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REqEIVeo· 

... oq262DOO . . . . ',. uNITED STATES. ENVIRONMENTAl. PROTECTION AGENCY 

RESEARCH TRIANGl.E PARK, NC 2771 1 

AIR DIVISION ·. U.S; EPA, REGION ·9 

OOT-18 

MEMORANDUM· 

SUBJECT: 

TO: Regional Office Air Division Directors 

OFFICJ! 01' 

AIR· OUAUT'f PlANNING .., 

ANOSTAtmAAos . 

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The purpose oftbis memorandum is to provide guidance pn !Wesignating .. ~ ~oxide 

(802) nonattaimi:Jent areas to attainment, in cases where the areas' historic violations were ' 

caused by inajor point. sources .of sulfur oxide (SOx) emissiops that are no Io11ger irJ. operation. 

States in some cases have, with our approval, removed 802 monitors frqm these areas 

immediately following the shutdown of the SOx e.m.issions sources .. In these tasi:s, states face 

the· prospect of continued nonattirinment desigqations· for areas where there is ho reas9nable basis 

for as~g that S02 violations persist. 

. . This.gmrum:ce provides an approach for redesi~g 'tl:ese ~~to atta'inment. in.tbe 

absence of monitbring data and for exetnpting tbe.Se are:i$ from tbe maintenance plan · . 

. requirements for conrlnued monitoring within tbe ar~ In addition, this policy deScribes· how 

a~ent aild continued maintenance should be dei:nonstrated and how sources currently shUt . 

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· davin should be treated if they resume· operations. Therefore, tbis policy ame.nds,portions of . 

previous redes1gnation policies, including •'Pto~ec;!t:q"es for PrOc~sing Requests to.Redesignate · 

.. .Areas to Aruiininent, ~memo from iohn Caicagni, AQMD Director, dated· 9/4/92;· "Section 'i'o7 . . Desigpation Policy siimmary," m~o from Sheldmi Meyers, OAQPS-DirectOt~ dli,ted 4121/83, . ·? 

per(hlning to amb~ent air quiilitj data shomng aitainment and maintenance of the S02 National-· 

· Ambient Air Quality Standar~s (NMQS); ani:!.~ Attainment Deiennination Policy for Sulfur . 

. Dioxide Nonattain!nent Areas;" memo ·frpm Sally L. Shaver, AQSSD Director, dated 1/26/95 .. 

All·otber pro:visions of the previous redesignation policies still apply, incltidfug provisions 

reJating to contingency meilsures. · .. . · . . . . · · . ' · 

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. The Environmental Protection Agency's (EP A)·historic redisi~ation policy for 802 has 

called-:for 8 quarters ofclean ambient air. quality data for redesignation, to iiittainment. ,'\lthough · 

EPA has allowed as few as 4 quarters of ambient data if an acceptable modeling analysis has 

been performed.' Areas that lack S02 monitors cannot meet. even the requirement for 4· quarters . 

ofclean·data.· However, EPA believes that it is not a reasonable use oflliirited monitoring 

resouxces to recistablish.monitors in ord.er to collect at least. 4 quarters of data.in areas where 

violations of the S02 NAAQS were caused by souxces that no longer operate . 

b.espite the absence of clean ii.ir quality· data, EPA believes ·that it may approve a State's 

request to .redesignate such. S02 nonattainment areas to attirlnment provid~ that the State 

submits a maintenance plan that addresses certain criteria. . 

First, the plan should include 3 emissions inventories: 

(a) An inventory representing actual emissions during the period ·when there were· 

violations of the S02 NAAQS; 

(b) An inventory representing current actual and allowable emissions (or potential 

emissions, if there is no allowable emissions l~vel); and 

(c) An inventory projecting allowable emissions (or potential emissions, ifihere is no 

allowable emissions level) to the 1Oth year after redesignation. 

'.(he inventories should display emissions from each poult source of SOx, with explanations ~f 

significant emissions changes, including source shutdoWr!s.2 The inventories should include SOx 

emissions fr<~m alf SOx point sources in; and within a 50 kilometer range of, the nonattainment 

area boundary .. Again, if there is no allowable emissions level, potential emissions should be 

used. · · . 

Second, the maintenance plan should u;clude ~ dispersion· modeling anaJysis: 6f au sox:· · 

point sources in, !ij]d within SO kilometers of, the nonattainment area boundanc;s using the 

emissions inventories described above. and the tec~ques and data prescribed in 40-CFR 51 

Appendix W. The modeling.analysis should sliow that: · 

'See the Meyers memq referenced above. Both the Meyers and Calcagni memos 

recoglrize that for S02 nonattainment areas monitoring data alone may not be su:f!icientfor 

redesignating areaS to attainment; dispersion modeling may be needed. 

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The inventories should include other sources if they were included in the attainment 

dempnstration. · · · · 
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(b) 

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No S02 NAAQS violations pres~y occur Or caii.be projected ·to occur dUring 

the next I 0 years imywh~e mtlllll the nonattainment area;.and, . . . ! • • • • • • •' • 

Point sources, which have since shut down, were th~ dominant souii:es 

contributing to high S02 concentrations in the airshed. ~-

Third, the mainteQance plan should include evidc;nce that if the S~ point source that 

caused the S02 NAAQS violations in the past resumes operation, it-would pe ·co!lSidered a . "new'' source .. 'fhus the maintenance plan should show that if this ''ilew" sox source w!lWd be a 

major source, it should obtain a permit conforining to applicable:requh:ements. of the Prevention 

of Significant Deterioration program b~:(ore resuming operation:i; or if it would not be a major . · 

source, it should obtain a imnor spurce permit under .the.State's SIP-approved minor source 

permitting rules in effect at the time it" obtains a. permit,: before it may resume operation. The 

. maintenance plan should ·provide that before such a permit is issued, the dispersion model should 

be re-run, using the same meteorological data base, to determine whether re-Starting. the source 

would 'interfere with maintenance, and should provide that the permit will not be issued if the 

model indicates that re-starting the source would interfere with maintenance.· · · 

. : _, Fourth, th~ maintenan6e plan should include commitments to.resurre ambient monitoring 

before any major source .of SOx emissions co=ences operation. ··~1 .,, . ~ 

. ··.fl . • •••• ,t .... -~ .... :\ .. · .. -Tli:is p~licy applies:only.to S02 nona~ent areas because viofailons in such areas are 

g<jnerally dominated by relatively few point ·sources (sucli as cOpper smelt~rs or power plants) 

arid have insignificant: area and mobile source emission coni:ributions. As: it result, there is a 

direct association between the point sources' emissions' and ambient S02 c-oncentrations. 

Disper-Sion modelfug will assure that S02 NAAQS violations are no longer occUIJ;ing and wo)ild 

not be expected te recur in the future. · . '·"; .. . ......... ·::. 

.-- This gUidance memorandum does not impose binding, enforceab1e~~q$ments on any 

· party, and inay not apply·to a particular situation based upon the circumstances. The EPA r¢tains 

th~. cjiscretion to adopt' approaches to addressing maintenance plan proViSionS that differ from this 

, : . · .. ··'gtlidance where appropriate •. Any final decisions by EPA regarding;a partic~ar 802 · 

. :, . : ' maintenance plan will only. be made. in the context of a rulemaking. action regarding that 

· mainteruince plan based upon the applicable statUtory and regulatory provisions, which do 

contain, legally· binding reql)irements. Therefore, interested parties, including States, are free to 

.· 'Iai,se questions and objections' about the appropriateness of this guidance or the app.iicati<;Jn of 

this guidimce to a particular situation; EPA will consider whether or not the recommendations in 

the guidance are appropriate in that situation. The EPA welcomes publiG ~omnients on J:!ris .. document at any time and will consi!ler those comments in any future revision of this guidance 

doctiment, which may occur withoUt public notice. · 

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. I urge Regions to coordinateclos~ly with OAQPS' Air Quality ~tandards and Strategies 

. Division in detemiining-whether S02 redesignation requests may be subject to this policy and to 

ensure. that States' submissions adequately address this and the·preVious polici~s' critena for redesignating 802 nomittainment areas to attainment · · 

cc: Lydia Wegman, AQSSD 

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David Mobley, EMAD f 

· Joe Paisie; IPSG 

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.!{ich Ossias, OGC. 

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