## DRAFT

FINAL REPORT

BART AIR MODELING

INDIVIDUAL SOURCE VISIBILITY

IMPAIRMENT ANALYSIS

April , 2006

Prepared For:



### State of Wyoming

Department of Environmental Quality

Air Quality Division

Cheyenne, WY 82002

Prepared By:

McVehil

- Monn ett Associates, Inc.

44 Inverness Dr. E., Bldg. C

Englewood, CO 80112

MMA Project Number 1938

- 05

- 3TABLE OF CONTENTS

Section Page

1.0 INTRODUCTION

................................ ................................ ................................ ............... 1

2.0 OVERVIEW

................................ ................................ ................................ ........................ 2

3.0 POLLUTANTS AND EMISSIONS

................................ ................................ .................... 5

4.0 MODELING DOMAIN AND METEOROLOGICAL DAT A

................................ ......... 11

5.0 CALMET INPUT

................................ ................................ ................................ .............. 14

6.0 CALPUFF MODELING

................................ ................................ ................................ .... 16

7.0 POSTPROCESSING

................................ ................................ ................................ ......... 18

8.0 DETERMINATION OF SOURCES SUBJECT TO BART

................................ ............. 22

APPENDIX A: SOURCES OF METEOROLOGICAL AND OZONE

MONITORING DATA

Tables

1 WYOMING BART

– ELIGIBLE SOURCES

................................ ................................ ..... 4

2 MAXIMUM 24

- HR EMISS ION RATES FOR BART

SOURCE ATTRIBUTION MODELING

................................ ................................ ....... 6

3 STACK PARAMETERS FOR BART SOURCE ATTRIBUTION MODELING

............. 9

4 SOURCE

- SPECIFIC MODEL DOMAINS AND METEROLOGICAL

DATA YEARS

................................ ................................ ................................ ............. 12

5 CALMET INPUT PARAMETERS THAT ARE APPLICATION

-

SPECIFIC OR DIFFER F ROM DEFAULT VALUES

................................ ................ 15

6 CALPUFF INPUT PARAMETERS THAT ARE APPLICATION

-

SPECIFIC OR DIFFER FROM DEFAULT VALUES

................................ ................ 17

7 MONTHLY F(RH) FACTORS FOR CLASS I AREAS

................................ .................. 20

8 NATURAL BACKGROUND CONCENTRATIONS OF AEROSOL

COMPONENTS FOR 20% BEST DAYS FOR BART AN ALYSIS (μg /m 3 )

............. 21

9 RESULTS OF CALPUFF VISIBILITY MODELING FOR BART

- ELEGIBLE

SOURCES

................................ ................................ ................................ .................... 241

1.0 INTRODUCTION

The U.S. EPA has issued final amendments to the Regional Haze Regulations,

along with Guidelines for Best Available Retrofit Technology (BART) Determination s. ( 1 )

The Guidelines address methodology for determining which facilities must apply BART

( s ources subject to BART) and the evaluation of control options.

The State of Wyoming has utilized air quality modeling, using the CALPUFF

modeling system, in accordance with the EPA Guidelines to determine the Wyoming

sources which are subject to BART. This report describes the specific methodology

applied in the air quality modeling analysis, and presents analysis results defining those

Wyoming sou rces that have been determined to be subject to BART.

(1) 40 CFR Part 51: Regional Haze Regulations and Guidelines for Best Avai lable Retrofit Technology

(BART) Determinations; Final Rule. 70 Federal Register, 39103

- 39172, July 6, 2005.2

2.0 OVERVIEW

The Wyoming Air Quality Divi sion determined that there are fourteen “BART

Eligible” sources in the State. The sources are listed in Table 1. Modeling and analyses

described in this report were used to determine, for each of these sources, wh ether they

are “subject to BART”. ( 2 ) A source is subject to BART if air quality modeling indicates

that the source causes or contribute s to visibility impairment in an y Class I area, within or

outside of Wyoming.

Class I areas that could potentially experience visibility impairment due to

emissions from Wyoming sources were initially defined as all of those within 300 km of

any BART

- eligible source

.

In Wyoming: N. Absaroka WA

Was h a kie WA

Yellowstone NP

Teton WA

Fitzpatrick WA

Bridger WA

Grand Teton NP

In Colorado: Rawah WA

Rocky Mountain NP

Mt. Zir kel WA

Flat Tops WA

Eagles Nest WA

Maroon Bells

– Snowmass WA

W est Elk WA

In Utah: Arches NP

In South Dakota: Badlands NP

Wind Cave NP

In Idaho : Craters of the Moon NM

Not all of these C lass I areas were included in modeling analyses. For each BART

eligible source, those Class I areas deemed most likely to experience visibility impacts on

the basis of distance, meteorology, and terrain were assessed in the analysis. Modeling

domains, sources, and the Class I area s addressed for each source are described in

subsequent parts of the report

.

2 All sources except Dyno Nobel N.A. and OCI Wyoming are addressed in this report. Those two sources

were analyzed in separate but identical anal yses.3 Wyoming has fo llow ed the BART guideline for evaluation of all BART

- eligible

sources. The threshold for classification of a source as subject to BART is a visibility

impact exceeding 0.5 deciview (dv) compared to the 20% best days natural background,

based on the 98 th p ercentile of modeled 24

- hour delta

– deciview values.4

Table 1. Wyoming BART

– Eligible Sources

Basin Electric Laramie River Power Plant Boilers # 1, 2, 3

Black Hills P & L Neil Simpson # 1 Power Plant Boiler

Dyno Noble N.A. Cheyenne Plant Misc. Sources

FMC Corporation Granger Soda Ash Plant Boilers # 1, 2

FMC Corporation Green River Sodium Plant Three boilers

General Chemical Co. Green River Soda Ash Two boilers

OCI Wyoming Big Island Soda Ash Plant Boilers # 4, 5, 6

P4 Production Rock Springs Coking Plant Calciner

PacifiCorp Dave Johnson Power Plant Boilers # 3, 4

PacifiCorp Jim Bridger Power Plant Boilers # 1

– 4

PacifiCorp Naughton Power Plant Boilers # 1, 2, 3

PacifiCorp Wyodak Power Plant Bo iler

Sinclair Oil Co. Casper Refinery Boiler # 7

Sinclair Oil Co. Sinclair Refinery Misc. Sources5

3.0 POLLUTANTS AND EMISSIONS

The pollutants included in the CAL PUFF modeling analyses were sulfur dioxide

(SO 2 ), nitrogen oxides (NO

x ), and par t iculate matter. Where data were available,

part iculate matter emissions were quantified separately as fine particles (PM2.5) and

coarse particles (PM10). If no particle size information wa s available, all particles were

assumed to be PM2.5. Emissions of ammonia (NH 3 ) and vola tile organic compounds

(VOC) were not considered. It is believed that emissions of these pollutants have

negligible impact on regional haze in Wyoming.

Table 2 presents a listing of emission rates modeled for all BART

- eligible

sou rces. The emission rates were determined by the Division based upon existing

permits, allowable rates, and emissions reporting data. They represent the best available

estimates of maximum 24

- hour average emissions for each source and pollutant. Table 3

lists stack parameters for each source. T he data in Tables 2 and 3 were used for all

BART modeling to define the individual source ’ s impact on visibility

.6

Table 2. Maximum 24

- hr Emission Rates for BART Source Attribution Modeling

Source Emission Unit NO

x SO 2 PM2.5 PM10

lb/hr g/s lb/hr g/s lb/hr g/s lb/hr g/s

Basin Electric Boiler # 1 2619.4 330.04 1284.0 161.78 158.3 19.95 387.7 48.85

Laramie River Boiler # 2 1502.3 189.29 1284.0 161.78 158.3 19.95 387.7 48.85

Boiler # 3 2719.2 342.61 1320.0 166.32 158. 9 20.02 389.1 49.03

Black Hills Boiler 112.8 14.21 351.6 44.30 28.0 3.53 68.7 8.66

Neil Simpson # 1

Dyno Nobel IC Engine 170.6 21.50

IC Engine 170.6 21.50

Nitric Acid Plant 6.0 0.76

Nitric Acid Plant 6.0 0.76

Prill Tower 54.0 6.80

Wet Scrubber 19.7 2.48

Wet Scrubber 15.8 1.99

Prill Tower 43.1 5.43

Boiler 6.1 0.77

FMC Corporati on Boiler # 1 251.0 31.63 71.7 9.03 35.8 4.51

Granger Soda Ash Boiler # 2 251.0 31.63 71.7 9.03 35.8 4.51

FMC Corporation NS

- 1A Boiler 523.3 65.93 1064.4 134.1 45.0 5.67

Sodium Products NS

- 1B Boiler 374.3 47.16 1064.4 134.1 45.0 5.6 7

PH

- 3 Boiler 43.4 5.47 8.4 1.06

General Chemical Boiler C 245.6 30.95 640.8 80.74 50.0 6.30

Green River Soda Ash Boiler D 501.6 63.20 1056.0 133.05 80.0 10.087

Table 2. Maximum 24

- hr Emission Rates for BART Source Attribu tion Modeling (Continued)

Source Emission Unit NO

x SO 2 PM2.5 PM10

lb/hr g/s lb/hr g/s lb/hr g/s lb/hr g/s

OCI Boiler # 4 13.3 1.68 7.5 0.95

Big Island Boiler # 5 13.3 1.68 8.6 1. 08

Boiler # 6 13.3 1.68

P4 Production Calciner 72.9 9.19 218.0 27.47 22.0 2.77

Pacificorp Boiler # 3 1194.2 150.47 2671.0 336.54 149.0 18.77 364.9 45.98

Dave Johns t on Boiler # 4 1447.3 182.36 1737.0 218.86 372.5 46.93 357.9 45.09

Paci ficorp Boiler # 1 2008.4 253.05 1683.0 212.05 162.7 20.50 39 8.3 50.19

Jim Bridger Boiler # 2 1716.7 216.30 1683.0 212.05 162.7 20.50 398.3 50.19

Boiler # 3 1941.1 244.57 1683.0 212.05 162.7 20.50 398.3 50.19

Boiler # 4 2030.8 255.88 1004.0 126.50 145. 6 18.35 356.4 44.91

Pacificorp Boiler # 1 1079.8 136.05 2218.8 279.56 129.5 16.32 317.1 39.95

Naughton Plant Boiler # 2 1322.5 166.63 2844.0 358.34 159.0 20.03 389.3 49.05

Boiler # 3 2052.9 258.66 1839.5 231.77 228.6 28.80 559.7 70.52

Pacificorp Boiler 1189.0 149.81 2050.0 258.3 0 118.9 14.98 291. 1 36.68

Wyodak

Sinclair Boiler 26.7 3.36 98.2 12.37 15.6 1.97

Casper Refinery8

Table 2. Maximum 24

- hr Emission Rat es for BART Source Attribution Modeling (Continued)

Source Emission Unit NO

x SO 2 PM2.5 PM10

lb/hr g/s lb/hr g/s lb/hr g/s lb/hr g/s

Sinclair Heater 15.6 1.97

Refinery Heater 7.9 1.00

Heater 5.5 0.69

Heater 5.5 0.69

Heater 9.6 1.21 1.0 0.13

Heater 2.1 0.26 0.5 0.06

Heater 2.6 0.33 0.3 0.04

Heater 3.2 0.40

Heater 3.8 0.48

Heater 8.6 1.08

Heater 3.4 0.43

Heater 9.0 1.13

Heater 1.8 0.23

H eater 4.3 0.54

Boiler # 10 23.0 2.90 2.3 0.29

SRU # 1 5.1 0.64 340.0 42.849

Table 3. Stack Parameters for BART Source Attribution Modeling

Source Emission Unit Height Temp V el Dia

(m) (K) (m/s) (m)

Basin Electric Boiler # 1 182.9 332.2 15.2 9.54

Laramie River Boiler # 2 182.9 332.2 15.2 9.54

Boiler # 3 182.9 358.2 22.9 8.66

Black Hills Boiler 76.2 442.4 21.9 1.83

Neil Simpson # 1

Dyno Nobel IC Engine 13.41 485.9 16.78 1.68

IC Engine 13.41 485.9 16.78 1.68

Nitric Acid Plant 21.34 438.7 11.88 0.61

Nitric Acid Plant 21.34 438.7 11.88 0.61

Prill Tower 39.93 310.4 24.23 1.52

Wet Scrubber 23.62 294.3 51.51 0.46

Wet Scrubber 51.21 369.3 6.89 0.46

Prill Tower 41.76 357.6 2.72 3.55

Boiler 21.34 505.4 5.15 0.33

FMC Corporation Boiler # 1 45.72 333.2 21.29 1.98

Granger Soda Ash Boiler # 2 45.72 333.2 21.2 1.98

FMC Corporation NS

- 1A Boiler 91.44 414.8 54.49 1.83

Sod ium Products NS

- 1B Boiler 91.44 410.9 54.96 1.83

PH

- 3 Boiler 21.34 394.3 8.34 2.29

General Chemical Boiler C 47.55 452.6 15.98 3.05

Green River Soda Ash Boiler D 47.55 460.9 25.12 3.05

OC I Boiler # 4 16.76 434.1 18.39 1.98

Big Island Boiler # 5 24.38 440.1 21.53 1.83

Boiler # 6 24.38 434.1 21.53 1.83

P4 Production Calciner 39.62 1255.4 12.24 4.75

Pacificorp Boiler # 2 152.4 444.8 33.22 4.57

Dave Johns t on Boiler # 3 76.2 325.9 8.53 7.0110

Table 3. Stack Par ameters for BART Source Attribution Modeling (Continued)

Source Emission Unit Height Temp Vel Dia

(m) (K) (m/s) (m)

Pacific orp Boiler # 1 152.4 333.2 22.3 7.32

Jim Bridger Boiler # 2 152.4 333.2 22.3 7.32

Boiler # 3 152.4 333.2 25.2 7.32

B oiler # 4 152.4 333.2 13 9.45

Pacific orp Boiler # 1 60.96 410.8 26.52 4.27

Naughton Plant Boiler # 2 68.58 410.8 21.34 4.88

Boiler # 3 137.16 323 19.81 8.08

Pacific orp Boiler 121.9 346.9 22.6 6.1

Wyodak

Sinclair Boile r 41.39 549.8 12.9 1.37

Casper Refinery

Sinclair Heater 33.53 672 10.3 0.76

Refinery Heater 36.6 477.6 4.39 1.22

Heater 27.43 1016.5 9.33 1.22

Heater 33.53 630.4 8.09 0.91

Heater 45.72 727.6 5.88 1.52

Heater 19.2 855.4 2.08 1.22

Heater 41.15 635.9 2.24 1.22

Heater 36.6 838.7 6.49 1.22

Heater 36.6 866.5 3.4 1.52

Heater 36.6 866.5 6.96 1.52

Heater 36.6 833.2 5.15 1.52

Heater 36.6 683.2 13.47 0.91

Heater 12.8 810.9 8.35 0.91

Heater 27.4 716.5 5.03 1.22

Boile r # 10 15.24 449.8 9.08 1.52

SRU # 1 49.1 810.9 1.4 1.5211

4.0 MODELING DOMAIN AND METEOROLOGICAL DATA

The determination of th ose sources subject to BART was carried out through

application of the CALPUFF modeling system. Wind and m eteorolo gical fields for

CALPUFF were developed using the CALMET meteoro logical processor; input data

consist ed of MM 5 prognostic model fields, augmented with surface and upper air data

from observing station s within the model domain.

The Class I areas p otentially affected by Wyoming sources are located over a

large area within and surrounding the state. Wyoming BART

– eligible sources are

widely distributed within the state. Therefore, a very large modeling domain would be

required to address all s ourc es and Class I areas. It was also desired to utilize to the

extent possible meteorological data fields previously used for long

- range transport

modeling that have been checked and quality assured. For these reasons, BART

modeling utilize d three separate modeling domains and two meteorological data sets.

The model domains include d a Southwest Wyoming domain, utilizing

meteorological data for 1995, 1996, and 2001, and Northeast and Southeast Wyoming

domains with 2001, 2002, and 2003 meteorological data. The southwest and northeast

data sets were developed for prior Wyoming analyses and were readily adapted for

BART modeling. The southea st domain meteorological fi elds were developed

specifically for the BART analyses. MM 5 model output for the southeast d omain were

acqui red by the Division, and used in CALMET (with additional surface and upper air

data) to generate required input meteorological fields for CALPUFF. The three modeling

domains, along with the locations of Class I areas and BART

– eligible so urces, are

shown in Figure 1.

Model domains and Class I areas used for each source’s BART evaluation are

shown in Table 4. The assignments in Table 4 w ere developed on the basis of

s ource/Class I area locations, distances to each Class I area, and profe ssional judgment

considering meteorological a nd terrain factors. All source

- Class I area distances exceed

50 km, and are less than 300 km, thus falling within the range of recommended

CALPUFF application

.

O nly those Class I areas most likely to be impac ted by each source were modeled.

Areas greater than 300 km from a source have been excluded. Also, when several Class I

areas are located in the same direction from a source, only the closest Class I areas were

evaluated. If impacts are less than the BA RT threshold for the Class I areas modeled, it

can be reasonably assumed that areas at a greater distance and in directions of less

frequent plume transport will not experience significant impacts.12

Table 4. Source

- Specific Model Domains and Mete orological Data Years

Source Modeling

Domain Meteorological

Data Years Class I Areas

to be Evaluated

1. Basin Electric Northea st WY 2001, 2002, 2003 Wind Cave, Badlands

Laramie River

2. Black Hills North e a st WY 2001, 2002, 2003 Wind Cave, Badlands

Neil Simpson # 1

3. Dyno Nobel South e a st WY 2001, 2002, 2003 Rocky Mountain NP, Rawah,

Cheyenne Plant Mt. Z i rkel

4. FMC Corporation Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Granger Soda Ash

5. FMC Corporation Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Sodium Products

6. General Chemical Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Green River Soda Ash

7. OCI Southwest WY 1995, 1996, 20 01 Bridger, Fitzpatrick

Big Island Plant

8. P4 Production Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Rock Springs Coking

9. Pacificorp North e a st WY 2001, 2002, 2003 Wind Cave, Badlands

Dave Johnston13

Table 4. Source

- Specific Model Domains and Meteorological Data Years (Continued)

Source Modeling

Domain Meteorological

Data Years Class I Areas

to be Evaluated

10. Pacificorp Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Jim Bridger

11. Pacificorp Southwest WY 1995, 1996, 2001 Bridger, Fitzpatrick

Naughton Plant

12. Pacificorp Northeast WY 2001, 2002, 2003 Wind Cave, Badlands

Wyodak

13. Sinclair Northeast WY 2001, 2002, 2003 Wind Cave, Badlan ds

Casper Refinery

14. Sinclair Southeast WY 2001, 2002, 2003 Rocky Mountain NP, Rawah,

Sinclair Refinery Mt. Zirkel14

5.0 CALMET INPUT

Input options for CALMET generally applied default values except where

applica tion

- specific choices are required. Table 5 summarizes the CALMET inputs.

All MM5 prognostic data had 36 km resolution, except for the 1995 (southwest

Wyoming) data set, which has 20 km resolution. The MM5 data were used in CALMET,

along with data fr om surface, upper air, and precipitation observations, to generate the

final meteorological files required as input to CALPUFF. Appendix A lists the surface

and upper air stations from which data were used for each domain and meteorological

year. The num ber of upper air stations used as input to the CALMET processing varied

from none (1996 only) to three, dependi ng upon the availability of data from

representative stations. For 1996 , the MM5 data fields were used alone to define upper

air conditions.15

Table 5. CALMET Input Parameters that are Application

- Specific or Differ from Default

Values

CALMET Input Parameter Value(s)

Input Group 2

Map projection (PMAP) Lambert Conformal

Grid spacing (DGRIDKM) 4

Numb er vertical layers (NZ) 10

Top of lowest layer (m) 20

Top of highest layer (m) 3500

Input Group 4

Observation mode (NOOBS) 0

1 (for 1996 only)

Input Group 5

Prog. Wind data (IPROG) 14

(RMAX1) 30

(RMAX2) 50

(RMAX3) N/A

Terrain influence (TERRAD) 15

(R1) 5

(R2) 25

Input Group 6

Max mixing ht (ZI MAX) 3500

CA LMET Model Version 5.53A, Level 04071616

6.0 CALPUFF MODELING

CALPUFF modeling was conducted for each BART

- eligible source to calculate

concentrations of each visibility

- impairing pollutant in each Class I area. Source

emissions, meteorolog ical data, and model domains were as prescribed in Sections 3.0

and 4.0

. Each source was modeled separately for each of three years of meteorological

data, utilizing the CALMET meteorological fields generated for the applicable

years/model domains.

C once ntration calculations were made for all receptors within the designated

Class I areas. Receptors were defined for each area by the standard receptor points

developed by the Federal Land Managers (FLMs) and available from the National Park

Service web site database.

CALPUFF model options conform ed with standard default values with limited

exception s . Table 6 lists non

- default and application

- specific parameters that were used

in CALPUFF. Chemical transformation calculations use d MESOPUFF II equations, and

dispersion coefficients were PG coefficients ( MDISP=3).

Since most of the sou rces have relatively tall stacks, and only impacts at distances

greater than 50 km are of interest, building wake effects were not considered for any

sou rces. Puff splitting were not used for CALPUFF modeling, in order to limit

computation time to reasonable levels.

Backgro und ozone concentrations were considered in the model by use of hourly

ozone files from representative monitoring sites in each model domain. ( 3 ) A defaul t

ozone concentration (for missing data hours) was specified as 44 ppb, based on average

data from northeast Wyoming. The backgro und ammonia concentration was specified as

2.0 ppb for all model domains. The value of 2.0 is based on monitoring data from n earby

states and IWAQM guidance. North Dakota has specified a background ammonia

concentration of 2.0 ppb for the western part of the state, as indicated by 2000

- 2001

monitoring data from Beulah. Colorado found background ammonia concentrations of

0.5 to 1.6 ppb for the Mt. Zirkel area. The IWAQM Phase II report suggests values of

0.5 ppb for fore sted areas, 1.0 ppb for arid lan ds, a nd 10.0 ppb for agricultural lan ds

(within a factor of two). Since a single background ammonia value must be specified

wi thin a model dom ain, a value of 2.0 ppb was selected as reasonable given the available

data. Experience has suggested that this value is conservative in that it is unlikely to

significantly limit nitrate formation in the model.

D efault particle size d ata were used for all modeled particles except PM10. Since

PM10 represents coarse particles with diameters between 2.5 and 10.0 μm, the mass

mean PM10 diameter was estimated as 7.0 μm.

3 See Appendix A for list of ozone stations.17

Table 6. CALPUFF Input Parameters that are Application

- Specific or Di ffer From

Default Values

CALPUFF Input Parameter Value(s)

Input Group 1

Number of species modeled (NSPEC) 7

Number of species emitted (NSE) 4

Input Group 2

Dispersion coefficients (MDISP) 3

Input Group 3

Species Modeled SO 2 , SO 4 , NO

x , HNO 3 , NO 3 , PM10, PM25

Species emitted SO 2 , NO

x , PM10, PM25

Input Group 4

Map projection (PMAP) Lambert Conformal

Grid spacing (DGRIDKM) 4

Cell face heights (ZFACE) same as used for applicable CALMET

Sampling grid F

Input Group 8

Particle size parameters mean 0.48, st. dev. 2.0

except 7.0, 2.0 for PM10

Input Group 11

Ozone input option (MOZ) 1 (hourly ozone files)

Monthly ozone (BCKO3) 44 ppb

Monthly ammonia (BCKNH3) 2.0 ppb

Input Group 12

Max mixing height (XMAXZ1) same as applicable CALMET

CALPUFF Model Version 5.711A, Level 04071618

7.0 POSTPROC ESSING

The CALPOST processor is used in the final processing step to calculate 24

- hour

average visibility results. Output w as specified in deciview (dv) units. The output

consist s of the highest deciview impact on each day from all receptors within eac h Class I

area.

Calc ulations of light extinction were made for each pollutant modeled (sulfate,

nitrate, coarse particles, and fine particles). T he sum of all extinction values is then used

to calculate the delta

- dv change relative to natural background . Default extinction

coefficients for each species, as given below, were used.

Ammonium sulfate 3.0

Ammonium nitrate 3.0

PM Coarse (PM10) 0.6

PM Fine (PM25) 1.0

Monthly ave rage relative humidity factors F (RH) were used in the light extincti on

calculations to account for the hygroscopic characteristic of sulfate a nd nitrate particles.

Monthly f

(RH) values, from the EPA Guidance for Estimating Natural Visibility

Conditions Under the Regional Haze Rule, are shown in Table 7 for each set of Cla ss I

areas. Values shown in Table 7 represent the average f (RH) for the Class I areas listed.

In many cases the tabulated f (RH) values for a given month are the same for each Class I

area within a group. Where differences occur, they are no greater than 0.3 units; the

average values are within 0.1 to 0.2 units of the Guideline values for any individual area.

CALPOST visibil ity Method 6 (MV ISBK=6) was used for determination of

background visibility. It should be noted that when Method 6 is us e d, the CA LPOST

calculation of f

(RH) and the CALPOST designation of ma ximum relative humidity

(RHMAX) are irrelevant and not used for calculations

.

The natural background conditions as a reference for determination of the delta

dv change due to a source should be representative of the 20% best natural visibility days.

EPA BART guidance provides the 20% best days deciview values for each Class I area

on an annual basis, but does not provide species concentration data for the 20% best

background condi tions. These c oncentrations were needed for input to CALPOST.

Annual species concentrations corresponding to the 20% best days were

calculated for each Class I area to be addressed, by scaling back the annual average

concentrations given in Guidance for Estimating Nat ural Visibility Conditions Under the

Regional Haze Rule (Table 2

- 1). A separate scaling factor was derived for each Class I

area such that, when multiplied by the Guidance table annual concentrations, the 20%

best days deciview value for that area would b e calculated. The scaled aerosol

concentrations were then averaged over the Class I areas to be addressed in each model

domain to provide data (to be used for each month) for CALPOST input. The 20% best

days aerosol concentration s used for Wyoming BART e valuations are listed in Table 8.19 Concentratio ns were generally very similar at all of the Class I areas in a given

model domain. Comparison of predicted deciview values for individual Class I areas

(using annual average f (RH) and concentrations from Ta ble 8) to the Guidance 20% best

deciview tabulations show agreement within one percent for all Class I areas.20

Table 7. Monthly f(RH) Factors for Class I Areas

Month Wind Cave NP

Badlands NP Bridger WA

Fitzpatrick WA Rocky Mt. NP

Rawah WA

Mt. Zirkel WA

Jan 2.65 2.50 2.10

Feb 2.65 2.30 2.13

Mar 2.65 2.27 2.00

Apr 2.55 2.10 2.10

May 2.70 2.10 2.23

Jun 2.60 1.83 1.87

Jul 2.30 1.57 1.77

Aug 2.30 1.53 1.83

Sep 2.20 1.80 2.00

Oct 2.25 2.03 1.87

Nov 2.75 2.47 2.07

Dec 2.65 2.43 2.0321

Table 8. Natural Background Concentrations of Aerosol Components for 20% Best Days for BART Analyses (μg/m 3 ).

Aerosol

Component Wind Cave NP

Badland s NP Fitzpatrick WA

Bridger WA Rawah WA

Rocky Mountain NP

Mt. Zirkel WA

Ammonium Sulfate .047 .045 .045

Ammonium Nitrate .040 .038 .037

Organic Carbon .186 .178 .178

Eleme ntal Carbon .008 .008 .007

Soil .198 .189 .189

Coarse Mass 1.191 1.136 1.13522

8.0 DETERMINATION OF SOURCES SUBJECT TO BART

Results of the CALPOST visibility processing for each BART

- eligible source

consisted of a listing of d aily maximum ∆dv values for each Class I area and year of

meteorological data. The visibility impact threshold to identify those sources subject to

BART is a 98 th percentile change in visibility (∆dv) of 0.5 dv. Therefore, if the 8 th

highest ∆dv value fo r any year is equal to or greater than 0.5 dv, the source is considered

to cause or contribute to visibility impairment in the subject Class I area.

Table 9 presents the model results for each source, year, and Class I area. The

table lists, in each cas e, the number of days on which the calculated ∆dv value at any

receptor exceeded 0.5, and the largest ∆dv value calculated for any day and receptor.

Based on the Table 9 results, the following Wyoming sources have been determined to be

subject to BART.

P acificorp Bridger Power Plant

Pacificorp Naughton Power Plant

FMC Granger Soda Ash Plant

FMC Green River Sodium Plant

General Chemical Green River Soda Ash Plant

Basin Electric Laramie River Power Plant

Pacificorp Dave Johnson Power Plant

Pacificorp Wyodak Power Plant

Four sources that were screened did not have results indicating a significant

visibility impact in the Class I areas modeled. The P4 Production Rock Springs Coking

Plant had no impacts exceeding 0.4 dv at the Bridger or Fitzpatrick WA s. The source is

more than 200 km from any other Class I area (compared to 115 km from Bridger WA).

Therefore it is concluded that P4 Production is not subject to BART.

Similarly, Black Hills Neil Simpson # 1 Power Plant produced only one day out

of three year s with an impact exceeding 0.5 dv at Wind Cave and Badlands NPs. The

plant is 165 km from Wind Cave (generally upwind) and 300 km or more from all Class I

areas in other directions. It is concluded that Neil Simpson # 1 has no significant Class I

area vi sibility impacts and is not subject to BART.

Results are slightly less clear in the cases of the Sinclair Refinery and Sinclair

Cas per Refinery. Screening of these sources (for the Southeast and Northeast domains,

respectively) indicate no impacts excee ding 0.5 dv. However, these sources are

approximately equidistant from Class I areas in other domains, with a possibility of

plume transport in those directions. Thus, a n additional CALPUFF model run was

executed for Sinclair; it was modeled in the North east domain to evaluate impacts at

Wind Cave and Badlands NPs. The result s of that analysis (included in Table 9) also

show no impact exceeding 0.5 dv. Since total emissions from the Sinclair Casper

Refinery are substantially less than from the Sinclair Refinery, and the latter is shown to23

have insignificant impacts in both the northeast and southeast domains, it is concluded

that neither Sinclair source is subject to BART.24

Table 9. Results of CALPUFF Visibility Modeling for BART

- Eligible Sources

SW Domain 1995 1996 2001 1995 1996 2001

(Num Values >.5 DV) (Num Values >.5 DV) (Num Values >.5 DV) Largest DV Change Largest DV Change Largest DV Change

P4 Production

Bridger Wilderness 0 0 0 0.143 0.38 1 0.388

Fitzpatrick Wilderness 0 0 0 0.081 0.129 0.094

Pacificorp Bridger

Bridger Wilderness 55 21 42 9.717 8.666 4.617

Fitzpatrick Wilderness 25 15 23 3.337 3.764 4.327

Pacificorp Naughton

Bridger Wilderness 105 109 128 5.984 6 .185 7.331

Fitzpatrick Wilderness 48 43 81 3.305 5.253 4.789

FMC

- Granger

Bridger Wilderness 3 13 7 0.862 1.719 1.090

Fitzpatrick Wilderness 0 2 0 0.260 1.140 0.272

FMC

- Green River

Bridger Wilderness 20 24 38 2.063 2.788 2.21 4

Fitzpatrick Wilderness 5 8 11 1.003 1.811 1.235

General Chemical

Bridger Wilderness 11 18 27 1.471 2.369 1.757

Fitzpatrick Wilderness 4 5 6 0.702 1.658 1.077

NE Domain 2001 2002 2003 2001 2002 2003

(Num Values >.5 DV) (Num Value s >.5 DV) (Num Values >.5 DV) Largest DV Change Largest DV Change Largest DV Change

Basin Electric

Bad Lands 81 57 62 5.503 5.879 5.441

Wind Cave 73 58 62 6.273 7.709 8.518

Black Hills

Bad Lands 0 0 0 0.207 0.346 0.374

Wind Cave 0 0 1 0.234 0.425 0.700

Pacificorp Dave Johnston

Bad Lands 88 65 79 4.299 4.051 3.482

Wind Cave 91 69 77 4.460 4.678 4.326

Pacificorp Wyodak

Bad Lands 20 23 29 1.155 2.160 2.484

Wind Cave 30 28 37 1.671 2.490 3.685

Sinclair Casper

Bad Lands 0 0 0 0.075 0.089 0.091

Wind Cave 0 0 0 0.112 0.119 0.106

Sinclair Refinery

Bad Lands 0 0 0 0.196 0.166 0.132

Wind Cave 0 0 0 0.303 0.189 0.247

S E Domain 2001 2002 2003 2001 2002 2003

(Num Values >.5 DV) (Num Valu es >.5 DV) (Num Values >.5 DV) Largest DV Change Largest DV Change Largest DV Change

Sinclair Refinery

Rocky Mountain NP 0 0 0 0.242 0.282 0.144

Rawah Wilderness 0 0 0 0.267 0.320 0.151

Mt. Zirkel Wilderness 0 0 0 0.425 0.213 0.177APPEN DIX A

SOURCES OF METEOROLOGICAL AND

OZONE MONITORING DATA

SOUTHWEST DOMAIN

Meteorological Data:

1995 1996 2001

Surface Upper Air Surface* Upper Air Surface Upper Air

Baggs, WY Denver, CO Rock Springs, WY None Rawlins, WY Riverton, WY

Craig, CO Grand Junction, CO Riverton, WY (Vertical profiles Riverton , WY Salt Lake City, UT

Tg Soda Ash Lander, WY Lander, WY Based on data Salt Lake City, UT Grand Junction, CO

OCIW Salt Lake City, UT Big Piney, WY Generated at each Rock Springs, WY

Naughton Power Plt Evanston, WY 36 km. spaced Big Piney, WY

General Chemical Jackson Hole, WY grid cell by MM5) Casper, WY

Whitney Canyon Worland, WY Evanston, WY

Shute Creek Gas Pl Rawlins, WY Jackson Hole, WY

Pinedale, WY Ogden, UT Pocatello, ID

Centennial, WY Salt Lake City, UT Ogden, UT

Ye llowstone NP Pocatello, ID

Craters of the Moon Idaho Falls, ID

Denver, CO Soda Springs, ID

Grand Junction, CO Malad City, ID

Cheyenne, WY Casper, WY

Lander, WY

Rock Springs, WY

Casper, WY

Salt Lake City, UT

Pocatello, ID

Rawlins, WY

Riverton, WY

*

- 63 National Weather Service stations were input because the original modeling domain developed with the 1996 data set is subs tantially larger than the

SWWYTAF domain, extending into a large par t of Montana, the entire state of Wyoming and the western Dakotas; only those stations located within the

SWWYTAF domain are listed

Precipitation Stations: total of 249 stations in original modeling domain

Ozone Monitoring Stations:

Pinedale, WY

Cente nnial, WY

Yellowstone NP, WY

Craters of the Moon NM, ID

Highland, UT

Hayden, CONORTHEAST DOMAIN

Meteorological Data: all years except where noted

Surface Upper Air

Ellsworth AFB, SD Rapid City, SD

Chadron, NE

Lander, WY

Scot tsbluff, NE

Sheridan, WY

Billings, MT

Cody, WY

Rawlins, WY

Riverton, WY

Worland, WY

Casper, WY

Rapid City, SD

Gillette, WY

Buffalo, WY

– 2003 only

Precipitation Stations: total of 62 stations (63 for 2003)

Ozone Monitoring Stations:

Thunder Basin, WY

Robbinsdale, SD (except 2001)SOUTH EAST DOMAIN

Meteorological Data: all years

Surface Upper Air

Lamar Municipal Airport , CO Denver, CO

Pueblo Memorial Airport , CO Grand Junction, CO

Goodland , CO Rapid Cit y, SD

Colorado Springs Municipal Airport , CO Riverton, WY

Limon , CO

Leadville Lake County Airport , CO

Meeker Airport , CO

Eagle County Airport

, CO

Aspen Pitkin County Airport , CO

Gunnison County Airport , CO

Burlington Carson Airport , CO

Akron Washingt on Co Airport , CO

Grand Junction Walker Field , CO

Montrose Regional Airport , CO

Greeley

- Weld County Airport , CO

Loveland Ft Collins

– Loveland , CO

Cheyenne , WY

Laramie Regional Airport , WY

Denver International Airport , CO

Douglas Converse County Airport , WY

Casper Natrona Co International Airport , WY

Craig Craig

- Moffat Cnty Airport , CO

Hayden Yampa Valley Airport , CO

Rifle Garfield County Airport , CO

Rock Springs Sweetwater Co Airport , WY

Rawlins Municipal Airport , WY

Lander Hunt Field , WY

Torrington M unicipal Airport , WY

Riverton , WY

Big Piney Marbleton Airport , WY

Precipitation Stations: total of 108 stations

Ozone Monitoring Stations:

Centennial, WY

Rocky Mountain NP, CO