)(B). Nonattainment areas may
    reduce emissions by less than 15 percent if they (1) implement
    controls on a broader range of new and existing stationary
    sources and (2) include in their SIP “all measures that can
    feasibly be implemented in the area, in light of technological
    achievability” and “measures that are achieved in practice by
    sources in the same source category in nonattainment areas of
    the next higher category.” § 7511a(b)(1)(A)(ii). Likewise,
    nonattainment areas may reduce emissions by less than three
    percent if the SIP “includes all measures that can feasibly be
    implemented in the area, in light of technological
    achievability” and “measures that are achieved in practice by
    sources in the same source category in nonattainment areas of
    the next higher classification.”          § 7511a(c)(2)(B)(ii).
    Moreover, states may also ask the EPA to approve new
    boundaries for air quality control regions. See 42 U.S.C.
    § 7407(b)-(c). In light of the alternatives provided for in the
    Clean Air Act, South Coast has failed to meet the
    “exceptionally high burden” required to demonstrate absurdity.
    Friends of Earth, Inc. v. EPA, 
    446 F.3d 140
    , 146 (D.C. Cir.
    2006).
    In sum, considering the grammar and context of
    § 7511a(b)(1)(B), we hold at Chevron step one that “in the
    area” unambiguously refers to baseline emissions within the
    nonattainment area. Accordingly, we deny South Coast’s
    petition.
    12
    IV.     ENVIRONMENTAL PETITIONERS’
    PETITION
    Environmental Petitioners petition this Court to vacate
    several parts of the Final Rule. We take each challenge in turn.
    A. Waiver of Statutory Attainment                 Deadlines
    Associated with the 1997 NAAQS
    Environmental Petitioners seek to invalidate the Final
    Rule’s revocation of the 1997 NAAQS. 80 Fed. Reg. at 12,296.
    They argue that by revoking the 1997 NAAQS, the Final Rule
    arbitrarily waives the obligation to attain the 1997 NAAQS by
    the statutory deadline. The EPA counters that the Clean Air
    Act authorizes revocation of a superseded NAAQS so long as
    adequate anti-backsliding measures are in place.
    We have already held that the EPA may revoke a previous
    NAAQS in full “so long as adequate anti-backsliding
    provisions are introduced.” South 
    Coast, 472 F.3d at 899
    . But
    in the Final Rule, the EPA failed to introduce adequate anti-
    backsliding provisions.
    Pursuant to the Clean Air Act, anti-backsliding provisions
    “shall provide for controls which are not less stringent than the
    controls applicable to areas designated nonattainment before
    such relaxation.” 42 U.S.C. § 7502(e). Penalties for not
    meeting attainment deadlines such as fees and activation of
    contingency measures are unambiguously “controls” because
    they are “designed to constrain ozone pollution.” South 
    Coast, 472 F.3d at 902-03
    . Likewise, reclassification is also a control
    because it is “designed to constrain ozone pollution.” See 
    id. Areas that
    fail to timely attain are required to reclassify and be
    subject to more stringent emissions controls. 42 U.S.C.
    §§ 7511(b)(2), 7511a(i). If the EPA were allowed to remove
    13
    the deadlines that trigger those penalties, “a state could go
    unpenalized without ever attaining” the NAAQS. South 
    Coast, 472 F.3d at 902-03
    .
    The Final Rule provides that “the EPA is required to
    determine whether an area attained the 1-hour or 1997 ozone
    NAAQS by the area’s attainment date solely for anti-
    backsliding purposes to address an applicable requirement for
    nonattainment contingency measures and CAA section 185 fee
    programs.” 80 Fed. Reg. at 12,315. But the Final Rule
    specifically waives the obligation “to reclassify an area to a
    higher classification for the 1997 ozone NAAQS” based on a
    failure to meet the 1997 NAAQS attainment deadlines. 
    Id. As a
    result, the Final Rule allows areas that fail to timely attain to
    avoid being subject to more stringent emissions controls.
    Therefore, the Final Rule relaxed the controls applicable to
    areas designated nonattainment under the 1997 NAAQS in
    contravention of the anti-backsliding requirement.
    Accordingly, we grant this part of Environmental Petitioners’
    petition and vacate the Final Rule as to the waived statutory
    attainment deadlines associated with the 1997 NAAQS.
    B.      Removal of Anti-Backsliding Requirements
    for Areas Designated Nonattainment Under
    the 1997 NAAQS
    Environmental Petitioners also seek to invalidate other
    provisions of the Final Rule that they allege contravene the
    Clean Air Act’s anti-backsliding requirements. The Final Rule
    provides for three procedures by which areas designated
    nonattainment under the 1997 NAAQS may remove certain
    anti-backsliding requirements and shift other requirements
    from the active portion of their SIPs to the contingency
    measures portion. 80 Fed. Reg. at 12,299-12,304.
    14
    1.   Orphan Nonattainment Areas
    The first procedure applies to areas designated attainment
    for the 2008 NAAQS, but nonattainment for the 1997 NAAQS.
    
    Id. at 12,301-12,302.
    Environmental Petitioners refer to these
    areas as “orphan nonattainment areas.”             For orphan
    nonattainment areas, “states are not required to adopt any
    outstanding applicable requirements for the revoked 1997
    standard.” 
    Id. at 12,302.
    Under the Final Rule, orphan
    nonattainment areas “are not subject to transportation or
    general conformity requirements.” 
    Id. at 12,300.
    In addition,
    orphan nonattainment areas are no longer required to retain
    New Source Review programs in their SIPs. 
    Id. at 12,299.
    Instead, these areas are subject to Prevention of Significant
    Deterioration (“PSD”) requirements. 
    Id. States may
    also
    request that other anti-backsliding requirements be shifted to
    their list of contingency measures based on initial 2008
    designations. 
    Id. at 12,314.
    Finally, the Final Rule does not
    require orphan nonattainment areas to submit maintenance
    plans under § 7505a, and deems the requirement for
    maintenance under § 7410(a)(1) to be satisfied by the area’s
    approved Prevention of Significant Deterioration SIP. 
    Id. at 12,302,
    12,314.
    (a) Environmental Petitioners argue that elimination of
    New Source Review and conformity in orphan nonattainment
    areas violates the anti-backsliding requirements. The EPA
    argues that the Final Rule lawfully lifts the requirement for
    New Source Review and conformity for orphan nonattainment
    areas because the 2008 NAAQS is more stringent than the 1997
    NAAQS. According to the EPA, areas that have attained the
    2008 NAAQS have necessarily attained the 1997 NAAQS.
    This Court previously held that New Source Review is
    unambiguously a “control” under § 7502(e). South Coast, 
    472 15 F.3d at 901-02
    . Environmental Petitioners also contend that
    conformity is a “control” under § 7502(e). The EPA does not
    address general conformity requirements, but argues that our
    decision in South Coast does not require transportation
    conformity as an anti-backsliding control. According to the
    EPA, in South Coast we held that only existing motor vehicle
    emissions budgets are required anti-backsliding controls, not
    the conformity requirement itself.
    The Final Rule provides that 1997 nonattainment areas are
    “no longer . . . required to demonstrate transportation
    conformity for the 1997” NAAQS after the 1997 NAAQS is
    revoked. 80 Fed. Reg. at 12,284. Pursuant to the Final Rule,
    “the latest approved or adequate emission budgets for a
    previous ozone NAAQS . . . would continue to be used in
    conformity determinations for the 2008 ozone NAAQS until
    emission budgets are established and found adequate or are
    approved for the 2008 ozone NAAQS.” 
    Id. But the
    Final Rule
    provides that areas “designated attainment for the 2008 ozone
    NAAQS are not subject to transportation or general conformity
    requirements regardless of their designation for the 1997 ozone
    NAAQS at the time of revocation of that NAAQS.” 
    Id. at 12,300.
    The EPA is correct that South Coast held only that “one-
    hour conformity emissions budgets constitute ‘controls’ under
    section 
    172(e).” 472 F.3d at 904
    . Furthermore, on rehearing,
    we clarified that our decision with respect to conformity
    determinations “speaks only to the use of one-hour motor
    vehicle emissions budgets as part of eight-hour conformity
    determinations until eight-hour motor vehicle emissions
    budgets are available.” South Coast Air Quality Mgmt. Dist. v.
    EPA, 
    489 F.3d 1245
    , 1248 (D.C. Cir. 2007). But our decision
    that emissions budgets constitute controls does not preclude
    that “conformity” requirements in general are controls.
    16
    Conformity requirements are designed to constrain ozone
    pollution as they have the “purpose of eliminating or reducing
    the severity and number of violations of the [NAAQS] and
    achieving expeditious attainment of such standards.” 42
    U.S.C. § 7506(c)(1)(A). Therefore, conformity requirements
    also are unambiguously “controls” under § 7502(e).
    Although orphan nonattainment areas were originally
    designated attainment under the 2008 NAAQS, they have
    never been redesignated to attainment pursuant to
    § 7407(d)(3)(E) under the 1997 NAAQS. The EPA may not
    permit termination of New Source Review and conformity in
    the absence of formal redesignation under § 7407(d)(3)(E).
    See Natural Res. Def. Council v. EPA, 
    643 F.3d 311
    , 322-23
    (D.C. Cir. 2011) (rejecting final rule that allowed attainment of
    the 1997 NAAQS to permit termination of the fees control for
    the one-hour NAAQS). As we stated in our prior South Coast
    opinion, “EPA is required by statute to keep in place measures
    intended to constrain ozone levels—even the ones that apply to
    outdated standards—in order to prevent backsliding.” South
    
    Coast, 472 F.3d at 905
    . Accordingly, we grant Environmental
    Petitioners’ petition and vacate the Final Rule as to the removal
    of New Source Review and conformity controls from orphan
    nonattainment areas.
    (b) Environmental Petitioners argue that permitting states
    to shift other anti-backsliding requirements to contingency
    measures violates the Clean Air Act. The EPA responds that
    states must continue implementing all such measures in
    previously approved SIPs unless the EPA approves requests to
    amend SIPs to convert such requirements into contingency
    measures. For the same reasons that the EPA may not permit
    states to eliminate New Source Review and transportation
    conformity, the EPA also may not permit states to shift other
    anti-backsliding requirements to their list of contingency
    17
    measures without complying with the statutory requirements
    for redesignation.      Therefore, we grant Environmental
    Petitioners’ petition and vacate the Final Rule as to permitting
    states to move anti-backsliding requirements for orphan
    nonattainment areas to their list of contingency measures based
    on initial 2008 designations.
    (c) Likewise, without requiring nonattainment areas to
    meet the requirements for reattainment under § 7407(d)(3)(E),
    the EPA improperly waived the requirement that states adopt
    outstanding applicable requirements for the revoked 1997
    NAAQS. Therefore, we grant Environmental Petitioners’
    petition and vacate the Final Rule as to waiving the requirement
    that states adopt outstanding applicable requirements for the
    revoked 1997 NAAQS.
    (d) Environmental Petitioners argue that the Final Rule
    impermissibly waives the maintenance requirements under
    § 7410(a)(1) for orphan nonattainment areas. The Final Rule
    allows approved Prevention of Significant Deterioration SIPs
    to satisfy the obligation to submit a maintenance plan under
    § 7410(a)(1). 80 Fed. Reg. at 12,302. Prevention of
    Significant Deterioration SIPs bar the construction of major
    sources of emissions without compliance with certain statutory
    requirements. See § 7475(a).
    The Final Rule also does not require orphan nonattainment
    areas to submit a maintenance plan under § 7505a. 80 Fed.
    Reg. at 12,302. The EPA contends that there is no statutory
    requirement for a separate maintenance plan for orphan
    nonattainment areas. However, one of the five requirements
    for redesignation under § 7407(d)(3)(E) is that the EPA
    “approve[] a maintenance plan for the area as meeting the
    requirements    of    section     7505a     of   this   title.”
    § 7407(d)(3)(E)(iv). Therefore, the Final Rule is inconsistent
    18
    with the clear text of § 7407(d)(3)(E) in waiving the § 7505a(a)
    maintenance plan requirement for orphan nonattainment areas.
    Environmental Petitioners also appear to contend that even
    with a § 7505a maintenance plan, the Final Rule would violate
    the maintenance requirement under § 7410(a)(1) because
    § 7410(a)(1) requires something more than a Prevention of
    Significant Deterioration SIP and a § 7505a maintenance plan.
    Specifically, Environmental Petitioners argue that a SIP for an
    orphan nonattainment area must include a plan to ensure that
    pollution from existing sources and new sources not subject to
    the PSD requirements does not cause those areas to fall into
    violation of the 2008 NAAQS. According to Environmental
    Petitioners, without such safeguards, existing measures have
    proved insufficient to provide for continuing attainment of the
    2008 NAAQS.
    Section 7410(a)(1) provides that SIPs must provide for
    “implementation, maintenance, and enforcement” of the
    NAAQS.         The statute clearly requires “maintenance”
    provisions to be included in SIPs, but the statute does not
    require a separate SIP component entitled “maintenance plan.”
    In fact, the statute provides no guidance for what SIPs must
    include in order to comply with the § 7410(a)(1) maintenance
    requirement beyond the criteria laid out in § 7410(a)(2).
    Environmental Petitioners do not allege the agency has
    eliminated § 7410(a)(2)’s requirements. Therefore, the Final
    Rule will be upheld so long as it is neither unreasonable nor
    arbitrary.
    The EPA justified the rule by explaining that a § 7471
    “PSD SIP, in conjunction with the other already-existing
    statutory and regulatory provisions . . . are generally sufficient
    to prevent backsliding, and to satisfy the requirement for
    maintenance under” § 7410(a)(1). 80 Fed. Reg. at 12,302.
    19
    According to the EPA, the “control measures implemented by
    these areas and included in their SIPs have already produced
    sufficient emissions reductions to achieve air quality that
    attained the 1997 ozone NAAQS, and resulted in an attainment
    designation for the more stringent 2008 ozone NAAQS.” 
    Id. The EPA
    therefore concluded that “the burden of developing
    an approvable [§ 7410(a)(1)] maintenance plan for the 2008
    ozone NAAQS would outweigh any compensating benefit for
    an area that is already attaining that NAAQS and that is subject
    to prior nonattainment requirements which are already
    incorporated into the SIP and have been sufficient to bring the
    area into attainment of both the 1997 and 2008 standards.” 
    Id. The EPA
    adequately explained why measures that
    achieved attainment of both the 1997 NAAQS and the 2008
    NAAQS should be adequate to maintain the same 2008
    NAAQS that has already been attained. The EPA also
    thoughtfully responded to comments that suggested the
    measures on which the EPA relies are insufficient to satisfy the
    § 7410(a)(1) maintenance requirement.           Under these
    circumstances, the EPA’s determination is neither
    unreasonable nor arbitrary.
    Environmental Petitioners contend that the EPA has not
    addressed comments that identified examples of orphan
    nonattainment areas that purportedly were in fact not attaining
    the 2008 NAAQS. These comments were not raised in regard
    to the § 7410(a)(1) maintenance requirement. Instead, they
    appear to have been raised in response to other alleged
    shortcomings with the proposed rule. Moreover, the EPA
    appears to have addressed those arguments in its response to
    comments. Response to Comments on Implementation of the
    2008 NAAQS for Ozone: SIP Requirements (Feb. 13, 2015) at
    133. In any event, the comments are directed toward
    enforcement issues with the current NAAQS, not issues with
    20
    the underlying rule. Accordingly, the EPA’s decision not to
    implement a separate § 7410(a) maintenance plan is neither
    arbitrary nor unreasonable.
    Therefore, we grant Environmental Petitioners’ petition
    and vacate the Final Rule with respect to the EPA’s waiving of
    the § 7505a(a) maintenance plan requirement for orphan
    nonattainment areas, and we deny Environmental Petitioners’
    petition with respect to the § 7410(a)(1) maintenance
    requirement’s application to orphan nonattainment areas in
    other respects.
    2.   Formal Redesignation
    The second procedure by which areas designated
    nonattainment under the 1997 NAAQS may remove certain
    anti-backsliding requirements and shift other requirements
    from the active part of their SIPs to the contingency measures
    part involves areas designated nonattainment under both the
    2008 NAAQS and the 1997 NAAQS. 80 Fed. Reg. at 12,303-
    04. The Final Rule allows states to seek formal redesignation
    to attainment based on the 2008 NAAQS with an approved
    maintenance plan that addresses the current and revoked
    NAAQS. 
    Id. at 12,304.
    Under this procedure, states may
    terminate and remove any applicable anti-backsliding
    requirements, including New Source Review requirements,
    from the active part of their SIPs. 
    Id. The EPA
    properly subjected these areas to anti-
    backsliding requirements when the 1997 NAAQS was revoked
    because they were still in nonattainment at the time of
    revocation. See § 7502(e). The Act is ambiguous as to whether
    such areas must retain these anti-backsliding requirements after
    they are successfully redesignated as attainment areas under the
    2008 NAAQS. Unlike orphan nonattainment areas, these areas
    21
    have met the statutory requirements for redesignation under
    § 7407(d)(3)(E). Therefore, these areas have shown, for
    example, that “the[ir] improvement in air quality is due to
    permanent and enforceable reductions in emissions resulting
    from implementation of the applicable implementation plan.”
    § 7407(d)(3)(E)(iii). Although these areas may not have been
    redesignated with respect to the 1997 NAAQS, by meeting the
    statutory requirements for redesignation with respect to the
    2008 NAAQS, they necessarily also meet the less restrictive
    requirements for redesignation under the 1997 NAAQS.
    Accordingly, it is reasonable for these areas to shed their anti-
    backsliding controls by virtue of meeting the five statutory
    criteria for redesignation. Therefore, we deny Environmental
    Petitioners’ petition with respect to this aspect of the Final
    Rule.
    3.   Redesignation Substitute
    The third procedure by which areas designated
    nonattainment under the 1997 NAAQS may remove certain
    anti-backsliding requirements and shift other requirements
    from the active part of their SIPs to the contingency measures
    part also involves areas designated nonattainment under both
    the 2008 NAAQS and the 1997 NAAQS. This procedure
    allows states “to submit a redesignation substitute request for a
    revoked NAAQS.” 80 Fed. Reg. at 12,304. The redesignation
    substitute request “is based on” the Clean Air Act’s “criteria
    for redesignation to attainment” under § 7407(d)(3)(E), 80 Fed.
    Reg. at 12,305, but it does not require full compliance with all
    five conditions in § 7407(d)(3)(E). The Clean Air Act
    unambiguously requires nonattainment areas to satisfy all five
    of the conditions under § 7407(d)(3)(E) before they may shed
    controls associated with their nonattainment designation. The
    redesignation substitute lacks the following requirements of
    § 7407(d)(3)(E): (1) the EPA has “fully approved” the
    22
    § 7410(k) implementation plan; (2) the area’s maintenance
    plan satisfies all the requirements under § 7505a; and (3) the
    state has met all relevant § 7410 requirements. 80 Fed. Reg. at
    12,305. Because the “redesignation substitute” does not
    include all five statutory requirements, it violates the Clean Air
    Act. Therefore, we grant Environmental Petitioners’ petition
    and vacate the Final Rule as to the “redesignation substitute.”
    C. Baseline Year
    The Clean Air Act measures Reasonable Further Progress
    by using a baseline year as the starting point. Nonattainment
    areas must reduce emissions of pollutants by fixed percentages
    compared to the pollutant level in a baseline year. 42 U.S.C.
    § 7511a(b)(1)(A), (B). The initial baseline year under the
    statute is 1990, 
    id., but the
    statute does not define baseline years
    for future NAAQS. In the Final Rule, the EPA defined the
    baseline year as 2011, which is the “calendar year for the most
    recently available triennial emission inventory at the time [rate-
    of-progress/reasonable further progress] plans are developed.”
    80 Fed. Reg. at 12,272. The Final Rule also allows states to
    select an alternative baseline year between 2008 and 2012 if
    they provide appropriate justification. 
    Id. Environmental Petitioners
    argue that this rule is unlawful
    because the Clean Air Act requires the baseline year to be the
    year of designation/classification, which in the case of the 2008
    NAAQS is 2012. While an initial baseline year of 1990 is
    specified by statute, the Clean Air Act is silent regarding future
    baseline years. Therefore, this question is governed by
    Chevron step two.          The Reasonable Further Progress
    requirement ensures that states make regular emissions
    reductions to achieve timely attainment. See § 7511a. To
    monitor their progress in achieving regular emissions
    reductions, states are required to prepare an emissions
    23
    inventory every three years. § 7511a(a)(3)(A). The EPA’s
    selection of 2011 as the baseline year is reasonable because it
    is tied to the three-year statutory cycle for emissions
    inventories.    
    Id. Therefore, we
    deny Environmental
    Petitioners’ challenge to the setting of 2011 as the baseline
    year.
    With respect to selection of an alternative baseline year
    between 2008 and 2012, the EPA has failed to provide a
    statutory justification. The “EPA must ‘ground its reasons for
    action or inaction in the statute,’ rather than on ‘reasoning
    divorced from the statutory text.’” Natural Res. Def. Council
    v. EPA (NRDC 2014), 
    777 F.3d 456
    , 468 (D.C. Cir. 2014)
    (quoting Utility Air Regulatory Grp. v. EPA, 
    134 S. Ct. 2427
    ,
    2441 (2014)). The EPA based its creation of the alternative
    baseline year option on the convenience of allowing
    nonattainment areas to receive credit for emissions reduction
    measures adopted prior to the baseline year. Because the EPA
    has no statutory basis for the alternative baseline year
    provision, we grant Environmental Petitioners’ petition and
    vacate the Final Rule as to the alternative baseline year option.
    D. Fifteen-Percent Rule
    The Clean Air Act requires an area in a moderate or greater
    degree of nonattainment to reduce emissions of VOCs by
    fifteen percent within six years of the baseline year. 42 U.S.C.
    § 7511a(b)(1)(A). The Final Rule interprets this requirement
    as meaning that “an area that has already met the 15 percent
    requirement for VOC under either the 1-hour ozone NAAQS
    or the 1997 ozone NAAQS (for the first 6 years after the
    [reasonable further progress] baseline year for the prior ozone
    NAAQS) would not have to fulfill that requirement again.” 80
    Fed. Reg. at 12,271; see also 
    id. at 12,276.
    The Environmental
    Petitioners argue that the rule is unlawful because the
    24
    interpretation allows areas to avoid actually achieving
    emissions reductions to satisfy the fifteen-percent requirement.
    The Final Rule does not require nonattainment areas that
    have previously revised their SIPs to address the Clean Air
    Act’s fifteen-percent requirement to revise their SIPs again. If
    an area fails to achieve this reduction according to their plan, a
    petitioner may file for injunctive relief or the EPA may pursue
    an enforcement action. Environmental Petitioners argue that
    the Final Rule allows nonattainment areas to omit the fifteen-
    percent requirement even if they never previously achieved a
    fifteen-percent reduction. The EPA has represented that the
    provision at issue in this case is the same as that at issue in
    NRDC 2009, 
    571 F.3d 1245
    . In NRDC 2009, the EPA rule
    allowed areas that had revised their SIPs to include a fifteen-
    percent VOC emissions reduction to not be subjected to a
    second fifteen-percent requirement under the new NAAQS. 
    Id. at 1261.
    We held that “the EPA reasonably resolved a statutory
    ambiguity under step 2 of the framework set out in Chevron.”
    
    Id. at 1262.
    We accept the EPA’s representation that the
    fifteen-percent requirement in the Final Rule is the same as the
    provision at issue in NRDC 2009. Therefore, because the
    EPA’s interpretation is permissible, we deny Environmental
    Petitioners’ challenge to the fifteen-percent reduction plan
    waiver.
    E. Area-Wide Emissions Reductions
    The Clean Air Act requires nonattainment areas to achieve
    “such reductions in emissions from existing sources in the
    area” as can be achieved by the adoption of Reasonably
    Available Control Technology (“RACT”).            42 U.S.C.
    § 7502(c)(1). The Final Rule allows nonattainment areas to
    satisfy the NOx RACT requirement by using averaged area-
    wide emissions reductions. 80 Fed. Reg. at 12,278-79. Thus,
    25
    “states may demonstrate as part of their NOx RACT SIP
    submittal that the weighted average NOx emission rate from all
    sources in the nonattainment area subject to RACT meets NOx
    RACT requirements.”          
    Id. at 12,278.
         Environmental
    Petitioners argue that this rule violates the clear terms of the
    Clean Air Act, which require each individual source to meet
    the NOx RACT requirement.
    They contend that § 7511a(b)(2) requires implementation
    of RACT with respect to “all” major sources, and “all” means
    “each one of.” Section 7511a(b)(2) requires states to submit
    revisions to SIPs “to include provisions to require the
    implementation of reasonably available control technology
    under section 7502(c)(1) of this title with respect to each of”
    three specific categories of VOC sources, including “all . . .
    major stationary sources of VOCs that are located in the area.”
    Pursuant to § 7511a(f), that plan provision applies to “major
    stationary sources” of NOx. Section 7511a(b)(2) refers to “all”
    “major stationary sources” and requires implementation of
    RACT “with respect to” that entire category of sources. The
    statute does not specify that “each one of” the individual
    sources within the category of “all” “major sources” must
    implement RACT. Environmental Petitioners argue that the
    only reasonable dictionary definition of “all” when used with a
    plural noun (major stationary sources) is “each one of.”
    Instead, when used to refer to a plural noun, the word “all” may
    express an aggregate and be defined as the “whole number or
    sum of.” Black’s Law Dictionary 74 (6th ed. 1990). This
    definition is consistent with the categorical approach taken by
    the EPA. In short, the plain language—in the context of the
    interrelationship between §§ 7511a(b)(2) and 7502(c)(1)—
    does not mandate RACT for each individual source.
    Therefore, as discussed above, we cannot strike down the
    EPA’s reasoned interpretation of the ambiguous term at
    26
    Chevron step one, see Section 
    II, supra
    . We must instead
    uphold the EPA’s interpretation, provided it is reasonable,
    under Chevron step two. See 
    Chevron, 467 U.S. at 842-43
    .
    We further note that § 7511a(b)(2) refers to § 7502(c)(1),
    which provides that SIP “provisions shall provide for the
    implementation of all reasonably available control measures as
    expeditiously as practicable (including such reductions in
    emissions from existing sources in the area as may be obtained
    through the adoption, at a minimum, of reasonably available
    control technology).” § 7502(c)(1). Section 7502(c)(1) does
    not require reductions from each individual major source.
    Instead, it requires “reductions in emissions from existing
    sources in the area,” and other than mandating that
    implementation be as “expeditious[] as practicable,” the
    section is ambiguous as to how areas are required to achieve
    those reductions.
    The EPA’s interpretation reasonably allows nonattainment
    areas to meet RACT-level emissions requirements through
    averaging within a nonattainment area. Therefore, we deny
    Environmental Petitioners’ petition as to the EPA’s
    construction of the RACT requirement.
    F.      Waiving Requirements for Areas Designated
    Maintenance Under the 1997 NAAQS
    Environmental Petitioners seek to have us invalidate
    several provisions of the Final Rule that apply to areas
    designated attainment for the 2008 NAAQS after being
    designated maintenance areas under the 1997 NAAQS
    (“orphan maintenance areas”).
    27
    1.    Elimination of Transportation
    Conformity
    As with orphan nonattainment areas, the Final Rule
    declares that orphan maintenance areas are “no longer . . .
    required to demonstrate transportation conformity for the 1997
    ozone NAAQS after the 1997 ozone NAAQS is revoked.” 80
    Fed. Reg. at 12,284. Environmental Petitioners argue that the
    elimination of transportation conformity in orphan
    maintenance areas violates the Clean Air Act. Section
    7506(c)(5) provides that conformity requirements apply to
    “(A) a nonattainment area and each pollutant for which the area
    is designated as a nonattainment area; and (B) an area that was
    designated as a nonattainment area but that was later
    redesignated . . . as an attainment area and that is required to
    develop a maintenance plan under section 7505a.”
    We previously explained that the EPA lacks the authority
    to revoke transportation conformity for orphan nonattainment
    areas. See Section 
    IV.B.1(a), supra
    . The EPA argues that it
    is permitted to remove conformity requirements for orphan
    maintenance areas because such areas became attainment areas
    for the 1997 NAAQS prior to the date on which it was revoked.
    As a result, the EPA argues that these areas are not subject to
    anti-backsliding requirements, so there is no statutory
    requirement that they maintain the transportation conformity
    requirement. We disagree.
    In contrast to nonattainment areas, which § 7506(c)(5)
    references by their status as “nonattainment area[s],”
    maintenance areas are referenced by previous events: “an area
    that was designated as a nonattainment area but that was later
    redesignated . . . as an attainment area and that is required to
    develop a maintenance plan under section 7505a.”
    § 7506(c)(5) (emphases added). Although the Final Rule
    28
    revoked the 1997 NAAQS, it cannot revoke the statutory status
    of orphan maintenance areas. Even after revocation of the
    1997 NAAQS, an orphan maintenance area is “an area that was
    designated as a nonattainment area but that was later
    redesignated . . . as an attainment area.”
    It is irrelevant that this previous designation and
    redesignation occurred before the prior NAAQS was revoked
    because nothing in the Clean Air Act allows the EPA to waive
    this unambiguous statutory requirement. Moreover, the Act
    clearly contemplates new NAAQS being promulgated within
    ten years of an area’s redesignation to attainment because the
    statute requires the EPA to review NAAQS every five years
    and to “promulgate such new standards as may be appropriate.”
    § 7409(d)(1). Therefore, the revocation of the 1997 NAAQS
    does not waive the unambiguous mandate that conformity
    requirements apply to orphan maintenance areas. Accordingly,
    we grant Environmental Petitioners’ petition as to the
    elimination of transportation conformity in orphan
    maintenance areas.
    2.    Section 7410(a)(1) Maintenance Planning
    Requirement
    Environmental Petitioners contend that the Final Rule
    unlawfully waives the § 7410(a)(1) maintenance planning
    requirement for the 2008 NAAQS. 80 Fed. Reg. at 12,301.
    The Final Rule provides that an orphan maintenance area’s
    § 7505a(a) maintenance plan for the revoked 1997 NAAQS
    and the state’s approved Prevention of Significant
    Deterioration SIP satisfy the area’s obligations for maintenance
    of the 2008 NAAQS under § 7410(a)(1) of the Clean Air Act.
    80 Fed. Reg. at 12,301, 12,314. Environmental Petitioners
    argue the Prevention of Significant Deterioration SIP is the sole
    maintenance plan requirement for the 2008 NAAQS, and it
    29
    only addresses pollution from very large sources. According
    to Environmental Petitioners, the EPA has no statutory
    authority to waive the § 7410(a)(1) maintenance requirement.
    The EPA justified its rule on the ground that orphan
    maintenance areas have already been redesignated to
    attainment for the 1997 NAAQS and designated attainment for
    the more stringent 2008 NAAQS. 80 Fed. Reg. at 12,301.
    According to the EPA, “[a]ny further [§ 7410(a)(1)]
    maintenance plan requirement under the 2008 . . . NAAQS
    would be unnecessarily burdensome.” 
    Id. Although the
    § 7505a(a) maintenance plans for orphan maintenance areas
    “were established for maintenance of the 1997 . . .
    NAAQS, . . . they also provide a foundation for maintenance
    of the 2008 . . . NAAQS, which, in combination with other
    active requirements for the 2008 ozone NAAQS, contribute to
    maintenance of the new standard.” 
    Id. The Final
    Rule
    explained that “no additional measures beyond the prior
    [§ 7505a(a)] maintenance plans and the PSD plans for the 2008
    [NAAQS] should be necessary to provide for maintenance in
    those areas.” 
    Id. We previously
    addressed the alleged waiver of the
    § 7410(a)(1) maintenance requirement with respect to orphan
    nonattainment areas. See Section 
    IV.B.1(d), supra
    . As we
    explained, § 7410(a)(1) does not provide clear requirements as
    to what SIPs must include in order to comply with the
    § 7410(a)(1) maintenance requirement beyond the criteria laid
    out in § 7410(a)(2). As with orphan nonattainment areas, with
    respect to orphan maintenance areas, the EPA adequately
    explained why no additional measures beyond the § 7505a(a)
    maintenance plans and the Prevention of Significant
    Deterioration plans for the 2008 NAAQS are necessary to
    provide for maintenance of the 2008 NAAQS. Therefore, we
    deny Environmental Petitioners’ petition with respect to the
    30
    § 7410(a)(1) maintenance requirement’s           application   to
    “orphan maintenance areas.”
    3.    Elimination of Second Maintenance Plan
    Environmental Petitioners challenge the Final Rule’s
    elimination of the requirement that orphan maintenance areas
    prepare a second maintenance plan under § 7505a(b). 80 Fed.
    Reg. at 12,301. Section 7505a(b) provides that “8 years after
    redesignation of any area as an attainment area,” states “shall
    submit . . . an additional revision of the” maintenance plan “for
    10 years after the expiration of the 10-year period referred to in
    subsection (a).” The EPA argues that the requirement for a
    second 10-year maintenance plan is based on an area’s
    designation status under an operative NAAQS. When the 1997
    NAAQS was revoked, the orphan maintenance areas’
    designations as maintenance under the 1997 NAAQS were
    revoked as well.
    The statutory requirement for a second maintenance plan
    is unambiguous. § 7505a(b). And the Clean Air Act clearly
    contemplates new NAAQS being promulgated within eight
    years of an area’s redesignation to attainment because the
    statute requires the EPA to review NAAQS every five years
    and to “promulgate such new standards as may be appropriate.”
    § 7409(d)(1). Therefore, the revocation of the old NAAQS
    does not waive the unambiguous requirement for second
    maintenance plans under § 7505a(b). Accordingly, we grant
    Environmental Petitioners’ petition and vacate the Final Rule
    provision waiving the second 10-year maintenance plan for
    “orphan maintenance areas.”
    31
    V.      Conclusion
    For the reasons set forth above, we deny South Coast’s
    petition for review and grant in part and deny in part the
    Environmental Petitioners’ petition. Specifically, we grant
    Environmental Petitioners’ petition and vacate as to (1) waiver
    of the statutory attainment deadlines associated with the 1997
    NAAQS; (2) removal of New Source Review and conformity
    controls from orphan nonattainment areas; (3) grant of
    permission to states to move anti-backsliding requirements for
    orphan nonattainment areas to their list of contingency
    measures based on initial 2008 designations; (4) waiver of the
    requirement that states adopt outstanding applicable
    requirements for the revoked 1997 NAAQS; (5) waiver of the
    § 7505a(a) maintenance plan requirement for orphan
    nonattainment areas; (6) creation of the “redesignation
    substitute”; (7) creation of an alternative baseline year option;
    (8) elimination of transportation conformity in orphan
    maintenance areas; and (9) waiver of the requirement for a
    second 10-year maintenance plan for orphan maintenance
    areas. In all other respects, Environmental Petitioners’ petition
    is denied.
    So ordered.