,,I/ **--------**

**--** --- CLECO March 30, 2016 U.S. Environmental Protection Agency EPA Docket Center Docket: EPA-HQ-OAR-2014-0464 Mail Code 28221

T 1200 Pennsylvania Avenue, NW Washington, D.C. 20460 RE: Docket ID No. EPA-HQ-OAR-2014-0464

Cleco Corporation 2030 Don

a hu e Ferry Rd P. 0
. Box 5000 Pineville

, LA 71361

- 5000 FILED VIA EMAIL AND U.S. MAIL Cleco Corporation-

Do let Hills Power Station (DeSoto Parish) Comments

to EPA Recommendation

for S02 NAAQS Designation LDEQ Agency Interest No. 585 Dear Sir or Madam: These comments and the attached supplemental modeling and monitoring reports are submitted

by Cleco Corporation ("Cleco")
on behalf of the Do let Hills Power Station located
in DeSoto Parish, Louisiana. Cleco requests that these comments

be included

in the administrative record for this docket and that these comments

be considered

by the U.S. Environmental Protection Agency ("EPA") when making

a final designation related
to the 1-hour sulfur dioxide ("S0

2 ") national ambient
air quality standard ("NAAQS")

for DeSoto Parish. As discussed below, Cleco believes EPA should accept the Louisiana Department

of Environmental Quality's ("LDEQ's") recommendation

to designate DeSoto Parish

as "attainment"

for the 1-hour S02 NAAQS. Based on air quality modeling conducted

by American Electric Power (AEP) and monitoring data derived from

a properly-sited

air monitor located
in DeSoto Parish, there
is substantial evidence

to accept LDEQ's attainment recommendation

for this area.
If EPA does not accept LDEQ's recommendation,

a designation

of "unclassifiable/attainment"

is more appropriate

for DeSoto Parish than the designation recently proposed
by EPA. Background On March

1, 2016, EPA published

a "notice
of availability
and public comment period" in the Federal Register for certain state designation recommendations

for the 2010 1-hour S02 NAAQS. See, 81 Fed

. Reg. 10,563. This notice relates
to a second round of S0 2 NAAQS designations

for certain areas of the country

as required
by
a consent decree that included

a court-ordered designation schedule. Sierra Club

v. McCarthy, No. 3-13-cv-3953
(SI) (N.D. Cal. Mar.
2, 2015).
In response

to the above-referenced consent decree, EPA notified the state ofDocketIDNo.EPA-HQ-OAR-2014-0464March30,2016Page2Louisianaofthecourt-ordereddesignationscheduleincorrespondence,datedMarch20,2015.Initsletter,EPAidentifiedthreeelectricpowerplantsourcesintwoLouisianaparishes(CalcasieuandDeSoto)thatmeetthecriteriaestablishedinthecourt'sorder.Theletterfurtherprovidedadesignationscheduletocomplywiththecourt-ordereddeadline.InresponsetoEPA'snoticeletter,theLDEQsubmittedareporttoEPARegion6onSeptember18,2015thatprovidedrecommendationsfordesignationoftheS02NAAQSforCalcasieuandDeSotoParishes.TheLDEQalsosubmittedarevisedrecommendationtoEPAspecificallyforDeSotoParishincorrespondencedatedNovember17,2015.Inthisletter,theLDEQrecommendedthatDeSotoParishbedesignatedas"attainment"forthe1-hourS02NAAQS.TheSierraClubalsoprovidedcommentstotheLDEQonSeptember18,2015thatincludedairmodelingforDeSotoParishandsubmittedupdatedairmodelingtotheEPAAirQualityPolicyDivisionincorrespondencedatedDecember14,2015forareasinTexasandLouisiana,includingDeSotoParish.InresponsetoLDEQ'srecommendation,EPARegion6providedanotificationtothestateofLouisianaofitsintendedmodificationstothestate'sproposedrecommendationsincorrespondence,datedFebruary11,2016(alsoknownasthe"120-dayletter").WithrespecttoDeSotoParish,EPAnotifiedthestatethatitintendedtodesignateapartoftheparishas"nonattainment"fortheS02NAAQS,andthereby,didnotacceptthestate'srecommendation.EPA's120-dayletterattachedaTechnicalSupportDocument,whichincludedaTechnicalAnalysisfortheDeSotoParish,LouisianaArea("TechnicalAnalysisforDeSoto").See,LetterfromRonCurrytoGov.JohnBelEdwards,datedFeb.11,2016,pp.6-19.AsdiscussedintheTechnicalAnalysisforDeSoto,EPAproposestodesignatearectangularareainDeSotoParish(shownonFigure1(p.8)ofthedocument)thatwouldincludetheDoletHillsPowerStationandInternationalPaper'sMansfieldMill.SpecificCommentstoEPA120-DayLetterRelatedtoDeSotoParishClecoprovidesthefollowingspecificcommentsinresponsetoEPA'sletterfromRonCurrytoGov.JohnBelEdwards,datedFebruary11,2016.ClecobelievesthesecommentsandtheattachedmodelingandmonitoringanalysesjustifyadifferentdesignationfortheDeSotoParishareathanwhatwasproposedbyEPAinits120-dayletter.ClecorequeststhattheEPAprovideadetailed,writtenresponsetoeachofthefollowingcomments.1.SupplementalairmodelingconductedbyAEPdemonstratesthatS02emissionsfromtheDoletHillsPowerStationandthepapermillarebelowthe1-hourS02NAAQS.ThismodelingismoreaccuratethanpriormodelinganalysesconductedbytheSierraClubandtheLDEQandrespondstospecificissuesraisedbyEPAinitstechnicalanalysis.InresponsetoEPA's120-dayletter,Clecoworkedwiththeco-owneroftheDoletHillsPowerStation,AEP,toconductadditionalairmodelingfortheDeSotoParishareathatincludedmoreaccurateemissionsdataandstackparametersforthecoal-firedelectricutilityandalsoincludedthepapermilllocatedapproximately14kilometersnorthoftheutility.UnliketheDocketIDNo.EPA-HQ-OAR-2014-0464March30,2016Page3modelingconductedbytheLDEQ,AEPdidnotusetheLOWWIND3modelingoption.Asdiscussedbelow,thismodelinganalysisdemonstratesthattheDeSotoParishareaisinattainmentwiththe1-hourS02NAAQSbasedontheactualoperatingconditionsofbothmajorsources.ThemodelingwasperformedinaccordancewithEPA'sdraftairmodelingguidancedocumententitled,S02NAAQSDesignationsModelingTechnicalAssistanceDocument,datedFebruary2016,andcommentsmadebyEPAintheTechnicalSupportDocumentattachedtothe120-dayletter.Withrespecttotheemissionsmodelingparameter,EPAnotedinthe120-dayletterthat"continuousemissionsmonitoringsystems(CEMS)dataprovideacceptablehistoricalemissionsinformationwhenitisavailable,andthatthesedataareavailableformanyelectricgeneratingunits."Id.atp.12.EPAfurthernotedinitstechnicalanalysisthatLDEQused"normalizedhourlyemissionsandactualstacktemperatureandexitvelocityfromtheCEMSfor2012-2014"andthatSierraClub'smodelingused"hourlyemissionsdatameasuredbytheCEMSfromCAMD(2012-2014)andconstantstacktemperatureandexitvelocity."Id.atp.12.Concerningthesourcecharacterizationmodelingparameter,EPAstated:SierraClubmodeledconstantexitflowrateandtemperaturebasedon100%load.Noconsiderationwasgivenoffacilityoperationatlessthan100%load.Stackparameterssuchasexitflowrateandtemperaturearetypicallylowerthanfullload,havingtheeffectofreducingpollutantdispersionandincreasingpredictedairqualityimpacts.Inaddition,noconsiderationwasgiventobuildingorstructuredownwash.Downwasheffectstypicallyincreasepredictedconcentrationsnearthefacility.Thestateidentified InternationalPaperlocated14kmnorthoftheDoletHillsfacilitywithannualemissionsexceeding1,300tpyastheonlyotherlargenearbyemissionsource.However,nosourcesotherthanDoletHillswereincludedinthemodelingperformedbytheSierraCluborthestate.Id.atp.11(Emphasisadded).Initssupplementalmodelinganalysis,AEPincludedmoreaccurateinformationforthreespecificcategories:(1)stackparameters,(2)emissionsdata,and(3)effectsofdownwash.Withrespecttostackparameters,AEPreviewedtheflatstackexittemperatureandexitvelocityusedbySierraClubandconcludedthatthesewerearbitrarilylow.DatacollectedbyAEPrevealstemperaturesabove200°Fandanexitvelocitygreaterthan90ft/secatthelow-endoffullloadoperatingconditions.Incontrast,SierraClubusedatemperatureof161°Fandanexitvelocityofabout85ft/sec.Withrespecttoemissionsdata,AEPusedCEMSdatafortheDoletHillsPowerStationincluding,heatinput(MMBtu/hr)data,flowrate(scfh),andhourlyS02emissionsdata(lb/hr)thatwasreportedtotheUSEPACleanAirMarketsDivision("CAMD").Inadditiontotheseparameters,thetemperaturedatacollectedbytheCEMS(butnotreportedtoCAMDbasedonthe40CFRPart75reportingprotocolsdevelopedbyCAMD)wasusedtoadjusttheflowdatabackintoactualflowunitsandthehourlytemperatureinputrequiredbyAERMOD.ThedatawasprocessedonaparameterbasisinwhichflowratewasadjustedbacktoactualhourlystackconditionsusingthetemperaturedataforconcurrenthourforwhichtheexitvelocitywasDocket ID No. EPA-HQ-OAR-2014-0464 March 30

, 2016 Page4 being calculated. This hourly data was then passed through multiple checks
to ensure the validity of the data. Sierra Club's frrst modeling analysis only used one year of data to estimate the required three-year average. The Sierra Club report claims that updating the inventory

to reflect load change and including

a proper downwash analysis will increase the predicted impacts

. See, Dolet Hills Power Station report, dated August

9, 2015,
p. 4 . Based on AEP's review, this statement

is generally not correct for emission sources like the Dolet Hills Power Station with

a stack that is significantly taller than surrounding structures. For this reason, AEP included proper downwash in its air quality model and estimated emissions based on actual operating data, which better reflects the dispersion

of S0 2 emissions

in a given hour. Startup conditions were also reflected

in the inventory used by AEP based on available information. The ambient
air modeling report prepared
by AEP, entitled Air Quality Modeling Technical Note, Dolet Hills Power Station, Mansfield, Louisiana,

is attached

to these comments in Attachment

1. The modeling files have also been provided

to EPA Region

6 personnel
for further review and examination.
The final refined modeling simulation shows that the highest concentration

due to all sources and the background concentration

is 171.0 f.!g / m

3 , which

is below the 1-hour S02 NAAQS
of 196.5 flg/m

3 . As discussed

in Comment

3 below

, a seasonal hourly background concentration ranging from 4.88 flg/m

3 to 24.85 f.!g/m

3 was used for this analysis. However,
the AEP modeling still demonstrates compliance with the 1-hour S02 NAAQS

if the higher background concentration used by Sierra Club and LDEQ (31.4 f.!g
/ m 3 ) is used. Cleco believes that EPA should use the attached modeling report
in lieu of prior reports submitted

by Sierra Club and the LDEQ. As discussed,
the AEP modeling analysis used more accurate information

for stack parameters
and emissions data for the Dolet Hills Power Station

as well as the effects of down wash, and included emissions

of the paper mill. Cleco further asserts that based on this modeling information alone, EPA should classify DeSoto Parish

as "attainment"

in the final S0 2 NAAQS designation.

As discussed below, this modeling result comports much closer
to the monitoring data that has been attained for this area in recent months. 2. Emissions from International Paper's Mansfield Mill do not contribute

to concentration gradients around the Do let Hills Power Station
or to the south of this facility

as asserted in EPA's 120-day letter. Because such emissions have now been adequately considered in AEP's modeling analysis,
an attainment designation

is appropriate. The Technical Analysis for DeSoto discussed
the fact that neither Sierra Club nor the state's modeling included emissions from International Paper's Mansfield Mill. EPA further speculated that "when winds are out of the north and resulting

in some of the highest values modeled around Dolet Hills, the IP source would be upwind and could contribute

to concentration gradients around Dolet Hills and to the south ofDolet Hills." !d. at p. 10. Based on this observation
and the proximity between the Dolet Hills Power Station and the Mansfield Mill ( **~** 14 kilometers), EPA concluded that "it is likely that the source causes concentration gradients

# Docket ID No

. EPA-HQ-OAR-2014-0464 March 30,2016 Page

5 that extend
to area impacted
by Do let Hills with some of the higher modeled values that are near the standard."



# Id. EPA concluded

its analysis
of the proposed jurisdictional boundaries

by stating: The EPA believes that the IP facility has reported emissions that are large enough such that if they were explicitly modeled

in accordance with the Modeling TAD would likely be shown

to contribute

to the ambient concentrations
that have already been modeled

to show violations,

or near violation

, of the NAAQS. Inclusion

of IP emissions may likely increase modeled values just below the standard

to exceedance levels. Therefore,
our intended area includes portions
of DeSoto Parish that include the area of modeled exceedances
and near exceedances

as well as the IP facility because
of its likely contribution

to the modeled ambient concentrations resulting

in additional potential NAAQS violations

if IP were included

in the modeling. The EPA believes that our intended nonattainment
area, consisting

of the area around Dolet Hills and including Cleco,

is comprised

of clearly defined boundaries

, and we find these boundaries

to be a suitably clear basis for defining our intended nonattainment area. 

# Id at p. 18 (Emphasis added). As discussed

in the prior section, the air modeling performed

by AEP included the utility and the paper mill, and confirms compliance with the 1-hour S0 2 NAAQS

. AEP's modeling further reveals that S02 emissions from the Mansfield Mill do not 

# contribute

to the concentration gradients near the Dolet Hills facility
or to the south of the facility. With respect

to modeled emissions
for the paper mill, the analysis used

a conservative representative estimate for the maximum hourly S0 2 emissions rate for Power Boilers No.

1 and 2. These rates were developed from

a statistical evaluation

of the hourly S0 2 CEMS data (lb/MMBtu)

for the period 2012-2014. The .factors were then multiplied

by the maximum heat input of each boiler
to obtain the maximum actual S0 2 emissions rates. All other S0 2 emissions sources were modeled using the maximum permitted emission rates. As noted in the report, atypical operating scenarios were excluded from the modeling analysis since they are not representativeness

of typical mill operation and are not expected

. to coincide with the other · conservative modeling inputs. To address EPA's comment related

to assumptions made in the LDEQ and Sierra Club modeling

, hourly exit flowrate/velocity

data was developed

in the refmed modeling analysis. As discussed,
the refined modeling analysis shows that the highest concentration

due to both 

# sources plus monitored background

is below the 1-hour S0 2 NAAQS.

In addition

, the contribution

of emissions sources

at the Mansfield Mill to the total modeled concentration

is extremely low (approximately

0.4 11g/m

3 ). 

# This refutes any supposition

in EPA's 120-day letter that the Mansfield Mill "could contribute

to concentration gradients around Dolet Hills and to the south of Dolet Hills"
in any meaningful way. Instead, the refined modeling shows that the highest concentrations associated with the Mansfield Mill sources are at the facility boundaryDocket ID No. EPA-HQ-OAR-2014-0464 March 30, 2016 Page

6 and drop off significantly with distance from mill property. None of these concentrations exceed the 1-hour S02 NAAQS (196.5 !lglm

3 ). As discussed, AEP's refined modeling analysis considers the paper mill and is based on accurate and conservative emissions data from this facility. Based on this analysis, EPA should classify
all of DeSoto Parish
as "attainment"

in the final S02 NAAQS designation. 3. A more representative background concentration should be used for the DeSoto Parish area modeling analyses than what was used by the Sierra Club or LDEQ. Ambient
air quality data is typically used

· to represent the contribution

of non-modeled sources

to the total ambient
air pollutant concentrations

for
a NAAQS analysis. With respect

to background concentration, EPA's Technical Analysis for DeSoto references that 31.4

d llg/m

3 was used by the LDEQ and Sierra Club in their respective modeling analyses. This was purportedly based on the "99th percentile

of the annual distribution

of daily maximum 1-hour concentrations averaged
across 2011-2013

for the Bossier Parish monitor -the lowest measured background concentration

in the state." Id. at p. 14. Thus, the Sierra Club and LDEQ analysis used monitored data from

a monitor located

in Shreveport, Louisiana approximately

54 kilometers north of the Do let Hill Power Station. Although EPA states in the TAD that the Shreveport monitor has

. "the lowest measured background concentration

in the state," this monitor

is the most representative monitor available for any modeling analysis and likely conservative.
The Mansfield Mill and Dolet Hills facilities are surrounded

by rural land use generally consisting

of agricultural
and undeveloped forested and grassland areas, whereas the Shreveport monitor

is in
a more urban/developed

area consisting

of commercial
and compact residential land uses.
A wind rose of the Shreveport meteorological
data indicates winds
in the region are predominantly from the south. Thus, S02 are likely transported from both the power station and **th~** paper mill toward the Shreveport monitor. Therefore
the use of this monitor may result in some double counting
of emissions

in the analysis. For these reasons, the Shreveport monitor should be conservative

to represent background

in the vicinity
of the Mansfield Mill and Do let Hills. EPA's recommends

a tiered approach
for adding monitored background concentrations (representing non-modeled sources)

in the NAAQS analysis.
As noted in the Technical Analysis for DeSoto, the first tier approach

is conservatively based on adding the monitored design value (3-year average 99th percentile daily 1-hour maximum concentration)

to the modeled design value. The second tier uses

a temporally varying approach, based on combining
the monitored concentrations,

by hour of day and season, with the hourly modeling results. The total hourly modeled plus monitored concentrations

are then used to determine
the design concentration

for comparison

to the NAAQS. These computations

are all done within AERMOD. Rather than conservatively adding the modeled design concentration with the monitored design concentration

for this analysis, the second tier refinement should be used. Under this approach, the ambient background concentration should
be combined with modeled concentrations

on a seasonal hour-of-day basis in accordance with EPA guidance

as outlined

in

# Docket ID No. EPA-HQ-OAR-2014-0464 March 30, 2016 Page

7 the TAD. For the AEP analysis, the ambient background concentrations were updated based on 2013-2015 data for the Shreveport monitor. The Sierra Club and LDEQ purportedly used data :from 2011-2013; however,

it appears that only data :from 2013 was used since the Shreveport monitor was not in operation

in 2011 and 2012. Based on the foregoing, Cleco believes EPA should accept the seasonal hourly background concentrations developed

by AECOM/Intemational
Paper ranging from 4.88 IJ.g/m

3 

# to 24.85 IJ.g/m

3 

# based on 2013-2015 data for the Shreveport monitor. This background concentration

is based on an actual three years of data (not an extrapolation

of one year) and

a more recent period. As discussed

in Comment

1 above, the AEP modeling still demonstrates compliance with the 1-hour S0
2 

# NAAQS ifthe higher background concentration used by Sierra Club and LDEQ (31.4 IJ.g/m

3 ) 

# is used. Nevertheless,

the use of the lower background concentration

is justified

in this instance. 4. EPA accepted similar air modeling

in Arkansas that used better site data and more closely adhered

to EPA's technical assistance document. For consistency, EPA should also accept the attached modeling report that demonstrates attainment with the S02 NAAQS. In the February

11, 2016 notification

by EPA
to the Governor

of Arkansas

of its designation intention
for Jefferson County, Arkansas,

a Technical Assistance Document (TAD) was included which discussed
the reasoning behind EPA's intention. This discussion mainly focused
on the White Bluff Steam Electric Station ("White Bluff') and the dispersion modeling of the plant by both the Arkansas Department

of Environmental Quality ("ADEQ") and Sierra Club. EPA wrote in the paragraph titled Other. Relevant Information 

# (page
18 ofthe TAD) that it had identified multiple errors in stack parameters,

as well as less-refined modeling approaches

as compared with the state's submittal (e.g., variable stack velocity and temperature were not included). With respect

to the less-refined modeling approaches, EPA stated: Sierra Club also did not include the additional refinement

of variable stack parameters,

as allowed
by the modeling TAD, and was not as representative

of daily operations when compared with the state's analysis. The state's modeling was determined

to follow the modeling TAD more closely, and is more representative

of actual operation conditions

at White Bluff station. Therefore,
our intended unclassifiable/attainment designation

for Jefferson County

is based on the state's analysis. Letter from Ron Curry
to Gov. Asa Hutchinson, attaching Technical Analysis for Jefferson County Arkansas Area, 

# dated Feb. 11, 2016,
p. 18. Similar

to the modeling conducted

by ADEQ, the AEP modeling analysis for Desoto Parish used variable stack parameters

as allowed
by EPA's modeling TAD. Sierra Club's modeling

of Desoto Parish, like its modeling
of Jefferson County, Arkansas,
did not 

# use variable stack parameters and, therefore,

is not as representative

of daily operations

as AEP's modeling. Therefore,

as it did in Arkansas, EPA should base its designation

of Desoto Parish on the

# Docket ID No. EPA-HQ-OAR-2014-0464 March 30, 2016 Page

8 modeling that
is more 

# representative

of actual operating conditions, which

IS 

# the attached modeling analysis submitted
on behalf of the Do let Hills Power Station. 5. EPA should consider the existing ambient
air monitoring data that exists for the DeSoto Parish area that was located using EPA-accepted protocol. This monitoring data confirms that the 1-hour S02 NAAQS has been satisfied
for

a representative period.
At
a minimum,
the monitoring data demonstrates
that not enough data exists
to classify the area as nonattainment. On July
8, 2015, representatives

of Cleco, EPA and the LDEQ met to discuss issues related

to the S0
2 

# NAAQS designation

for DeSoto Parish, including
the installation

of a S0
2 

# ambient
air monitoring system
to characterize

the quality of the ambient
air near the Do let Hills Power Station. On August 19, 2015, Cleco submitted

a report
to the LDEQ and EPA entitled, Siting for Source-Specific

S02 Ambient Monitoring for Dolet Hills Power Station." 

# Cleco's consultant used

a "normalized design value" (NDV) approach

to determine

an acceptable SOz monitoring location based on EPA's guidance document entitled, S02 NAA QS Designations Source-Oriented Monitoring Technical Assistance Document, 

# dated December 2013. Cleco subsequently installed

a S0
2 

# ambient
air monitoring system based on the results of the siting analysis prepared
by CB&I. The LDEQ referenced
the use of data from the ambient
air monitor

in its S0
2 

# NAAQS recommendation
letter to EPA, dated September 18,2015, and noted that the "data provided
by the new monitoring station will allow for an accurate characterization of air quality nearest the source of S0
2 

# without ambiguity." See, 

# p. 3 of DeSoto Support Document 

# attached

to LDEQ letter to EPA. Representatives

of LDEQ have reviewed the data collection and processing
for this ambient
air monitor since installation. CB&I submitted

a S02 Ambient Monitoring Quarterly Report



# to the LDEQ on February 26, 2016 that provided monitoring data from October 23, 2015 through January 31, 2016. Thus, the statement
by EPA on page

8 of the technical analysis that "there are no S0
2 

# air quality monitors

in DeSoto Parish"

is not accurate

. All data collected
for this period demonstrates compliance with the 1-hour S0
2 

# NAAQS. The report dated February
26, 2016 noted that the highest daily maximum one-hour concentration from October 23, 2015 through January 31, 2016 was 32.6 parts per billion (ppb). The average daily maximum 1-hour concentration

for this period was only 3.5 ppb and the 99th percentile daily maximum 1-hour concentration
was 25.6 ppb. The ambient
air monitoring report prepared
by CB&I are attached

to these comments

in Attachment

2. The above monitoring data, based on an ambient
air monitoring station (properly sited using EPA's source-oriented monitoring technical assistance document) demonstrates
that actual 

# S0
2 

# concentrations

are well below the 1-hour S0
2 

# NAAQS. This information further supports the modeling analysis prepared
by AEP that shows the design value
to be below the standard. Cleco believes that the use of both sets of data justify
an "attainment" designation.

At
a minimum, Cleco believes the S0
2 

# monitoring

· data for this representative period justifies

a designation

of "unclassifiable/attainment."

EPA should not make

a premature and unwarranted

# Docket ID No. EPA-HQ-OAR-2014-0464 March 30, 2016 Page

9 nonattainment designation

for DeSoto Parish due to the consent decree deadline based onoverlyconservative
and faulty analysis provided

in 2015. The final Data Requirements Rule (and many other EPA documents) states that an area will be designated

as "unclassifiable"

if the EPA has determined "that sufficient information
has not yet been identified

to support
an attainment

or nonattainment designation."
See, 

# 80 Fed. Reg. 51,084.
In this case, we believe there

is sufficient information

for EPA to make

a fmal designation

of "attainment"

or "unclassifiable/attainment." Likewise,

in light of conflicting modeling reports, there
is not enough information

for EPA to make

a definitive determination that any part of DeSoto

is not attaining the standard. EPA
is clearly authorized

to consider this monitoring data and should do so in this case: (1) because

it was properly located using EPA guidance documents,

(2) because

it demonstrates monitored 

# attainment with the S0
2 

# NAAQS, and (3) because

it substantiates AEP's modeling analysis which also confirms compliance with the standard. 6. Based on the available information, EPA should allow more time
to evaluate the monitoring data before designating
any part of DeSoto Parish

as nonattainment. Sufficient data does not exist to make

a conclusion that the DeSoto Parish area is not meeting the 1-hour S02 NAAQS. With respect
to NAAQS, the federal Clean Air Act defines an area as "nonattainment"

as "any areas that does not meet (or that contributes

to ambient
air quality
in a nearby area that does not meet) that national primary

or secondary ambient
air quality standard for the pollutant." See, 

# 42 U.S.C.§ 7501(2) and 42 U.S.C.§ 7407(d)(l). Implicit

in this statutory definition

is the criteria that

. enough significant data exists (in the case of the 1-hour S0
2 

# NAAQS through either monitoring

or modeling)
for EPA to conclude that an ambient
air quality standard has been or is being violated
in a particular geographic area. With respect
to DeSoto Parish, Cleco believes that EPA has not presented enough data in the 120-day letter to designate any portion
of the parish
as nonattainment. Rather, this data more properly leads
to a designation

of "unclassifiable"

if LDEQ's
air modeling analysis

is disregarded

by EPA. However, based on the AEP modeling results that use significantly more accurate emissions and source parameter data for the Do let Hills Power Station and International Paper's Mansfield Mill, enough data exists
to designate DeSoto Parish
as "attainment," which

is defined in the federal Clean Air Act as "any area

. . . that meets the national primary

or secondary ambient
air quality standard
for the pollutant."



# Id. This higher-quality modeling analysis

is further supported
by recent ambient monitoring data that confirms that the anticipatedhighestmodeled area near the Dolet Hills facility

is well within the

1 - hour S0
2 

# NAAQS. EPA clearly has the authority

to consider this data (hence, the non-mandatory solicitation

for public comments

by EPA in the March

1, 2016 Federal Register notice) before

a final designation

is made. Based on this clear and overwhelming information, Cleco urges the EPA to designate DeSoto Parish
as attainment

by July 2, 2016. At a minimum,
the data justifies

a recommendation of "unclassifiable/attainment"

for this geographic region.

# Docket ID No. EPA-HQ-OAR-2014-0464 March 30,2016 Page 10 Summary For the reasons discussed

in these comments and as presented

in the attached modeling and monitoring reports

, Cleco requests that EPA make

a final designation

of

" attainment"

for all of DeSoto Parish. The air modeling conducted

by AEP demonstrates
that S02 emissions from the major S0

2 

# sources located
in this region meets the 1-hour S0 2 NAAQS. This conclusion

is further supported

by data from the properly-located ambient
air monitoring station currently operating

in DeSoto Parish. We appreciate your review
of these comments and look forward

to EPA's written response.

If you have any questions,

I can be reached

at (318)484-7718. Respectfully submitted, Bill Matthews Director---: Environmental Policy and Planning Attachments cc: Mark Hansen, U.S. EPA Region

6 Tegan Treadaway, LDEQ Air Permits Division

# Attachment

1

# Attachment

2