JOHNBELEDWARDSGOVERNORofJLoutstanaDEPARTMENTOFENVIRONMENTALQUALITYOFFICEOFTHESECRETARYRonCurry,AdministratorUSEPARegion6,(6-RA)1445RossAvenue,Suite1200Dallas,TX75202-2733CHUCKCARRBROWN,PH.D.SECRETARYRE:Recommendationsfor2010SulfurDioxideNationAmbientAirQualityStandards(NAAQS)forLouisianaDearMr.Curry:OnMarch20,2015,theUnitedStatesEnvironmentalProtectionAgency(USEPA)issued"UpdatedGuidanceforAreaDesignationsforthe2010PrimarySulfurDioxideNationalAmbientAirQualityStandard."ThisguidancewasbaseduponaconsentdecreeenteredintoonMarch2,2015,intheUSDistrictCourtoftheNorthernDistrictofCaliforniabytheUSEPAandplaintiffsSierraClubandNaturalResourcesDefenseCouncil(CaseNo.13-cv-03953).StateswithindicatedareasweregivenuntilSeptember18,2015,tosubmitarecommendationtoUSEPA.Twoareas(3facilities)inLouisianawereidentifiedasfittingthesecategories:1.)NelsonIndustrialSteamCompany-CalcasieuParish;2.)RSNelsonGenerationPlant-CalcasieuParish;and3.)DoletHillsPowerStation-DeSotoParish.Thestaterecommended,onSeptember18,2015,thattheseareasbedesignatedattainmentbasedonthemostcurrentinformationatthattime.ByletterdatedFebruary11,2016,EPAdisagreedwiththisdesignationrecommendationandprovidedadetailedtechnicalsupportdocumentasevidenceastowhytherecommendationsshouldbechangedtosomethingotherthanattainment.EPAindicatedthatCalcasieuParishwouldbedesignatedasunclassifiableandthatDeSotoParish(oraportionthereof)wouldbedesignatedasnonattainment.Furthermore,theletterindicatedthatthestatehaduntilApril19,2016toprovideyouroffice withanyadditionalinformationthattheEPAshouldconsiderpriortofinalizingthesedesignations.ThestateappreciatesthisopportunitytopresentadditionaldataandmodelingoutcomeswhichwillshowthattheEPA'sintendeddesignationsshouldbeadjustedsuchthatbothareasaredesignatedattainment.Thestateoffersthefollowinginformationforconsiderationandbelievesthatthefinaldesignationshouldbechangedaccordingly:PostOfficeBox4301•BatonRouge,Louisiana70821-4301•Phone225-219-3953•Fax225-219-3971www.deq.louisiana.govIntended Unclassifiable
Area: Calcasieu Parish The Westlake monitor, which

is located

in Calcasieu Parish, had historically monitored attainment
with the new standard, even before

it was established.

The current design value

at that monitor

is 32 parts per billion (ppb

). EPA resists this data, although

it has been duly certified,
due to monitor location. Based
on this information,

the state disagrees with the designation

of unclassifiable. Furthermore, industry modeling indicates
that the area

is in attainment
with the standard. EPA asserts that the area of analysis

or grid was not sufficient according

to its draft Technical Assistance Document (TAD); however,

no receptors

in the modeling presented were greater than 

### 170.0~-tg/m which

is less than the standard 

### (196.5~-tg/m\ near the edge of the grid.

It is widely accepted
that AerMod over predicts concentrations

when used

to determine

a one-hour standard
and provides conservative results. Furthermore,

it is apparent from EPA's own TSD that S02 emissions from the facilities

in the area of analysis have been reduced

by some 20% over the three-year period of2012-2014.

1 These factors
are indicative

of an area that

is in attainment
with the standard

for the sulfur dioxide NAAQS.

. EPA should hold the same for Calcasieu Parish and designate

the area
as attainment. Intended Nonattainment

Area: Desoto Parish The state initially recommended DeSoto Parish

(a partial portion

of the parishi

as unclassifiable due to lack of sufficient monitoring
data and/or modeling results. After completing model runs using the EPA proposed Beta option ofLowWind3 within the most current version ofthe EPA approved Aermod model,
the state revised

its initial recommendation

from unclassifiable

to attainment.
EPA has stated that

it intends

to designate

the area
as nonattainment. The state would like to provide further information

that will reinstate

the designation

of attainment

for the DeSoto Parish area. Dolet Hills Power Station owners have conducted additional

air modeling

for the DeSoto Parish area that included more accurate emission
data and stack parameters

for the coal-fired electric utility and also included

the International Paper Mansfield Mill, which

is located approximately

14 kilometers north ofthe utility

. This modeling run did not use the Beta option that EPA discounted

in the state's revised designation recommendation.

This model was performed

in accordance
with EPA's draft TAD, dated February 2016

as well
as the EPA Technical Support Document attached

to the 120 day letter. Specifically,
more accurate information

was included

for three categories: stack parameters, emissions data, and effects

of downwash.

The data was processed

on

a parameter basis

in which flowrate was adjusted back

to actual hourly stack conditions using the temperature

data for concurrent
hour for which the exit velocity was being calculated.

The final refined modeling 1 See Table

1: Actual S02 Emissions between 2012-2014 from Facilities

in the Calcasieu Parish Area of Analysis

, Technical Support Document, Louisiana 2 The area bounded

by the following UTM Coordinates (excluding portions

of Red River Parish, Louisiana

that falls within this UTM-based boundary)

at NAD

83 Datum, UTM Zone
15: X ,Y coordinates respectively: 441287,35410 19;441287;35620 19;450500,35620 19;450500,3541

019.

### simulations show that the highest concentrations

due to all sources and the background concentration

is 171.0J..lg/m

3

, 

### which

is below the 1-hour S02 NAAQS

of 196.5J..lg/m

3

. 

### Further,
the Dolet Hills Power Station has installed

a monitor

at the facility and
is providing quarterly ambient

air quality data
to the LDEQ. Since the installation

of the monitor,

all data shows that the area

is in attainment
with the standard.

See the attachments

for data. Based upon the additional information presented,

the state recommends

a designation

of attainment

for both the Calcasieu

and DeSoto Parish areas. Documentation

to support
the LDEQ's recommendation

for each parish can be found

in the attached enclosures.

If you have any questions, please contact Donald Trahan, Administrator

of the Air Permits Division, at (225) 219-3408. Sincerely, 

# :}

;1 _ ) c_

- )


# 0 I )


# fJ **~**



# -
u 

## ~~ **~{.**

-

/!: e:;;> --fo.- 

### Chuck Carr Brown, Ph.D. Secretary C: Mark Hansen, Acting Associate Director

of Air Programs Guy Donaldson, Chief Air Planning Section CCBNHANH 

### Enclosures: Calcasieu Parish Supporting Document De Soto Parish Supporting Document