                  FOR PUBLICATION
  UNITED STATES COURT OF APPEALS
       FOR THE NINTH CIRCUIT

ASSOCIATION OF IRRITATED                
RESIDENTS, an unincorporated
association; EL COMITÉ PARA EL
BIENESTAR DE EARLIMART, an
unincorporated association;
COMMUNITY & CHILDREN’S
ADVOCATES AGAINST PESTICIDE
POISONING, an unincorporated
association,                                 No. 09-71383
                         Petitioners,
                                              EPA No.
                                            EPA-R09-OAR-
                  v.
                                              2008-0677
UNITED STATES ENVIRONMENTAL
PROTECTION AGENCY; LISA JACKSON,
in her official capacity as
Administrator of the U.S. EPA;
LAURA YOSHII, in her official
capacity as Regional Administrator
of Region IX of the U.S. EPA,
                        Respondents.
                                        




                              753
754           ASSOC.   OF IRRITATED   RESIDENTS v. EPA


NATURAL RESOURCES DEFENSE                        No. 09-71404
COUNCIL, INC.,
                      Petitioner,                   EPA No.
               v.                               EPA-R09-OAR-
                                                   2008-0677
UNITED STATES ENVIRONMENTAL
                                                  AMENDED
PROTECTION AGENCY,
                                                   OPINION
                     Respondent.
                                          
          On Petition for Review of an Order of the
             Environmental Protection Agency

                  Argued and Submitted
        November 1, 2010—San Francisco, California

                    Filed February 2, 2011
                   Amended January 27, 2012

       Before: Sidney R. Thomas and N. Randy Smith,
           Circuit Judges, and Robert S. Lasnik,
                   Chief District Judge.*

                    Opinion by Judge Thomas




  *Following the untimely death of Judge Cynthia Hall, the Honorable N.
R. Smith was drawn to replace her on the panel. The Honorable Robert S.
Lasnik, Chief United States District Judge for the Western District of
Washington, is sitting by designation.
758         ASSOC.   OF IRRITATED   RESIDENTS v. EPA




                          COUNSEL

Brent J. Newell and Marybelle N. Nzegwu, San Francisco,
California, and David Pettit, Melissa Lin Perrella, and Adri-
ano Martinez, Santa Monica, California, for the petitioners.

Austin D. Saylor, United States Department of Justice, for the
respondent.
               ASSOC.   OF IRRITATED     RESIDENTS v. EPA              759
                               OPINION

THOMAS, Circuit Judge:

   The Association of Irritated Residents, El Comité para el
Bienestar de Earlimart, the Community of Children’s Advo-
cates Against Pesticide Poisoning, and the Natural Resources
Defense Council, petition for review of a final action by the
Environmental Protection Agency approving in part and dis-
approving in part revisions to California’s State Implementa-
tion Plan for meeting air quality standards for ozone under
the Clean Air Act. We have jurisdiction under 42 U.S.C.
§ 7607(b)(1). We grant the petition for review and remand to
EPA for further consideration.

                                     I

                                    A

   Congress enacted the Clean Air Act (the “Act”) to help pro-
tect and enhance the nation’s air quality. 42 U.S.C. §§ 7401-
7671q. The Act requires the Environmental Protection
Agency (“EPA”) to establish National Ambient Air Quality
Standards (“NAAQS”) for a variety of pollutants, one of
which is ozone.1 Id. §§ 7408-09. EPA then designates areas as
“attainment” or “nonattainment” based on whether the areas
meet the clean air standards for each particular pollutant. Id.
§ 7407(d). EPA classifies nonattainment areas based on the
severity of the area’s pollution, from Marginal to Extreme. Id.
§ 7511(a). The area at issue in this litigation—the Los
Angeles-South Coast Air Basin (“South Coast”)—is classified
  1
    Ground-level ozone is a primary component of what is commonly
known as “smog.” It is formed when oxides of nitrogen (NOx), volatile
organic compounds (VOC), and oxygen react in the presence of sunlight,
generally at elevated temperatures. When inhaled, even at very low levels,
ozone can cause serious health problems by damaging lung tissue and sen-
sitizing lungs to other irritants. See 73 Fed. Reg. 63,408, 63,409 (Oct. 24,
2008) (to be codified at 40 C.F.R. pt. 52).
760          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
as Extreme. 73 Fed. Reg. 63,408, 63,409 (Oct. 24, 2008) (to
be codified at 40 C.F.R. pt. 52).

  Under the Act, states have primary responsibility for ensur-
ing that the quality of their air satisfies the NAAQS, and they
must detail their efforts in a State Implementation Plan
(“SIP”) for each region within that state. 42 U.S.C. § 7410(a).
States must submit these SIPs and SIP revisions to EPA for
review. EPA may either fully approve the plan, partially
approve and partially disapprove the plan, or conditionally
approve the plan. Id. § 7410(k). Once approved, SIPs become
enforceable as federal law. Id. § 7413.

   An EPA determination that a state has failed to submit a
required plan, or EPA disapproval of a submitted plan, trig-
gers two time periods. First, a “sanctions clock” begins during
which time the state must either remedy the deficiency or face
sanctions. Id. § 7509(a)-(b). Second, a “FIP clock” begins by
the end of which EPA must either approve a state-submitted
SIP or promulgate a Federal Implementation Plan (“FIP”). Id.
§ 7410(c)(1). Additionally, EPA must issue a “SIP call,” and
thereby require the state to make necessary revisions, if it
finds that a previously approved SIP is “substantially inade-
quate” to attain or maintain air quality standards. Id.
§ 7410(k)(5).

   The Act also contains “conformity” requirements. Under
these conformity provisions, the federal government may not
approve, accept, or fund any transportation plan, program, or
project unless it conforms to an approved SIP. Id. § 7506(c).
To make conformity determinations, transportation agencies
must look to an approved SIP to find the maximum amount
of pollution allowed from motor vehicle emissions. This
motor vehicle emissions budget (“MVEB”) is determined by
the states in their SIPs by identifying the total allowable emis-
sions consistent with meeting the statutory clean air require-
ment, and then allocating that total among various types of
sources, such as motor vehicles. 40 C.F.R. § 93.101. Because
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA        761
SIPs sometimes take years to review, EPA may make prelimi-
nary adequacy determinations regarding the MVEBs found in
the SIPs. Id. § 93.118. After further review, EPA may declare
the MVEB to be inadequate. Id. § 93.118(e)(3).

   In addition to the SIPs and conformity requirements appli-
cable to all areas, the Act contains further requirements for
nonattainment areas, depending on the severity of the ozone
problem in the area. 42 U.S.C. §§ 7511-7511f. Two of these
requirements are at issue in this case. The first requirement is
for these nonattainment areas to submit SIP revisions demon-
strating attainment of the ozone standard by the applicable
date. These “attainment plans” have two main parts: (1) a
control strategy to reach compliance; and (2) an attainment
demonstration to show that under the strategy the area will
meet the NAAQS by the statutory deadline. Id.
§§ 7511a(c)(2)(A), (d)-(e); 7410(a)(2)(A).

   The second requirement for these nonattainment areas is to
develop enforceable transportation strategies and control mea-
sures “to offset any growth in emissions from growth in vehi-
cle miles traveled . . . and to attain reduction in motor vehicle
emissions as necessary.” Id. § 7511a(d)(1)(A). Suggested
transportation control measures include programs for
improved public transit, restrictions of certain lanes for high
occupancy vehicles, and programs for secure bicycle storage
facilities. Id. § 7408(f)(1)(A).

                                B

   In 1994, California submitted a SIP revision that included
an ozone attainment demonstration for the South Coast nonat-
tainment area and a “Pesticide Element” designed to reduce
emissions from pesticide applications. In 1997, EPA approved
the SIP revision with respect to both the ozone attainment
demonstration and the Pesticide Element. In 1999, California
sought again to update the SIP with new emissions invento-
ries and a new ozone attainment demonstration. EPA
762           ASSOC.   OF IRRITATED   RESIDENTS v. EPA
approved these elements in 2000. All of these plans and revi-
sions form the 1997/1999 South Coast Ozone SIP
(“1997/1999 SIP”).

  After EPA approved the 1997/1999 SIP, California con-
ducted new modeling, demonstrating that the existing SIP
underestimated vehicle pollution in the area. Specifically,
California realized that, with respect to ozone:

      [T]he basic strategy of the 1997 Plan and the 1999
      amendments must be significantly overhauled to
      address the new realities of higher mobile source
      emissions and lower carrying capacities for ozone as
      indicated by new modeling and meteorological epi-
      sodes. Additional reductions, above and beyond
      those committed to in the 1997 Plan and 1999
      amendments, will be necessary to demonstrate
      attainment with the federal ozone standard and pre-
      sent a significant challenge.

   Concluding that “a plan update [was] necessary,” Califor-
nia submitted the 2003 SIP Revision to EPA in 2004. The
2003 SIP Revision consisted, in relevant part, of three things:
the 2003 Attainment Plan, PEST-1, and a demonstration that
no transportation control measures were required. Petitioners
seek review of EPA’s final determination as to each of these
three elements.

   The 2003 Attainment Plan revised the existing SIP in two
ways. First, it updated the attainment demonstration (and
therefore the MVEBs) to account for the increased emissions
projections under the new modeling. Second, it added addi-
tional control measures to offset the increase in predicted pol-
lution. In 2004, EPA found the MVEBs in the attainment
demonstration adequate for purposes of the conformity provi-
sions, but did not make a final decision as to the 2003 Attain-
ment Plan as a whole. In 2008, California withdrew some of
            ASSOC.   OF IRRITATED   RESIDENTS v. EPA     763
the 2003 Attainment Plan’s key elements, including many of
the control measures.

   PEST-1 was a control strategy that called for continued
implementation of the Pesticide Element approved in the
1997/1999 SIP. In 2008, we concluded that the portion of the
Pesticide Element representing the enforceable commitment
(the Wells Memorandum), was not part of the 1997/1999 SIP.
See El Comité para el Bienestar de Earlimart v. Warmerdam,
539 F.3d 1062 (9th Cir. 2008).

   Finally, because nonattainment areas must propose enforce-
able transportation control measures “to offset any growth in
emissions from growth in vehicle miles traveled,” California
submitted to EPA a demonstration purporting to show that
there would be no such growth in emissions. Although Cali-
fornia acknowledged that vehicle miles traveled would
increase by about 30%, it showed that aggregate motor vehi-
cle emissions would decrease.

   In 2008, EPA proposed to approve the control measures
that were not withdrawn from the 2003 Attainment Plan
(including PEST-1), but disapprove the attainment demonstra-
tion (and therefore the MVEBs) in the 2003 Attainment Plan
because the demonstration was largely based on the with-
drawn commitments. EPA explained the consequences of its
proposed partial disapproval by saying: “No sanctions clocks
or FIP requirement would be triggered by our disapprovals, if
finalized, because the approved [1997/1999] SIP already con-
tains the plan elements that we are proposing to disapprove.”
73 Fed. Reg. 63,408, 63,419 (Oct. 24, 2008) (to be codified
at 40 C.F.R. pt. 52). EPA also proposed to approve Califor-
nia’s assertion that no transportation control measures were
required based on California’s demonstration that there would
be no growth in aggregate vehicle emissions.

   In 2009, after considering public comments from petition-
ers on the proposed rule, EPA finalized action on the 2003
764          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
SIP Revision as proposed. This timely petition for review fol-
lowed.

   Petitioners raise three issues in their petition for review.
First, they contend EPA’s failure to order California to submit
a revised attainment plan for the South Coast after it disap-
proved the 2003 Attainment Plan was arbitrary and capri-
cious. Second, petitioners contend EPA’s approval of PEST-
1 violates the Clean Air Act because PEST-1 lacks enforce-
able commitments. Third, petitioners contend EPA violated
the Act by failing to require transportation control measures
to combat the increase in vehicle miles traveled. We grant the
petition as to all three claims.

                                II

   [1] EPA’s failure to evaluate the adequacy of the existing
SIP was arbitrary and capricious. The Act requires each non-
attainment area to submit a SIP that includes an attainment
demonstration for the 1-hour ozone standard. 42 U.S.C.
§ 7511a(c)(2)(A), (d)-(e). Although EPA approved such an
attainment demonstration for the South Coast in the
1997/1999 SIP, California submitted a revised attainment
demonstration in the 2003 Attainment Plan, which made clear
that the attainment demonstration in the 1997/1999 SIP was
not accurate. When EPA partially disapproved the 2003
Plan’s attainment demonstration (because California subse-
quently revoked many of the control strategies on which the
attainment demonstration was based), EPA concluded that no
further action was required. See 74 Fed. Reg. 10,176, 10,177
(Mar. 10, 2009) (to be codified at 40 C.F.R. pt. 52) (“[N]o
sanctions clocks or Federal Implementation plan (FIP)
requirement[s are] triggered by our disapprovals because the
plan revisions that are the subject of the proposed disapprov-
als represent revisions to previously-approved SIP elements
that EPA determined met the CAA requirements, and thus,
the revisions are not required under the Act.”).
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA       765
   [2] EPA is mistaken that its duties under the Act end upon
approval. Instead, EPA had an affirmative duty to evaluate the
existing SIP and determine whether a new attainment demon-
stration was necessary to ensure California satisfies the Act’s
attainment requirements. Its failure to evaluate the adequacy
of the existing SIP in any way was arbitrary and capricious.

   [3] Through the 2003 SIP Revision, EPA knew, or should
have known, of the inadequacy of the 1997/1999 SIP. As Cal-
ifornia specifically stated, “this revision points to the urgent
need for additional emission reductions (beyond those incor-
porated in the 1997/99 Plan) to offset increased emission esti-
mates from mobile sources and meet all federal criteria
pollutant standards within the time frames allowed under the
federal Clean Air Act.” EPA’s public comments also indicate
that it understood that the new modeling undermined the
existing SIP. See, e.g., 73 Fed. Reg. 63,408, 63,415 (Oct. 24,
2008) (to be codified at 40 C.F.R. pt. 52) (“[I]n view of the
magnitude of the reductions now understood to be needed for
attainment of the 1-hour ozone NAAQS in the South Coast,
[California] has adopted [additional control measures].”); id.
at 63,416 (“[California] revised the 1-hour ozone attainment
demonstration in the 2003 South Coast [Air Quality Manage-
ment Plan (AQMP)] in light of updated emissions inventories
that show higher mobile source emissions than prior projec-
tions and updated modeling that indicates a lower carrying
capacity in the air basin.”). However, even if EPA did not
actually know the extent to which the new modeling under-
mined the existing SIP, it has a duty to evaluate the adequacy
of the existing SIP as a whole when approving SIP revisions.
See Hall v. U.S. EPA, 273 F.3d 1146, 1159 (9th Cir. 2001)
(“The EPA must be able to determine that, with the revisions
in place, the whole ‘plan as . . . revised’ can meet the Act’s
attainment requirements.” (quoting Train v. Natural Res. Def.
Council, 421 U.S. 60, 90 (1975)). In partially approving the
2003 Plan, EPA should have analyzed the adequacy of the
whole 1997/1999 SIP.
766           ASSOC.   OF IRRITATED   RESIDENTS v. EPA
   [4] The closer question is whether, given the knowledge
that a previously approved SIP likely no longer meets the
Act’s attainment requirements, EPA has an affirmative obli-
gation to request a new attainment demonstration. Two sec-
tions of the Act may give rise to such an affirmative duty. The
first is the requirement that EPA issue a FIP when it disap-
proves any plan or plan revision. 42 U.S.C. § 7410(c)(1); see
also id. § 7509 (mandating sanctions upon disapproving a
required State submission). The second is the requirement that
EPA issue a SIP call upon a finding that the existing SIP is
substantially inadequate. Id. § 7410(k)(5).

   EPA argues that the FIP clock is triggered only where the
plan revision is “required” under the Act. The first step in
statutory construction cases is to begin with the language of
the statute. Barnhart v. Sigmon Coal Co., Inc., 534 U.S. 438,
450 (2002). The plain text refutes EPA’s argument. Section
7410(c)(1) states:

      The Administrator shall promulgate a Federal imple-
      mentation plan at any time within 2 years after the
      Administrator—

          (A) finds that a State has failed to make a
          required submission or finds that the plan
          or plan revision submitted by the State does
          not satisfy the minimum criteria established
          under subsection (k)(1)(A) of this section,
          or

          (B) disapproves a State implementation
          plan submission in whole or in part,

      unless the State corrects the deficiency, and the
      Administrator approves the plan or plan revision,
      before the Administrator promulgates such Federal
      implementation plan.
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA       767
42 U.S.C. § 7410(c)(1). Although subsection (A) applies to
“required” submissions, subsection (B), which applies to dis-
approvals of SIPs and SIP revisions, does not have such a
limit. “Nor should we infer as much, as it is a general princi-
ple of statutory construction that when ‘Congress includes
particular language in one section of a statute but omits it in
another section of the same Act, it is generally presumed that
Congress acts intentionally and purposely in the disparate
inclusion or exclusion.’ ” Barnhart, 534 U.S. at 452 (quoting
Russello v. United States, 464 U.S. 16, 23 (1983)).

   [5] EPA contends that reading subsection (B) as requiring
EPA to issue a FIP whenever it disapproves a discretionary
revision would “yield absurd results, because it would require
the agency to promulgate a FIP where the State’s fully
approved SIP remains in effect.” EPA provides as an example
a state proposing a revision to make an existing SIP less strin-
gent, arguing that requiring a FIP when EPA disapproves such
a relaxing of the SIP would be irrational. EPA’s point is well
taken in a situation where the existing SIP remains adequate
to attain the NAAQS. The facts in this case, however, are
much different because EPA knew, or should have known,
that the “fully approved SIP” was no longer adequate. While
it may seem counterintuitive to require EPA to promulgate a
FIP when it disapproves a revision seeking to undercut an
effective existing SIP, it is entirely logical to require EPA to
promulgate a FIP when it disapproves a revision seeking to
update what it recognizes are serious deficiencies in an exist-
ing SIP.

  [6] Furthermore, although the plain language requires a
FIP every time EPA disapproves a plan revision, the FIP can
be avoided if an existing plan is in place that meets the Act’s
requirements because § 7410(c)(1) has a grace period in
which states can bring their plans into compliance before the
FIP is enacted. See 42 U.S.C. § 7410(c)(1) (mandating a FIP
“unless the State corrects the deficiency”). EPA must simply
evaluate the existing SIP (as already required under Hall, 273
768          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
F.3d at 1159), and if it meets the Act’s requirements, EPA can
find that the state has “corrected the deficiency,” 42 U.S.C.
§ 7410(c)(1).

   This analysis aligns with Congress’s intent in writing the
statutory language to mandate promulgation of a FIP upon
any disapproval. In 1988, when Congress was debating the
amendments to the Clean Air Act, EPA sought an amendment
that would have left promulgation of FIPs solely to EPA’s
discretion. See Coal. for Clean Air v. S. Cal. Edison Co., 971
F.2d 219, 223 (9th Cir. 1992) (citing S. 1630, 101st Cong.
§ 105 (1989)). Although the Senate passed such an amend-
ment, a House Committee deleted the language, and the
“House language retaining EPA’s mandatory obligation to
promulgate a FIP whenever it disapproves a SIP was ulti-
mately enacted by Congress and signed into law.” Id. (citing
Clean Air Act Amendments of 1990, Pub. L. No. 101-549,
104 Stat. 2399).

   Even if, as EPA argues, the FIP requirement is triggered
only when the revision was “required” under the Act—and
not upon every EPA disapproval of a plan revision as we
determined above—the partial disapproval of the 2003 SIP
Revision here still triggers the FIP requirement because large
portions of the 2003 Attainment Plan were not discretionary.
For example, the Act explicitly requires states with nonattain-
ment areas to update their SIPs every three years with a
revised inventory of actual emissions from all sources of rele-
vant pollutants. See 42 U.S.C. §§ 7502(c)(3); 7511a(a)(3)(A).
Additionally, the Act requires transportation projects to con-
form to the existing SIP and states that, “[t]he determination
of conformity shall be based on the most recent estimates of
emissions, and such estimates shall be determined from the
most recent population, employment, travel and congestion
estimates . . . .” Id. § 7506(c)(1)(B). The conformity provi-
sions thereby require a state to submit a SIP revision to ensure
the MVEBs in the SIP are current, otherwise the state will not
be able to receive federal funding. Indeed, the 2003 SIP Revi-
               ASSOC.   OF IRRITATED   RESIDENTS v. EPA             769
sion explicitly referenced these two reasons in explaining why
it submitted the changes:

      The California Clean Air Act requires a non-
      attainment area to update its AQMP triennially to
      incorporate the most recent available technical infor-
      mation.[2] In addition, U.S. EPA requires that trans-
      portation conformity budgets be established based on
      the most recent planning assumptions (i.e., within
      the last 5 years). Both the 1997 SIP and the 1999
      amendments were based on demographic forecasts
      of the mid-1990’s using 1993 as the base year. Since
      then, updated demographic data has become avail-
      able, new air quality episodes have been identified,
      and the science for estimating motor vehicle emis-
      sions and air quality modeling techniques for ozone
      and PM10 have improved. Therefore, a plan update
      is necessary to ensure continued progress toward
      attainment and to avoid a transportation conformity
      lapse and associated federal funding losses.

   [7] In summary, EPA’s duty to issue a FIP represents one
statutory source of EPA’s duty to take further action upon
partial disapproval of California’s 2003 Attainment Plan.

   [8] Alternatively, EPA’s obligation to take further action
can be derived from the statutory requirement that the Admin-
istrator issue a SIP call upon a finding that the existing SIP
is substantially inadequate. 42 U.S.C. § 7410(k)(5)
(“Whenever the Administrator finds that the applicable imple-
mentation plan for any area is substantially inadequate to
attain or maintain the relevant national ambient air quality
standard . . . or to otherwise comply with any requirement of
this chapter, the Administrator shall require the State to revise
  2
   Although the 2003 SIP Revision references the triennial requirement in
the California Clean Air Act, the Federal Clean Air Act also mandates
such a triennial inventory. See 42 U.S.C. §§ 7502(c)(3); 7511a(a)(3)(A).
770          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
the plan as necessary to correct such inadequacies.”). EPA
argues that the decision about when and whether to review an
existing SIP for substantial inadequacy is entirely within the
Administrator’s discretion. In support of this argument, EPA
cites the text of the statute and two out-of-jurisdiction cases.
The text of § 7410(k)(5), however, only says that the Admin-
istrator must make the finding, not that the finding must be a
product of Administrator-initiated review procedures. The
two cited cases also provide little support for EPA because
they only show that the Administrator must have some discre-
tion in deciding whether to find a SIP substantially inade-
quate. See Sierra Club v. Johnson, 541 F.3d 1257, 1265-66
(11th Cir. 2008); Citizens Against Ruining the Env’t v. EPA,
535 F.3d 670, 677-78 (7th Cir. 2008). We do not dispute this
point. However, the question is not whether EPA has discre-
tion in determining substantial inadequacies exist, but whether
EPA has unlimited discretion to ignore evidence indicating an
existing SIP might be substantially inadequate and choose to
do nothing. We believe EPA’s failure to act in light of the
strong evidence provided in the 2003 SIP Revision demon-
strating the substantial inadequacies of the 1997/1999 Plan is
arbitrary and capricious. See Motor Vehicle Mfrs. Ass’n of
U.S. v. State Farm Mut. Auto Ins. Co., 463 U.S. 29, 43 (1983)
(“Normally, an agency rule would be arbitrary and capricious
if the agency . . . entirely failed to consider an important
aspect of the problem . . . .”); see also 1000 Friends of Mary-
land v. Browner, 265 F.3d 216, 235 (4th Cir. 2001) (leaving
open the possibility that “there may be cases where previously
performed modeling is inadequate to demonstrate attainment
such that EPA’s failure to require new modeling in those
cases might be found to be arbitrary or capricious”). EPA’s
decision to do nothing is especially troublesome in light of the
Act’s overall purpose of ensuring states come into compliance
with clean air standards. See 42 U.S.C. § 7470.

   [9] EPA also notes that a demonstration that the 1997/1999
SIP is outdated or ineffective is not equivalent to finding that
the SIP as a whole is substantially inadequate because a SIP
             ASSOC.   OF IRRITATED    RESIDENTS v. EPA      771
is a complex, multi-faceted set of obligations. Again, the
determination about whether the SIP is substantially inade-
quate is within the Administrator’s discretion. We merely
determine that the Act requires EPA to evaluate the existing
SIP and actually make the determination as to whether a new
attainment demonstration is required.

  [10] Because EPA’s failure to evaluate the adequacy of the
existing SIP was arbitrary and capricious in light of the 2003
SIP Revisions alerting EPA to the new modeling, we grant the
petition for review. Specifically, EPA has an affirmative duty
to ensure that California demonstrate attainment with the
NAAQS, see 42 U.S.C. §§ 7410(a)(2)(A), 7502(c)(6), either
by promulgating a FIP or evaluating the necessity of a SIP
call.

                                III

   EPA’s action in approving the pesticide element of the SIP
was arbitrary and capricious. EPA approved PEST-1—the
portion of the 2003 SIP Revision re-committing to imple-
menting the Pesticide Elements from the 1997/1999 Plan—in
its 2009 final action. Petitioners claim our decision in War-
merdam, 539 F.3d at 1072, in which we stated the Wells
Memorandum was not part of the existing SIP, rendered the
Pesticide Element’s commitments discretionary, thereby vio-
lating the Act. See 42 U.S.C. § 7410(a)(2)(A) (“Each imple-
mentation plan . . . shall include enforceable emission
limitations and other control measures, means, or techniques
. . . as well as schedules and timetables for compliance.”);
§ 7502(c)(6) (same).

  EPA does not address the merits of this contention. It only
argues that petitioners lack standing to challenge the Pesticide
Element. Specifically, EPA argues that petitioners’ injuries
were not caused by EPA’s 2009 rulemaking and cannot be
redressed by the relief they seek. We disagree.
772          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
   [11] Petitioners bear the burden of demonstrating a causal
connection between their injuries and EPA’s conduct. See
Lujan v. Defenders of Wildlife, 504 U.S. 555, 560 (1992).
EPA argues that because its 2009 action approving PEST-1
merely maintained the status quo with respect to the Pesticide
Element, either approval or disapproval would have resulted
in the same regulatory outcome: continuation of the existing
Pesticide Element as approved by EPA in 1997. EPA’s argu-
ment assumes incorrectly that approving PEST-1 does not
require an evaluation of the existing Pesticide Element as part
of the SIP as a whole. As we determined above, when EPA
approves a plan revision, it must ensure that the whole plan,
as revised, satisfies the Act’s requirements. Hall, 273 F.3d at
1159. This responsibility is even more important where, as
here, the revision simply reiterates the commitments of the
prior plan.

   EPA also claims it had a “false choice” because its
approval of PEST-1 did not make the Pesticide Element any
more or less enforceable. This contention is not entirely true.
Although EPA approved an identical plan in the 1997/1999
SIP, it wasn’t until our 2008 Warmerdam decision that EPA
approved the plan with the knowledge that the plan may not
include enforceable commitments. As first submitted in 1994,
EPA worried the Pesticide Element did not meet the require-
ments of the Act, primarily because it failed to include spe-
cific dates for adoption and implementation of the regulations
necessary to achieve the required reductions. See Warmer-
dam, 539 F.3d at 1067. EPA did not propose approval of the
Pesticide Element until California submitted the Wells Mem-
orandum, which committed to adopting any necessary regula-
tions by specific years and in specific areas. Id. In proposing
approval of the Pesticide Element, EPA responded to ques-
tions about the Pesticide Element’s enforceability by citing to
the Wells Memorandum, thereby indicating its belief that the
Wells Memorandum provided the required enforceable com-
mitments. See, e.g., 62 Fed. Reg. 1150, 1169-70 (Jan. 8, 1997)
(to be codified at 40 C.F.R. pt. 52). After Warmerdam, EPA
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA         773
affirmatively knew that the Wells Memorandum was not part
of the 1997/1999 SIP, and therefore its approval of PEST-1
(and by incorporation the existing Pesticide Element) in light
of this knowledge represents the causal link giving rise to
petitioners’ injuries.

   [12] EPA further argues petitioners cannot demonstrate
redressability because if it disapproves PEST-1 on remand,
the existing Pesticide Element as approved in 1997 would
remain in effect. As we determined above, however, any dis-
approval of a SIP revision triggers the FIP and sanction clocks
unless EPA determines the existing Pesticide Element has suf-
ficiently enforceable commitments to meet the Act’s require-
ments. See 42 U.S.C. §§ 7410(c)(1); 7509. Therefore, a
remand is required to allow EPA to make that determination.

                                IV

   [13] EPA’s failure to require transportation control mea-
sures was arbitrary and capricious. Petitioners contend EPA
violated the Act when it partially approved the 2003 SIP
Revision without requiring California to submit transportation
control measures to offset the emissions resulting from an
increase in vehicle miles traveled. EPA argues that because
aggregate motor vehicle emissions will decrease each year,
California did not need to adopt control measures. The dis-
agreement centers on one sentence in the Act requiring trans-
portation control measures “to offset any growth in emissions
from growth in vehicle miles traveled.” 42 U.S.C.
§ 7511a(d)(1)(A). The relevant sentence states in full:

    Within 2 years after November 15, 1990, the State
    shall submit a revision that identifies and adopts spe-
    cific enforceable transportation control strategies and
    transportation control measures [“TCMs”] to offset
    any growth in emissions from growth in vehicle
    miles traveled or numbers of vehicle trips in such
    area [“VMT”] and to attain reduction in motor vehi-
774           ASSOC.   OF IRRITATED   RESIDENTS v. EPA
      cle emissions as necessary, in combination with
      other emission reduction requirements of this sub-
      part, to comply with the requirements of subsection
      (b)(2)(B) and (c)(2)(B) of this section (pertaining to
      periodic emissions reduction requirements).

Id. § 7511a(d)(1)(A). Petitioners argue that in determining
whether to impose TCMs, EPA should identify the level of
emissions emanating solely from VMT in a prior year, and
use that as the baseline from which to measure the change in
emissions. EPA’s current approach, in contrast, is to use the
aggregate emissions from a prior year as the baseline against
which to measure the change in emissions. Aggregate motor
vehicle emissions reflects the combination of numerous vari-
ables unrelated to VMTs such as vehicle turnover, tailpipe
control standards, and use of alternative fuels. Because the
parties agree that VMTs will increase by around 30%, but that
aggregate motor vehicle emissions will decrease, the question
for the court is whether “any growth in emissions” can mean
any growth in aggregate motor vehicle emissions, or is unam-
biguous in meaning any increase in the level of emissions
solely from VMTs.

   To interpret § 7511a(d)(1)(A), we utilize Chevron’s “famil-
iar two-step procedure.” Nat’l Cable & Telecomms. Ass’n v.
Brand X Internet Servs., 545 U.S. 967, 986 (2005); Chevron,
U.S.A., Inc. v. Natural Res. Def. Council, 467 U.S. 837
(1984). To determine whether the phrase “to offset any
growth in emissions from growth in [VMT]” is ambiguous,
we must determine “whether Congress has directly spoken to
the precise question at issue.” Chevron, 467 U.S. at 842. “If
the intent of Congress is clear, that is the end of the matter;
for the court, as well as the agency, must give effect to the
unambiguously expressed meaning of Congress.” Id. at 842-
43. At Chevron step one, if, employing the “traditional tools
of statutory construction,” we determine that Congress has
directly and unambiguously spoken to the precise question at
issue, then the “unambiguously expressed intent of Congress”
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA       775
controls. Id. at 843 & n.9. In determining congressional intent,
we not only examine the precise statutory section in question
but also analyze the provision in the context of the governing
statute as a whole, presuming a congressional intent to create
a “symmetrical and coherent regulatory scheme.” FDA v.
Brown & Williamson Tobacco Corp., 529 U.S. 120, 131-33
(2000).

   [14] We begin with the plain words of the statute. The use
of the word “growth” in reference to both “emissions” and
“vehicle miles traveled” suggests two baselines: one pegged
to changes in emissions and the other pegged to changes in
VMT. EPA argues that petitioners’ interpretation reads the
phrase “growth in emissions” out of the statute because the
Act would then only require a simplistic analysis of whether
VMT is increasing. Although EPA is correct in stating that
any increase in VMT is very likely to result in an increase in
aggregate emissions, we cannot ignore the possibility that
with advances in clean car technology, one day VMT could
increase without a corresponding increase in emissions. If that
happens, under the statute, EPA would not need to impose
TCMs even though VMT increased. Therefore, although
some increase in emissions is required (such that there are two
baselines), it doesn’t change the ultimate question of whether
the baseline for the increase in emissions can be viewed in
terms of aggregate vehicle emissions (as EPA contends), or if
the baseline must be viewed as any increase in emissions due
solely to VMT.

   [15] EPA’s interpretation only gives effect to the second
clause of the relevant sentence, and not to the first. According
to the statute, states shall implement TCMs not only “to offset
any growth in emissions from growth in [VMT]” but also “to
attain reduction in motor vehicle emissions as necessary . . .
to comply with the. . . periodic emissions reduction require-
ments[ ].” 42 U.S.C. § 7511a(d)(1)(A). While the second
clause contemplates using TCMs to reduce aggregate emis-
sions, the first clause contemplates using TCMs to reduce
776          ASSOC.   OF IRRITATED   RESIDENTS v. EPA
emissions from VMT. See United States v. Wenner, 351 F.3d
969, 975 (9th Cir. 2003) (utilizing principles of statutory con-
struction to determine that general, catchall provisions should
not trump more specific provisions). Looking at both clauses
not only demonstrates that EPA’s interpretation—equating
“growth in emissions” with “growth in aggregate emissions”
—is redundant, it shows that Congress used the phrase “motor
vehicle emissions” when referring to aggregate emissions, but
simply “emissions from growth in [VMT]” when referring to
only those emissions from VMT.

   We conclude that under the plain text of § 7511a(d)(1)(A),
“any growth in emissions” refers to any increase in the level
of emissions emanating solely from VMT in a prior year.
Although there is no ambiguity in this provision that requires
consulting legislative history to reject the EPA’s contrary
interpretation, we note that the legislative history supports our
interpretation. The House Committee Report, for example,
specifically states how “growth in emissions” should be mea-
sured, explaining: “The baseline for determining whether
there has been growth in emissions due to increased VMT is
the level of vehicle emissions that would occur if VMT held
constant in the area.” H.R. REP. NO. 101-490, pt. 1, at 242
(1990). This Report is very persuasive because, “the authori-
tative source for finding the Legislature’s intent lies in the
Committee Reports on the bill, which ‘represen[t] the consid-
ered and collective understanding of those Congressmen
involved in drafting and studying proposed legislation.’ ”
Garcia v. United States, 469 U.S. 70, 76 (1984) (quoting
Zuber v. Allen, 396 U.S. 168, 186 (1969)). EPA even admits
that “it is true that the language of [the House Committee
Report] appears to support the alternative interpretation of the
statutory language,” and that “the original authors of the pro-
vision and [the House Committee Report] may in fact have
intended this result.” 57 Fed. Reg. 13,498, 13,522 (April 16,
1992) (to be codified at 40 C.F.R. pt. 52).

  [16] Further review of the legislative history provides
additional support for our conclusion. See, e.g., S. REP. NO.
             ASSOC.   OF IRRITATED   RESIDENTS v. EPA       777
101-228, at 44 (1989) (“Severe and extreme areas are required
to offset growth in vehicle miles traveled by implementing the
transportation controls listed . . . .”); 136 Cong. Rec. 16,956
(1990) (floor statement of Sen. Max Baucus, sponsor of the
legislation) (“It is clear that the goals of this bill—a healthy
and safe air supply for every American—will not be achieved
without implementing strategies that effectively limit the
growth in vehicle use in the major urban centers where pollu-
tion levels are the worst.”). Because the statutory language,
clearly supported by legislative history, demonstrates that
Congress has spoken directly to the question at issue, we do
not owe deference to EPA’s interpretation, Chevron, 467 U.S.
at 842-43; Wilderness Society v. U.S. Fish & Wildlife Serv.,
353 F.3d 1051, 1062 (9th Cir. 2003), and we grant the petition
for review.

                                V

   In summary, EPA’s approval of the 2003 SIP Revision was
arbitrary and capricious. EPA should have ordered California
to submit a revised attainment plan for the South Coast after
it disapproved the 2003 Attainment Plan. EPA should have
required transportation control measures. EPA is required to
determine whether the Pesticide Element has sufficient
enforcement mechanisms to satisfy the requirements of the
Act. We grant the petition for review and remand to the EPA
for further proceedings consistent with this opinion.

  PETITION GRANTED.
