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-. UNITEDSTATES ENVIRONMENTALPROfECTlONAGENCY OfficeofAir QualityPlanningandStanUards ResearchTrianglePark. NorthCarolcna27711 

# 4

# SEP1992 *

SUBJECT: 

### Procedures for 

### Processing ignate meas 

### to Attainment

FROM:

. 

### John Calcagni, 

### Direc AirQuality 

### nantsgeme
'TO: 

### Director, Air, 

### Pesti 

### s and 

### Toxics Division, Regions Director, Air

### and Waste 

### Management Division, 

### Region I1 Dirbctor; Air, 

### Radfazi~n and Toxics Division, Region 

### 1x1 Director, Airand Radiation Division, Region V

. 

### Director, Air, Pesticides 

### and Toxics Division, 

### Region VI 

### Director, 

### Air and Toxics Division,
* 

### Regions 

### VXI, VIII, IX, 

### and X



### mse
The 

### dffice of Air ~uality Planning and Standards (OAQPs) eipects mata 

### n&r of redesignation requests will be submitted in the near 

### future. Thus, 

### Regions will need 

### to have quidance 

### on the applicable

### procedures for handling these 

### requests, including maintenance plan prwisfons. Thism;amora.ndup~, therefore, 

### consolidates the 

### ~nviromentkl Protection

### Agency's (EPAfs) guidance regarding the processing sf requests for redesignation of nonattair~a~t areas to attainment far 

### ozone (Oj), 

### carbon monoxide (CO), particulate matter (QM-IQ), sulfur dioxide (SO2), 

### nitrogen dioxide [NO ), 

### and lead (Pb).. Regions should use thzs guidance as a genera? framework 

### for drafting Federal

## mtex notices pertaining to red~tsi~natian requests. Special 

### concerns for areas seeking redesignation from unclassifiable t~ attainment will be addressed on a case-by-case basis,

Section 187(dj(31(~) sf the clean Air Act, as amended, ignated to attainment 

### %@PIW1. The EPA has determined that the national 

### anbient 

### air quality 

### standards (NMQS) have been attained.

2. The applicable 

### implementationplan 

### nas henfully approved by EPA under section llO(k), -..ILLI

__LI 3, The EPA has determined that the improvement in 

### air quality isdue to 

### permanent and enforceable reductions 

### in 

### emissions.
8, The State fias 

### met dl'i 

### app22~~Je 

### er~i~~vts 

### fnr llbe 

### area under saction 110 

### and Part DI
5, 'The

### EPA has 

### fully approved a 

### maintenance. plan, 

### including a contingency 

### plan, 

### far the 

### area under section 175A. -A.

# -
+he- 

### czitsda is discus~ed

### in more detail 

### in the following paragraphs, 

### -Particularattention 

### is.given to 

### maintenance plan provisio~s

### at.-khe.end of this

### docunant since 

### maintenance glans constitute a 

### new requirement under the amended Clean 

### Air Act. .Exceptionsto the guidance willbe considered on a case-by-case basis.

The State

### must show that the 

### area is

### attaining the applicable NMQSo There are tw 

### components involved in making this 

### demonstration 

### which should 

### be 

### considered interdependently. 

### - The 

### fixst component relies upon The 

### e product of ambient 

### monitoring Mat

### is 

### representative of the area og highest 

### concentration. These monitors ~h~~ld remain 

### at the saae 

### location 

### for the 

### duration of the

### monitoring 

### period required 

### for demonstrating attainment. The data 

### should be collected md quality-assured 

### in accordance 

### with 40 CFR 58 and recorded 

### inthe 

### Aercmetxic 

### ~nformation Retrieval System (AIRS) 

### in order 

### for it to be available to the 

### public 

### for review. For purposes of redesi-qnation, 

### the 

### Regional Offiar

### sbuldverify that 

### the

. integrity 

### of the 

### air quality 

### monitoring net:mrR 

### &as 2wm preserved.

Sa3tP 

### 3ymms df

7W3.T 

## "mw, Wxpp*~ 

### to 40 

### eER Wd~&*# ke&-"may*@'

a

### *a ;a*** For d3, the 

### must that the 

### average anrmal 

### number of expected exce&anees, according t;o 40 CFR 50.9, isless than or equal t~ Z.0 

### baaed 

### an data 

### from all

### monitoring 

### sites 

### in the 

### area or its affected 

### downwind environs. 

### xrr making this showing, btbPH-10 

### and O3 aust rely an 3 complete. 

### consecutive calendar years of quality-assured air quality lnanitoring data, 

### callacted in 

### accordance with BO CPR 50, ~ppcndices K 

### and K. For CO, 

### an area oay be considered attaining &he NMOS if there 

### are no violations, as 

### aatsnnined in acrcotdancewith 40 CFR 50.8, based 

### on 2 

### complete, 

### consecutive calendar years of quality-assured 

### monitoring data. 

### Ear SQ2, ~ccuH%TW~ tcr 80 CFR m.4, 

### ah &tea

### mm&i dww

### nB MY&

### Wan ons aseeedanca 

### anntkaliy and for Pb, 

### accorrling to 

### section 50.12, 

### an area may show no 

### .- exceedances on a 

### quarterly badpis-


### ~ent relies upa No such 5uppl 

### areas seeking 

### retiesignation. Modeling 

### Pay

ine the 

### representativsness

### af the 

### amnitored data. 

### For pol1u- 

### such as SO2 

### and CO, 

### a 

### soall number of 

### monitors typically 

### is not representative of 

### areawide 

### air quality 

### or areas .ofhighest 

### cancentratian. When dealing 

### with SoZ, Pb, PW-10 (except fur a liaited 

### number of 

### initial Poderate nonattairunent dds), and CO 

### (except

### moderate areas with -sign 

### values of 12.7 par% per 

### lillion or.lo#er

### et the time 

### of passgge 

### of the Clean

### Air Act

### AaenUments of 1990), 

### ;rX$~~znim Weiinq

. 

### wB-UgenqwPlybe 

### m&smasjptm~wid~3ua$e 

### ~r~Qvcrly s4prcesc impebs

### and W de4sc~spfna the -'as oS iWfmcfiI& h&gB 

### &&me&*- baaapcm 

### aurruht ;?i()ndi%isnt.

### Ueas which 

### were

. 

### designated 

### nonattaiment bcrsea on modeling will generally not be 

### redesignated to 

### attainaent.unless

### an acceptable

### modeling 

### analysis indicates 

### attainment. .~egions should consult with OAQPS for 

### further guidance addressing 

### the need 

### for madeling 

### in specific circunstances.

Thf SIP 

### for +h. area must be fully apprwd under section 110(k), and 

### must satisfy all 

### requirements that apply 

### to the area. It should be 

### noted that approval 

### action on SXP 

### elements and the 

### redesignation 

### request aay occur 

### ~imultaneau~ly. An area 

### cannot be 

### redesignatd if a 

### required element 

### of its plan 

### is the subject 

### of a disappraval; a finding of 

### failure to submit 

### or to fnpiemt 

### the SZP~ or 

### partial,

### -condit" 

### ,or limited 

### apnroval. However. thisdoes 

### notmean uut 

### earlwssueswithraJard to ' 

### the SIP willbe 

### reopaned, 

### Regions shmld 

### not reconsider those tnings, that have already been approved and far which the Clean 

### Air ~ct 

### &enaterats did 

### not 

### altarwhat 

### is required. In contrast, to the axtent the Aaendments add a 

### requirement 

### or alter an 

### existing 

### requirement so that it adds 

### sonething

### more, Regions should cansider those 

### issues. In 

### addition, requests from

### areas hewn 

### to 

### b 8ffecteri by dispersion 

### techniques which are incorksistent with EPA guidance will continue to

### be eonsidered 

### unappmvable undtt aection 110 and will 

### not qualify 

### far redesignation.



### %section 110tk) 

### contains the requitemenes for IWA aotibln on plan subraissions- Itaadresses completeness, deaQlines, full and partial approval. conditional approval, and disapproval,. - 3. Perinanent and Enforceable Im~eovement 

### in Air~uality

The Statemust be able to reasonably attribute the 

### - improvement in air quality 

### to emission reductions which are permanent 

### and enforoeablee2 ~ttainment resulting from temporary reductio'ns in eh~ission rates (-e. g,

### , reduced production or ' shutdown due to temporary adverse economic conditions) or ' unusually favorable meteorolqgy would*

### not Qu&lifyas

### an air quality improvement due to permanent and enforceable emission - reductions.

In making thisshowing, the State should estimate,th& percent reduction 

### ($rom 

### the year that 

### was.'usedto determiqe.the design value far designation 

### and classi-fication) achieved 

### from

, ' Federal measures such as the-Federal.Motor ~ehiele."~bntrol -Program and fuel volatilfiy rules as well--as 'pohf rolmeasareq '

### . 'f that have been adopt& and implemented by the State. 

### his ' 

## . estipate should consider emission rates, production capacities, and.other related information to.clearly .shac\!that the air -qualityimprovements 

### are the result of implemented-controls- 

### The '

analysis should assume that sources nre-operating atpermitted. 

### .

. levels

.(orhistofic .peak 'levels)unless evidence 1s presented.-

. . '

.. .. . . . that such an assumption is'.unrealistic. 

### i -

### - *. 

### - -. 

### - 4
, 

## - Seetion 118 and Part D Requirements :

, .

. .. 

# or. the purposes of redesignktiofi, a.State

### mustmeet ail '' ' requirements of section 110 'and Park.

### D.that were 

### applikable pr2or

,



### . . . ..

.to. submi.tta1 of the complete redesi.gnation 'reqoest

# . . 

### .Whbn .- ' 

## -.

## -

. evaluating a redesignation request, Regions should. not,cons%der 'whether the State-hasmetrequirements that &me due under the a.-

-. Act aftair

.submittal of '

### a complete fed6signation 

### request, ' '. '' 

# - 2~h.is is consjLstent 

### with..EPA" existingpolicy 

### on redesigr~ations 

### as stated 

### i.n

### an April 21! 1983. 

### memorandum titled



### . *'sect iorr .I07

### Designation policy Stpunary;

## " This 

### memuthndum.sgates 

### .' that in order for 

### an area to be redesignated.to 'attainmeng, the State

### must show 'that "actual enlEorceable 

### emission reductions 

### are respons iblefor the recent air quality irnprovem.ent



## . This element of the policy 

### retains its validity under the amended Act- 

### pursuant: to section 193 

### INote: cothey aspects of 

### the .April 21, 1983 menorandum .havesince been superseded by subsequent memoranc3lums; inkerested parties should co'nsult 

### with OAQPS before relying on the'se aspects, e.g. those-relating ko required years of air cguality data,]

3~nder section 175A(c) , however, the requirements of Part b remain :Ln force and effect for the area until such time as.itis. redesigraated. Upon redesignation to attainment, the requirements that became due under section 195A(c) after submittal of the complete redesignation request would no longer be applicable.

### Noweves, any requirements that 

### came due 

### prior to submittal of the redesignation 

### request must be fully approved into the 

### plan at 

### or before the time 

### EPA redesignates the 

### area.

m To avoid canfusian concerning what requirements willbe applicable 

### for purpcrses of 

### rdlesi~nation, Re#ons should encourage States ta work 

### closely 

### with the appropriate Regional Office 

### early 

### in Me 

### process. This

### will help 

### to 

### ensure that a 

### redesignation request submitted by the State 

### has a nigh 

### likelihood of 

### befng agprwed by EPA. Regions should 

### advise States of the 

### practical planning 

### consequences if 

### EPA disapproves the redesignstion 

### request or 

### if the 

### request is invalidated because 

### of violations recorded during EPA's 

### review. Under such 

### circurstdnces, 

### EPA does nothave the 

### discretion +a 

### adjust schedules 

### for iqpleaenting SZP 

### requirentnts. As 

### aresult; 

### an areaaay risk s~ctione and/or 

### Fsd?ral ihpXemenC&tion fr.'arr 

### implementation that 

### could result

### from failure to

### meet SIP submittal 

### or implementationrequirements.



### Section 110(a)(2) 

### contains 

### general requirements for 

### nonattainment plans. Hust 

### of the-provisionsof this section ase the same as those containad inthe pre-mended Act. Wewill 

### provide 

### guidance on these 

### rqufrements as flaeded.

Part D consists 

### of general 

### requirements applicable 

### to 

### all
areas which are 

### designated 

### nonattainnent based 

### on 

### a violation of the MS. The general requirements are followed by a series of subparts specific 

### to 

### each pollutant. The 

### general requirements appear 

### in subpart 1. The 

### requirements relating to 03, CO, PM-10, SOZ, NOZ, 

### and Pb 

### appear in subparts 2 through 5. In those instances where an area 

### is subject 

### to both the general 

### nonattainment 

### provisions 

### in subpart 1 

### as well 

### ass 

### one of the pollutant-specific subparts,'the general 

### provisions may be su&sumed within, 

### or superseded by, the

### more specific 

### requirements of subparts 2 through 5,

If am 

### area was 

### not claecified under section 181 for 03,or 

### section 186 

### for Co, men that 

### area is only subject to the provisions of subpart 1, 

### RNonattainment

### Areas in 

### General," In addition 

### to relevant provisions insubpart 1, 

### an 

### o3 and 

### co area, which 

### is classified, must meet 

### all applicable 

### requarements in subpart 2, RAdditionalProvisions fer 

### Ozone Nonattainment.Ueasem 

### and subpart 3, 

### nAdditional

### Provisions 

### for Carbon Honoxide

4General guidance regarding the requirements for SIP'S may be found 

### in the @General

### Preamble.

### to Title I of the 1990 Clean Air Act

### mendment~,~ 57 FR 13498 (April 16, 15392).Nonattainment 

### AreasDa@ respectively, before the area may be redesignated to 

### attafnment. All PM-10 nonattafnnent areas (wilether 

### classified as moderate 

### or serious) 

### must similarly 

### meet the applicable 

### general provisions of subpart 1 and the specific 

### - Pn-10 

### provisions 

### in subpart.4,*M&itimal Prwisims for Particulate Hatter Nonattainment Areas.' Likewise, SO2, NO 

### , Pb 

### nonattai~~nt areas are 

### subject 

### to +he 

### applicable 

### generat nonattaiment provisions 

### in subpert 1 

### as well as themore 

### specificrequirmnents 

### in sub* SDuAdditional

### Provisions for keas Designated 

### Wonattainment for Sulfur Oxides, Witrogen 

### Dioxide, and 

### Leadam

This 

### section wntains general requ5rurents for nanattainment plans. 

### A thorough 

### discussion 

### of these 

### requirements mybe 

### found 

### in the Prmleutle 

### 3 (57 FR 13498 (April 16, 1992)J. 

### The EP& anticipates.that

### areas will already have met, most or all of these rquimments to .the extent that.they ara not superseded by 

### more specific Part D.require~mks.me requirewnts Lor reasonable further progress, identificationof 

### certain 

### emissions increases, and 

### other 

### mea6wes needed 

### for attainment will 

### not apply for redesignatfans kcawe they only have 

### aeaning for 

### araas 

### mt attaining the 

### standard. The 

### requirements for 

### an emission inventory 

### will be satisfied by 

### the 

### inventory requirenents of 

### the 

### maintenance plan. ~Sm~~ts

&%%* W'"W 

# * *-**aw&&?q@ 

## m-- -&&&',&&*y*&g&~& 

### &

## "a*

The State 

### must work with EPA 

### %a show that its SIP 

### provisians are 

### wnsistentwith section 176[c)(4) 

### Canfo requirementsm The redssignation.requestshould include 

### confonaity procedures, 

### if the 

### State 

### already has 

### these procedures in place. Additionally, we currently 

### f-ntarpretthe conformity 

### requirement to apply tcl

### axtaimment areas. %awes-, EPb has wt yet issued its conformity regulations specifying what 

### areas are 

### subject to the 

### conformity requirement. Therefore, fF 

### a State daea not have canforntity 

### procedures 

### In place at the time that it 

### submits a 

### redesignation request, me State

### must c=ollrrit 

### to folzow EPA's 

### conformity 

### regulation 

### upon issuance, as applicahxe, ~f the State submits the 

### redarsignatian request SUbSefpent tc EPArs issuance of the conformity regulations, 

### and the conformity 

### requirement 

### became applicable to the 

### area prior tea submission,the State laus% adopt the applicable 

### conformity requirements before 

### EPA can redesignate the area.

Section 107(d)(3)(E) of the amended Act stipulates that for
an area to be redesignatcd, EPA

### must fully approve a maintenance 

### plan Which 

### meets the 

### requirements of 

### section 175A. A State my submit both 

### the redesignatian 

### request and +he 

### maintenance plan at the same 

### time and rulemaking 

### on both may 

### praceed 

### on a 

### parallel track- 

### Maintenance plans nay, 

### of 

### course, be submitted and 

### approvsd by BPA 

### -fore a 

### redesignation 

### is requested. 

### However, according to 

### section 175A'(c), 

### pending ap roval of themaintenance requirements shall remain inprace.

. 

# P plan apd'redesignationrequest, all 

### appl 

### cable 

### nanattainment area

Section 175A defines the general framework of a maintenance 

### plan. 

### The 

### naintenance plan will 

### constitute 

### a SIP 

### revfsion and must provide 

### for maintenance of the relevant NMQS in the area 

### for at 

### least 10 years.after 

### redesignation. -yactfm 175h 

### fukther states that the plan mall contain such additional nmasures, 

### if 

### any, as may be 

### neccesary to 

### ensure 

### such

### msintenance. Because the Act requires a demonstration of maintenance for 10 

### years after an area 

### is redesignated (not 10 

### years after mbmitt:aL of a redesignation 

### request), the State should plan for 

### some lead 

### time for SPA 

### action 

### on the request. 

### In 

### other

### words, the 

### maintenance demonstration should project maintenance 

### for 10 years, beginning 

### from a date 

### which factors 

### in the 

### time.nacessaryfor EPA review

. and approval action 

### on the redesignation 

### request- In determining the amount 

### of lead time 

### to allow, States should consider that 

### sectfon 107(8)(3)(D) grants the 

### Administrater up to 18 months frcrm rmceipt of a complete submittal to process a redesignation 

### rwjuest. The statute 

### also 

### requires the State to 

### submit a 

### revision of the 

### SIP 8 

### years after the 

### original redesignatian 

### request is approved to g'r2wcidids

### for 

### maintenance of 

### .theNMQS 

### far.
an additional 10 years following the first 10-year periad [see 

### section 175A(b)'j.

In addition, the maintenance plan shall 

### contain such theAdmfnistrator deems necessary to ensure 

### prom* 

### correction of any 

### violation 

### of the NAAQS 

### [see

willi&l&t 

### aA1 maastx~es c~ata-in~ Xn 

### the 

### m&mainmentSIP 

### q&xbs%a x~iir~tbqa. Pallure CO

### mafnkaiir NAAQS and

The follbwing is a list of core provisions that we anticipate will be necessary to ensure

### maintenance of the relevant NAAQS 

### in an 

### area seeking redesignatian fromnonrttairrrent 

### to attainment. We 

### therefore

### recommend that States seeking 

### redesignation of a 

### nanattaiment area considasr these 

### provisions. troy~ver,any final SPA

### detrr8ination 

### reqarding the adequacy of a Wntenance 

### plan will be matla 

### following 

### review af the 

### plan sub3ittaZ 

### in light 

### of the psrticular 

### circumstunces facing the area 

### proposed 

### for 

### redesignation and based 

### on all 

### relevant inforration available at 

### the 

### time.

The State should dwalap 

### an attaimtemissions inventory ta identify the 

### leva1 of 

### desi 

### in the rc+a

### whicb.

### is sutiicieqt 

### to attain WMgs.~~i~ imnwory sbculd 

### censistent with=A's mot 

### rscent guidencc 

### on 

### c8.issi.on 

### inventories for 

### mnattainment areas available at the! 

### ti= and should 

### tnclude the 

### dssionsduring the tfl~~period .ssociacr(L

. with the 

### mn&torifig data showing 

### rt+ainrcu\t.

I 

### ue100 

### +ons/yeu for SO 

### NO 

## ,and 

## m-3 im ~t, b.8~ 

### upon 

## ro cFa'sl.f~o(u)

- and 51.322, a8 

### wall a6 

### estublished 

### practice for Aa3data. The 

### source sizethreshold 

### for 

### serious P!U-10 

### areas La 70 tons/yeah



### &re the State has made 

### an adequate 

### d#onstration that air 

### quality bag 

### iapcovod as; a 

### ramult of the SIP 

### (asdi8~~86d previously),-the

### attainrent 

### inventory will cp~nwally 

### be +he 

### actual 

### inventory at the tine

### the 

### -+a 

### attain88 the 

### stamhrd.
BPA8scurie* guibrmcce 

### ion tQm 

### preparation eC 

### emission inventories 

### far 0 and CO 

### nanattainnent areas 

### is cclntained 

### in the 

### .followingdwzimenb: *Procrdtm. 

### for th. Rmparation of 

### mission 

### Invsntorisr 

### for Carbon 

### Monoxide and PmmuBOrs

### of Ozone: Value fm (EPA-450/4-91n016), 

### aPrecedures

### fur thr 

### Preparation

### of Emission 

### Inventories for Carbon

### Monoxide and 

### Prm~~.gom of Ozone: 

### volune IT* (Ep~-450/+-91.-014), 

### @smissfanfnventory

### ~wimenfor 

### Ozone State 

### Iirplsrantati~n 

### Plansm(EPA-450/4-9!t-orQ), 

### mBmieeionInventoryXequirenents 

### for Carbon

### Monaxirie ImplamentationPlansa (BPA-450/4-91-Oil), 

### *Guibslh~e 

### far

. 

### Regulatmry A~licmtia 

### of the 

### Urban Aimhad-1" (gPA-45afa-0dl013), 

### aPracaduros*or mission 

### Inventory 919parath)n: woi 3F1%, c.U..bilm- SDL"



### .tEPA-450/4-81426d) 

### and "P~~WIBS for 

### Preparing

### E.iu.8ion-

### Inventory Pro$&zW.rSlu-"~~FPw~~~~~sP* 

### ~ef p~

## - Tha SF& does 

### not cnrrrently hevc

### specificguidance #onattai~etlt 

### missions inventories 

### for 

## so m liru #+reof, 

### sktes me referred 

### to a-guidan~t 

### on 

### &ssionm data 

### tobe 

### us& 

### as 

### in* to .nd~ling d-SmtimS, wnrfrrt- 4b 9.1 af =A'S 

### nGuibeline

### on Air Quality Wwls [Rettised)* I1BPA-450/2-7@-02m], July &987,which is gensrally applicable 

### te all 

### cziteria plollutants. Ermierion 

### inventory 

### proeredures and 

### requirements doamente 

### ara currently beiq prepared by OZIQPSfctr PLa-1.0 and pb: these ~OCUIUI~Q 

### are due dmtelearrrr by suuet 1092:-according to Clean 

### Air Act

### section 189(B)(3). 

### Hmever, the inventory 

### should 

### include sources belaw 

### these size thresholds if thace 

### smallmr 

### sources

### were included inthe 

### SIP 

### attainment demnsttrtion. Where eroeurcesbelaw 

### the tO0, ?O, and S 

### tons/year- 

### sire thresholds (e.g,, anws with

### sraaller 

### source site 

### definitions) are sdbjQet 

### to a StM.e8r

### mr 

### source permit progr-, there rourocha 

### need 

### only kr 8ddreSssd 

### in the aggregate to the extent 

### that tnay 

### reeult 

### in areawide grouth.'


### For O3 

### nnrttaitment weas. the 

### inventory sh6uld 

### be based on 

### actual rntyplcal rummaw 

### day* 

### emiesiuam of 0, grecurooxs (volatile 

### organic compeunde and n&tsoQan 

### oxides) durxng 

### thc 

### attainnent

- 

### year. Tbis

### will generrlly 

### oorrt~opond 

### to one of the priodic 

### imr~teries raquLred 

### fur nanattalnunt

### amas to 

### r+c~ncile milestones. For 

### co 

### nanattafluent areas, the inventaiy 8hou.ld be 

### basd

### on ac+ual mtypic.1 CO

### seamdayw 

### emissions fer 

### the attainment year. Thie will 

### generally 

### correspond to one of thcJ perfodic 

### invmtorirs required 

### for nonattainrent. areas

# -
- b*

# s * A State.~y 

### generellydemonstrata

### maintenance of the HAWS 

### by 

### eithar 

### snminp that 

### future

### dssiens

### of a 

### pollutant 

### or its 

### precursors

### will wt exceed the 

### level of 

### the attainment 

### inventory, Or by 

### mocbling to show that the future

### mix of 

### sources and 

### erisoion rates 

### will 

### not cause 

### a violation of 

### the HAMS. Under 

### the Clean Air Act, ~ny arers 

### are 

### required to stahit 

### nodeled 

### attairment dearomstrations 

### to show that proposed 

### reductions 

### in enimsions will 

### be 

### sufficient 

### to 

### attainthe applicable 

### #Ms. 

### or these 

### areas, thr 

### raintenmea daronstration shauld be 

### based upon the came 

### Level 

### of modeling. 

### In areas 

### where no 

### euch modeling 

### was requited, the 

### State should be 

### ibls .torely 

### on the r.ttaiment 

### inventory 

### appmacb. Inboth 

### instances, the denanstcation should k 

### for a priad af 10 years fallawing the 

### rrdesignatian. 

### Where abdeling 

### is relied 

### upon to 

### domonatrate

### maintenance, eacb 

### plan should 

### contain a shmary of 

### the 

### airquality 

### concentratians expected to 

### rmsult 

### from application of the 

### control 

### strategy. 

### In t4e prbc~ss, 

### tbe 

### plan should ibantify 

### and describe 

### the dispersim

# -

a?- akWw &ir guality model used fo project 

### ambient oaMIhntratfans (6- 40 CFR St.46).
Xn 

### eiuter 

### case, 

### to satisfy the

### deaonetration roguitrnent the State ehcnrld project 

### emissiarus for the 

### 10-year 

### period fallowing 

### redesignation, erther 

### for tbe 

### purpose air showing that edrtians will 

### nut 

## )riseoru the attaiwnt

### inventory or for conducting aodeling. The projected 

### inventory should 

### cansfdar 

### future qrovth, 

### including population 

### atrd 

### industry, slmuld be consistent

'Gufdance 

### for projactinp 

### emissions may &e formd in the aissions fmrenkory quidawe 

### cfted 

### in footnote 6.

.

,.with the 

### attainment inventory, 

### and should 

### dM?unent data inputs and 

### assumptions, All 

### elements 

### of the de~po~~stration (e.g., 

### emission pm$ections. 

### new source growth, 

### and 

## .$cling) should b. ceneiotent 

### wrth

### earrant EPA 

### nodeling guidance. 

### 8'or.o and CO, 

# - +Ile -projec+rd~uiom should 

### reflect thc -czt~ 

### .dual ~E~SS~O~S met3

### on emfarceable

### ~iarsiorr rates 

### and typical 

### production rates. 

### For cO, 8 

### State shard

### address the 

### sra~wide component 

### of the 

### raintenmce demmmtration either by 

### elmwing that 

### future CO 

### dreionrwill not 

### increase or by conduetirtg ueawida 

### lodeling* PreFarmb1yltha Stare 6hoUU carry 

### ~ut hot-spot 

### robeling 

### that is 

### cansistent

### viathe [RCIYised), 

### in 8-r 

### to_.~*lil.r, if the 

### nonattainuurt prob1em iarelated 

### to 

### a pattern of 

### hot-spats

. then hat-spbt mdeling

### should generally be OOnductrLI.. 

### However, hot-spot 

### rodeling irnot2 autcmatically 

### requirad. .For example, 

### if +Rc 

### nonattminnmnt problem warn 

### relatsd molely 

### to 

### etationary point sources, or if highvay 

### fasrovemmnts havrs 

### been 

### irparaented and the 

### sssoc atcd 

### omfarion reductions 

### and travel 

### characterimtics 

### can tw? 

# i -lit 

### tivelybacumantsd, them hot-spot~modrlinq 

### is not required., 

### m such cacree, adequate 

### cbcumentation 

### as well 

### as the: 

### concurrence of Headguartmrr is nded. Any aseumptimr 

### concerning 6tmi~810n 

### rates lumtreflect permanent, 

### enforceable wasures. 

### In

### etherwords, a Shte 

### generally 

### cannot take credit in the 

### maintekmcedemonstration 

### for rcrBuctions unl- th- .re 

### mqulatierunAn place 

### -pairing those 

### reductions or-- reducticms 

### are otplrnsise &own 

### tabe 

### perarmant., 

### Thmf 

### ore, the 

### Statewill 

### be 

### to

### raintatn its ipplmentml 

### control stntmgy Qe8pite

### r*de= to 

### attainment, unless such 

### measures 

### are ohawn 

### tobe 

### umetz~~ssary for 

### maim-e or 

### are replecod with ~errsums that mchirnre

### equivalent 

### recluctions [see additiamal disms8ion

### under *Centingency 

### Plana). .Smbsin 

### ~sdo&ons 

## fror: abu-5 bur bs

### to~~~amzad, nt and 

## wt)ucrt.nt mt atwe

## mlr-s tmwc:%ZY 

### mS&acQM 

### iama gZP! 

### and 

### all- applScable palmits 

### hat'e 

### been 

### i*lt@ac;corrlfngl$. 

### Modeling 

### used to 

### dcmanatrato attainment may be relied upn inUle

### raintanance dcnnastratian where 

### the 

### lsodslincj

### aan ent EPA 

### gui4arrce Uiduherm 

### the !!itate has projected no 

### ifiaant cbmqms 

### in theKrdQling inputs 

### during the i 

### time. Where tQe 

### original 

### attainwntdenonstration nay no 

### reabed upon, States

### will.bs WpCtaM to

### remoasr using

+he ~~~-8pproved ling guidance may ba farcnd in +he following Wumente: 

### abuidalina

### on Air Quality UadeLs 

### (~evisud],~ OAQPS, R!CP, UC ~~A-450/2-'78-02?R)r Ju.ly 1984; and "P#-LQ SIP I)IMcslop~~t. Guideline,* WPS,

### RTP, #C (EPh-450/2-86- 0013, Ywm 3983-EPA referenced tecbniquas.9 mis 

### may 

### he 

### necessary Where, for example, there 

### has 

### been a change 

### in 

### emissions or 

### a change 

### in the siting 

### of new 

### 6ourcrcs or modifications such the+ air quality may 

### no 

### ~bnver- rk'&ezuw~5'p ..xv~entBd 

### by the 

### existing mdelirqg

Once 

### an area has 

### Men lvdesignated, 

### the State ehould continue to operate 

### an appropriate 

### air quality 

### mnitoring netwurk, 

### in accordance

### with 40 CFB 

### Part 58, to

### verify the 

### atanwntstatus 

### of ths 

### area. The 

### maintenance plan 

### sbould 

### contain provisions 

### for eantinucd operation of 

### air qu.ality 

### ranitars.thatwill provide 

### suchverifiaation. 

### In cwsas 

### when 

### masurdmobile 

### source parameters (reg.,

### vehicle miles 

### traveled congeetien) bave changed 

### over time, the 

### htemay 

### also need to pUfoZlE a saturation

### monitoring atudy 

### ta determine Wm need 

### for, and lacation of,

### aU6tiwral pcr'~~~cnIt 

### memitors.



# . . d. - 

### verlfliMItfan of


### Each 

### should

### murethat 'i~-h.. the 

### lagal arrthoriey to 

### implement and 

### enforceall 

### reasurer necessary to 

### attiin

### and 

### to 

### maintain the IOMQS. 

### Sectians 110(a)(2)(B) 

### and (P) 

### ,ofthe Clean AirAct, 8s 

### ammdeb, and 

### regulations proaulgatea 

### at 40 

### CPR Sl.llO(k), 

### suggest 

### #at one 

### such

### measure is

### tha 

### acquisition 

### of ambient and 

### souree- errSssion data to 

### demonstrate 

### attainment 

### and maintenance. Regardless 

### of whether the maintenance 

### demonstration fs.based - 

### on a 

### showinu that future 

### mission inventorieswill not eaccee4 the 

### attainment 

### inventory or 

### on abodeling, 

### the S-te suJmitta2

### shouLd inbicsta 

### the statewill 

### tra~k 

## me aP 

## +hemaintenance Ip%&- 

### This 

### is 

### necessary due to 

### the faet.that

### the 

### emission projections ~radefor 

### the wlnt- 

### demmmtration depend 

### on rasunptions 

### of point and we8 eource growth.



### one 

### option 

### for tractking the 

### progress 

### of tne maintenance demonstration,provided 

### bere a8 

### an errample, wotikd lxs 

### for the State 

### to 

### periafcally update the 

### emisrions inventory. In this case, 

### the 

### maintsnancm

### plan should specify thefrequency 

### of any planned 

### invanwry updates, Such 

### an updata 

### could be baaed, 

### in part, 

### on the 

### annual AIRS 

### update .nd 

### could indicute 

### nmw source growth and other &magus ffar 

### the 

### attainment 

### inventary (e,g., 

### changes 

### in

### vehicle ailam 

### travelled 

### or in txaffic patterns), As 

### an alternative 

### to a 

### complete update 

### of 

### the 

### inventalry,the state 

### may choose 

### to do a 

### ceaprehen.dvcl

### review of 

### the 

### fa~ters that were used 

### in developing the attainrent 

### inventory 

### to shew 

### no sfgnlficant cburqe. If

### as 

### review does 

### shewa 83-gnificant

. 

### change, 

### the 

### State should then 

### perform an update of the inventory.Where the 

### demomtzation 

### is based on 

### modeling, m

### option fob rrrcklnq prapress would be 

### for th. State to 

### periodically (typically every 3 years) 

### reevaluate themodel* 

### uk~tians aM input data, 

### In any event, the State 

### should 

### aonit~r the 

# - inatcatoms for triggering 

### contingency maeures (asdlectl&sed below).

Section 1751

### of the ~ct 

### also requires that 

### a 

### aalntenance plan inc2uba, 

### oontimgemcp 

### provirlom, as necessaty, to pc08ptly 

### correct any 

### violation of t&e #MQS 

### that 

### occurs after 

### rsdesignation mf tbr ar:m. 

### These ~~ntingeney aeasmrr are 

### distinguished

### from those 

### generally 

### rvguired for 

### nonattairmrent anasundex 

### seetion 172(c)(9).mdthose 

### spadfioally mired

### for 0 

### and CO notiattainment 

### areas under 

### nections 182(c)(9) dnd aa7(r)(3), 

### rupecti.yely. 

### Por tha.purpocmsot 

### .-ion 175A. 

### a ' State 

### is 

### not mired

### to have 

### fulZy rdoptd

### amtingency

### measures th&t will

### taka 

### eZ2emwWkmch FH- wa. 

### hv, the State 

### in order far the

### maintenance 

### plan to be 

### approved. Rowever. the 

### continqancy plan,ir

### considered 

### to be 

### an anforceable part t?f Me 

### SIP 

### and should 

### ensure that the contingency mommres 

### ure adopted 

### expediently once 

### they 

### are triggered. The 

### plm .ehUULb 

### cz-rly identify Ole Wa6UTes-

### tobe 

### abop-, a s&e&&r .nd pzase&ure

### far &option and 

### iiap1-tation, and;

### a 

### epe~iffc &me for 

### action by the Stat& U 

### r necmmazy ofsthe 

### Nut, the State shoaald 

### alsa iddhtify 

### rp.cifie 

### indicators, 

### or triqgerto, whir* 

### will be 

### used ?s 

### deterwinewhen t.bcontingurcy redSlures need 

### to ba 

### implementad.
Utmre 

### the

### maintenance aemonetration istwmed en tb6

. 

### inventory, the Stata may, 

### for example, idenrify 

### sn nmctionlevel@ of 

### emissions as 

### the indicator, 

## rf later invantary-updates 

### show that 

### the 

### inventory has etcceeded 

### the 

### action level, the Sate

### would take tlse 

### necessary steps to 

### implement the 

### oontingenoy measures. 

### The.inUicatorswould 

### allow 

### a.Stateto take 

### early action 

### to address 

### potential 

### vdolations'of the

### NMOS beform 

### they 

### occur.. By taking 

### early 

### action, States ray be able 

### to.preourtany 

### actual violationsof 

### the NMQS and, 

### therefore, 

### rlirfnata the need on 

### tka park of EPA 

### to siqnate 

### an 

### area to 

### nonattainment;,

ez 

### indicators ta 

### consider 

### include monitored or eeled 

### violstions of tile PAAQS 

### [due to the 

### inadequacy 

### of aronitoringda%a 

### An 

### same situations); 

### xtis 

### important 

### to 

### note that 

### air quality data 

### in excess 

### of the WQswillnot 

### autoraticelly

### necrssitate a 

### rwislonof the SfP 

### mere implamentation

### of ccurtinqency ueaswes 

### is adequate to rddrei~ t&e 

### cause of 

### the violation. The 

### need 

### fez
a SlF

### revioisn issubject 

### tm the 

### AdPinistrator@rdieeretion.


### Tne SPA 

### will 

### review what 

### constitutes a 

### contingency plan err a case-by-case 

### Baris. && 

### c it,map!& 

### d~equPfa--~ );ha State eiF1I 

### fa&lenmt a&L nemtw(b8amtained fn the 9- D nomttafnment

### aW&%m@Bm 'WWC ~~4,~~~~~~?&~~12~~~~d) 

### 12 Thls language suggests that 8 

### Statemay submit a SIP 

### revision at 

### the tire of itsrebesignation request to ~UOVQ 

### or 

### reduce the 

### stringency of 

### control masures. Such 8 

### revision can be 

### approved

# - by EPA if

### it provfdes for 

### compensating equivalent 

### reductions. A 

### deromtration thmt 

### rrrirsures are 

### equivalent would have 

### to include 

### ap-riate 

### 8Wellng

### or m adrqwtm 

### justificcrtiwr. Alterna

### tively, a 

### State 

### right k 

### able ta deamstrate 

### (+hrough EPA-rppmved 

### Waling) that 

### the ma6ure.s

### ars metnacassary for 

### 8aintenance of the 

### standard. 

### In 

### either case, 

### the contingency plan wUU 

### heve 

### to provide 

### for impleaendation of 

### any reaeures 

### that ware reduced or reaovsd

### after 

### reUesignation of the 

### area.

AP stated 

### previously, 

## this memorandum coneolida.tesBPAos 

### redesignistien and 

### ralntemnat plan guidance Md 

### Region6 

### should rely tlpan 

### it 

### as a 

### general 

### framwrk in drafting mathas. It 

### -isatronqly suggoatad that the 

### Rogional Off 

### ices 

### ahare this'docurentwitb the 

### appropriate States. Ttria 

### should


### - give the Stat- a hettar Unaerstanding of what iso:geetQd

### from a redesfgnation 

### request 

### and maintenance 

### plan under exj-sting

### policyMy

### nrcessary =hangas 

### to 

### existing Agency policy 

### will be made 

### through 

### our 

### action

## on specific rebesignationreques155 

### and the 

### rev&- of saction 17SA

### maintenance plans 

### for 

### these lmrticular 

### areas, bth

### of 

### mich are subsect- tb 

### notktt anuacoamrn~rp.r&aanki~qmdures. 

### Thus, 

### in applying 

### thin memo&um to 

### specific 

### circurrstancas in a 

### rulemaking, Regions should 

### mnsider the applicability of the 

### underlying policies to Me 

### -icular facts 

### and 

### to 

### comments submitted by 

### any petson. 

### If your si;rff.wmbers have 

### questions which 

### wire

### clar&ticatfon, they 

### may contacrt Sharon Reindets at (919) 511-5284 for 03- mdCCbre'1ated

### issues, and Eeio 

### Ginsburg at (919) 541-0877 

### for SO2-, M-20.-. 

### and Pb-related!

### issues.

ec: Chief, Air 

### Branch, rCegf f-X John Csbaniss, OMS Denise Devae, OAQPS 

### Bill LwfoR, 

### TSD Rich 

### Oesias. OGC 

### John 

### Rasnic, Jahn 

### seitz, Hike

### Shapira, 

### OAR Lydia Weqaan, 

### QAQPS