# Unite d States Court of Appe als

F O R T H E D I S T R

I C T O F C O L U M B I A

C I R C U I T

Arg ued Oc tober 17, 2012 De cided January 4, 2013

No. 08-1250

N A TU R A L R E S O U R

C E S D E F E

N S E C O U

N C I L A N D S I E R R A C L U B , P E TI TI O N E R S

v.

E N V I R O N M E N TA L P R O TE C TI O

N A G E N C Y , R E S P O N D E

N T

F I N E P A R TI C U L A TE L I TI G

A TI O N G R

O U P E T A L ., I N TE R V E N O R S

Consolidated with 09-1102, 11-1430

On Petitions for Review of F inal Rules of the United States Environmental Protec tion Age ncy

Paul Cort arg ued the cause for the petitio n er s. Tim D. Ballo and David S. Baron enter ed appe ara nces.
Brian H. Lynk
, Att o rn ey , United States Depa rtment of J ustice, arg ued t h e ca u se for the responde nt. Geoffrey L. W ilcox and S t ephanie L. Hogan
, Attorney s, United States Environmental Protec tion Age ncy , wer e on brie f.
Charles H. Knauss
, Shannon S. Bro o me , Robert T. Smith
, Denise W

. Kennedy
, John A. Bryson
, Emily C. Schilling
,2

Leslie S. Ritts
, Norman W

. Fichthorn
, Lauren E

. F r eem an , Lucinda Minton Langwort hy and Lorane F. He b er t wer e on brief for the i n terve nors. Michelle M. Schoeppe enter ed an appea ranc e.
Be fore : H E

N D E R S O N and T A TE L , Circuit Judges
, and W I L L I A M S , Senior Circuit Judge

. Opinion for the Court filed by Circuit Judge H E N D E R S O N

. K A R E N L E C R A F T H E N D E R S O N , Circuit Judge : The four petitio n er s seek revie w of two final rules, promulg ated

1
p u rsuant to the Clean Air Act (CAA, Act), which g overn implementation of the national ambient air q u al i ty standard (NAA QS) for “fine ” particula te matter—that is, particula te matter (PM) having a diameter eq ual to or less than 2.5

2

2 .5 m i crometers (PM ). See Final Clean Air Fine Particle I mplementatio n R u l e, 72 Fe d. Reg

. 20,586 (Apr. 25, 2007)

2 .5 (PM I mplementation Rule); I mplementati o n of the New Source Review (NS R ) Prog ram for Particulate Matter L ess

2 .5 Than 2.5 Micrometer s (PM ), 73 Fe d. Reg

. 28,3 2 1 (M ay 16,

2 .5 2008) (PM NSR I mplementation Rule) (collec t i vely
, Final

They incl ude th e Nat

ura l Res our ce s Def

ens e Counc il
, Sie rr a 1 Club, Am er ic an L ung Ass oc ia ti on and Me dica l Advo ca te s fo r Hea lt

hy Air

.
“Pa rt ic u la te m at

te r is the ge ner ic te rm fo r a bro ad cl as s of 2 che m ic al ly an d phy si ca ll y div er se subst anc es that exis t as disc re te par ti cl es (l iquid dro plet s or so li ds) ov er a wid e ra nge of si ze s.” The par ti cl es “or ig inate fr om a va ri et y of anthr opo ge nic st at io nar y and

m obi le so urc es as w el l a s f ro m natur al so urc es ” and “ma y be em it te d dire ct ly or fo rm ed in the at m os phere by tr ans fo rm at io ns of ga se ous

x x emissi ons suc h as sulf

ur oxi des (SO ), nitr og en oxi des (NO ), an d

vo la ti le org anic co m

pounds (VOC) .” Nat io nal Am bient Air Qual it

y Sta ndards for Par

ti cula te Ma tt er , 62 Fed. Reg

. 38,6 52, 38,6 53 (July 18, 1 997).3

2 .5 PM I mplementation Rules). I n particula r, the petitioners 3 challeng e the decision of the Environmental Protection

2 .5 Age n cy (EPA) to promulg ate the Final PM I mplementatio n Rule s pursuant to the g ener al implementation provisions of Subpart 1 of Part D o f Title I of the Act, 42 U.S.C. §§ 7501- 7509a (Subpart 1), rathe r than the particula te-matter -spec ific provisions of S ubpart 4 o f P art D of Tit le I
, id

. §§ 7513-7513b (S u b p ar t 4). We ag ree with the petitioners that EPA err ed in apply ing the provisions of Subpart 1 rathe r than Subpart 4.

I.
Section 109 of the Act mandates that EPA establ i s h a primary NA AQ S for eac h air pollutant for which EPA has issued “air quality criter ia” u n d er CAA section 108. 42 U.S.C. § 74 0 9 (a )( 1 ). The Act define s eac h such NAAQS as 4 that s t an dard “the attainment and maintenanc e of which in the judgme nt of t h e Administrator, based on such criter ia and allowing an adequa

te marg i n o f safe ty , are requisite to protec t the public health.” Id

. § 7409(b)( 1). EPA is re quired to “complete a thoroug h revie w” of eac h pollutant ’s standard and air quality criter ia “at five-y ear in t ervals” and “make such revisions in such criter ia and standards and prom u l gate such

n ew standards as may be appropr iate.” Id

. § 7409(d)( 1). Onc e a NAAQS has been established, eac h state must adopt

Under the Act ’ s N S R pro vi si ons , new or m odi fi ed pol luta nt 3

so urc es m

ust m ee t “str ic t st andar ds,” w hile ex is ti ng so urc es ar e “ ‘gra ndfat her ed.’ ” New York v. U.S. EPA
, 413 F.3d 3, 13 (D.C. Cir

. 2005 ).

The Ac t al so re quire s EPA t o pro m ulg at e a se co ndary

st andar d, 4 “the at ta inm ent and m ai ntena

nce of w hich

. . . is re quisi te to pro te ct the public w el fa

re fr om any kno wn or an ti ci pate d adv er se ef fe ct s
as so ci at ed w it

h” the pol lutan t. 42 U.S.C. § 7409 (b)( 2). I n this ca se , EPA pro m

ulg at ed a si ngl e NAAQS as bot h the prim ar

y and the

se co ndary st andar d.4

and submit to EPA for approva l a State I mplementation Plan (SI P) that “provide s for implementation, maintenanc e, and enfor ceme nt of [t he NAAQS] in eac h air quality co n t rol reg ion (or p o rt ion there of) within such State.” Id. § 7410(a) (1). Eac h SI P must “include enfor cea ble emission limit ati o ns and other control measure s, means, or techniques

. . . , as wel l as s ch edules and timetables for compliance
, as may be nece ssary or appropriate to meet the [C AA’s] applicable require ments.” Id. § 7410(a) (2)( A).

Part D of C AA Title I g overns “Plan Requirements for Nonattainment Are as” (that is, are as that have not attained compliance with the applicable NAAQS) and Subpart 1 there of, added to the Act in 1977, addre sses “Nona ttainment Are as in Gene ral.” Subpart 1 provides g ener ally that, once EPA desig nates an are a as “nonattain ment,” it “may classify the are a” so as to establish an attainment d ea d l i n e and it must establish a schedule for the state encompa s s i n g the nonattainment are a to submit a SI P

. Id

. § 7502(a) (1)( A). The SI P, in turn, is re q uired, inter alia, to (1) provide for implementation of control measure s, (2) invent o ry exis ting emissions, (3) identify and quantify pollutant emis sions permissible under the SI P from the construction and opera tion of all major n ew stationary emission source s, (4) require NSR permits fo r such construction and opera tion and (5) establish compliance schedule s and ti metable s

. Id

. § 7502(c)

. Pursuant to this reg ime, in 1971, EPA established a particula te m att er NAAQ S applicable to “Total Suspended Particles,” i.e., particula te matter up to 25-45 micr ometers in diamete r.
I n 19 8 7
, E P A revised the NAAQS to apply only to

1 0 particle s equal to or smaller than 10 micrometer s (PM )—a “s ize-specific indicator” it deter mined “re prese nt[ ed] tho s e particle s small enoug h to penetr ate to th e t h o rac ic reg ion” beca use “[t] he ris k s o f adver se health eff ects associate d with depositio n of ty

pical ambient fine and coar se particle s in the5

thorax (trac heobronc hial and al v eolar reg ions of the respira tory trac t) are marke dly g rea ter th an t hose associate d wi t h deposition in the extrathoracic (hea d) reg ion.” Revisions to the National Ambient Air Qu al i t y Standards for Particulate Matter, 52 Fed

. R eg

. 24,634, 24,639 (Jul y 1, 1987) (footnote omitted) (1987 PM NAAQS Revisions).

I n 1990, the Congr ess amende d CAA Pa rt D b y adding to i t Subparts 2 throug h 5, eac h of which contains additional p ro v isions g overning nonattainment plan require ments for a particula r pollutant or g roup of pollutants. At i s sue here
, S u b p art 4 applies to “Particula te Matter Nonattainment Are as” and cover s such mat t er s as setting attainment dates for PM nonattainment are as, classify ing the n onattainment are as (as “moder ate” or “ser ious ”)
, reclassify ing them (e.g
., upon failure t o att ain) and extending attainment dates. 42 U.S.C. §§ 7513-7513b; s ee also id

. §§ 7511-7511f (ozone-spec ific require ments); id

. §§ 7512-7512a (ca rbon monox ide- s pecif

ic require ments).

I n 1997, EPA ag ain revised the particula te matter

2 .5 NAAQS, this time setting separ ate PM stand ar d s for fine particle s (having a diameter of 2.5 micrometers or less), while

1 0 reta ining the exis ting PM standards. National Ambient Air Quality Standards for Particulate Matter, 62 Fe d. Reg

. 38,652, 38,65 4 n n

. 5-6 (Jul y 18, 1997) (F inal PM NAAQS Rule). We upheld the new particul ate matter standards in 2002 afte r
rema nd from the United States Supreme Court. See Am. Trucking A s s ’n s v. EPA
, 283 F.3d 355 (D.C. Cir. 2002) (apply ing W

hi t man v. Am. Trucking Ass’ns
, 531 U.S. 457 (2001))

. I n 2005, EPA published its Proposed Rule T o I mplement t he Fine Particle National Ambient Air Quality Standards, 7 0 Fe d. Reg

. 65,984 (Nov. 1, 2005 ). EPA subsequently issued the final fine p ar t i cl e implementation rule in two stag es. I n

2 .5 2007, it published the PM I mplementation Rule, set ting out6

2 .5 the g ener al SI P requ i re m ents for PM

. EPA followed up in

2 .5 2008 with the PM NSR I mplementation Rule to g overn the

2 .5 NSR permitting proce ss. I n eac h of the two Final PM I mplementation Rules, EPA expressly followed the g eneral implementatio n p ro v isions in Subpart 1 of Part D rathe r than Su bpart 4’s particula

te-mate rial-spe cific provisions. See

2

. 5 P M I mplementation Rule, 72 Fe d. Reg

. at 20,589 (“EPA is

2 .5 issuing this rule to impleme n t t he 1997 PM NAAQS in

acc ord an ce with the statutory require ments of the CAA set forth in Subpart 1 of Part D of Title 1, i.e., sections 1 7 1 -1 7 9 B of the Act.

. . . EPA has conclude d that Congres s did not intend the Ag ency to implement particul ate matter NAAQS

1 0 other than those using PM as the indicator in acc ordanc e

2 .5 with Subpart 4 of Part D of T i t l e 1

. . . .”); PM NSR I m p l em entation Rule, 73 Fe d. Reg

. at 28,332 (“We do n o t

2 .5 ag ree t h at subpart 4 of part D applies to PM nonattainment

are as. Subpart 4 was added to the Act by Congr ess

1 0 specific ally to addre ss the PM NAAQS. We believe that the

2

. 5 PM s t andar d should be implemented under subpart 1 of part D, which is the g ener al provision of the Act rela ted to NAAQS implementation.”). The petitioners filed timely

2 .5 petitions for revie w of both the PM I mple mentation Rule

2 .5 and the PM NSR I mplementation Rule.

II.

We revie w EPA’s interpre tation of the CAA under C h ev r on U.S.A. Inc. v. Natural Res. Def. Council, Inc.
, 467 U. S. 837 (1984). See Natural Res. Def. Council v. EPA
, 4 8 9 F.3d 1250, 1257 ( D.C. Cir. 2007). Under Chevron :
We first ask “whe ther Congr ess has direc tly spoken t o the prec ise question at issue,” in which cas e we “must g i v e effect to the unambig uously expressed intent of Congr ess.” I f the “statute i s silent or ambi gu ous with respe ct to the specific issue,” howeve r, we move to the second step and defe r to7

t he ag ency ’s interpre tation as long as it is “base d o n a per missibl e construc tion of the statute.”
Id

. (quot ing Chevron
, 467 U.S. at 842-43) (other quotation marks omitted). Be fore addre ssing whether EPA corr ectly applied S u bpart 1 under the Chevron fra mework, we first consider the timeliness of the petitioners’ instant cha lleng e.
A.

EPA contends the petitioners’ challeng e i s untimely b eca use it should have been raised in 1997 when EPA issu ed the Final PM NAAQS Rule, which, EPA maintains, set out i ts final decision on Subpart 1’s applicability

. Be cause we conclude EPA did not take final revie wable action in 1997, the petitioners’ c halleng e is timely

. 5

I n urg ing that it fi n al ized its decision in 1997, EPA relies

on two excerpts from the prea mble to t h e 1 9 9 7 Final PM NAAQS Rule. First, EPA cites its response t o co mments

2 .5 challeng ing its authority to promulg ate a separ ate PM standard g iven that the 1990 amendments ref erred only to a

1 0 PM standard. At the conclusion of i ts response , EPA offe red the following defe nse of its authority to promul gat e the new

2 .5 P M standards, rooted in Subpart 1, couche d in plainl y tentative lang uag e:

2 .5 E P A’ s analy sis of its ability to implement a PM standard under the prov i s ions of subpart 1 of Part D of Title I does not support the view that Congr ess p ro h ibited EPA from promulg ating such a standard. Congr ess clea

rly specifie d an approa ch to the

2

. 5 EPA ac kno w le dge s the inst ant peti ti ons fo r rev ie w of the PM 5

2

. 5 I m plem enta ti on Rule and the PM NSR I m plem enta ti on Rule w er e ti m el y fi le d w it

hin si xty day s af

te r ea ch rule ’s publica

ti on as re quire d under 42 U.S.C. § 76 07(b)(1)

. See Br. o f Re sp’t 1.8

1 0 implementation o f the PM standard in the provisions of subpart 4 of P art D of Tit le I of t he Act. The EPA believe

s that the clea

r and express linkag e

1 0 of that approa ch t o t h e PM standard indicates that a differ ent PM standard should be implement ed under the gene ral prin ci p l es of subpart 1 of P art D of Tit le I of the Act. Th at C o ng ress direc ted specific ally how

1 0 EPA and the States sho u l d implement the PM standard does not car

ry with it the implication that Congr ess intended to prohibi t E P A from exercising its oth er wi s e clea

r and express authority to adopt a PM standard base d on a diffe rent metric

. . . . Final PM NAAQS Rule, 62 Fe d. Reg

. at 3 8
, 695 (empha ses added)

. Some pag es later, in a foot n o t e, EPA more aff irmatively
, albeit summarily
, stated its position that implementation of the new standard need not and would not be gover ned b y S u b part 4: “The SI P require ments of subpart 4 of Part D of Title I of the Act apply to SI Ps for are as

1 0 desig nated as not attaining NAAQS for PM

. Those

2 .5 require ments will not apply to SI Ps to impleme n t t h e PM NAAQS.” Id

. at 38,704 n.96. We conclude t h es e two unembellished snippets, buried in the prea mb l e to the 1997 Final PM NAA QS R u le, did not constitute final ag ency action so as to be re viewable in 1997.

“A final ag ency action is o n e t h at marks the

consum mation of the ag ency ’s decisionmaking proce ss and that establish es ri g hts and obliga tions or cre ates binding leg al conseque nces.” Natural Res. Def. Cou n cil v. EPA
, 559 F.3d 561, 564 (D

. C. Cir. 2009) (citing Benne tt v. Spear
, 520 U.S. 154, 177-78 (1997))

. We have observe d that “[w ] h ile prea mble statements,” such as those just quoted, “may in

some unique case s constitute b i n d i ng , final ag ency action susceptible to jud i ci al revie w, this is not the norm.” Id

. at9
564-65 (citations omitted). As this case is n o t a “unique” one,
we a dhere to the norm.
The above quoted excerpts appear in a document expressly intended to “desc ribe[] EP A’ s decision to revise the

n at i o nal ambient air quality standards (NAA QS) for particula te matter (PM),” Final PM NAAQS Rule, 62 Fe d. R eg. at 38,652 (empha sis added) —it did not purport to detail how t h e revised standards should be implemented. I ndeed, E P A had ear lier addre ssed the issue of implementation in a separ ate I nterim I m p l ementation Policy on New or Revised Ozone and Particulate Matter (PM) National Ambient Ai r Quality Standards (NAA QS ), 61 Fe d. Reg

. 65,752 (De c. 13, 1996) (I nterim I mplementation Policy ). Although the I nterim I mplementation Policy likewise express ed an intent to apply

2 .5 Subpart 1 to implement the PM standard, 61 Fe d. R eg. at 65,753, it made clea

r that, as its name sugges t s , i t was only a temporar y policy
, which “would repr esent EPA’s pr eliminary views” and “while it m[ ight] include various statements that States must take cer

tain actions, these statements [we]re made pursuant to EPA’s preliminary inter p retations , and thus d[i d]
not bind the Stat es and public as a matter of law.” Id

. at 65,752 (empha ses added)

. Acc ording ly
, “[o] nly afte r E P A ha[d] made its interp re t ations final throug h rulemaking ”— “f o l l o w[ i n g] t h e re q u i re m en t s o f t h e A d m i n i s t ra t i v e Procedur e Act, 5 U.S.C. section 553(b) and (c) ”—“w ill they be binding on the States and public as a matter of law.” Id

. Given EPA’s exp re s s ed intent to issue a final, binding noticeand-c omment rule on the issue—to supplant its “pre limin ary ” policies—we do not see how the q u o t ed lines from the prea mb le to the 1997 rule revising the standard itself “mar k the consummation of the age ncy ’s decisionmaking proce ss”

on how to implement the standard s o as t o constitute final ag ency action. Benne tt v. S p ear , 520 U.S. at 177-78 (interna l quotation marks omitted). I nstead, we conclude EPA consummated the decisionmaking proce ss to impl ement the10

2 .5 PM standard only when it publi s h ed its final views in the

2 .5 two Final PM I mplementation Rules now under revie w. Notwithstanding its express and indefinite defe rra l o f a final impl em en t ation policy in 1997, EPA arg ues the Supreme Court’s decision in W hitm a n v. A me r i ca n T r u cking Associations
, 5 3 1 U.S

. 457 (2001), require s us to hold otherwise. We a

re not so per suaded.

I n W hitman, the Supreme Court revie wed EPA’s d ecision to implement its “8-hour ” 0.08 ppm NAAQS for ozone— which repla ced the previous 1-hour ozone standard of 0.12 ppm—u n d er S u b p ar t 1 ’s gen er al n o n at t ai n m en t area provisions rathe r than under Subpart 2’s ozone-specif ic provisions added in 1990. See National Ambient Air Quality Standards for Ozone, 62 Fe d. Reg

. 38,856, 38,873 (Ju l y 18, 1997) (F inal Ozone NAAQS Rule) (“[ T ] he provisions of subpart 1 of part D of Title I of the Act would apply to the

3 implementat i on of the new 8-hour O standards.” ). The Court conclude d that, in the m ain, t he new ozone NAAQS s h o u ld be implemented pursuant to Subpart 2 notwithstanding Subpart 2

was enac ted to addre ss the former 1-hour stand ar d and some provisi o n s might there fore be “ill fitted to implementation of the revised st an d ard” and thus leave “g aps” for EPA to fill

u n d er Chevron step 2. W hitman
, 531 U.S. at 483-84. The W hitman Court first addre ssed the th re shold question whether Subpa rt 1 constituted final ag ency action subject to revie w and conc luded that it did. See id . at 477-78.
Addre ssing the I nterim I m plementation Policy
, which

cover ed both t h e o zone and the particula te matter standards, the W hitman Court ac k n o wledg ed: “I f the EPA had done no more, we p er h ap s could acc ept its curr ent claim that its action

was not final.” Id

. at 477. The Court expl ained, howeve r, that, vis-à-vis the ozone sta n d ard, EPA had done “more .” After the Whit e House issued a “ ‘Memora ndum for the Administrator of the Environment al Protection Ag ency ’ that11

presc ribed implementation proce du re s for the EPA to follow,” EPA “supplemente d this memorandum with an explan ati on of the implement ati on proce dures.” Id .; see I mplementation of Revised Air Quality Standards for Ozone and Particulate Matter, 62 Fe d. Reg

. 38,421, 38
, 4 22 (Jul y 18, 1997) (Memora ndum of J uly 16, 1997); I mplementation Plan for Revised Air Quality Sta ndards, 62 Fe d. Reg

. 38,423 (I mplement at i o n Memorandum Supplement). I n a section of t h e Im p l e m e n t a t i o n M e m o r a n d u m S u p p l e m e n t t i t l e d “I mplementation of Ozone Standard,” EPA explained that,

a f t e r r e c e i v i n g co m m en t s o n t h e p ro p o s ed I n t e r i m I mplementation Policy
, it had “re considere d” its interpre tation in part an d d etermined that “Subpart 2 should continue to apply as a matter of law for the purpose o f ac hieving attainment of the curr ent 1-hour standard.” Id

. at 38, 4 2 4

. But EPA made clea

r it adher ed to its previously expres s ed v i ew that “[o] nce an are a attains the 1-hour standard, those provisions will no longe r apply and the are a’s imple m en t at ion of the new 8-hour standard would be g overned o n ly by the p rovi sions of Subpart 1 of Part D of Title I .” Id

. E P A

s u b s e q u e n t l y “ p u b l i s h e d [ t h i s i n t e r p r e t a t i o n ] i n t h e explanatory prea

mble to its final o z one NAAQS under the heading
, ‘Fi n al decision on the primary standard.’ ” W hitman
, 531 U.S. at 477-7 8 (citing Final Ozone NAAQS Rul e, 62 Fe d. Reg

. at 38,873). Ba sed on this chronolog y , the Supreme Court found EPA’s ozone implementat i o n policy was fina l and re viewable , explaining:
The EPA’s “dec isionma k ing proce ss,” which beg an with the 1996 proposal and co ntinued with the

rec eption of publi c comments, conclude d when the ag ency , “in light of [t hese co m m ents],” and in conjuncti o n with a corr esponding direc tive from the Whit e House, adopted the interpre tation of Part D at issue here

. Since that interpre tati o n issued, the EPA has ref used in subsequent rulemaking s to rec ons i d er12

it, explainin g t o disappointed commenter s that its

ear lier dec ision was conclusive.

W h i t man , 531 U.S. at 478-79 (citing 63 Fe d. Reg

. 31,0 1 4
,

2 .5 31,018-19 (1998))

. The h i s t ory of the PM standard reve als

n o c o m p a r a b l e d e c i s i o n m a k i n g p r o c e s s r e g a r d i n g i m p l e m e n t a t i o n

. T h e Im p l e m e n t a t i o n M e m o r a n d u m Supplement did not even mention Subpart 1 or S ubpart 4 in i ts

2

. 5 d i s c u s s i o n o f t h e P M i m p l em en t at i o n

— m u ch l e s s distinguish betwee n them or di scuss their applicability v el n on

2 .5 to implementation of the PM standard. See 6 2 Fe d. Reg

. at

2

. 5 3 8
, 427-29 (sec tion titled “I mplementation of New PM NAAQS”)

. Nor did EPA there afte r overtly trea t its “interim”

2 .5 PM implementation policy as final when it promulg ated the

2 .5 2007 and 20 0 8 Final PM I mplementation Rules challeng ed here

. Acc o rding ly
, we conclude the petitioners’ challeng e is timely and proce ed to EPA’s substantive decision to implement the NAAQS under Subpart 1.

B.

EPA contends that beca

use Subpart 4 repe atedly re fer s to

1 0 2

. 5 P M

— ra t h er t h an t o P M o r “p ar t i cu l at e m a t t e r ” gen e r al l y

— t h e s t at u t o ry l an gu age l i m i t s S u b p ar t 4 ’s

1 0 applicability t o i mplementation of the curr ent PM standard.

2 .5 Thus, by defa

ult, EPA co ntends, PM must be implemented pursuant to the g ener al (and les s stringe nt ) implementation 6

For exa m ple, (1) Subp ar

t 4 re quire s a nona tt ai nm ent ar ea to be 6 cl as si fi ed as “mo der at e” and upon fa il ure to at ta in to be re cl as si fi ed as “se ri ous ,” 42 U.S.C. § 7513 (a )- (c ), w hile under Subp ar t 1, EPA “ma

y ” but is n ot require d to cl as si fy a nona tt ai nm ent ar ea , id

. § 7502 (a )( 1)(A) ; (2) under Subp ar t 4, a “se ri ous ” at

ta inm ent date m ay be exte nded onl y onc e (f

or a m axim

um of 5 y ea

rs ) and onl y if the SI P incl udes the “m os t s tr ing ent m ea sure s” incl uded in any st at e’s SI P or
ac hiev ed in any State an d fe as ible fo r the ar ea , id

. § 7513 (e ), w hile Subp ar t 1 a ll ow s at

ta inm ent date exte nsio ns of up to 10 y ea rs w it h no13

proce dure in Subpart 1. This arg ument ignor es the plain meaning of the statute a

nd the lesson of W

hitman

. Be fore the Congr ess enac ted Subpart 4, EPA had

1 0 promulg ated a single particula te matter standard—the PM sta n d ard—w hich encompa ssed all particula te matter with a diamete r of 10 micrometer s or less—including both coar se and fine particula te matter, that is, particula te matter now

1 0 2 .5 g overne d by both the PM and PM standards— an d the 1990 CAA amendments adopted this broa d meaning in

1 0 defining “PM .” 1987 PM NAAQS R evisions, 52 Fe d. Reg

. at 2 4 ,639 (“The Administrator

. . . has decide d to repla ce [Total Suspended Particles] as the particle indicator for the primary standards with a new indicator that includes only t h o se particle s less than a nominal 10 [m icromete rs] i n diameter

. . . . I n defining the s tandar ds for particula te m atter,

1 0 this new indicator is termed PM .”); 42 U.S.C. § 7602(t) (“The term ‘PM-10’ means particula te matt er with an
aer ody namic diameter less than or equal to a n ominal ten micrometer s

. . . .”). T h u s , b y its express terms, Subpart 4,

1 0 when enac ted, g overne d all PM particle s, incl u d i ng those

2 .5 now denominated PM

. The scope of the statutory definition—and conseque ntly of Subpart 4’s appli cation—did

1 0 not chang e when EPA subdivided PM by reg u l at ion. As the

“ st ri nge nt m ea sure s” re quire m ent ther ef or , id

. § 7502 (a )( 2)(A) ; (3) Subp ar t 4 subject s a “se ri ous ” nona tt ai nm ent ar ea that fa il s to ti m el y at ta in to a m andat or

y annual 5% pol luta

nt re ducti on, id

. § 7 5 13a(d),

w hile Subp ar

t 1 i nclude s no s uch re quire m ent; (4) Subpart 4 r equir es that “rea so nable av ai la

ble co ntro l meas u res” m ust be im plem ente d

w it hin 4 y ear s af

te r des ig nati on, id

. § 7513 a( a) (1)( C), w hile Subp ar t 1 re quire s suc h m ea sure s be imp lem ente d “as expedi ti ous ly as pra ct ic able ,” id

. § 7502 (c )( 1); and (5) Subp ar t 4 re quire s that bes t

av ai la ble co ntro l m ea sure s be im plem ente d no la te r tha

n 4 y ea rs af te r
an a re a i s c la ss if

ie d or re cl as si fi ed a s “se ri ous ,” id . § 7 513a(b)( 1)(B)
, w hile Subp ar

t 1 has no bes t a

va il able co ntro l m ea sure s r equir em ent.14

W hitman Court made clea r, the intent of the 1 9 9 0 amendments was t o limit the broad implementation discretion Subpart 1 had previously g rante d EPA. Cf. W hitm a n , 531 U.S. at 484 (“The principal distinction betwee n Subpart 1 and Subpart 2 is that the l at t er eliminates reg ulatory discretion that the former allowed.” ). I t makes no sense then that the Congr ess would have wanted EPA to rela x Subpart 4’s more stri ng ent, nondiscretionar y require ments for implementing

2 .5 the PM standard at the same time EPA decide d to

2 .5 streng then the PM standard itself based on “ev i d ence from

numerous health studies demonstrating that serious health eff ects are associate d with exposures to eleva t ed l evels of

2 .5 2 .5 PM .” PM I mplementation Rule, 72 Fe d

. R eg. at 20,586;

see also id

. at 20,586-87 (“E p i d emiologic al studies have shown statis tically signific ant corr elations betwee n eleva ted

2 .5 PM levels and prema ture mortality

. Other important ef fe cts

2 .5 associate d with PM exposure include ag g rava tion of respira tory an d car diovascular disease (as indicated by incre ased hospital admissions, eme rg ency room visits, ab s en ces from school or work, and restric ted activity day s ), chang es in lung function and incre ased respira tory sy m p t oms,
as well as new evidenc e for more subtle indicators of

car diovascular hea lth. I ndividuals particula rly sensitive to

2 .5 PM exposure include older adults, people with hear t and lung d isease, and children.” ). Notwithstanding the plain 7

The re gul at io ns’ tr ea

tm ent of pre cur so rs pro vi des a use ful 7

exa m ple of how the Age ncy has use d Subp ar t 1 to es ta

blis h a le ss st ri nge nt im

plem enta ti on re gi m e th an env is io ned by Subp ar t 4. Am m oni a is a pre cur so r to fi ne par ti culate matter, m ak ing it a

2

. 5 1 0 1 0 pre cur so r to b oth P M and PM

. For a PM nona tt ai nm ent ar ea go ve rne d by Subp ar

t 4, a pre cur so r is pre sum

ptiv el y re gul at ed. See 42

2

. 5 U.S.C. § 7513 a( e)

. But under th e P M rule s cha ll eng ed her e, the EPA es ta blis hed a re butta

ble pre sum

ptio n ag ai nst re gul at ing am m oni a unles s a Sta te or the EPA “prov ides an appro pria te te chnic al dem ons tratio n” that sho w s em is si ons fr om am m oni a “sig nifi ca

ntly15
meaning of the statutory lang uag e and the forc e of W hitman
, 8 EPA offe rs sever al unconvincing arg ument s to support

2 .5 i m plementing the new PM standard pursuant to Subpart 1 rathe r than Subpart 4. First, E P A claims Subpart 4 “conta ins require ments that

1 0 are ex p re ssly based upon the form of the PM NAAQS.” Br

. o f R esp’t 31. This may be true but Subpart 4 also expressly g overns implementation of the “P M -10” standard, see 42 U.S.C. §§ 7513-7513b
, and the Act define s “PM-10” as “par ticulate matter with an aer ody namic diam eter less than or

2

. 5 contr ibute to PM co nce ntra ti on in the nona tt ai nm ent ar ea .” 4 0 C.F.R. § 51.1 002(c)( 4)(i ). When Cong re ss ena cted Subp ar t 4, it

so ught t o e nd this a dm inis tr at iv e g am es m ans hip.

E P A of fe rs se ve ra l gr ounds to dist ing uish W hitman —no ne of 8 them per sua si ve

. Firs t EPA not es that the te xt of Sub p art 2 re fe rs ge ner ic al ly to “oz one ” wh ile Subp ar t 4’s te xt re fe rs spe ci fi ca ll y to

1 0 PM
, EPA Br. 36—but Subp ar t 4’s ti tl e re fe rs ge ner ic al ly to “Part ic ulat e Ma tt er ” and, as w e hav e not ed, w hen the 1990

1 0 2

. 5 am endm ents to the CAA w er e ena ct ed, PM in cl u ded PM under bot h the new st at

uto ry def init io n and the exist in g E PA def init io n. Sec ond, EPA ar gue s that S u b par t 4’s pro vi si ons do not “co m pre hensi ve ly pre sc ri be[ ] cla ss if ic at io ns and atta inm ent date s for all par ticula te m at te r nona tt ai nm ent ar ea s.” Br. of Res p’t 37 (e m phasi s in or ig inal ). Subp ar t 4 m ay not be as co m

pre hensi ve as Subp ar t 2 but it s re quire m ents ar e spe ci fi c, m or e st ri nge nt and fa

r le ss disc re ti ona

ry than Subp ar

t 1. See supra not e 6. Third, EPA co ntends

2

. 5 that in co ntra st to W

hitman
, EPA’s appli ca

ti on of Subp ar

t 1 to PM d oes not re nder Subp ar

t 4 “utte rl y nuga

to ry ” bec aus e Subp ar

t 4 st il l

1 0 appli es to the remain in g PM st andar d. Br. of Res p’t 37 (quot ing W hitman
, 531 U.S. at 484). B u t if EPA’s inte rpre ta ti on st ands, Subp ar t 4 w il l be “utte rl y nuga to ry ” w it h re spe ct to im

plem enta ti on of

2

. 5 the PM st andar d—not

w it hsta nding the Cong re ss expre ss ly dire ct ed

1 0 2 5 the st andar d ap p li ca

ble to al l PM par

ti cl es , incl uding PM
, be

re gul at ed under Subpart

4.16
equal to a nominal ten micrometer s,” 42 U.S.C. § 7602(t). T hus, under Chevron step 1, EPA must implement al l

1 0 2

. 5 s t a n d a r d s a p p l i c a b l e t o P M

— i n c l u d i n g i t s P M standards—pur suant to Subpart 4. Second, EP A urge s that beca use i n the 1987 PM NAAQS Revisions, i t “had considere d whether to establish a separ ate

2 .5 NA AQS for fine particle s, using PM as the indicator,” the Congr ess should have fore seen that it might do so later. Br

. o f Resp’t 32. I t is not at all clea r that the Congr es s s h o u l d have so fore seen—EPA cites a single
, vag ue foot note to

s upport its claim the Congr ess was on notice such a chan ge
was likel y

. Id

. at 32 (citing 52 Fe d. Reg

. at 24,639 n.2 (“Par ticles in ambient air usually occur in two somewhat overla pping siz e distribut i o n s , fine (diamete r less than 2.5 [m icromete rs]) and coar se (diamete r larg er than 2.5 [m icromete rs]. T h e two siz e fra ctions tend to have differ ent orig ins and composition.” (staff document citation omitt ed))

. But eve n wer e such notice clea r, it does not follow that the

2 .5 Congr ess there fore intend ed t hat a separ ate PM standard (if promulg ated) be ex empt from Subpart 4’s require ments. As in W hitman
, the possibili ty of such a chang e s ug g ests only that gap s resulting there from might “pre vent us from concluding that Congr ess clea rly intended [ t h e specific pollutant subpart] to be the exc lusive, per ma n ent means of enforci n g a revised ozone standard in nonattainment are as.” W h i t ma n , 531 U.S. at 484 (empha sis added)

. I t does not rende r “utterl y n ug atory ” the restric tions that the 1990 amendments imposed on EPA’s discretion in implementing the particula te matter s t andar ds for all particle s 10 micrometer s or less in diam et er

. See id

. As the Supreme Court observe d reg ar d i n g Subpart 2, “[a] plan rea ching so far into the fut u re was not enac ted to be abandone d the next time the E P A re v i ew ed the [pol lutant’s] standard—which Congr ess knew c ould happen a t any time.” Id . at 485.17

EPA also arg ues that the Congr es s “could have easily used the g ener al term ‘par ticulate matter,’ rathe r than the specific term ‘PM -10.’ ” Br

. of R esp’t 33. That t h e C ong ress

1 0 could have done so does not neg ate the re ali ty that the “PM ” standard to which the Congr ess ref err ed in fac t included fine

2 .5 PM (both un d er the 1987 Rule and the 1990 statutory definition).

I n a final Chevron step 1 eff ort , E P A asser

ts that the leg islative history makes the Congr ess’s intent clea r. Assuming leg islative history could overr ide th e plain, unambig uous direc tive of Subpart 4, the history cited here is unconvincing

. EPA relies o n a single cong ressman’ s statement: “ ‘The Title I PM-10 provisions of H.R

. 3030

so mewhat resc hedule the attainment dates that would otherwise apply under the PM-10 s t an d ards as promulg ated by EPA.’ ” Br

. of R esp’t 39 (quoting A Legislati ve Hi s t o r y of the C lean Ai r Act Amendments of 1990
, at 2996 (Com m. Print 1993) (statement o f Rep. J ohn Murtha))

. This statement

av ai l s EPA noug ht. “[P] utting to one side the fac t that this

wa s the statement of a single [m ember of Congr ess],

. . . it i s not nece ssarily inconsistent with” the petitioners’ view that

2 .5 Subpart 4 conti nues to apply to PM standards. See Grand Canyon Air Tour Coal. v. FAA
, 154 F.3d 455, 474 (D.C. Cir. 1998). At the time t h e s t atement was uttered, “the PM-10 stand ards as promulg ated by EPA” applied to all particula te matter having a diameter equal t o o r l ess than 10

2 .5 microm eter s—including what is now denominated PM

. 9

Mo re ov er , “

j u dge s m

ust exe rc is e extr em e ca utio n bef

or e 9

co ncluding th at a st at em ent m ade in fl oo r debat e, or at a hea ri ng, or print ed in a co m

m it te e doc um ent m ay be ta

ke n as st at

uto ry go spe l, in li ght of the endem ic inte rpla y , in Cong re ss , of pol it ic al and le gi sl at iv e
co nside ra ti ons li ke ly unrel at ed to the inte rpre ti ve ta sk s of a co urt.” Tex

. Mun. Power Agency v. EPA
, 89 F.3d 858, 875 (D.C

. Cir

. 1996 ) (pe r cur ia m ) (quot at io n m ar

ks and al te ra ti ons om it

te d). Her e, it is18

See 1987 PM NAAQS Revisions, 52 Fed. Reg . at 24,639.

EPA additionall y ar gu es t h at i t s “re ading of the act is, at minimum
, a ‘per

missibl e’ interpre t at ion entitled to defe renc e under Chevron step two.” Br

. of Resp’t 41 (upper case lowere d). This arg ument is fore closed, howeve r, under Chevron step 1 bec ause the statute is plain on its face.

For the fore g oing rea sons, we g rant the p et i t ions for

re view of the Final Clean Air Fine Particle I mplementatio n Rule, 72 Fe d. Reg

. 2 0
, 5 86 (Apr. 25, 2007), and the I mplementation of the New Source Review (NSR) Prog ram

2 .5 for Particulate Matter L ess Than 2.5 M i crome ters (PM ), 73 Fe d. Reg

. 2 8
, 3 2 1 (May 16, 2008). We rema nd to EPA to repromulg ate these rules pursua n t to Subpart 4 consistent with this opini on. 1 0

So ordered

.

h ar d to ig nor e “the ir ony that [EPA] poi nts to the same fl oo r st at em ent that the [pe ti ti one rs ] con tend[] suppor ts [t heir ] oppo si te vi ew .” Grand Canyon Air Tour Coal. , 154 F.3d at 474 (e m phasi s in

or ig inal ).

I n lig ht of our dispo si ti on, w e ne ed not addre ss the pe ti ti one rs ’ 1 0 cha ll eng e to the pre sum

ption s in 40 C.F.R. § 51.1 002(c)( 3)- (4) that

2

. 5 vo la ti le or ga

nic c om pounds a nd am m oni a a re not PM pre cur so rs as Subp ar t 4 expre ss ly go ve rns pre cur so r pre sum ptio ns. See 4 2 U

. S

. C. § 7513 a( e)

. Mo re ov er , w e decl ine the p et it io ner s’ inv it at io n to se t a dea dline fo r EP A upon re m and or to re ta in jurisdict io n pending such

ac ti on. See Natural Res

. Def

. Council v. EP

A
, 4 8 9 F.3d 1364
, 1375 (D.C. Cir

. 2007 ) (“We d ec li ne to se t a tw o y ea r li m it on EPA’s procee dings on re m and as the NRDC re quest s; m andam us af fo rds a
re m edy fo r undu e dela

y .”) ; North Caroli na v. EPA
, 550 F.3d 1176
, 1178 (D.C. Cir

. 2008 ) (pe r cur ia m ) (de cl ining inv it at io n to “im pos e a def init iv e dea dline by w hich EPA m ust co rr ec t [c le an ai r rule ’s] fl aw s” and re m inding peti ti one rs of av ai la bili ty of m andam us).