### Additional Regional Haze Questions August 3, 2006

Note: The following are questions EPA has recei ved from various States and Regional Planning Organizations (RPOs) related to the submission of regional haze SIPs under the program described by 40 CFR 51.308. This document provide s guidance to the State air pollution control agencies and the general public on meeting th e regional haze SIP requirements. These requirements can be found in sections 169A and 169B of the Clean Air Act and 40 CFR 51.300- 51.309. This document does not substitute for th ose provisions, nor is it a regulation itself. Thus, it does not impose binding, enforceable requir ements on any party, nor does it assure that EPA may approve all instances of its applicati on, and thus the guidance may not apply to a particular situation based upon the circumstances. The EPA and State decision makers retain the discretion to adopt approaches on a case-by-case basis that differ from this guidance where appropriate. Any decisions by EPA regarding a pa rticular SIP demonstration will only be made based on the statute and applicable regulations , and will only be made following notice and opportunity for public review and comment. Ther efore, interested parties are free to raise questions and objections about th e appropriateness of the application of this guidance to a particular situation; EPA will, and States shou ld, consider whether or not the recommendations in this guidance are appropriate in that situati on. This guidance is a living document and may be revised periodically without public notice. The EPA welcomes public comments on this document at any time and will consider those comments in any future revisions of this guidance document.

BART

1. Should a State promulgate a BART rule? Should a State's BART rule declare that VOC (and possibly ammonia) is/are not visibility im pairing pollutant(s), or can this declaration be part of the SIP narrative?

The regional haze rule (RHR) does not require that States promulgate BART rules. States are, however, required under 40 CFR 51.230 to show they have the legal authority to carry out the SIP. To the extent a BART rule can aid in this requirement, then itshould be considered. A State’s regional haze (RH) SIP submittal must include sourcespecific BART emission limits and compliance schedules for each source subject to BART. See 40 CFR 51.308(e). All regulatory re quirements must be approved into the SIP.

A State’s BART rule should not declare th at VOCs or ammonia are not visibilityimpairing pollutants unless the State has evidence that VOCs (or ammonia) from its BART-eligible sources are not significant cont ributors to particle formation. Such a declaration must be substantiated in the SI P documentation. This declaration may be placed in the SIP narrative, which will be a pproved into the non-regulatory portion of the SIP following an opportunity for public review and comment on the State’s conclusion. Furthermore, we recommend that prior to SIP submittal that collaboration between and among States and RPOs and Federal Land Ma nagers (FLMs) occur such that theapplication of exe mptions or other princi ples used by a State/RPO is done with full knowledge among the affected States/RPOs/FLMs.

2. At sources that require BART but that have PT Es of less than 250 TPY for VOCs an d ammonia, must the BART proposal anal yze controls for VOCs and amm o nia?

States m u st use their jud g m e nt to determ ine whether VOC or ammonia em issions from individual sources in their State are likely to hav e an impact on visibility in an area. For a source such as the one you have described, the State m u st consider whether its VOC or ammonia em issions are likely to have an impact on visibility at a Clas s I area. If so, the BART proposal m u st analyze con t ro ls for such VOCs and/or amm onia.

3. Should a State declare the exemption threshol d value is 0.5 dv (or som e other value) in their rule? EPA has si mply set an upper bound.

The exemption thresho l d value selected by the State in d e term ining whether a BARTelig ible sou r ce can reaso n ably be an ticipa ted to cause or contribute to visibility impairm e nt must be spe c if ied in the SIP doc um entation, as must the bas i s for the States’ selec tion of this th resho l d. The appr opria tene ss of the threshold used by the State will be subject to public review and comm e n t, a nd States should consult with the affected States /RPOs/FLMs in es tablish i ng th is value.

4. How should a State do cu m e nt in the SIP th at BART controls will be installed and in operation as expeditiously as practicable, but no later than 5 years after approval of the SIP? Must BART controls be housed in a Title V perm it m o dification?

As specified in 40 CFR 51.308(e )(1)(v), States are required to ensure each source subject to BART install and oper a te BART as expeditiously as practicable , but in no event later than 5 years after approval of the implem entati on plan revision. Stat es sh ould ensure that BART requirem e nts in a SIP are written in a way that clearly s p ecifies the individual

em ission unit(s) subject to BART reg u lati on and the tim e by which the em ission unit(s) must begin to comp ly wi th the BART lim it. Because the BART requirem e nts are ‘‘applicable’’ requirem e nts of the CAA, th ey must be in clud ed as title V perm it conditions according to the procedures establis hed in 40 CFR part 70 or 40 CFR part 71. Under 70.7(f)(1)(i) Title V perm its must be reopened and revised to include new applic able r e quirem e nts if the perm it has th ree or m o re years of life. The reopening must be comp leted within 18 months after prom ulga tion of the new applicable requirem e nt and the reop enin g m u st f o llow the sam e procedur es ( public com m e nt, etc) as apply to initial

perm it issua n ce. This may require th at Sta t es pro v ide comm itm ents in the SIPs to ens u re that all applicable construction perm its under T itle 1, and the operating perm its under Title V ar e r e vised in tim e

.

The following elem ents, at a m i nim u m, m u st be addressed to ensure the BART controls are adop ted into th e State’s SIP. Th ese el em ents are dis c usse d in deta il w ith oth e r circum stances in 40 CFR Part 51, Appendix Y – Section V.

2• Nam e of source f acility a nd the spec if ic em ission units and po llutants be in g controlled. (40 CFR 51. 308(e)(1)(i) & (ii)).

• Specifics of the controls, contro l effici ency (ies ), em issions reductions exp ected

• Enforceable em ission lim itations repres enting B A RT (40 CFR 51.308(d)(3);(e))

• Schedules for comp liance with BART (40 CFR 51.308(d)(3);(e))

• A requirem e nt that each source sub j ect to BART m a intains th e contro l eq uipm ent and establish procedures to ensure su ch equipment is properly operated and

m a intained. (40 CFR 51 .308(e)(v))

• Reporting, monitoring, and recordkeeping r e quirem e nts adequate to d e te rm ine the source’s compliance (40 CFR Part 51, Appendix Y – V).

• Averaging tim es and refe rence m e thods to determine comp liance (40 CFR Part 51, Appendix Y – V).

5. In the BART guidelines under st ep 4 of a BART determ inati on is a discussion of average cost effectiveness, yet w e don' t see anything be ing averaged. If one were to average all the individual annual cost eff ectiveness over the rem a ining life of a plant, then we could see that we were averaging so m e thing. Can you explain this?

The term “average cost effectiven ess” is a term that the Agen cy has long used to describe

one m e thod of looking at the costs of contro l when considering econom ic impacts. See e.g. New Source Review Draft Manual (Oct. 1990) at B. 36 describing the process for

m a king best available control technology dete rm inations (BACT). The Appendix at the end of this docum e nt contains equations thatcan be used for determ ining average cost effectiveness and should help you to unders tand how to estim a te the “average cost effectivenes s” of vari ous control m e a s ures.

6. Is there a gu ideline on h o w to "annu alize" co s t s (capital reco very factors and levelizing inflation adjusted operation & m a intenance costs)?

Yes. The EPA Control Cost Manual , ref e ren ced in the f i na l BART rule (see 70 FR 39104, 39163-39167 (July 6, 2005). As noted in the Guidelines, the Control Cost Manualis u pdated pe rio d ically. This docum ent is available a tthe f o llowing W e b site: http://www. epa.gov/ttn/catc/products.html

7. In the BART guidelines under step 4 of a BA RT determ ination, "how do I calculate baseline em issions?" it w ould help if a m e thod we re suggested to depict anticipated annual em issions from t h e source. Otherwis e, sources will do this in m a ny different ways. Should States suggest facilities us e a m e thod sim ilar to PSD - the highest 12 consecutive months in the past 120 m onths (or whatever it is for PSD)? If so, should it be di fferentfor EGUs as i ti s for PSD? Or , shou ld a facility ta ke the highest 24-hour

actua l ra te a nd m u ltiply it tim e s their average u t ilization ra te f o r the h i ghe st 2 of the p a st 5 years ? In either cas e, if these cost effectivenes s num bers are comp ared to the BACT/RACT/LAER clearinghouse, it will m a ke a difference.

The BART Guidelines s t ate that the baseline em issions used f o r estim a ting the averag e cost effectiveness of a cont rol technology should represen t a realistic depiction of

3anticipated annual em issions for the s ource. The approach for m a king BACT determ inations in the PS D program i s sim ilar. T h e m e thodology of looking at the annual average of the highest 24 consecutive m onths in the past 120 months is one approach that has been use d in PSD when dete rm ining if there h a s been an em issions increase as a result of a modification. In som e cases , this approach could a reasonable m e thod of estim ating anticipated annual em issions for a source.

8. How do you address an issue in which the in stallation of a BART control causes an incre a se in a n other po llu tant?

In som e cases, the insta l lation of controls to reduce em issions of a pollutant can result in colla ter a l in creas es in an other po lluta nt. Fo r example, the use of low NOx burners can result in an increas e in C O em issions

. If the inc r ease in em issions of a co lla tera l pollutant would trigger other requirem e nts unde r the Clean A i r Act, such as New Source Review, the State m a y include th e co sts, if a ny, of controlling em issions of a collateral pollutant to m eet these other requirem e nts in considering the econom ic impacts of a technology under consideration for BART.

9. How will EPA address the cost ef f

e c tivene ss of control op tio ns? If an option r e duces more than o n e pollu tant, how is that addressed ?

If an option reduces m o re than one visibility -imp airing pollutant, it could be justified in

term s of the greater overall em ission reduction. The State will need to ev aluate the co steffectiveness of controlling both pollutants in light of its evaluation of the other BART factors. In g e neral, the g r eater th e ov erall em issio n s f r om m u ltiple pollu ta nts, the m o re closely the S t ate should consider controls on m u ltiple pollutants.

10. It is un cle a r in the respo n ses to th e BART Q an d A the m e a n ing of so me term s. Som e appear to be interchangeable. It would be helpful to have definitions for source, site, unit, and plant-wide (as they pertain to BART).

General term s not defin e d in the BA RT Gu idelines should be given the sam e plain language m eaning that they have under othe r Clean Air Act program s. Term s which a r e defined in this and other CAA regulations, and in the statute, should re tain those def i nition s ; note howeve rtha tthe “B ART-elig ible source ” ref e rs only to s t ationary sources bu ilt within th e BART tim e period (1962-77) comp rised of the em issions units

m eeting all three BART-elig ibility cr ite ria. See 4 0 CFR 51.301 f o r def i nitions of “stationary s ource” and “BART-eligible source .” “Plantwide” m eans across the en tire geographic entity, or across all “BART-eligib le” sources at the geograph i c entity (depending on the context).

11. In the BART rule, a r e we to assum e that de m i nim i s levels f o r pollu tants are only b a s e d on BART-eligible sourc e s, even when the term “plant-wide ” is used ?

Generally y e s. The app r oach used b y EPA in the BART Guidelines for identifying a BART-eligible sourc e b e gins with the identi fication of those em issions units at a plant

4that f a ll with in one or m o re BART categorie s and that were put in to ope ration within th e 1962-1977 tim e fra m e. I n 2004, after proposing that States be allowed to establish de minimis lev e ls for pollu tants at BART-eligi ble sou r ces, EPA received comm ents suggesting that de minimis levels be applied on a unit by unit basis. EP A rejected this suggestion in the final rule; the regu lations allow States to establish de minimis lev e ls tha t apply to a B A RT-eligible source. In light of the comments received requ esting that the de minimis exemption be applied on a unit by unit basis and its decision to reject this approach, E P A m a de the statem ent in the BART Guidelines that “[these de minimis levels m a y o n ly be applied on a plant-wide ba s i s. ” This state m ent was intended to c l a r if y that the State should consider the cumula tive em issions from the units at a plant that comprise the BART-eligible source in determ inin g whether th e BART-eligible sou r ce

m eets the de m i nim i s exemption requirem e nts.

Note, however, that for category on e (fossil fuel fired s t eam electric plants >250 m illion Btu/hour), our interpretation of the source cate gory title is that th e State should add all EGU em issions at a p l an t together w h en determ ining plan t c a pacity, in o r der to see if the plant falls within category one. Once you have determ ined that the plant does fall within the category

, the State would only co nsid er those EGUs built within th e 1 962-77 tim ef ram e to actua lly be BART-eligible.

12. If a State determ ines that a recen t BACT determ ination on an em ission unit is BART, then is a BART em ission lim it crea te d that is th e sam e as the BACT lim it, and is th e Title V perm it changed so tha tBART is also lis ted as a basis f o r th at em ission lim it?

Yes, if a State m a kes such a determ inati on and includes it in it s SIP, then a BART

em ission lim it is create d that is the sam e as the BACT lim it. The Title V perm it m u st be

am ended to “specify and reference th e orig in of and authority for” the em ission lim it. 40 CFR 70.6(a)(1)(ii).

13. Is EPA pres um ing a lev e l of contro l f o r BART eligib le sou r c e s in guid a n ce to cons id er CAIR plus BART plus other "reasonable" m easures?

Guidance on the lev e l of BART controls is not being developed. BART ca n only be determ ined on a case-by-case-basis and sour ce-b y -source-bas is usi ng the modeling and statutory factors listed in 40 CFR 51.308(e)(1 )(ii)(A). Sources have expressed concern that reasonable progress guidance m i ght be in terpreted to override BART guidance. T h e BART assessm ent is a separate requ irem ent fr o m the reasonable progress test. It m a y be that to m eet reasonab l e p r ogress, m o re cont ro ls are needed fro mcertain so urces which

m a y or m a y not include those sources previ ously controlled under BART. There is no way f o r EPA or the Sta t es to de term ine the f i na l stra tegy to c o mp ly with the reason able progress d e monstration until the BART assessmen t is comp leted and the suite of controls that ar e need ed f o r RH is determ ined. There could also be ad dition a l con trols th at m a y be identified as needed to dem onstrat e comp liance for the 8-hour ozone and PM2.5 NAAQS. This m a y or m a y not affe ct the c ontro l iden tif ied u nder BART or CAIR. T h e States h a ve f l exib ility in determ ining the type , pollutants and m i x o f sources that could be

5used in developing a strategy for attain ing a NAAQS per the modeling guidance and imple m entation policy.

14. Can a source avoid BART by taking synthe tic m i nor lim its on the PTE of visibilityimpairing pollutants? If so, by when do those lim its need to be in place? W h at kind of

m echanis m must be in p l ace to ensure those lim its are m e t? F o r how long?

Yes, a source can opt to revise its Title I perm it to provide for synthetic m i nor lim its so that it falls under the BART eligibility thre shold. That perm it modification m u st be done prior to the State going to public hearing on its R H SIP. The State m u st include th e relev a nt e l e m ents of the m odif i ed perm it in its R H SIP. The lim its m u st be in pla ce f o r as long as the RH SIP is applicable or for as long as the source is operational.

15. If the unit is already c ontrolled (e.g., under MACT or BACT ) and it is the best, the latest control technology, does the source still need to conduct a full blown BART analysis and control technology evaluation incl uding the installed control device? Or, can the source just describe the control devi ce on their BART-eligible source unit and m a ke the case that it qualifies as BART, without having to evaluate other technologies?

If

the unit h a s “best, la te st...”, th en the sour ce can just describe the control device on their BART-eligible source un it and m a ke the case that it qualifies as BART, without having to evaluate other technologies. Th e stream lining of BART analyses in this situa tion is a ddressed in S ection IV.C of the BART Guidelin es, “How does a BART review relate to [MACT] Standards unde r CAA section 112, or to other em ission lim itations r e quired und er the CAA?”

16. A source is built p r io r to 1962. Between 1962 an d 1977, it bu ilds a n e w em ission unit that o t herwise m eets BART eligible require m e nts. Is the new unit subject to BART?

If a State is following th e approach fo r iden tif ying BART-eligible units des c ribed in the BART Guidelines, the unit built between 1962 and 1977 is considered to be BARTelig ible.

17. Although the rule in the Federal Register (FR), July 6, 2005 page 39107 and elsewhere indicates that the m a x 24 hour em issions should be used, would EPA approve using double the actuals instead for CALPUFF BART modeling?

As noted in the f i nal BART rule, em issions from a source can vary widely on a day to day basis and the “24-hour actual em ission rate could be more than double the daily

average. See 70 FR at 39129. W e recomm end t h at States use the highest 24-hour average actu a l em ission rate for the m o st recent three or fi ve year period of

m e teorological data in the CALPUFF m odel. As EPA explained, “[t]he em ission estim ates used in the m odels are intended to reflect steady-st ate operating conditions during periods of high capacity utilization. ” Id. Given the p o tential variability in actual

em issions, use of actual em issions (even doubl e actual em issions) does no t necessarily

repres ent this.

618. If a State participa t es f u lly in CAIR, and satisf ies its BART obliga tion f o r

EGUs f o r NOx and SO2, must the PM BART eligibility ana l ys is consid er whether a ll visibility impair ing pollutants, summ ed across a facility, exceed 250 tpy, or m u st only the PM em issions be considered ?

If

at the f i na l step of ide n tif ying the em ission units tha tcons titute a BART-eligible source, the State finds that a potential BART-eligible sour ce has the poten tial to em it 250 tpy of any visibility -imp airing po llu ta nt, then th e s ource is con s idered BA RT-eligib le. For example, if a potential BART-eligible so urce has em issions of m o re than 250 tpy of SO2 and m e ets the other applicable requirem e nts, then it m a y be subject to BART rev i ew for its em issions of PM. However, if the source’s em issions of PM 10 are less than 15 ty p (assum i ng the State h a s estab lished a de minimis level of 15 tpy), then the source’s PM 10

em issions need not be addressed in a BART determ ination.

19. An EGU has three boilers: a) coal boiler (5500 mmbtu/hr); an d b) two auxilliary boilers (181.6 mmBtu/hr each). The State has determ ined the coal b o iler to m eet the first test for BART-eligibility. Since the two aux illiary bo ile r s do not app ear to f a ll un der any of th e 26 BART categor ies, would they pa s s the f i rs t te s tf o r BART-elig ibility b e cause th ey contribute to the "s team electric plan t"?

As a genera l m a tter, a ll the em ission units, in cl uding any auxiliary boilers, at a fossil-fuel fired steam electric plan t of m o re than 250 m illion BTU/hour heat input would be considered part of the sam e stationary sour ce. U nder the RH regulations, BART appl ies

to cer tain ex isting sta tio nary sourc e s ; sta tiona ry s ources, in tu rn, are d e f i ned to inc l ud e “all of the pollutant-em i tting activities which belong to the sam e industrial grouping, are located on o n e or m o re contiguous or adjacen t properties, and are under th e contro l of the

sam e person (or persons under common contro l).” 50 CFR 51 .301. The regulations f u rther prov ide that “[ p] ollutant- e m itting activi tie s m u st be considered p a r tof the same industrial grouping if they belong to the sam e Major Group (i. e . which have the sam e two-digit [SIC] code).” For m o st plants on th e BART list, there will be only one 2-digit SIC code that applies to the entire plant. As you have described the source in your question, the auxillia ry b o ile rs would f a ll with in the sam e 2-digit SIC code as the co al boile r; th ese units a ccord ingly are part of the same stationary source as th e coal bo iler.

Note, however, tha tif the auxiliary bo ile rs ar e only used during startup, then since we do

not m odel startup conditions, those boilers would not contribute any em issions to the modeled visibility impact from the source; therefore those particular boilers m a y be

exempted.

Reasonable Progress

1. Is the r e a m e tr ic f o r dete rm ining if contro ls required for PM2.5, O3, CAI R , or BART are "reasonable" without defini ng benefit of controls?

7Unlike the technical demons tration for CAIR or BART, the reasonable progress dem onstration involves a test of a strategy. Th e strategy includes a suite of controls that has been id e n tif ied th rou gh the iden tif i ca tion of pollutants and source categories of pollutants f o r visib i lity impairm e nt - the po ssib l e contro ls f o r these po llu tants (and th eir precursors) and source categories - the applica tion of four statutory factors and how much progress is m a de with a potenti al s t r a tegy with r e spect to the glide pa th. Modeling o c curs with a strategy and is not a source-specifi c dem onstra tion lik e the BART assessm ent.

2. How can States dem onstrate benefits of controls from a single source for RH without doing single source impact m odeling, e.g. CALPUFF?

Reasonable progress is not required to be dem ons trated on a s ource-by -so u rce bas i s. It is dem onstrated based on a control strategy develope d fro m a suite of controls that has been assessed with the four statuto r y facto r s and the uniform rate of progress.

3. What if a State is on the glidepath, b u t can s till install cos tef f

ective con t r o ls ? Is it obliga t ed to insta ll those contro ls ?

From the pream ble to the Regional Haze Rule (64 FR 35732), EPA explained :

“If the State determ ines that th e am o unt of pr ogr ess iden tif ie d through the analysis is reasonable based upon the statutory f actors, the State should identify this am ount of progress as its reasonable progress goal for the first long-term strategy, unless it determ ines that additional progress beyond this amount is also reasonable. If the State determ ines that additi onal progress is reasonable based on the statutory factors, the Stat e should adopt that amount of progress as its goal for the first long-term strategy.

The statutory factors m u st be applied be fore determ ining whether given em ission reduction measures are reasonable. For exampl e, even if em i ssions reductions from o n e source category are projected to be enough to achieve the uniform rate of progress towards natural background in 60 years, Stat es should not forego an analysis of what degradation is being caused by pollutants from other source categories, or what improve m e n t s could be m a de by con t rolling them.

4. A. W h at type of de m o n s tration is accep tab l e to justif y a re as onable progress goal (RPG) that is less than the glid epath ? B. What if controls needed for other program s (e.g., PM2.5, ozone, CAIR) are installed?

A. If after applying the four statutory reasona ble progress factors, th e rate of visibility improve m e n tis still less than the uniform glide path, States may adopt the calculated RPGs, provided that they explain in the SIP how achieving the uniform glide path is not reasonable based on the application of the f actors. States m u st dem onstrate why the slower rate is reasonab l e, and state th e pr ojected date for achie ving natural background under th is alterna tive rate of progress.

8B. Existing contro ls tha t are ins t a lled as a resu lt o f other exis ting CAA program s can contr i bute to a State ’ s ab ility to s a tisf y its RP G. However, the statutory f actors m u st be applied before determ ining whether given em ission reduction m easur es are reason able. In particular, the State should adopt a rate of progress greater than the glidepath if this is found to be reasonable according to the statutor y factors. See in pa rticular the directive in the preamble to the RHR at 64 FR 35732.

5. Can a source comm it to extra control of one visibility-imp airing pollutant in exchange for doing less to contro l a le ss signif i c a n tpollu tant (inter-po llu ta nt tr ading) ?

The regulations require the States to adopt m easures that will m a ke reasonable progress toward the n a tiona l goal. States h a ve the f l exib ility in deve lo ping thes e measures to focus on those pollutants that have the m o stsignificant impact on visib i lity. A State could conclude that afte r application of the four statutory reasonable progress factors, it is “reason able ” to control one pollu tan tto a h i gher level than another pollutant.

In the context of BART, the RHR do es not provide for inter-pollutant trading where the source is installing controls based on the St ate’s BART determ ination. The regulations, however, do allow States to adopt alternative m easures in lieu of BART, so long as the alternative m easures provides for greater re asonable progress than would BART. Interpollutant tra d ing is no t a llowed in a trading prog ram alternative to BART, -- see 64 F R at 35743.

In addition, States m a y allow sources to “average” em issions across any s e t of BARTelig ible em ission units within a f e n celin e, so long as the em ission reductions from ea ch pollutant being controlled for BART would be equal to thos e reductions that would be obtained by simp ly controlling each of the BART-elig ible u n its th at con s titu te BARTeligible source (70 FR 39172).

Coordination with RPOs, States, and FLMs

1. What are EPA' s expectations and th e ba sis f o r con s ulta tion req u irem ents re garding f

o rm al consulta tive p r oc edures ? W h at cons titu te s ef f

ective F L M communication ? C a n it be assum e d that if the FLM attend s the RP O m e e tings and calls and doesn’t raise any concerns it has no problem s with a State’s S I P ?

40 CFR 51.308(i) requires that States consult with FLMs before adopting and subm itting their RH SIPs. These requirem e nts are summ arized as follo ws:

States m u st provide the FLM an opportuni ty for consultation, in person and at least 60 days prior to holding any public hearing on the SIP. The State m u st also provide the opportunity for the FLMs to discuss their: (i) assessm ent of impair m e nt of visibility in any Class I area; and, (ii) recommendations on the developm ent of the RPG and on the developm ent and implem entation of

stra tegies to address v i sibility impair m e nt . Further, the S t ate must includ e in the

9SIP a description of how it addressed any comm e n ts provided by the FLMs. Lastly, the S I P m u st provide procedures for continuing consultation between the State and FL Ms on the implem entation of 51.308 , including developm ent and review of SIP revisions and 5-year progr ess reports, and on the imple m entation of other program s having the potential to cont ribute to impairm e nt of visibility in Class I areas

.

This is a f o r m al consulta tive p r ocess. The basis f o r requiring written cons ulta tion procedures is 40 CFR 51 .308(i)(4). To satisfy this requirem ent, States should contact the FLMs to ens u re the i r inp u t to th e RH SIP process is solicited and docum e n ted. W h ile effective FLM consultation relies on both parties (States and FLMs) communicating early and often, the State is only required to m eet the provision s of 40 CFR 51.308(i) and is not responsible if a FLM chooses not to participat e in the either the RP O activities or the S I P developm ent and review process. In such cases, the State sho u ld docum ent its ou treach ef

f

o rts to the FLM.

2. Is there a protocol for resolving disputes between States and RPOs regarding technical differences between upwind and downwind Stat es on EI, m o deling, natural background, apportionm e n t, controls, etc. ? How will EP A address States /RPOs adopting different IMPROVE algorithm s (old vs. new) to look at the sam e Class I area?

EPA is developing a State and Federal Prot ocol which will describe the goals and objectives, consultation requirem e nts, prin ciples of collaboration, and process for collabo ratio n f o r the RH process. While con ceptual in na ture , this docum ent will be designed to for m the basis for a comm on understanding, approach, process and expectations for consultation and con s isten c y in d e veloping th e 308 Regio n al Haze SIPs. EPA is encouraging the early identif i cation of any potential d i sputes. Th is will a llow a ll parties ample opportunity to address and docum e n t any disagreem ents.

3. We understand that EPA is requ iring each Stat e with a Class I area to submit a SIP th at addresse s its obliga tions rela tive to th at Cla ss I area including estab lishm ent of a uniform rate of progress, imposition of requirem e nts to install controls on sources in tha tState that a r e cons idered reaso n able, docu m entation of its co llabo r a tive ef f

o rts with othe r States impacting th at Class I area, an d also docu m entation of inte ractions with surrounding States regarding th at State’s con t ribu tions to C l as s I areas in o t her States. The question is, “W hen is a State no longer ob ligated to consult w ith another State? ”

States are required under 40 CF R 51.308(d)(3), to collaborate and develop coordinated

em ission m a nagem e nt strategies to address RH visibility impairm e nt not only for Class I areas within their own borders, bu t also fo r each Class I areas located outs i de their borders which m a y be affected by their em issi ons. The obligation for States to consult with each o t her ultim ately rem a ins in place for th e period of tim e covered by 40 CFR 51.308. In practice, States will s a tisfy this obligation m a inly during th e p r eparation o f the RH SIPs for the first planning period ( 2018), due by 12/17/07, and in the preparation of the ten-year periodic revi sions, and the five-year periodi c reports described in 40 CFR 51.308(f) and (g), respectively.

104. A. Does a State h a ve obligations und er the RHR for reasonab le progress to initiate discussions with another State whose sources impact one of its Class I a r e a s if the projected interim visibility improvem e nt in 2018 falls directly on the unifor m rate of progress lin e for that area? Or can th e Stat e focus on defining reas onable progress for its sources without engaging other States with contributing sources in discussions?

B. Conversely, do States have obligations under the RHR to evaluate whether their sources are contributing to Class I areas in surrounding States ev en though the Class I

areas su rrou nding it are achiev i ng th e uniform rate of progress?

A. Yes, a State m u st consult with S t ates hav i ng s ources reaso n ably anticipated to cau se or contribute to visibility impair m e nt in a Cl ass I area to develop their RPGs pursuant to 40 CFR 51.308(d)(1)(iv) rega rdless of the uniform rate of progress for an area.

B. Yes, States m u st evaluate whether thei r sources are contributing to Class I areas in surrounding States even though the Class I areas surrounding it are achieving the uniform rate of progress as noted in answer 4. A. Note also that 40 CF R 51.308(d)(3)(i) specifically requires th at States with em i ssions th at are reason ably anticip a ted to contribute to visibility impairm e nt in anothe r S t ate’s Class I area consu lt with that State to develop coordinated em i ssion m a n a gem e nt strategies.

5. For Class I areas th at sp an two or m o re St ates, is there a requirem e nt for establishing a “lead” S t ate?

There is no requirem e nt in the RH regulati ons nor in guidance docum ents to identify a “lead” S t ate for shared Class I areas. Howe ver, states m a y choose to establish a “lead” state if it f a c ilitates the i r collabo ratio n and consultation. The RH rule relies on States collaborating and using the cons u ltation process (RPOs) to address shared Class I areas. Also, we ass u m e the tech nical work that is used as the basis would be the sam e for all SIPs. One m a y also wa nt to take a look at where the IMPR OVE mon itor is located that "represents" the Class I area in question, as th at location m a y also help define the "lead" State. Another option is the St ate with the larges t portion of the Class I area in th eir S t ate to be the “lead” State. These are ideas that could be used, but it is up to the States to work this ou t as par tof the collabora ti on and consultation process. W e view shared Class I areas sim ilar to interstate NAAQS nonattainm e nt areas. The States involved would collaborate to set one RPG fo r the area, and work together to define a consistent, coordinated approach to develop the long-term strategy for the area. As with interstate NAAQS nonattainm e nt areas, each State has le ad responsib ility for dev e loping, adop ting and subm itting its own SIP revis i ons af f

ecti ng the i r por tion of the Class I ar ea.

6. What if one State with th e Class I area sets an RP goal that req u ires an upw ind State to

m a ke reductions that it won' t m a ke?

If a State with a Class I area determ ines that a contributing State is not doing what is reasonab l e to m eet the R P G set for the area, and h a s attemp ted to reso lve this issu e, th e

11State with the Class I area should notify EPA and docum ent this issue in its initial RH SIP. For all revisions to the initial R H SIP revision, 40 CFR 51.308(h)(2) requires that the State with the Class I area p r ovid e notific a tio n to EPA and to the o t he r States which participated in the regional planning process. Th is subsec tio n f u rther r e q u ires the Sta t e with the Cla ss I ar ea to c o llabo rate w ith thos e Sta t es in the r e gional p l ann i ng proces s to develop add ition a l s t ra te gies. I tis E P A’s expectation that iss u es of communication/collaboration problem s such as this be brought to our attention as early in the process as possib l e.

7. If State A is at or below the glide p a th for an area, and a neighboring State (State B) impacting State A' s Class I area does not do all it can to m eet that area' s RPGs, what happens ? Is State A res ponsible to file a 126 p e tition o rother action ? C ould State A' s Regional Haze SIP be disapproved b ecause of State B ? Are the answers to these questions any different if State A' s RPG is above the glide path? In summary, if consultation does not work what happens and who is responsible?

State A is responsible fo r estab l ishin g RPGs for i t s Class I areas based on its consideratio n of the factors set f o r t h in the s t atu t e and imple m enting regulations, in consultation with State B and ot her States that m a y be contri buting to impairm e nt in the area. See 40 CFR 51.30 8(d)(1). Each Stat e, including State B, is required to subm it a SIP with a long-term strategy that includes m easures as necessary to achieve the RPGs estab lished f o r the Class I areas. W h ere States have participated in a regional planning process, the State m u st ensure that its SIP includes all m easures needed to achieve its share of em issions reductions agreed upon th rough that process. If there is a disagreem e n tam ong States as to what cons titutes reasonable progress, the question of whether Sta t e A’s or Sta t e B’s RH SIP coul d be d i sapproved will depend on the spec if ic of the situation. Each State is also res ponsible for docum enting its good faith attemp t to consult with State B, as outlin ed in 4 0 CFR 51.308(d)(1 )(iv )

. EPA will take this inform ation into account in determ ining whether the State’s g o al for vis i bility improve m e nt provid e s for reason able progre ss to wards natural vis i bility conditions. States are under no obligation to file petitions under Sect ion 126 of the CAA to satisfy the reasonable progress requirem e nt under the R H program

.

8. What is necessary in a S I P/temp late to dem onstrate “continuing consultation” under 51.308(i)(4)?

Most States are cu rren tly cons ulting with other States and wi th the FLMs by participating in an RPO. EPA anticip ates that m o st Stat es will address their future FLM consultation requirem e nts by continuing to participate in an RPO that is engaged in an ongoing

assessm ent of visibility issues. If a State dem onstrates that it has m e t current consultation requirem e nts through participation in an RP O that is engaging in the necessary consultation s , and if the State intend s to sa tisfy future consultation requirem ents (for periodic comprehensive SIP revisions or for other issues that arise) by continued participa tion in the i r RPO, then such a State n eed only comm it to such p a r tic ipation.

12For a State that has no t fully engag e d in the RP O process, the State m u st provid e a description of the process by which it in tends to consult with the FLMs in prepar ing f u ture subm itta ls and add r essing issue s that aris e. Sim ilarly, if a State h a s p a rticipa t ed in an RPO but intends to discontinu e th is par tic ipation, the Sta t e m u st provid e extens ive descrip tion of the alte rn ative m eans by wh ich th e State will enga ge in the required consultations.

9. To what extent does EP A expect RPOs to m o tivate States to communicate directly with and engage the FLMs, particularly for Cla ss I areas where those FLMs have not been participa ting in the RPO's work?

EPA expects that the RPOs will serv e as the coor dinating entities to f acilitate Sta t e- toState and S t ate-FLM co nsultation. To th at end, EPA recomm ends that RPOs individually set up a form al process to encourag e State-to -State and State-FLM consultation to take place, perhaps in th e form o f a coordinating workgroup. Through

m a naging this process, RPO’s can help identi fy areas where m o re FLM participation may be needed. However, RPO’s are not responsible if a FLM opts not to participate in these consultation opportunities. Ultim ately, it is th e State’s resp onsibility to ensure th e FLM consultation requirem e nts housed in 40 CFR 51.308(i) are satisfied.

10. What are EPA' s expectations of an RPO f o r written consultation procedur es with th e other RPOs/States outside its jurisdiction? Given lim ited funds and m u ch technical and policy work needed, it is suggested this be m a de as simp le and straightforward as possible.

EPA expects that RPOs will se rve as the f aci litating entities f o r State-to -S tate reso lution of issues relating to State appor tionm e nt of visibility impairm e nt at Class I areas. RPOs should also assist States in the resolution of disputes over the leve ls of control required by upwind States that contribute to visibili ty impairm e nt of downwind States’ Class I areas. Th is process sho u ld begin by each RPO identifying C l ass I areas for which their

m e mber States indiv i dually cau se or contribute to visibility impairm e nt. Following th is, the RPOs should m eet to broker consensu s between the States on the technical approaches to these issues.

There is no requirem e nt for an RPO to estab lish written cons ulta tion pro c edures with the other RPOs/States ou tsid e its jur i sdic tion. EPA expects RPOs to f acilita te and/or establish procedures in any for m at (infor m a l or form al) as needed that works best for the parties invo lved.

11. Does section 169A(c)(3) of the CAA require a State to obtain FLM concurrence with a State’s prop osal to exempt sources from be ing subject to BART in its Regional Haze SIP subm itted to EPA?

No. The CAA requires States to make BART determ ination s f o r BART-elig ible sou r ces that m a y reasonably be anticipated to cause or contribute to any impairm e nt of visibility in a Class I area. In the BART Guidelines , we provides States with an approach for

13exempting potential BART sources from BA RT by dem onstrating that a source does not

m eet this threshold. In contrast, under se ction 169A(c)(1) of the CAA, the Ad m i nistrator has the au th ority to exe m pt m o st sources f r om BART if he determ ines that the sourc e is

not reason ab ly anticipated to cause o r contribute to significant impair m e nt of visibility. Section 169A(c)(2) contains a sim ilar provision for certain po werplants. The exemptions under section 169A(c), however, are effective only on concurrence by the FLM. In sum, while States must consult with FLMs as part of th e SIP proces s, they are n o t requ ired to obtain FLM concurr e nce with the i r d e term in ation that a BART-elig ible so urce does no t

cause or con t ribu te to any impairm e nt.

M i s c el l a ne ous

1. On Dece m b er 20, 2005, the IMPROVE St eering Comm ittee approved a new algorith m for calculating current and natural background visi bility. If states use the new equation in BART and r easonable progress ana l y s es, will EP A accept it?

Yes, either the new IMPROVE extinction equation as recom m e nded in 2 0 05 by the IMPROVE Steering Committee or the orig in al equation recommended b y EPA in the "Guidance for Estim atin g Natural Visibility Con d itions Und e r the Reg i o n al Haze Ru le" (Septem b er 2003, EOA- 454/B-03-00 5) m a y be used to develop Regional Haze SIPs. Regardless of which algorithm is used for a Class I area, that m e thodology should be applied in a consistent m a nner. Consistenc y should be m a intained across Regional Haze applications (i.e., BART and Reasonable Progr ess), across tim e (e.g., baseline and future calculation for natural conditions ), and am ong the stakeholders involved w ho need to be consulted on the developm ent of a LTS for a Class I Area (i.e., FLMs, states, industry). Specifically, we recommend that the sam e ve rsion of the IMPROVE equa tion be used by States /sources which are impacting the sam e Cl ass I area to calculate v i sibility conditions for that area.

The curren tCALPUFF modeling sy stem uses an approach th at is s i m ilar to the o r igin al IMPROVE equation. Therefore, a m e thod to ap ply the new equation with this m odel for a BART assessm ent is needed. Consultation with the EPA Reg i onal Office and FLMs on proposals to use the new IMPROVE equation with CALPUFF for a BART assessm ent is

recomm end e d prior to its use in the modeling.

2. Instead of a single v a lue, can the RP G be sa tisfied using a natural conditions range that captur e s the variab ility in year-y ear em issions of natural events?

The 1999 RHR states that in comp aring “curren t conditions” against “n atural conditions,”

natura l cond itions m eans “[ t] he level of visibility (in decivi ew s) for the 20 percen t m o stimpaired days, and for the 20 percent least-impa ired days, th a twould exis t if ther e were

no m a n m ad e impairm e n t .” 64 FR at 35730. EPA issued a guidance docu m ent concerning this en titled, “Guidance f o r Estim atin g Natural Visibility Con d itions Und e r the Reg i o n al Haze Rule.” Under this guidance, a single v a lu e for natural v i sibility for each class I area is calculated for each of the 20 percen t m o st-imp ai red days and the 20 percent leastimpaired days. This guidance docum ent descri bes “default” and “refin ed” approaches for

14estim ating natural conditions. The E P A m e thodo logy that allows for the 20% best days and 20% worst days to calculate natural a nd background levels is designed to avoid a single v a lue (i.e., the sin g le best day or the single worst day). The single value that represents the 20% best days is cons idered repres entative of the range. Consequently, it would be redundant and unnecessary to further consider ran g es of visibility v a lues in determ ining natural and background levels.

3. What obligation does a downwind State have if it conducts m ode ling based on an upwind State’s em ission inventory, and the upwind Stat es subsequently changes its inventory? What is EPA’s expectation here?

EPA expects that State s will con tinu e to work to gether in ad dressing the problem of RH, both inside and outside the RPO context and th at States will s h are pertin ent aspects of their SIP planning with other States, as appropr iate. Upwind States should use their best efforts to provide potentially relevant in form ation, such as ch anges in em issions inventories, to downwind States in tim ely f a shion. W e are r e lying on th e RPOs, in large part, to ensu re th is coord i nation takes place.

The Regional Haze Rule does not establish a deadline by w h ich States should finalize their em ission inventories for purposes of SI P planning. EPA recognizes that addressing visibility impairm e nt is an ite rative ef f

o rt a nd that States will not always be capable o f incorpor atin g the m o st up-to-da t e inf o rm ation in their analy s es for the SIP s due in 200 7. If there is a lack of coordination on this issu e tha taf f

ects the integr ity of a

particular State’s SIP, EPA will exam ine it on a case- by-case basis and take in to account the specif i cs of the situ ation in its rev i ew of the SIP.

4. How does the CAIR substitu te f o r BART?

States sub j e c t to and p a r tic ipating in the CAIR cap and trade program for SO2 and NOx

m a y treat th e CAIR requirem e nts f o r EGUs as a substitu te f o r the applica t ion of BART controls for these pollutants. States do not need to require BART-eligible EGUs subject to the CAIR to install, maintain, and operate BART per 40 CFR 51.308(e)(4).

In addition, a State which is only subject to CAIR for NOx, bu t which also chooses to participa t e in the CAIR trad ing prog ram f

o r both SO2 and NOx, m a y co nsider BART to be satisfied for both SO2 and NOx fr om EGUs . Because EPA m odeled these States as controlling f o r both SO2 and NOx in the CAIR NFR, the better than BART dem onstration presented in that action would be valid in that scenario. Conversely, if such States choose to participate only in the ozone season N O x trading program , the updated projections presented in the BART rule (70 FR 3910 4) dem onstrate that BART would be satisfied for NOx, but such States would still need to address B A RT for SO2

em issions fro m EGUs (70 FR 39143).

Also, EPA’s assessm ent that the CAIR cap a nd trade programs can substitute for BART

contro ls does not extend to cases where a State has identified s ource-sp ecif i c BART

15requirem e nts as a result of a reasonable attribution determ in ation. In su ch cases, the source-specific BART re quirem e nts must be m e t at the source.

Finally, the CAIR does not addres s other po ten tial vis i bility impairing po llutants su ch as PM, VOCs, and ammonia. Also, the dete rm inatio n that the CAIR m a kes greater reasonab l e p r ogress than BART f o r EGUs is not a determ ination that the CAIR satisf i es all reasonable progress requirem e nt s in CAIR affected States.

5. If a CAIR fa cility is found to be exem pt fro m BART for SO2 and NOx, and the State does exemption m odeling on PM10 and concludes there is no impact on a Class I area, can the State tota lly exe m pt the utility f r om BART?

States sub j e c t to and p a r tic ipating in the CAIR cap and trade program for SO2 and NOx

are a llowed to tr eat the CAIR requir e m e nts f o r EGUs as a substitu te f o r the application of BART controls per 40 C F R 51.308(e)(4). This does not m ean EGUs are exempt for SO2 and NOx, only tha tCAIR satisf i es the BART re quirem e nt for those pollutants.

The rem a ining visibility polluta nts to consider f o r

determ ining BART-eligible sourc e s are PM, and, using judgm ent, VOCs, and ammonia. For PM, the July 6, 2005, final BART rule at 70 F R 39160 notes PM10 m a y be used an indicator for PM in this step of the determ ination and thus, PM10 can be used for the exemption m odeling.

6. What is the rela tionsh i p of CAIR to reas onable progress? Does CAIR satisfy reasonable progress requirem ents for EGUs for NOx and SO2?

As discusse d in the an s w er to the p r evious ques t ion, par tic ip ation in the CAIR can substitute f o r a Sta t e’s B A RT obligation in ce rtain narrowly defined areas. However, for the purpose of satisf y ing the RPG, CAIR ha s no more applic ability th an does BART – it is a control that can be part of a State’ s RPG. Th e pream ble to the 2005 BART Rule states tha tE P A’s determ ination tha tpartic ipa tion in the CAI R trading p r ogram would provide for greater reasonable progress fr om EGUs than would BART “is not a determ inatio n that CAIR satisf i es all reasona b l e p r ogress requ irem ents in CAIR affected States. ” (70 FR 39143). In other words, a lthough EPA has determ ined that the CAIR trading program would prov ide greater reasonab l e progress than source s p ecific BART

contro ls for affected EGUs for SO2 and NOx, a State’s reaso n able prog ress analys es m a y indicate th at additional controls b e yo nd CAIR m a y be necess ary to m eet th e RPGs set for

one or m o re the Class I areas.

7. What is the rela tionsh i p of RH BART to RAVI BART?

RAVI BART (Part I of the visibility program ) is a separate regulatory requirem ent from RH BART ( P art II of the visibility program ). RAVI BART tr eats visibility impacts fro m

one source or a sm all group of sources, as opposed to RH BART, which treats visibility impacts over a wide geographic area. EPA pro m ulgated regulations addressing “reasonably attributable vi sibility impairm e nt” or RAVI in 1980. Under these regulations, the requ irem ent for a BART anal ysis is triggered where the F L M certifies

16there exis ts reasonable attribu t able impairm e nt of visibility. You m a y fin d this docum ent a useful guide to understandi ng the RAVI process: http://www.wrapair.org/foru m s / m tf/docum ents/ravi_bart/Final_RA_BART_Report.pdf

Once a State has m e t the requirem e nts in the RH regulations for BART or imple m ented an alternativ e m easure, then the BART requi rem e nts of the Act have been m e t and BART sources will be subject to re gulation under the RH program in the sam e m a nner as other sources. 40 CFR 51.308 (e)(3). Therefore, even though a State m a y satisfy BART via a 308 SIP, an FLM m a y still cer tif y RAVI, t hus triggering a R AVI BART attribution determ inatio n.

8. What happens if RH SIPs are late?

Section 110(m ) o f the CAA provides discretiona ry authority for EPA to impose sanctions f

o r f a ilure to subm it a required p l an.

9. What is EPA' s position on the need to tr eat VOCs and ammonia as v i sib ility-imp airing pollutants ? If a State wishes to add r ess VOCs and/or amm o nia as visibility impairing pollutants, what tools a r e ava ilab l e to do this ?

The BART Guidelines direct that States should look at SO2, NOx, and direct PM

em issions in determ ining whether sou r ces c a us e or contribute to vi sib i lity impairm e nt, including both PM10 and PM2.5. As stat ed in the BART Guidelines (70 FR 39160), “States should exercise their judgm e n t in deciding whether [VOCs or a mmonia] i mpair visibility in an area ... a nd in deciding whether VOCs or a mmonia em issions from a source are likely to have an impact on visibili ty in an area. ” A for m al showing of an individual decision that a s ource of VOC or a mmonia em issi ons is not subject to BART review is no t necess a ry.

10. 51.308(d)(3)(v)(B) requires th at the State, in developing its L T S, consider m easures to

m itigate the impacts of construction ac tiv ities. What should this in clude?

States shou ld include co nstruc tion a c tiv ities in their em issio n invento r ies that are us ed for long-term strategy develop m ent. When EP A pro m ulgated the RHR in 1 999, em issions f r om construction a c tiv ities, su ch as em issions fro m non-road diesel equip m ent, and large scale wind-blown dust fro m rapidly growing areas like Las Vegas and Phoenix, were a

m a jor concern. Subsequently, EPA has pr om ulgated rules for on-road and non-road heavy duty diesel engines. St ates should include the em ission reductions fro m those rules in their SIP planning. If St ates have areas where wind blown dust from hu m a n activities contributes to a reduction in vi sibility at Class I areas, they should consider m easures to

m itigate th is source of visibility -imp airm ent. The W e stern Re gional Air Partne rship (WRAP) ha s a num ber of products related to dus t that can be downloaded fro m their site

at: http://w ww.wrapair.org

1711. What is EPA' s expectation f o r f illin g m i ssing da ta in the IM PROVE record ? How m a ny years are required to determ ine the baseline visibility if data is m i ssing in the 2000-2004 record ? Are 3 years sufficien t (IMP ROVE e xpectation)? N eed to create 5 years ?

The "Guidance for Tracking Progress Under the Regional ha ze Rule" ad dresses this question in several areas. Five (5) year s of data fro m the 2000-2004 period should be used. However, becau se of the deplo y m e nt of m o nitors this length of data m a y not be available for all Class I areas. The Tracki ng guidance recognizes this and recomm ends that a m i nimu m of three years of data shoul d be used if m o re years do not exist (see pages 1-4, and 2-8).

All five years should be used if available a nd suitable per guidance recomm endations. If not, then a m i ni m u m of three years is reco mm ended. You should not recreate data for years that the m onitor was not operational because of the f u rther unce r ta inty tha tthis data adds. If less than th ree y ears of complete d a ta ar e not ava ilab l e, consu lta tion with EPA is

recomm end e d. The Tracking guidance suggest s that a case-by-case proposal on how this data should be processed should be devel oped in consultation with EPA OAQPS ( a nd the Regional Office).

12. How are international em issions and na tura l ev ents addr ess e d in the RH SIPs?

EPA addressed the treatm ent of internationa l em issions in the 1999 RHR in a discussion of the long-term strategy for m a king reasona b l e p r ogress in section III.G o f the pream ble to the f i na l r e gional h aze rule as f o llo w s:

"The EPA agrees th at th e proje c ted e m issions f r om interna tio nal sourc e s will in som e cases affect the ability of States to meetreasonable progress goals. The EP A does not expect States to res t rict em issions from dom e stic sources to offset the impacts of inte rnational transpo r t of pollution. We believe that States sh ould evalu a te the impacts of

curren tand projected em issions from inte rnatio nal sources in their reg i o n al haze

program s, particularly in cases where it has already been well docum e nted that su ch sources are important. At the sam e tim e , EP A will work with the govern m e nts of Canada and Mexico to seek cooperative solutions on transboundary pollution problem s ." 64 Fe d. Reg. 35714, 35736 (July 1, 1999).

EPA provided additional clarification in th e preamble to the 1999 RHR o n how States should properly evaluate in ternational em issions, when we discussed the States' obligation to subm it five-year reports evalua ting p r ogress toward the RPG for each Clas s I are a :

"If the State finds that international em issi ons sources are responsible for a substantial increase in em issions affecting v i sib i lity conditio n s in any Class I area or causing a deficiency in plan implem entation, the Stat e m u st subm it a techni cal demonstration to EPA in support of its fin d ing. If EPA agr ees with the State' s finding, EPA will take appropriate action to address the international em issions through available m echanism s

. Appropriate m echanis m s for addressing visibi lity -imp airing e m issions f r om interna tio nal

18sources are further d i scu ssed in unit III.G on the long-term strategy. " 64 Fed. Reg. at 35747.

Both in explaining RPGs and in assessing wh ether current implem enta tion plan strategies are ach ievin g them , States can take into acc oun t the natu re of inte rnationa l em issions. For instan ce, after havin g a pplied the four statutory fact ors and calculate d their RPGs, states can at their discreti on, quantif y the ef f

ects o f interna tion a l em issions on their ability to reach RPGs. However, States s hould not directly cons ider the ef fects of international em issions when calculating thei r uniform rates of progress by either adding the ef f

ects o f interna tion a l em issions to the i r es tim a tes of natural cond itio ns, or by subtracting international em issions fro m curre nt conditions. Either of these approaches conflicts with the bas i c d e finition s of "current con d itions " (bas eline conditions for the first SIP) and "natural conditions, " as de scribed in the 1999 RHR. 64 Fe d. Reg. 35728, (July 1, 1999).

Those natural events m o st comm onl y linked to RH are wind blown dust and em issions fro m bio m ass burning. E P A has long recognized th e natural role of fire in the ecosystem. Consequently, in determ ining natural backgr ound for a Class I area, EPA believes States should be perm itted to co nsider som e am ount of fi re in the calculation. If a State finds during the five year period review that an unusua l natural event such as a large wildfire is af

f

ecting pr ogress, th is can be tak e n into ac c oun t in its ass e s s m e nt of whether the cu rrent SIP are sufficient to m eet the RPGs. The State sh ould subm it a techn i cal d e m onstratio n showing its estim ate of the wildfires’ contribu tion to visibility impair m e nt to support its conclusion.

19APPE NDI X: Question 5 cost equations

Average cos tfor an individual sou r ce

Average cost of control option A = annualized capital + operating and m a intenance $ option A /

tons rem oved option A

Average cost of control option B = annualized capital + operating and m a intenance $ option B /

tons rem oved option B

We use the following def i nitions for analyzi ng control options acro ss a sou r ce category or subcatego r y:

Average of individual source costs :

Average of individual source costs of control option A =

control costs sour ce 1 / tons rem oved sour ce 1 + control costs sour ce 2 / tons rem o ved sour ce 2

....

------------------ ------------------ ----------------- ------------------ --------------- -------------- total num ber of sources

Average cos tover the category :

Average cos tover the cate gory of control option A =

control costs sour ce 1 + control costs sour ce 2

....

------------------ ------------------ ----------------- ------------------ --------------- -------------- tons rem oved sour ce 1+ tons rem oved sour ce 2

....

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