Sierra Club v. EPA , 774 F.3d 383 ( 2014 )


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  •                           In the
    United States Court of Appeals
    For the Seventh Circuit
    ____________________
    Nos. 12-2853, 12-3142 & 12-3143
    SIERRA CLUB,
    Petitioner,
    v.
    UNITED STATES ENVIRONMENTAL PROTECTION AGENCY and
    GINA MCCARTHY, Administrator, United States Environ-
    mental Protection Agency,
    Respondents.
    ____________________
    ARGUED SEPTEMBER 15, 2014 — DECIDED DECEMBER 16, 2014
    ____________________
    Before FLAUM, KANNE, and SYKES, Circuit Judges.
    FLAUM, Circuit Judge. Sierra Club challenges the Envi-
    ronmental Protection Agency’s decisions to redesignate
    three geographic areas—Milwaukee-Racine, Greater Chi-
    cago, and the Illinois portion of the St. Louis area—as
    having attained the 1997 National Ambient Air Quality
    Standards for ozone. The Clean Air Act mandates that
    before redesignating an area, EPA must confirm not just
    that ozone in an area dropped below a certain level, but
    also that the improvement in air quality resulted from
    “permanent and enforceable reductions in emissions.”
    2                          Nos. 12-2853, 12-3142 & 12-3143
    EPA interprets that edict to require a finding that the
    requisite ozone drops are “reasonably attributable” to
    permanent and enforceable reductions. Sierra Club does
    not contest EPA’s reading of the statute, but argues that
    the Agency acted arbitrarily and capriciously in making
    this causation finding in each of the redesignations at is-
    sue. We disagree and therefore deny Sierra Club’s peti-
    tion for review.
    I. Background
    A. Statutory and Regulatory Background
    The Clean Air Act (“CAA”), 
    42 U.S.C. § 7401
     et seq.,
    establishes a comprehensive program for controlling and
    improving the nation’s air quality through both state and
    federal regulation. Title I of the CAA charges the Envi-
    ronmental Protection Agency Administrator with identi-
    fying air pollutants that endanger public health and wel-
    fare and with formulating National Ambient Air Quality
    Standards (“NAAQS”) that specify the maximum per-
    missible concentration of those pollutants in the ambient
    air. 
    Id.
     §§ 7408–09. Pursuant to the CAA, EPA designates
    areas of the country as either “attainment,” “nonattain-
    ment,” or “unclassifiable” for specific NAAQS, based on
    whether that area has attained the standard and/or con-
    tributes to a nearby area’s nonattainment. Id. § 7407(d).
    Primary responsibility for ensuring that ambient air
    quality satisfies the NAAQS falls to the states. Id.
    § 7407(a). Each state must draft a state implementation
    plan (“SIP”) for each pollutant, the review of which is
    conducted by EPA according to the process outlined in
    section 110(k) of the CAA. Id. § 7410(a), (k). Although cer-
    Nos. 12-2853, 12-3142 & 12-3143                                 3
    tain SIP requirements apply to an area regardless of its
    designation, nonattainment areas are subject to more
    regulations as compared to attainment areas. See id.
    §§ 7501–15. 1
    Relevant to this case, ozone is among the pollutants
    that EPA has identified and, consequently, for which
    EPA has promulgated NAAQS. See 40 C.F.R. pt. 50.
    Ground-level ozone “can cause lung dysfunction, cough-
    ing, wheezing, shortness of breath, nausea, respiratory
    infection and, in some cases, permanent scarring of the
    lung tissue.” S. Coast Air Quality Mgmt. Dist. v. EPA, 
    472 F.3d 882
    , 887 (D.C. Cir. 2006). Ozone is “formed from
    [the] chemical reactions between [nitrogen oxides]” and
    other “volatile organic compounds in the presence of
    sunlight.” West Virginia v. EPA, 
    362 F.3d 861
    , 865 (D.C.
    Cir. 2004). Ozone’s precursors (nitrogen oxides (“NOx”)
    and volatile organic compounds (“VOCs”)) are produced
    by a variety of sources, including cars, power plants, and
    manufacturing facilities. 
    70 Fed. Reg. 30,396
    , 30,398 (May
    26, 2005). Ozone pollution levels, however, are not de-
    pendent solely on the quantity of precursor pollutants in
    an area—weather (especially sunlight and wind), for ex-
    ample, also drives the equation. 
    75 Fed. Reg. 24,844
    ,
    24,846 (May 6, 2010). And once ozone is formed, the ef-
    fect of adding or subtracting NOx to/from the air is un-
    known—ozone levels may increase or decrease. New York
    v. EPA, 
    133 F.3d 987
    , 989 (7th Cir. 1998). In other words,
    1 Subpart 1 of Part D of Subchaper I of the CAA, 
    42 U.S.C. §§ 7501
    –
    7509a, sets forth baseline requirements for all nonattainment areas,
    and Subpart 2 of Part D, 
    id.
     §§ 7511–11(f), sets forth more specific
    requirements for ozone nonattainment areas.
    4                             Nos. 12-2853, 12-3142 & 12-3143
    “predicting the total effect on ozone … of a reduction in
    [precursor] emissions, and the geographical incidence of
    that effect, is a tricky business.” Id.
    At issue in this case are the 1997 NAAQS for ozone.
    An area attains the 1997 ozone NAAQS when the 3-year
    average of the annual fourth-highest daily maximum 8-
    hour average ozone concentration is less than or equal to
    0.08 parts per million (“ppm”) 2 at all monitoring sites in
    the area. 40 C.F.R. pt. 50, App. I. But if EPA deems an ar-
    ea “nonattainment,” the CAA provides a path to reclassi-
    fication. 
    42 U.S.C. § 7407
    (d)(3)(E). To be redesignated, the
    governor of a state must submit a request for designa-
    tion, which EPA must approve or deny within 18 months
    on the basis of five criteria. 
    Id.
     § 7407(d)(3)(D), (E). Specif-
    ically, EPA will approve a redesignation to attainment
    only if:
    (1) EPA determines that the area has attained the ap-
    plicable NAAQS,
    (2) EPA fully approves the applicable SIP under 
    42 U.S.C. § 7410
    (k),
    (3) EPA determines that the improvement in air quali-
    ty is due to permanent and enforceable reductions in
    emissions resulting from the applicable implementa-
    tion plan and applicable federal air pollutant control
    regulations and other permanent and enforceable re-
    ductions,
    2However, based on the rounding convention used, an area does not
    actually violate the standard if ozone concentrations are at 0.084
    ppm or below. 40 C.F.R. pt. 50, App. I, § 2.3
    Nos. 12-2853, 12-3142 & 12-3143                        5
    (4) EPA fully approves a maintenance plan under 
    42 U.S.C. § 7505
    (a), which has been adopted by the state
    and demonstrates that the area will maintain the
    NAAQS for at least 10 years after redesignation, and
    (5) EPA determines that the State containing the area
    seeking redesignation has met all applicable SIP re-
    quirements for that area under § 7410 and part D of
    subchapter 1, §§ 7501–15.
    
    42 U.S.C. § 7407
    (d)(3)(E).
    On April 30, 2004, EPA designated the Milwaukee-
    Racine area, the St. Louis area, and the Greater Chicago
    area as nonattainment for the 1997 8-hour ozone stand-
    ard and classified the areas “moderate” nonattainment
    under CAA Subpart 2 of Part D, 
    42 U.S.C. §§ 7511
    –11f. 
    69 Fed. Reg. 23,858
    , 23,898, 23,915, 23,947 (Apr. 30, 2004).
    Roughly eight years later—upon review of applications
    submitted by Illinois and Wisconsin—EPA redesignated
    these three areas from nonattainment to attainment. Sier-
    ra Club challenges these actions as violative of the CAA’s
    causation requirement (the third requisite listed above).
    In Sierra Club’s view, EPA failed to adequately deter-
    mine that the ozone improvement in these areas resulted
    from “permanent and enforceable” emissions reductions.
    B. Procedural Background
    On September 11, 2009, Wisconsin requested redesig-
    nation of the Milwaukee-Racine and Sheboygan County
    areas based on monitoring data gathered by its Depart-
    ment of Natural Resources. On March 1, 2011, EPA de-
    termined that the Milwaukee-Racine and Sheboygan
    County areas had attained the 1997 8-hour ozone stand-
    6                          Nos. 12-2853, 12-3142 & 12-3143
    ard based on data for the 2006–2008, 2007–2009, and
    2008–2010 time periods. 
    76 Fed. Reg. 11,080
     (Mar. 1,
    2011). On February 9, 2012, EPA issued a rulemaking ac-
    tion proposing to approve Wisconsin’s requests to redes-
    ignate both Milwaukee-Racine and Sheboygan County to
    attainment of the 8-hour ozone standard, and to approve
    the State’s emissions inventories and maintenance plans
    for the areas. 
    77 Fed. Reg. 6727
     (Feb. 9, 2012); see also 
    77 Fed. Reg. 45,252
     (July 31, 2012). EPA received comments
    on the proposed rule from Sierra Club, which advanced
    the position that EPA’s proposed redesignation lacked
    support in the administrative record and violated the
    law. Nevertheless, on July 31, 2012, EPA published its
    final approval of Wisconsin’s request as it pertained to
    Milwaukee-Racine. 
    77 Fed. Reg. 45,252
     (July 31, 2012). In
    its final rule, EPA cited to the discussion in its proposed
    rule as the basis for its decision, and it responded to the
    adverse comments received from Sierra Club. 
    Id. at 45
    ,253–60. As for Sheboygan County, EPA opted not to
    finalize redesignation because preliminary 2012 data in-
    dicated that the area was again violating the 1997 8-hour
    ozone standards. 
    Id. at 45,252
    .
    On May 26, 2010, Illinois submitted a request to re-
    designate the Illinois portion of the St. Louis area to at-
    tainment for the 8-hour ozone standard. See 
    76 Fed. Reg. 79,579
    , 79,580 (Dec. 22, 2011). Three months later, on De-
    cember 22, 2011, EPA proposed to grant Illinois’s redes-
    ignation request based on air quality monitoring data
    from 2008–2010, and to grant the State’s approval request
    concerning its maintenance plan SIP revision and com-
    prehensive emissions inventory. 
    Id. at 79,592
    . On June 12,
    2012, EPA published its final approval of Illinois’s re-
    Nos. 12-2853, 12-3142 & 12-3143                        7
    quest. As in Milwaukee-Racine’s redesignation process,
    EPA’s proposal explained the rationale for its decision,
    and its final approval responded to the adverse com-
    ments it received in response. 
    77 Fed. Reg. 34,819
     (June
    12, 2012).
    Illinois also sought redesignation of the Greater Chi-
    cago area, submitting its request on July 23, 2009 based
    on ozone data from 2006 through 2008. See 
    77 Fed. Reg. 6743
    –44 (Feb. 9, 2012). On September 16, 2011, Illinois
    provided supplemental ozone data for 2008–2010, and
    EPA proposed to approve Illinois’s redesignation re-
    quest—along with the state’s SIP revisions, maintenance
    plan through 2025, and 2002 emission inventories for cer-
    tain pollutants in the Chicago area—on February 9, 2012.
    
    Id.
     As it had done with respect to Milwaukee-Racine and
    the Illinois portion of St. Louis, EPA’s proposed rule set
    forth the bases for its decision, and its final approval—
    issued on August 13, 2012—responded to the adverse
    comments that the Agency had received. 
    Id.
     at 6746–58;
    
    77 Fed. Reg. 48,062
     48,064–70 (Aug. 13, 2012).
    Sierra Club’s petition challenging EPA’s redesigna-
    tions is properly before this court on account of the
    CAA’s edict that “[a] petition for review of … any … fi-
    nal action of the Administrator under this chapter …
    which is locally or regionally applicable may be filed on-
    ly in the United States Court of Appeals for the appropri-
    ate circuit.” 
    42 U.S.C. § 7607
    (b)(1). However, EPA argues
    that Sierra Club lacks Article III standing to bring this
    lawsuit at all.
    8                           Nos. 12-2853, 12-3142 & 12-3143
    II. Discussion
    A. Standing
    Standing, “an essential and unchanging part of the
    case-or-controversy requirement of Article III” of the
    Constitution of the United States, contains three ele-
    ments. Lujan v. Defenders of Wildlife, 
    504 U.S. 555
    , 560
    (1992). The party invoking federal jurisdiction bears the
    burden of establishing them: (1) the plaintiff must have
    suffered an “injury in fact”—that is, “an invasion of a le-
    gally protected interest which is (a) concrete and particu-
    larized, and (b) actual or imminent, not conjectural or
    hypothetical; (2) “there must be a causal connection be-
    tween the injury and the conduct complained of” (i.e., the
    injury must be fairly traceable to the challenged action of
    the defendant); and (3) “it must be likely, as opposed to
    merely speculative, that the injury will be redressed by a
    favorable decision.” Lujan, 
    504 U.S. at
    560–61 (citations
    and internal quotation marks omitted). “An organization
    has standing to sue if (1) at least one of its members
    would otherwise have standing; (2) the interests at stake
    in the litigation are germane to the organization’s pur-
    pose; and (3) neither the claim asserted nor the relief re-
    quested requires an individual member’s participation in
    the lawsuit.” Sierra Club v. Franklin Cnty. Power of Ill. LLC,
    
    546 F.3d 918
    , 924 (7th Cir. 2008). EPA argues that Sierra
    Club lacks standing because it has failed to establish that
    EPA’s redesignations are likely to cause any of its mem-
    bers an injury in fact.
    Nos. 12-2853, 12-3142 & 12-3143                          9
    “[I]n reviewing the standing question, the court must
    be careful not to decide the questions on the merits for or
    against the plaintiff, and must therefore assume that on
    the merits the plaintiffs would be successful in their
    claims.” City of Waukesha v. EPA, 
    320 F.3d 228
    , 235 (D.C.
    Cir. 2003). Sierra Club premises its standing argument on
    declarations submitted by several of its members, all of
    whom express concern that EPA’s redesignations will
    ultimately cause pollution in the areas in which they live
    and, therefore, reduce their quality of life. EPA argues
    that these declarations contain speculative allegations
    concerning hypothetical events that are insufficient to es-
    tablish standing. As EPA points out, Sierra Club does not
    dispute that the three geographic areas at issue had at-
    tained the applicable NAAQS at the time the EPA ap-
    proved the redesignations. Moreover, EPA notes that it
    issued more stringent NAAQS in 2008, which, it argues,
    make it even less likely that the areas at issue will exceed
    the 1997 standards. EPA also highlights the existence of
    various safeguards designed to ensure compliance with
    the NAAQS going forward—namely, the maintenance
    plans developed by the states and approved by EPA, and
    stricter nonattainment standards to which each area will
    again be subject if it falls out of compliance.
    Sierra Club counters by contending that nonattain-
    ment areas are more likely to emit pollutants at higher
    levels than attainment areas. As evidence of this phe-
    nomenon, Sierra Club notes that ozone levels in the St.
    Louis area have already risen to exceed the 1997 NAAQS,
    despite the measures that EPA concluded were both
    permanent and enforceable and that, therefore, should
    have ensured continued compliance. Sierra Club also
    10                               Nos. 12-2853, 12-3142 & 12-3143
    highlights the predicament of Wisconsin’s Sheboygan
    County, which is subject to the same measures as Mil-
    waukee-Racine, yet lapsed into nonattainment after EPA
    proposed to approve its redesignation but before it took
    final action. To Sierra Club, the rises in St. Louis 3 and
    Sheboygan County ozone demonstrate the inadequacy of
    EPA’s methodology and support the proposition that—
    because EPA failed to tie each area’s pollution decrease
    to permanent and enforceable measures—ozone increas-
    es are more likely now that the more stringent nonat-
    tainment standards no longer apply.
    Sierra Club discounts the supposed fail-safes that
    EPA suggests will mitigate the consequences of emis-
    sions increases and, in effect, prevent potential pollution-
    related injuries. Moderate nonattainment areas, Sierra
    Club points out, are subject to “non-attainment new
    3 We note that the pollution monitor in the St. Louis area that ex-
    ceeded the statutory limit following redesignation is located in West
    Alton—a town located in Missouri, not Illinois. See Dkt. No. 17. The
    St. Louis area, which straddles the Missouri-Illinois border, was des-
    ignated nonattainment for the 1997 Ozone 8-Hour NAAQS on April
    30, 2004, based on air quality monitoring data from 2001–2003. See 76
    Fed. Reg. at 79,579. EPA redesignates areas to attainment at the state
    level, based on a given state’s request, but only if the entire area has
    attained the NAAQS at the time of redesignation. See 
    42 U.S.C. § 7407
    (d)(3)(E). During the 2010–2012 timeframe, the monitor in
    West Alton indicated an average ozone level of 0.087 ppm. See Dkt.
    No. 17. Based on that data, Sierra Club filed an administrative peti-
    tion for reconsideration of its redesignation of the Illinois portion of
    St. Louis with EPA, arguing (as it does here) that that data reveals
    that the measures on which EPA relied in redesignating St. Louis are
    not permanent and enforceable. That petition is still pending, and we
    denied Sierra Club’s motion to compel EPA to decide it. Dkt. No. 18.
    Nos. 12-2853, 12-3142 & 12-3143                          11
    source review” provisions pursuant to 
    42 U.S.C. § 7503
    .
    Those provisions demand that new and modified sources
    of ozone-forming pollutants meet the “Lowest Achieva-
    ble Emissions Rate” and purchase “offsets” sufficient to
    decrease the areas’ overall precursor emissions. See 
    42 U.S.C. §§ 7503
    (a), (c). Having been redesignated attain-
    ment, the three areas at issue are no longer subject to that
    requirement, and neither Wisconsin’s nor Illinois’s
    maintenance plans self-impose it. Moreover, at least with
    respect to Wisconsin, EPA’s redesignation relieved the
    State of the obligation to impose “reasonably available
    control technologies” on several categories of existing
    sources of ozone precursors that it has not yet regulated,
    and Wisconsin’s maintenance plan includes no such pro-
    vision. By relaxing certain pollution-prevention
    measures, Sierra Club argues, the risk of injury (the oc-
    currence of which Sierra Club characterizes as an ozone
    level that exceeds .084 ppm) to its members has in-
    creased. Sierra Club dismisses the states’ maintenance
    plans’ contingency measures as curative of Sierra Club’s
    potential injuries since (1) these measures do not kick in
    until ozone levels exceed 0.084 ppm four times a year for
    three consecutive years, and (2) they merely commit to
    an “evaluation of additional control measures” rather
    than prescribe specific pollution reductions.
    At bottom, Sierra Club contends that EPA redesignat-
    ed these areas without demonstrating that permanent
    and enforceable measures caused the corresponding
    drops in ozone levels. Attainment areas are subject to
    fewer regulations than nonattainment areas, and so, says
    Sierra Club—with less incentive to behave well (i.e., re-
    12                          Nos. 12-2853, 12-3142 & 12-3143
    duce pollution)—Milwaukee-Racine, St. Louis, and Chi-
    cago are now more likely to pollute.
    In Mainstreet Org. of Realtors v. Calumet City, Ill., 
    505 F.3d 742
    , 745 (7th Cir. 2007), citing Lujan, 
    504 U.S. at 560
    ,
    we reiterated that “abstract psychic harm or a one-day-
    I’ll-be-hurt allegation” is insufficient to establish stand-
    ing. But we highlighted that “standing in the Article III
    sense does not require a certainty or even a very high
    probability that the plaintiff is complaining about a real
    injury, suffered or threatened.” Id. at 744. “All that a
    plaintiff need show to establish standing to sue [in the
    Article III sense] is a reasonable probability—not a cer-
    tainty—of suffering tangible harm unless he obtains the
    relief that he is seeking in the suit.” Id. at 745 (quoting
    Hoover v. Wagner, 
    47 F.3d 845
    , 847 (7th Cir. 1995)).
    On some level, EPA is correct that Sierra Club’s stand-
    ing argument—largely premised on the notion that re-
    duced regulation will result in additional pollution—is
    speculative. But Sierra Club does more than speculate,
    offering evidence in support of the notion that its mem-
    bers are likely to be injured by EPA’s alleged mis-
    designations. By highlighting the increases in St. Louis,
    Missouri (which began to occur in 2010, prior to redesig-
    nation) and Wisconsin’s Sheboygan County (which pre-
    vented the area’s redesignation completely), Sierra Club
    makes a compelling argument that ozone levels are rea-
    sonably likely to rise above the 0.084 ppm threshold in
    the areas at issue here now that the less stringent attain-
    ment standards have been imposed. If impermissible pol-
    lution increases occurred even while the more stringent
    nonattainment standards governed—and EPA employed
    Nos. 12-2853, 12-3142 & 12-3143                         13
    the same causation methodology in those two areas that
    it did everywhere else—then ozone levels above 0.084
    ppm are even more likely now that the regulations have
    been relaxed in the three areas at issue here.
    Sierra Club’s standing argument also finds support in
    D.C. Circuit cases involving similar standing challenges
    brought by EPA. Most on-point is Sierra Club v. EPA, 
    754 F.3d 995
     (D.C. Cir. 2014), decided just weeks before Sierra
    Club filed its opening brief in this case. At issue there
    was EPA’s reliance on the Clean Air Interstate Rule
    (“CAIR”) in redesignating an area from nonattainment to
    attainment. 
    Id. at 997
    . CAIR—a law which prohibited cer-
    tain activities in a state that polluted other states—had
    been vacated by the D.C. Circuit, but the court allowed
    the rule to remain in effect until the creation of a re-
    placement rule. 
    Id.
     In the meantime, EPA—as communi-
    cated in an official Memorandum—continued to rely on
    the effects of CAIR in making its determinations that an
    area’s pollution reductions were “permanent and en-
    forceable.” 
    Id.
     Sierra Club challenged EPA’s policy, argu-
    ing (among other things) that the Memorandum was ar-
    bitrary and capricious in allowing regions to rely on re-
    ductions attributed to CAIR, which, by virtue of its im-
    pending replacement, were only temporary. 
    Id. at 998
    .
    EPA contended that Sierra Club lacked standing, because
    the organization failed to demonstrate that EPA’s policy
    caused injuries to its members.
    Sierra Club argued that its members suffered an inju-
    ry in fact because the Memorandum “strip[ped] away the
    Clean Air Act’s guarantee of enduring air quality protec-
    tions.” 
    Id. at 1000
    . The court, however, sided with EPA,
    14                         Nos. 12-2853, 12-3142 & 12-3143
    concluding that Sierra Club lacked standing because its
    members lived in areas “which [were] currently achiev-
    ing the NAAQS” and its speculative “claims of injury
    fail[ed] to qualify as actual or imminent.” 
    Id.
     at 1000–01.
    The D.C. Circuit noted that “because environmental and
    health injuries often are purely probabilistic,” petitioners
    who claim increased health risks must demonstrate a
    “nontrivial” probably that they will be injured, “suffi-
    cient to take a suit out of the category of the hypothet-
    ical.” 
    Id.
     Sierra Club could not do that, “relying on a
    highly attenuated chain of possibilities” and making “no
    attempt to tie EPA’s alleged failure to implement the
    CAA’s guarantees to a substantial probability that they
    will suffer diminished air quality.” 
    Id.
     (citation and inter-
    nal quotation marks omitted). Because Sierra Club “of-
    fered no evidence to suggest that CAIR-based emissions
    reductions will be fleeting or that a replacement program
    will result in increased emissions,” its suit was “tanta-
    mount to ‘an abstract, and uncognizable, interest in see-
    ing the law enforced.’” 
    Id.
     (citation and internal quotation
    marks omitted). Relevant to the D.C. Circuit’s conclusion
    was the fact that, “[u]nlike the petitioner in Natural Re-
    sources Defense Council v. EPA, 
    643 F.3d 311
    , 318 (D.C. Cir.
    2011), Petitioners [did] not claim that the Memorandum
    delayed attainment or eliminated incentives to reduce emis-
    sions.” Id. at 1002 (emphasis added).
    In Natural Resources Defense Council, 
    643 F.3d at 316
    ,
    NRDC challenged a “Guidance” document issued by
    EPA, which counseled the Agency’s regional directors on
    the implementation of the 1997 “8-hour” ozone NAAQS
    (which replaced older, less stringent “1-hour” standards
    for ozone pollution). The Guidance permitted the direc-
    Nos. 12-2853, 12-3142 & 12-3143                         15
    tors—for the purpose of transitioning nonattainment are-
    as from the older ozone standard to the new one—to re-
    tain old (previously mandatory) programs that states had
    implemented or, alternatively, to allow states “flexibility
    to adopt new programs” so long as the alternatives were
    “not less stringent” than the older mandated program. 
    Id. at 317
    . In other words, EPA afforded nonattainment areas
    some discretion in choosing “between the statutorily
    mandated program and an equivalent.” 
    Id.
     If EPA, which
    reviewed alternative programs on a case-by-case basis,
    approved the state’s proposed program, it would not as-
    sess non-compliance fees, even if the area violated the
    old ozone standards. 
    Id.
     (Because of the complexities of
    the two standards, it is theoretically possible to comply
    with the newer, more stringent 8-hour standard while
    violating the older, more lenient 1-hour standard. See id.)
    NRDC challenged this Guidance, arguing, among
    other things, that the new program and attainment alter-
    native violated the CAA. 
    Id.
     EPA argued that NRDC
    lacked standing—any injuries to NRDC members are
    purely hypothetical since EPA may never approve a
    state’s alternative program, EPA argued. 
    Id. at 318
    . The
    D.C. Circuit agreed with NRDC, however, and found
    that the Guidance injured its members in three inde-
    pendent ways, one of which was that the “Guidance had
    a present, concrete effect because it eliminated [the Clean
    Air Act’s] powerful incentive for major stationary
    sources to reduce emissions before the deadline.” 
    Id. at 318
    .
    A compelling argument for standing emerges from
    reading these two D.C. Circuit cases in conjunction with
    16                         Nos. 12-2853, 12-3142 & 12-3143
    our guidance in Mainstreet. As it did in Sierra Club v. EPA,
    
    754 F.3d 995
    , Sierra Club challenges the methodology by
    which EPA made its “permanent and enforceable” de-
    termination. In that case, Sierra Club challenged EPA’s
    reliance on CAIR in making its determination. CAIR, an
    interstate pollution rule struck down by the D.C. Circuit,
    was certain to change. But because the replacement rule
    had not been drafted, petitioner’s “injury”—premised on
    the possibility that the new rule might be less stringent—
    was purely hypothetical. Here—unlike in the CAIR case,
    where the new regulation was a mystery—we know the
    new rules that apply to Milwaukee-Racine, St. Louis, and
    Chicago: the rules that apply to areas in “attainment.” By
    definition, these new rules are less stringent than those
    governing areas in nonattainment, so Sierra Club’s stand-
    ing is tied to the likely effects that this new set of rules
    may have on polluters in the areas at issue. In other
    words, what is speculative in our case is the effect of those
    new rules, not that they will be more lax than the rules
    that are currently in place. Although those effects are
    somewhat hypothetical, our decision in Mainstreet and
    the D.C. Circuit’s opinion in NRDC inform our conclu-
    sion that the increased probability of injury to Sierra Club
    members creates standing here—especially in light of the
    fact that St. Louis and Sheboygan have since violated the
    ozone NAAQS. Furthermore, NRDC strongly suggested
    that “powerful incentives” (specifically, the incentives of
    “major stationary sources”), in and of themselves, can
    create standing in cases challenging an EPA regulation
    under the CAA. Sierra Club’s petition here involves in-
    centives for major pollution sources; Sierra Club argues
    that attainment relieves “new and modified major
    Nos. 12-2853, 12-3142 & 12-3143                           17
    sources of ozone-forming pollutants [from meeting] the
    ‘Lowest Achievable Emissions Rate,’ and purchas[ing]
    ‘offsets’ sufficient to decrease the areas’ overall precursor
    emissions.” Reply Br. 10.
    In light of the above, we are convinced that the prob-
    ability that ozone levels will rise has, for standing pur-
    poses, sufficiently increased on account of the relaxed
    regulations that accompany redesignation. Sheboygan
    County and a portion of the St. Louis area already are vi-
    olating the ozone standards despite EPA’s determination
    that the reduced levels in those areas were “permanent
    and enforceable.” Accordingly, we conclude that Sierra
    Club has met its burden of demonstrating the requisite
    likelihood that EPA’s redesignations will harm its mem-
    bers such that Sierra Club has standing to challenge
    EPA’s actions.
    B. EPA’s Redesignations
    We will not overturn an EPA action unless we deem it
    to be “arbitrary, capricious, an abuse of discretion, or
    otherwise not in accordance with law.” 
    5 U.S.C. § 706
    (2)(A); Alaska Dept. of Envtl. Conservation v. EPA, 
    540 U.S. 461
    , 497 n.18 (2004). Review under the arbitrary and
    capricious standard is
    principally concerned with ensuring that EPA has
    examined the relevant data and articulated a satis-
    factory explanation for its action including a ra-
    tional connection between the facts found and the
    choice made, that the Agency’s decision was based
    on a consideration of the relevant factors, and that
    the Agency has made no clear error of judgment.
    18                          Nos. 12-2853, 12-3142 & 12-3143
    Bluewater Network v. EPA, 
    370 F.3d 1
    , 11 (D.C. Cir. 2004)
    (citation and internal quotation marks omitted).
    Under this highly deferential standard, an adminis-
    trative decision should be upheld “as long as the agen-
    cy’s path may be reasonably discerned.” Mt. Sinai Hosp.
    Med. Ctr. v. Shalala, 
    196 F.3d 706
    , 708 (7th Cir. 1999) (cita-
    tion and internal quotation marks omitted). EPA’s redes-
    ignation can be considered arbitrary and capricious if the
    Agency relied on factors that “Congress did not intend
    for it to consider, entirely fails to consider an important
    aspect of the problem, offered an explanation for its deci-
    sion that runs counter to the evidence before the agency,
    or is so implausible that it could not be ascribed to a dif-
    ference in view or the product of agency expertise.”
    North Carolina v. EPA, 
    531 F.3d 896
    , 906 (D.C. Cir. 2008);
    see also Adventist GlenOaks Hosp. v. Sebelius, 
    663 F.3d 939
    ,
    942 (7th Cir. 2011) (citing Motor Vehicle Mfrs. Ass'n of U.S.
    v. State Farm Mut. Auto. Ins. Co., 
    463 U.S. 29
    , 43 (1983)).
    Before EPA may redesignate a nonattainment area,
    the CAA mandates, among other things, that it (1) de-
    termine that the area has attained the applicable NAAQS
    (i.e., that ozone has decreased sufficiently) and (2) deter-
    mine that the improvement in air quality is due to per-
    manent and enforceable reductions in emissions resulting
    from the SIP and applicable federal air pollutant control
    regulations and other permanent and enforceable reduc-
    tions. 
    42 U.S.C. § 7407
    (d)(3)(E). After Congress amended
    the CAA in 1990, EPA articulated its interpretation of this
    provision of the statute in “State Implementation Plans:
    General Preamble for the Implementation of Title I of the
    Clean Air Act Amendments of 1990” (“General Pream-
    Nos. 12-2853, 12-3142 & 12-3143                        19
    ble”). 
    57 Fed. Reg. 13,498
    , 13,561–64 (Apr. 16, 1992). The
    Agency further interpreted the statutory requirements
    for redesignation in several guidance documents, the
    most relevant of which is entitled “Procedures for Pro-
    cessing Request to Redesignate Areas to Attainment,” J.
    Calcagni, EPA Dir. of Air Quality Mgt. Div. (Sept. 4,
    1992) (“the Calcagni Memo”). According to EPA, these
    interpretations have served as the basis for evaluating
    redesignation requirements in numerous final rule-
    makings.
    The phrase “permanent and enforceable” is not de-
    fined in the statute. The General Preamble, however, sets
    forth EPA’s position that reductions in emissions are
    “temporary” if they result “from a suspension of indus-
    trial production or other temporary change in the indus-
    trial or economic activity in the area.” By contrast,
    “[r]eductions in emissions from shutdowns are consid-
    ered permanent and enforceable to the extent those shut-
    downs have been reflected in the SIP, and all applicable
    permits have been modified accordingly.” The General
    Preamble also states that “[m]easures are enforceable
    when they are duly adopted, and specify clear, unam-
    biguous, and measureable requirements. A legal means
    for ensuring that sources are in compliance with the con-
    trol measure must also exist in order for a measure to be
    enforceable.” And the Calcagni Memo makes clear that
    the “State must be able to reasonably attribute the im-
    provement in air quality to emission reductions which
    are permanent and enforceable” and that “[a]ttainment
    resulting from temporary reductions in emission rates
    (e.g., reduced production or shutdown due to temporary
    adverse economic conditions) or unusually favorable me-
    20                         Nos. 12-2853, 12-3142 & 12-3143
    teorology would not qualify as an air quality improve-
    ment due to permanent and enforceable emissions reduc-
    tions.” In making the “permanent and enforceable” de-
    termination, the Calcagni Memo counsels, the state seek-
    ing redesignation must “estimate the percent reduction . .
    . achieved from Federal measures such as the Federal
    Motor Vehicle Control Program and fuel volatility rules
    as well as control measures that have been adopted and
    implemented by the State.” The State’s estimate “should
    consider emission rates, production capacities, and other
    related information to clearly show that the air quality
    improvements are the result of implemented controls.”
    Sierra Club does not challenge the wisdom of the Cal-
    cagni Memo’s statutory interpretation. Instead, Sierra
    Club argues that EPA failed to observe its own guidance
    in determining that ozone reductions were due to per-
    manent and enforceable measures. More specifically, Si-
    erra Club argues that EPA is required to “determine
    whether ([and] to what extent) the observed reduction in
    [an] area’s ozone pollution resulted from newly adopted
    state and federal regulations—rather than from tempo-
    rary fluctuations in weather or the economy, or from oth-
    er similarly impermanent and unenforceable factors.”
    Pet’r Br. 36. What EPA did instead, Sierra Club claims, is
    (1) confirm the requisite drop in ozone levels, (2) deter-
    mine that ozone precursors (NOx and VOCs) also
    dropped, (3) note the state and federal regulations that
    coincided with those decreases, and (4) draw a conclu-
    sion that (3) caused (1) and (2). Thus, Sierra Club con-
    tends that EPA identified a correlation, but failed to iden-
    tify causation. Sierra Club argues that EPA should have
    undertaken an “analysis of the meteorology, [and] the
    Nos. 12-2853, 12-3142 & 12-3143                          21
    timing and location of precursor emissions, that pro-
    duced the improved air quality.” Pet’r Br. 44. In Sierra
    Club’s view, EPA should have more closely considered
    the possible effects of the economic recession, fuel prices,
    weather, and “other impermanent conditions” on the re-
    ductions in ozone (and ozone precursor) levels; without
    quantifying the effect of each of these variables, EPA
    cannot meet the requirements of the statute, Sierra Club
    says. Pet’r Br. 47, 52. To Sierra Club, the spike in ozone
    levels in Sheboygan County and in St. Louis illuminates
    the inadequacy of EPA’s determination that ozone levels
    in Milwaukee-Racine and the Illinois portion of St. Louis
    were due to “permanent and enforceable” measures.
    EPA does not dispute that a causative connection is
    required. In fact, in its final approval of the Milwaukee-
    Racine redesignation, EPA echoed the Calcagni Memo’s
    interpretation of the CAA’s causation requirement: “the
    improvement in air quality necessary for the area to at-
    tain the relevant NAAQS must be reasonably attributable
    to permanent and enforceable reductions in emissions.”
    77 Fed. Reg. at 45,258 (emphasis added). To EPA, the ev-
    idence demonstrated that the various state and regulato-
    ry measures enforced during the relevant periods “repre-
    sent[ed] an adequate demonstration that the improve-
    ment in air quality can reasonably be attributed to the
    significant reduction in emissions resulting from perma-
    nent and enforceable emissions control programs.” Id.
    EPA defends its methodology, asserting that in each
    case it did more than simply draw a correlation in the ab-
    sence of an adequate causative link. Specifically, EPA
    listed each state and federal measure that it deemed
    22                         Nos. 12-2853, 12-3142 & 12-3143
    “permanent and enforceable” that had been implement-
    ed in each state. For example, in Milwaukee-Racine, EPA
    catalogued: (1) Wisconsin’s enhanced automobile inspec-
    tion and maintenance programs; (2) Wisconsin’s regula-
    tions governing nitrogen oxide emissions at electric utili-
    ties and large industrial combustion sources and estab-
    lishing emission standards for new sources; (3) federal
    standards for vehicles and gasoline sulfur that phased in
    between 2004 and 2009; (4) an EPA rule effective in 2004
    that limits the sulfur content of diesel fuel; (5) EPA’s 2004
    rule applying to diesel engines used in the construction,
    agriculture, and mining industries; (6) new source per-
    formance standards; (7) national emission standards for
    hazardous air pollutants, including maximum achievable
    control technology standards; and (8) control measures in
    upwind areas, such as the NOx SIP Call, which required
    twenty-two states in the region to reduce NOx emissions.
    See 77 Fed. Reg. at 6737. EPA made similar findings with
    respect to St. Louis and Chicago. See 76 Fed. Reg. at
    79,586; 77 Fed. Reg. at 6754–55.
    For nearly all of these measures, EPA estimated the
    impact that each would have on emissions that cause
    ozone pollution. Regarding Milwaukee-Racine, for ex-
    ample, EPA noted that, with respect to Wisconsin’s regu-
    lation of stationary sources, such controls were estimated
    to achieve a 55-ton-per-day reduction of NOx by 2007.
    EPA estimated that federal rules designed to control
    VOCs and NOx emissions that phased in between 2004
    and 2009 would reduce vehicle NOx emissions nation-
    wide by 77% in passenger cars, 86% in light duty trucks,
    minivans, and SUVs, and between 69–95% in heavier
    trucks. EPA estimated that these regulations would re-
    Nos. 12-2853, 12-3142 & 12-3143                         23
    duce VOC emissions from 12–18%, depending on the
    class of vehicle, over the 2004 through 2009 period. And
    EPA believed that its 2004 rule applying to diesel engines
    in construction, agriculture, and mining would result in a
    90% reduction in NOx emissions from nonroad diesel en-
    gines. Sierra Club counters that EPA failed to specifically
    determine how these reduction estimates affected ozone
    levels in just the Milwaukee-Racine area, and specifically
    for the 2005–2008 timeframe. In other words, Sierra Club
    believes that EPA’s analysis was too imprecise.
    EPA points out that there is no information in the rec-
    ord to support a conclusion that any of these reductions
    were temporary or that any temporary reductions con-
    tributed to the attainment of the NAAQS in the three ge-
    ographic areas at issue. In light of the evidence, EPA con-
    tends that—in its experience, expertise, and professional
    judgment—it “reasonably attributed” the reductions to
    permanent and enforceable measures, which is all that its
    interpretation of the CAA requires. Nevertheless, Sierra
    Club insists that EPA should have done more. In its view,
    EPA could have conducted a more sophisticated analysis
    or utilized scientific modeling to rule out—with a higher
    degree of certainty—the other variables (wind, sunlight,
    economic conditions) that affect ozone levels. But, as EPA
    says, “[e]ven if it were scientifically possible” to do so,
    such an “elaborate analytical exercise is not required by
    the CAA.” We agree.
    At bottom, the CAA required EPA to confirm the nec-
    essary ozone reduction and tie it to a “permanent and
    enforceable” drop in precursor emissions (VOC and NOx)
    resulting from “permanent and enforceable” regulation.
    24                         Nos. 12-2853, 12-3142 & 12-3143
    EPA did that. If estimating ozone conditions is as
    “tricky” as Sierra Club emphasizes throughout its brief-
    ing, then of course EPA’s determinations are not infalli-
    ble. If, for example, a mixture of sunlight and wind can
    alter ozone levels in unexpected ways, no amount of sci-
    entific modeling employed by EPA in making its causa-
    tion determination will preclude subsequent increases in
    ozone. Regardless, the CAA does not require EPA to
    prove causation to an absolute certainty. Rather, in ac-
    cord with its own internal guidance (which, again, Sierra
    Club does not challenge) EPA had to “reasonably attrib-
    ute” the drops in ozone to permanent and enforceable
    measures. Only if EPA’s path cannot “be reasonably dis-
    cerned,” Mt. Sinai Hosp., 196 F.3d at 708, or if EPA relied
    on factors “that Congress did not intend it to consider” or
    “fail[ed] to consider an important aspect of the problem,”
    Adventist GlenOaks Hosp., 
    663 F.3d at 942
    , will we con-
    clude that EPA acted arbitrarily or capriciously. In light
    of the above, we cannot conclude that EPA’s approach in
    making a reasonable attribution was not discernable, that
    EPA relied on errant factors, or that it failed to consider
    an important aspect of the problem.
    In addition to challenging EPA’s causation approach
    generally, Sierra Club objects to EPA’s use of actual emis-
    sions data from power plants in determining that the re-
    ductions were “permanent and enforceable.” Because
    “actual” emissions vary from year to year, those figures,
    by definition, are neither “permanent” nor “enforceable,”
    Sierra Club argues. The Calcagni Memo expressly in-
    structs EPA to “assume that sources are operating at
    permitted levels (or historic peak levels) unless evidence
    is presented that such an assumption is unrealistic.” Sier-
    Nos. 12-2853, 12-3142 & 12-3143                           25
    ra Club therefore argues that, by using “actual” emis-
    sions, EPA defied its own interpretative guidance. In
    EPA’s view, using maximum permissible emissions lev-
    els in its analysis would have been ill-advised, artificially
    inflating power plant emissions in a way that does not
    reflect reality.
    EPA maintains that it is the Agency’s “long-standing
    practice and EPA policy” to use actual emissions data for
    power plants “when demonstrating permanent and en-
    forceable emission reductions.” Resp’t Br. 49. EPA has
    implemented this policy because “assuming that all
    sources would be operating at maximum capacity at once
    would result in a gross overestimation of emission lev-
    els.” Resp’t Br. 49–50. Sierra Club counters by pointing
    out that state regulations permitted power plants in Mil-
    waukee-Racine to emit six times the nitrogen oxides that
    EPA ascribed to all stationary sources in the area, and
    more than four times the nitrogen oxides that were emit-
    ted during Milwaukee-Racine’s years of nonattainment.
    EPA does not refute those figures. Instead, EPA high-
    lights that it considered emissions inventories from both
    periods of nonattainment and periods of attainment and
    scrutinized the control measures in the relevant SIPs and
    maintenance plans, in arriving at its conclusion that us-
    ing maximum allowable emissions levels would be unre-
    alistic in projecting ozone levels for the areas at issue.
    Resp’t Br. 50.
    Further, EPA contends that the Berry Memo, “Use of
    Actual Emissions in Maintenance Demonstrations for
    Ozone and CO Nonattainment Areas,” D. Kent Berry,
    Acting Dir., Air Quality Mgmt. Div. (Nov. 30, 1993), su-
    26                        Nos. 12-2853, 12-3142 & 12-3143
    persedes the Calcagni Memo with respect to the use of
    actual emissions, expressly permitting the use of actual
    emissions in ozone maintenance projections. Resp’t Br.
    51. The reason for the change, EPA says, is that the Agen-
    cy uses actual emissions data for power plants in making
    nonattainment determinations. Therefore, EPA’s position
    is that “it would be akin to comparing apples and orang-
    es to use . . . allowable emissions from an attainment
    year.” Resp’t Br. 51–52.
    Sierra Club disagrees, arguing that the Berry Memo
    only supersedes the Calcagni Memo—as the Berry Memo
    plainly states—with regard to “maintenance demonstra-
    tions for ozone and CO nonattainment areas seeking re-
    designation to attainment.” Though somewhat ambigu-
    ous from the face of the two Memos, Sierra Club appears
    to have the better of the argument here—the Calcagni
    Memo provides guidance on “maintenance plans” in a
    separate and distinct section from its guidance on mak-
    ing the “permanent and enforceable determination.” That
    said, both sections discuss redesignations from attain-
    ment to nonattainment, so EPA’s position is not entirely
    unreasonable. We need not decide definitively whether
    the Berry Memo trumps the Calcagni Memo on this
    point, however, because even if the Calcagni Memo gov-
    erns (as Sierra Club argues), EPA followed its own inter-
    pretative guidance here. EPA has articulated a rational
    basis for its conclusion—consistent with the Calcagni
    Memo—that using maximum allowable emissions levels
    for power plants would have been unrealistic. Thus, EPA
    was free to rely on actual emissions data in concluding
    that ozone reductions resulted from “permanent and en-
    forceable” emissions reductions.
    Nos. 12-2853, 12-3142 & 12-3143                         27
    Lastly, Sierra Club challenges EPA’s reliance, as one
    factor among many, on the effects of the NOx SIP Call
    trading program in making its “permanent and enforce-
    able” determination. The NOx SIP Call, issued in October
    1998, is an EPA rule that requires states to address inter-
    state transport of air pollution. It is designed to prevent
    NOx that originates in an “upwind” state from causing or
    exacerbating nonattainment in a “downwind” state. The
    NOx SIP Call requires twenty-two states—including Illi-
    nois, and neighbors Indiana, Michigan, Missouri, and
    Kentucky—to reduce NOx emissions in an effort to re-
    duce their contributions to downwind ozone nonattain-
    ment. The NOx SIP Call limitations were implemented in
    two phases. Illinois fulfilled the requirements of Phase I
    in November 2001 and met those of Phase II in June 2009.
    Important here, the NOx SIP Calls have been codified as
    enforceable state laws. And although Wisconsin was not
    one of the states included in the NOx SIP Call, EPA con-
    siders Wisconsin to be one of the “downwind” states that
    benefits from the restrictions imposed on its neighbors.
    Sierra Club criticizes EPA’s reliance on the NOx SIP
    Call, because that program is aimed at reducing pollution
    in the region as a whole and permits the twenty-two af-
    fected states to purchase pollution “allowances” from
    one another. Accordingly, Sierra Club believes that the
    effects on any one area in particular are not necessarily
    permanent or enforceable. It cites two D.C. Circuit cas-
    es—Natural Resources Defense Council v. EPA, 
    571 F.3d 1245
     (D.C. Cir. 2009), and North Carolina v. EPA, 
    531 F.3d 896
    —in support of its position.
    28                          Nos. 12-2853, 12-3142 & 12-3143
    In Natural Resources Defense Council, 
    571 F.3d at 1251
    (“NRDC”), the petitioners challenged EPA’s conclusion
    that states could satisfy section 172(c)(1) of the CAA by
    participating in the NOx SIP Call. That section of the stat-
    ute mandates that states’ SIPs for nonattainment areas
    “provide for the implementation of all reasonably availa-
    ble control measures as expeditiously as practicable (in-
    cluding such reductions in emissions from existing
    sources in the area as may be obtained through the adop-
    tion, at a minimum, of reasonably available control tech-
    nology).” Id.; 
    42 U.S.C. § 7502
    (c)(1). Because section
    172(c)(1) requires that nonattainment areas implement
    control measures through “reasonably available control
    technolog[ies]” (“RACT”) that reduce emissions “from
    existing sources in the area,” the D.C. Circuit held that
    the EPA may not use reductions from the NOx SIP Call—
    which does not require RACT-level reductions from
    sources in a given area—in its section 172(c)(1) analysis.
    
    571 F.3d at 1256
    .
    In North Carolina, (as alluded to earlier) the D.C. Cir-
    cuit invalidated CAIR, another measure designed to re-
    duce interstate pollution, promulgated pursuant to Title I
    of the CAA. 
    531 F.3d at 902
    . Title I requires SIPs to “con-
    tain adequate provisions . . . prohibiting . . . any source . .
    . within the State from emitting any air pollutant in
    amounts which will contribute significantly to nonat-
    tainment in, or interfere with maintenance by, any other
    State with respect to any [NAAQS].” 
    Id.
     The D.C. Circuit
    invalidated CAIR because, although EPA issued initial
    emissions budgets to the states, the statute authorized
    pollution sources to purchase allowances from sources in
    other states, thus permitting states to exceed the caps im-
    Nos. 12-2853, 12-3142 & 12-3143                           29
    posed by the emissions budget. 
    Id.
     at 906–07. CAIR was
    “designed as a complete remedy to [Title I] problems,”
    and for that reason, the court deemed the program in-
    compatible with Congress’s directive in Title I. 
    Id. at 908
    .
    EPA refutes the applicability of NRDC and North Car-
    olina here. First, EPA points out that it relied on the NOx
    SIP Call as one of many bases for its “permanent and en-
    forceable” determination. EPA estimated that the NOx
    SIP Call reduced NOx emissions by 68,000 tons in states
    subject to it, and that Illinois’s implementation of Phase II
    would reduce NOx emissions by 82% at the sources sub-
    ject to it. Additionally, EPA noted that the NOx SIP Call
    has resulted in a downward trend in NOx emission rates
    (tons per hour of operation) for the Chicago area. Second,
    EPA points out that the observed benefits of the NOx SIP
    Call are much more static and predictable than Sierra
    Club acknowledges, and not just because the states have
    incorporated these requirements into their federally en-
    forceable SIPs. As EPA explains, a state cannot merely
    “purchase” allowances with impunity. Rather, the NOx
    SIP Call is a cap-and-trade program, which permits some
    flexibility through the purchase of allowances, but also
    caps the total emissions from covered sources. Therefore,
    while some fluctuations may occur, EPA insists that it
    was reasonable to factor the reductions resulting from
    the program into its analysis. We agree.
    This case is materially different from both NRDC and
    North Carolina. In NRDC, the D.C. Circuit struck down
    EPA’s attempt to use the NOx SIP Call to satisfy Con-
    gress’s requirement that nonattainment areas implement
    control measures through RACT that reduce reductions
    30                          Nos. 12-2853, 12-3142 & 12-3143
    “from existing sources in the area.” The NOx SIP Call was
    deficient in accomplishing that objective because it does
    not require the imposition of RACT-level reductions in a
    particular area, and, in any event, EPA never evaluated
    the NOx SIP Call’s effects in the areas at issue. 
    571 F.3d at
    1256–57. Here, though, no specific type of control meas-
    ure is required, emissions reductions need not result ex-
    clusively from sources in the nonattainment area, and
    EPA has estimated the relevant effects of the NOx SIP
    Call, as described above. And this case is different from
    North Carolina, where the Agency relied exclusively on
    CAIR to prevent pollution sources in one state from con-
    tributing to nonattainment in another state, because,
    here, the NOx SIP Call is not the sole basis for EPA’s de-
    termination that emissions reductions are “permanent
    and enforceable.” Moreover, because the program’s
    overall structure ensures a regional reduction in emis-
    sions—and because EPA avers (and Sierra Club does not
    challenge) that, in all practicality, the NOx SIP Call results
    in minimal fluctuation in precursor output at the area
    level—then it is reasonable to rely on the program as one
    basis, among many, for concluding that reduced emis-
    sions levels will persist.
    The overarching theme running through Sierra Club’s
    petition is that EPA could have done more. But the ques-
    tion before us concerns only whether EPA was required to
    do more. The CAA mandated that EPA determine that
    reduced ozone levels were “due to permanent and en-
    forceable reductions in emissions resulting from imple-
    mentation of the applicable implementation plan and
    applicable federal air pollutant control regulations and
    other permanent and enforceable reductions.” 42 U.S.C. §
    Nos. 12-2853, 12-3142 & 12-3143                          31
    7407(d)(3)(E)(iii). The Calcagni Memo interprets this cau-
    sation provision to impose on EPA an obligation to “rea-
    sonably attribute” air quality improvement “to emission
    reductions which are permanent and enforceable,” not to
    prove causation with any higher degree of confidence
    than that. While the Calcagni Memo made clear that
    “[a]ttainment resulting from temporary reductions in
    emission rates (e.g., reduced production or shutdown due
    to temporary adverse economic conditions) or unusually
    favorable meteorology would not qualify,” that language
    cannot fairly be read to impose—as Sierra Club would
    prefer—an affirmative obligation on EPA to analyze,
    model, and scientifically quantify the effects of those var-
    iables on emissions reductions. Instead, the Memo in-
    structed EPA to “estimate the percent reduction . . .
    achieved from Federal Measures . . . as well as control
    measures that have been adopted and implemented by
    the State . . . . to clearly show that the air quality im-
    provements are the result of implemented controls.” EPA
    did that here.
    Accordingly, EPA has demonstrated that it “exam-
    ined the relevant data and articulated a satisfactory ex-
    planation for its action including a rational connection
    between the facts found and the choice made, that the
    Agency’s decision was based on a consideration of the
    relevant factors, and that the Agency has made no clear
    error of judgment.” Bluewater Network, 370 F.3d at 11 (ci-
    tation and internal quotation marks omitted). For that
    reason, we cannot conclude that EPA’s actions were “ar-
    bitrary, capricious, an abuse of discretion, or otherwise
    not in accordance with law.” 
    5 U.S.C. § 706
    (2)(A).
    32                       Nos. 12-2853, 12-3142 & 12-3143
    III. Conclusion
    For the foregoing reasons, Sierra Club’s petition for
    review is DENIED.