# Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling Analysis DRAFT

April 15, 2010 (revised June 25, 2010 and August 19, 2010)

Colorado Department of Public Health and Environment Air Pollution Control Division

Technical Services Program 4300 Cherry Creek Drive South Denver, Colorado 80246Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 1Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# Table of Contents

1. INTRODUCTION ................................................................................................................... ..............................4

1.1. V ISIBILITY C ALCULATIONS .............................................................................................................................7

2. EMISSION ESTIMATES............................................................................................................. ........................9

2.1. P RE -C ONTROL E MISSION E STIMATES .............................................................................................................9 2.2. P OST -C ONTROL S CENARIO /S TRATEGY E MISSIONS .......................................................................................10 2.3. D OCUMENTATION AND S UPPORTING D ATA ..................................................................................................10 2.4. T REATMENT OF D IRECT P ARTICULATE M ATTER E MISSIONS AND P ARTICLE S IZE D ISTRIBUTIONS ...............10

3. CALMET, CALPUFF, POSTUTIL, CALPOST MODELING METHODOLOGY AND POSTPROCESSOR DATA PROCESSING ...................................................................................................... ...................11

3.1. CALMET/CALPUFF M ODEL S ELECTION ...................................................................................................11 3.1.1. CALMET ......................................................................................................................... ........................12 3.1.1.1. CALMET Modeli ng Domain......................................................................................................... ................ 12 3.1.1.2. CALMET Performan ce Evaluation .................................................................................................. ............. 14 3.1.1.3. Geophysical Processing (Te rrain, Landuse, Landcover)........................................................................... ..... 14 3.1.1.4. CALMET Paramete r Set tings...................................................................................................... .................. 17 3.1.1.5. CALMET Surface Stations........................................................................................................ .................... 19 3.1.1.6. CALMET Uppe r Air............................................................................................................... ....................... 19 3.1.1.7. CALMET Precipita tion Stations.................................................................................................. .................. 20 3.1.1.8. CALMET Parame ter Summary ....................................................................................................... .............. 20 3.1.2. CALPUFF ...............................................................................................................................................21 3.1.2.1. Receptor Network and Cl ass I Federal Areas ..................................................................................... ........... 21 3.1.2.2. CALPUFF Mete orolog y ............................................................................................................ .................... 22 3.1.2.3. CALPUFF Mode ling Domain........................................................................................................ ................ 22 3.1.2.4. CALPUFF Parame ter Summary ...................................................................................................... .............. 22 3.1.2.5. Chemical Mechanism ............................................................................................................. ....................... 23 3.1.2.6. Chemical Mechanism – Amm onia Sensitivity Tests ................................................................................. .... 26 3.1.2.7. Ammonia Assumptions - Discussion............................................................................................... .............. 31 3.1.2.8. Ammonia A ssumptions............................................................................................................ ...................... 33 3.1.2.9. Ozone Assu mptions....................................................................................................................................... 33 3.1.3. CALPOST Settings and Vi sibility Post -Processing................................................................................ .34 3.1.3.1. Natural Conditions - Determining Hygroscopic And N on-Hygroscopic Values For the Best 20% Visibility Days 35 3.1.3.1.1. Natural Backgro und - Obje ctive ................................................................................................. ................... 35 3.1.3.1.2. Natural Backgro und - Disc ussion ................................................................................................ .................. 36 3.1.3.1.3. Natural Backgr ound - Me thod .................................................................................................... ................... 36 3.1.3.2. CALPOST and POSTUT IL Parameters................................................................................................ ......... 38

4. BART ANALYSIS MODELING PROCESS................................................................................................. ...42

5. REPORTING OF RESULTS FOR THE DE GREE OF VISIBILITY CHANGE.........................................43

5.1. 1 ST -H IGH AND 98 TH P ERCENTILE M ETRICS .....................................................................................................44 5.2. M ETRICS FOR C HARACTERIZING THE C HANGE IN V ISIBILITY I MPACTS ........................................................44 5.3. P OSTPROCESSOR FOR G ENERATING M ETRICS ...............................................................................................44

6. REFERENCES ..................................................................................................................... ...............................45

APPENDIX A – NATURAL BACKGROUND VALUES ......................................................................................... 46

APPENDIX B – MONTHLY F(RH) VALUES .............................................................................................. ............54

APPENDIX C – SAMP LE CALMET FILE................................................................................................ ...............61

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 2Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 3Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# 1. Introduction

This protocol documents the Colorado Depart ment of Public Health and Environment Air Pollution Control Division (Division) CALPUFF modeling analysis for estimating the degree of visibility improvement from potential Best Av ailable Retrofit Technology (BART) control technology options. It describes dispersion modeling and analysis procedures and methods for quantifying the degree of visibility improvement from potential BART control scenarios/strategies. It does not explain how the visibi lity results are factored into the BART determination process (i.e., 5-step process) or di scuss the specific BART scenarios that will analyzed.

This protocol is based on the following two documents:

1. “ CALMET/CALPUFF BART Protocol for Clas s I Federal Area Individual Source Attribution Visibility Impairment Modeling Analysis .” Colorado Department of Public Health and Environment. October 24, 2005.http://www.colorado.gov/airquality/documents/Colorado-subject-to-BARTCALPUFFprotocol.pdf

2. “ BART Control Technology Visibility Im provement Modeling Analysis Guidance .” Colorado Department of Public Health and Environment. April 12, 2006. http://www.colorado.gov/airquality/docum ents/Colorado-BART-Analysis-ModelingGuidance.pdf

This protocol follows the procedures above with the following exceptions:

1. General changes were made to reflect the fact that this modeling analysis will be performed by the Division and not by the source operators. 2. CALMET settings are consistent with the Augus t 31, 2009 EPA memo "Clarification on EPA-FLM Recommended Settings for CALM ET" with the exception of three CALMET parameters (NZ, ZFACE, and ZIMAX). U.S. EPA Region 8 approved this deviation for CALMET modeling in Colorado via email on October 7, 2009. Details about these parameters and the technical justification are found else where in this protocol. 3. MM5 meteorological fields used in CALMET include th e following three years: 2001, 2002, and 2003. Specifically, 36 kilometer (km) reso lution meteorological fields are from a national U.S. EPA MM5 modeling analysis for 2001. For 2002, 12km resolution Western Regional Air Partnership (WRAP) MM5 fi elds are used. For 2003, 4 km resolution kilometer fields from a CDPHE MM5 analysis , performed by Alpine Geophysics, are used. Language in the CALMET section of this protocol has been revised accordingly. 4. Emissions estimation language from the subject-to-BART m odeling protocol was replaced with BART analysis modeling language. 5. The most recent regulatory model versions of CALMET, CALPUFF, and CALPOST are used. 6. CALMET processing for all three years has been revised. As compared to the 2005 Division BART modeling, this analysis uses higher resolution MM5 data for 2002 and 2003. As compared to the Division’s 2005 modeli ng, this analysis uses a larger modeling

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 4Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

domain and a different projection. All of th e geophysical processing and meteorological data preprocessing was revised. The CALMET modeling used in this analysis was performed by CH2M Hill for a recent PSD perm it application in Colorado. Prior to use for this modeling effort, the CALMET analysis was reviewed and approved by the Division earlier in 2010. This protocol has been updated accordingly to reflect the way the CALMET fields were developed by the permit applicant. 7. Degree of visibility improvement metr ics and associated modeling procedures have been revised to streamline the reporting process, to improve the clarity of the procedures, and to remove the methods that relied on use of presumptive limits as a starting point. 8. The June 25, 2010 revision to this protocol clarifies the modeling procedures. It includes language revisions to better desc ribe model settings and the modeling process. In addition, during the modeling process, there were a fe w deviations from th e April 15, 2010 protocol. A description of the devia tions is presented below: a. Ozone Stations . The Division inadvertently included an old ozone sta tion list in the April 15, 2010 draft protocol. The ozone st ation list in this protocol has been updated to match the stations used in this analysis.

b. Upper Air Stations . The Division inadvertently re tained language from the 2005 protocol in the April 15, 2010 draft protocol that stated the CALMET meteorological modeling would include th e Grand Junction upper air station. For this supplemental BART modeling, as indi cated in #6, above, the Division used the CALMET.DAT files developed by a recen t PSD permit applicant. The CALMET modeling performed by the applicant di d not use the Grand Junction upper air station. The Division did not make any changes to the permit applicant’s CALMET modeling for this supplemental BART analysis.

c. Ammonia Background . The April 15 protocol in dicated that an ammonia background of 44 ppb would be used for all sources in northeast Colorado. During the process of setting up m odeling runs for CENC (near Golden) and CEMEX (near Lyons), file review showed that the Di vision’s technical staff had previously approved an ammonia background of 5 ppb for CENC and CEMEX in 2006 during the BART Analysis process. To mainta in consistency with previous ammonia background decisions for these two BA RT-eligible sources, the ammonia background for CEMEX and CENC used in this analysis is 5 ppb, not 44 ppb. The ammonia section of this protoc ol has been updated accordingly. d. Degree of Visibility Improvement Metrics . Per U.S. EPA comments on the April 15, 2010 protocol, a statement has been added to the protocol to reflect the U.S. EPA Region 8 comment that “To show th e change in visibility impact between scenarios the most important metric to provide would be the delta-deciview between pre and post control 98 th percentile impacts for e ach scenario in the three modeling years. Also provide the number of days exceeding .5 and 1 deciview.” e. Postprocessors . The April 15 protocol indicated th at the Division might use its 98th percentile processor to st reamline the modeling. In fact, the Division’s 98 th percentile processor was not used becaus e the regulatory ve rsion of CALPOST adequately summarizes results. f. Domain maps . The protocol has been clarified to reflect the fact that the modeling domain for 2003 is slightly smaller th an the 2001 and 2002 domains due to the

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 5Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

limited size of the CDPHE 2003 4km MM5 fi elds. Language describing the domain has been updated to reflect the domains used in this analysis. g. Section 2 (Emission Estimates) revisions. The opening paragraph of Section 2 and Section 2.2 were revised to clarify the emi ssion estimation process for this analysis. 9. The August 19, 2010 revision to this protocol are limite d to Section 2.4. The revised language provides additional deta il and clarification regardi ng the treatment of direct particulate matter.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 6Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



### 1.1. Visibility Calculations The general theory for performing visibility calculations with the CALPUFF modeling system is described in several documents, including:

 “Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and Recommendations for Modeling Long Ra nge Transport Impacts” (IWAQM, 1998)

 “Federal Land Manager’s Air Quality Re lated Values Workgroup (FLAG): Phase I Report” (FLAG, 2000)

 “A User's Guide for the CALPUFF Dispersion Model” (Scire, 2000)

In general, visibility is charac terized either by visual range (the greatest distance that a large object can be seen) or by the light extinction coefficient, which is a measure of the light attenuation per unit distance due to scattering and absorpti on by gases and particles.

Visibility is impaired when light is scattere d in and out of the line of sight and by light absorbed along the line of sight. The light extinction coefficient (b ext ) considers light extinction by scattering (b scat ) and light extinction by absorption (b abs ):

b ext = b scat + b abs

The scattering components of extinction can be represented by these components:

 light scattering due to air mol ecules = Rayleigh scattering = b rayleigh
 light scattering due to particles = b sp

The absorption components of extinction can be represented by these components:

 light absorption due to gaseous absorption = b ag  light absorption due to particle absorption = b ap

Particle scattering, b sp , can be expressed by its components:

b sp = b SO4 + b NO3 + b OC + b SOIL + b Coarse

where:

 b SO4 = scattering coefficient due to sulfates = 3[(NH 4 ) 2 SO 4 ]f(RH)

 b NO3 = scattering coefficient due to nitrates = 3[NH 4 NO 3 ]f(RH)

 b OC = scattering coefficient due to organic aerosols = 4[OC]

 b SOIL = scattering coefficient due to fine particles = 1[Soil]

 b Coarse = scattering coefficient due to co arse particles = 0.6[Coarse Mass]

Particle absorption from soot is defined as:

 b ap = absorption due to elem ental carbon (soot) = 10[EC]

The concentration values (in brackets) are e xpressed in micrograms per cubic meter. The numeric coefficient at the be ginning of each equation is the dry scattering or absorption efficiency in meters-squared per gram. The f( RH) term is the relative humidity adjustment factor.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 7Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

The total atmospheric extinction can be expressed as:

b ext = b SO4 + b NO3 + b OC + b SOIL + b Coarse + b ap + b rayleigh

In this equation, the sulfate (SO4 ) and nitrate (NO3) components are referred to as hygroscopic components because the extinction coeffici ent depends upon relative humidity. The other components are non-hygroscopic.

The variation of the effect of relative humidity on the extinction coefficients for SO4 and NO3 can be determined in several ways. According to the BART guideline, monthly f(RH) values should be used.

The CALPUFF modeling techniques in this anal ysis provide ground level concentrations of visibility impairing pollutants. The concentrat ion estimates from CALPUFF are used with the previously shown equations to calc ulate the extinction coefficient.

As described in the IWAQM Phase 2 Report, the change in visibility is compared against background conditions. The delta-deciview, Δ dv, value is calculated from the source’s contribution to extinction, b source , and background extinction, b background , as follows:

Δ dv = 10 ln ((b background + b source )/ b background )

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 8Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# 2. Emission Estimates

The Division will perform the visibility chan ge analysis based on 24-hour emission rates, described herein, that are developed for each unit evaluated in this supplemental BART analysis.



### 2.1. Pre-Control Emission Estimates
Pre-control emission rates are intended to re flect peak 24-hour average emissions that may occur in the future under the source’s current pe rmit. There are several ways the emission rates may be determined.

For each BART-eligible unit at the facility, de termine the pre-control peak 24-hour average emission rate for SO 2 , NOx, and direct particulate matter (PM) emissions (e.g., filterable and condensable PM2.5 and PM10) for each fuel and operational scenario allowed under the source’s current permit. For simplicity and to reduce the number of modeling scenarios, the Division may determine the peak 24-hour emission rate for each pollutant from all fuel/operational scenario s and combine the peak emission rate s to produce a single pre-control emissions scenario. For example, the NOx emi ssion rate might be from a natural gas-fired scenario while the SO 2 emission rate is from a coal-fired scenario. However, if the Division believes it is problematic to combine emissions from different fuel/operational scenarios, individual emission scenarios may be develope d for each fuel/operational scenario allowed under the permit.

Historic data (e.g., CEM data) may be used to determine peak 24-hour emission rates. If historic emissions/operational data are used, it should: 1. Reflect operations from the most recent 3 to 5 year period unless a more recent period is more representative due to the recent inst allation of emission cont rols or due to other recent permit modifications. 2. Account for “high capacity utilizatio n” during normal operating conditions. 3. Not include periods of start-up, shutdow n, and malfunction, alt hough these periods may be included for simplicity. 4. Be a good indicator of anticipated future peak emissions allowed under the current permit. 5. Account for fuel/material flexibility allowe d under the source's permit. For example, if the unit is allowed to use more than one fuel, and the fuel resulting in the highest emission rates is not reflected in the hist oric data, conduct additional analysis to determine the peak 24-hour average emissions. Similarly, if a raw material has variable properties (e.g., variable sulfur content) and the raw materi al resulting in the highest emission rates was not used dur ing the historic data period, conduct additional analysis.

If historic data are not a good i ndicator of anticipated future p eak emissions allowed under the current permit, use supplemental emission calcula tions to determine the peak 24-hour average emission rates.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 9Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Allowable short-term ( ≤ 24-hours) emission rates or federall y enforceable short-term emission limits ( ≤ 24-hours) may be used instead of CEM data or other historic data. If 24-hour emission limits do not exist, use limits of a shorter aver aging period. If limits do not exist, use maximum hourly emissions based on emissi on factors and design capacity.



### 2.2. Post-Control Scen ario/Strategy Emissions The Division will determine the post-contro l emissions based on (1) estimated percent reduction for a particular contro l scenario using the highest 30 -day rolling average emission rate in lb/MMBtu over the 3-ye ar baseline period, or (2) the generally accepted lb/MMBtu emission rate documented for similar sources; depending on the availability of information from the source that specifies the expected post-control emission rate . Refer to section 2.4 for a discussion on PM speciation.



### 2.3. Documentation and Supporting Data The Division will document and support the emission rates.



### 2.4. Treatment of Direct Particulate Matter Emissions and Particle Size Distributions Direct filterable particulate matter (PM) emissions will be modeled initially with the same method used in the Division's original subjec t-to-BART CALPUFF mode ling. Specifically, all direct filterable PM is modeled in CALPUFF as a single species with a geometric mass mean diameter of 2.5 microns and a geometric stan dard deviation of five. In CALPOST, the extinction efficiency for direct PM is set equal to 1.0 1/Mm per μ g/m 3

.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 10Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# 3. CALMET, CALPUFF, POSTUTIL, CALPOST Modeling Methodology and Post-Processor Data Processing

This report includes sufficient technical documentation to support the application of CALPUFF at distances up to 300 kilometers. While CALPUFF may be used for source-toreceptor distances less than 50 kilometers at some receptors, depending on the sources modeled, there is a Class I area within the 50 to 300 km range from every BART source in Colorado.

According to “ Interagency Workgroup on Air Qualit y Modeling (IWAQM) Phase 2 Summary Report and Recommendations for Modeli ng Long Range Transport Impacts ” (IWAQM Phase 2 Report): In the context of the Phase 2 recommendation, the fo cus of the visibility analysis is on haze. These techniques are applicable in the range of thirty to fifty kilo meters and beyond from a source. At source-receptor distanc es less than thirty to fifty kilometers, the techniques for analyzing visual plumes (sometimes referred to as ‘plume blight’) should be applied.

For the few cases where BART source-to-recept ors distances are less than 50 kilometers, both the topography and the meteorological fields ar e complex and the use of CALPUFF appears to be appropriate based on the possibility of reci rculation, stagnation, and complex flows. If the CEMEX Lyons plant is modeled, for example, the shortest source-to-receptor distance modeled is about 25 kilometers, but it involve s an elevation change of about 3000 ft. In addition, in each case where a source has a source-to-receptor distance of less than 50 kilometers, such as the CEMEX, only a portion of the Class I area is le ss than 50 km from the

source.



### 3.1. CALMET/CALPUFF Model Selection The following model versions will be used:

• CALPUFF version 5.8, level 070623

• CALMET version 5.8, level 070623

• POSTUTIL version 1.56, level 070627

• MAKEGEO version 2.29, level 070327

• PMERGE version 5.32, level 070627

• SMERGE version 5.57, level 070627

• CALPOST version 5.6394, level 070622

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 11Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.1. CALMET The MM5/CALMET meteorological fields have been generated for 2001, 2002, and 2003. CALMET is based on the Diagnostic Wind Mode l (Douglas, S. and R. Kessler, 1988). The Diagnostic Wind Model has been significantly e nhanced (Scire, 2000). For this particular study, the model uses a Lambert Conformal Proj ection coordinate system to account for the Earth's curvature.

CALMET uses a two-step approach to calculate wind fields. In the fi rst step, an initialguess wind field is adjusted for slope flows and terrain blocki ng effects, for example, to produce a Step 1 wind field. In the second ste p, an objective analysis is performed to introduce observationa l data into the Step 1 wind field.

In this application, the initial guess wi nd fields are based on 36 km resolution MM5 1 meteorological fields for 2001, 12 km resoluti on MM5 fields for 2002, and 4 km resolution MM5 fields for 2003. CALMET setting IPR OG=14 will be used. Alpine Geophysics performed the CALMM5 extractions to convert the data format from MM5 output into a CALMET MM5.DAT format. The 2001 MM5 data were generated by the U.S. EPA. The 2002 MM5 data were generated by the Wester n Regional Air Partne rship (WRAP). The 2003 MM5 data were generated fo r CDPHE by Alpine Geophysics.

The BART guideline does not specify th e exact number of years of mesoscale meteorological data for use in CALPUFF, but according to 40 CFR 51 Appendix W, at least three years of meteorological data should be used.

3.1.1.1. CALMET Modeling Domain The CALMET computational modeling domain is shown in Figure 1 . It is based on a Lambert Conformal Conic (LCC) projection, as follows: Latitude and longitude (decimal degrees) of projection origin: RLAT0 = 38.4N RLON0 = 105.5W Matching parallels of latitude (decimal degrees) for project: XLAT1 = 36.4N XLAT2 = 40.5N Datum: DATUM = NAR-C (North American 1983 GRS 80 Spheroid, mean for CONUS (NAD83)

The domain includes all Class I areas in Co lorado with the excep tion of Mesa Verde NP. Mesa Verde was excluded because it is more than 300 km from all of the BARTeligible sources in Colorado and because the BART-eligible sources in Colorado would have higher impacts at other Class I areas. In addition, preliminary BART modeling in 2005 indicated that impacts at Mesa Verde would be small enough that its inclusion would not alter decisions based on impacts at other Class I areas that are

1 Fifth-Generation NCAR/Pen n State Mesoscale Model.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 12Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

closer to the BART sources. The domain doe s not include Class I areas in any nearby states because visibility impacts from Co lorado’s BART sources are expected to be highest at Class I areas in Colorado. This assumption is based on source-to-receptor distances, professional judgment regarding prevailing ai r pollutant transport regimes, and recent modeling for a PSD permit in Pueblo. The CALMET domain includes almost the entire state of Colorado. Fo r 2001 and 2002, it is 508 km x 688 km with 4-kilometer CALMET grid cells. For 2003, it is 504 km x 616 km with 4-kilometer CALMET grid cells. The domain for 2003 is sma ller due to limitations in the size of the CDPHE 4km MM5 domain for 2003.

Figure 1. CALMET/CALPUFF modeling domain for 2001 and 2002. For 2003, the southern end of the domain is about 72 km north of th e one shown above becaus e of limitations with the CDPHE 2003 MM5 domain. Refer to Figure 2 to view the southern end of the 2003 domain.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 13Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.1.2. CALMET Performance Evaluation The MM5 meteorological fields used in this analysis were evaluated historically as part of other projects. The CALMET meteorological fields us ed in this analysis were developed by CH2M Hill for a recent PSD permit in Colorado. CH2M Hill performed a CALMET performance ev aluation and concluded that the meteorological fields performed satisfactor ily for the PSD application. The Division also reviewed the performance evalua tion and the meteorological fields and concluded that the fields we re satisfactory for the PSD permit. After further review, the Division concluded that the CALMET fields, which are consistent with the August 2009 EPA CALMET memo, are satisfa ctory for this supplemental BART analysis modeling.

3.1.1.3. Geophysical Processing (Terrain, Landuse, Landcover) Gridded terrain elevations for the modeling domain are derived from 3 arc-second digital elevation models (DEMs) produced by the United States Geological Survey (USGS). The files cover 1-degree by 1-degree blocks of latitude and longitude. USGS 1:250,000 scale DEMs were used. The el evations are in meters relative to mean sea level and have a resolution of about 90 meters, shown in Figure 2. TERREL version 3.684, level 070327 was used.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 14Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Figure 2. CALMET terrain plus Class I Area receptors (blue) and BART sources. This example image is for the year 2003 configuration.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 15Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

The land use data are based on USGS NLCD 1992 data use categories were mapped into the CALMET land use categories, as shown in Figure 3 , using CTGPROC version 2.682, level 070430 with internal c oordinate transformations by COORDLIB version 1.98, level 060911.

Figure 3. Land Use (example shown is for year 2002).
MAKEGEO version 2.29, level 070327 was used to process the geophys ical data to create the GEO.DAT file.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 16Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.1.4. CALMET Parameter Settings U.S. EPA issued a memo regarding CA LMET settings dated August 31, 2009 titled "Clarification on EPA-FLM Recommended Se ttings for CALMET." As shown in the example CALMET file in Appendix C, the CALMET settings in the U.S. EPA memo will be used with the exception of thr ee CALMET parameters (NZ, ZFACE, and ZIMAX). U.S. EPA Region 8 approved th is deviation for CALMET modeling in Colorado via email on October 7, 2009.

Parameter Descriptions: NZ = number of vertical layers ZFACE = cell face heights in arbitrary vertical grid (ZFACE (NZ+1)) (m) ZIMAX = maximum overland mixing height (m)

EPA-FLM Recommended Setting: NZ = 10 ZFACE = 0,20,40,80,160,320, 640, 1200, 2000, 3000, 4000 ZIMAX = 3000 m

CDPHE Setting: NZ = 11 ZFACE = 0,20,40,80,160,320, 640, 1200, 2000, 3000, 4000, 5000 ZIMAX = 4500 m

Justification: A ZIMAX setting of 3000 m is too low for some summer days in Colorado. A value of 4500 m is recommended instead of 3000 m. A ZIMAX setting of 4500 meters is based on analyses of soundings for summe r ozone events. The analysis suggests mixing heights in the Denver area are of ten well above the CALMET default and EPA-FLM value of 3000 meters during the summer. For example, on some summer days, ozone levels are elevated all th e way to 6000 meters MSL or beyond during some meteorological regimes, including so me regimes associated with high ozone episodes. A sounding from the evening of July, 1 2002 (see Figure 4), which is a day the 8-hour ozone standard was exceeded at Rocky Mountain National Park, suggests the mixing height was likely around 6000 meters MSL. The mixing height estimate is based on the relative uniformity of the water vapor mixing ratio below 6000 meters, the temperature profile, the inverted "V" in the sounding, and data from a NOAA ozonesonde from Boulder that shows relativ ely constant ozone le vels with height. Although low mixing heights can occur duri ng the summer and other times of the year, maximum summertime daytime mixing heights in the Denve r area often range from about 12,000 feet (3700 m) to 20,000 f eet (6000 m) MSL. Since the CALMET ZIMAX setting is above ground level (AGL), not above mean sea level (MSL), the maximum summer daytime mixing height range over the plains would be about 15000 feet (4500 m) AGL. Thus, a ZIMAX settin g of 4500 m is appropriate. In order to implement a ZIMAZ of 4500 m, it woul d be appropriate to add one additional vertical layer with a ce ll face height at 5000 m.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 17Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Figure 4. Example Denver summertime sounding.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 18Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.1.5. CALMET Surface Stations

Figure 5. Surface meteorological stations.

3.1.1.6. CALMET Upper Air The Denver upper air station is included in CALMET.

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3.1.1.7. CALMET Preci pitation Stations

Figure 6. Precipitation stations.

3.1.1.8. CALMET Parameter Summary See Appendix C for a sample CALMET input file.

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3.1.2. CALPUFF The use of CALPUFF is recommended in 40 CFR 51 Appendix Y (BART guideline). Theprimary niche for CALPUFF is as a long-range transport model. It is a multi-layer, nonsteady-state puff dispersion model that can simu late the effects of time- and space-varying meteorological conditions on pollutant transpor t, chemical transformations, vertical wind shear, and deposition (Scire, 2000).

The default technical options in CALPUFF ar e used, unless specified otherwise in this report.

3.1.2.1. Receptor Network and Class I Federal Areas The modeling domain will contain all Cla ss I federal areas in Colorado within 300 kilometers of the BART-eligible source. Eleven federal Class I areas are included:

 Flat Tops Wilderness Area

 Rawah Wilderness Area

 Mt Zirkel Wilderness Area

 Weminuche Wilderness Area

 Rocky Mountain National Park

 Maroon Bells-Snowmass Wilderness Area

 La Garita Wilderness Area

 Great Sand Dunes National Park

 West Elk Wilderness Area

 Eagles Nest Wilderness Area

 Black Canyon of the Gunnison National Park

The discrete receptors for the Class I fe deral areas were generated by the National Park Service (NPS) NPS Convert Class I Areas (NCC) computer program. Receptor elevations provided by the NPS conversion program are used.

All receptors are included in a single CALPUFF simulati on for each pre-control or post-control BART scenario. The appropria te receptors for each Class I area were extracted from the CALPUFF or POST UTIL output files with the NCRECP parameter in CALPOST, which specifies th e receptor range to be processed in CALPOST, as shown below.

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3.1.2.2. CALPUFF Meteorology Refer to the CALMET section of the report for details.

3.1.2.3. CALPUFF Modeling Domain In this case, the CALPUFF and CALMET m odeling domains are identical. Based on prevailing transport and m odeling analyses done to s upport the subject-to-BART process, the Division concl uded that the modeling doma in used during the BART process would be sufficient for BART analys is modeling. In this case, the Division is using a larger CALPUFF domain that the one used in the subject-to-BART modeling. The larger domain retains more mass in the modeling system. Nevertheless, for some of the BART sour ces closer to the edge of the modeling domain, mass may be lost during some tran sport regimes. While this is less than ideal, modeling suggests that the periods with highest impacts occur with relatively direct transport from the BART source to the affected Class I areas and this same approach resulted in the inclusion of th ese BART-eligible sources in the BART process (i.e., the sources like Craig and Hayden near the domain boundary were found to be subject-to-BART based on CALP UFF modeling with a similar domain). Therefore, this modeling domain is sufficien t in size to capture impacts on the days likely to be associated with the highest degree of visibility impairment. The modeling configuration provide s a reasonable measure of the degree of visibility improvement associated with various BART alternatives.

3.1.2.4. CALPUFF Parameter Summary Figure 7 summarizes some of the key CALPUFF settings.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 22Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Figure 7. CALPUFF parameter summary.

3.1.2.5. Chemical Mechanism The MESOPUFF II pseudo-first-order chemi cal reaction mechanism (MCHEM=1) is used for the conversion of SO 2 to sulfate (SO4) and NOx to nitrate (NO3). Refer to the CALPUFF User’s Guide for a descri ption of the mechanism (Scire, 2000).

In the MESOPUFF II mechanism, the amm onia background concentration affects the equilibrium between nitric acid, ammonia, and ammonium nitrate. The equilibrium constant for the reaction is a non-linear func tion of temperature and relative humidity (Scire, 2000). Unlike sulfate, the calculated nitrate concentration is limited by the amount of available ammonia, which is pr eferentially sc avenged by sulfate (Scire, 2000). In particular, the amount of ammonia available for the nitric acid, ammonium nitrate, and ammonia reactions is determined by subtracting sulfate from total ammonia.

While the chemical mechanism simulates both the gas phase and aqueous phase conversion of SO 2 to sulfate, the aqueous phase me thod, which is important when the plume interacts with clouds and fog, can significantly unde restimate sulfate formation. In this report, as recomm ended by the IWAQM Phase 2 report, the “nighttime SO 2 loss rate (RNITE1)” is set to 0.2 percent per hour. The “nighttime NOx loss rate (RNITE2)” is set to 2.0 percent per hour and the “nighttime HNO 3 formation rate (RNITE3)” is set to 2.0 percent per hour.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 23Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

According to the 1996 “Mt. Zirkel Wilder ness Area Reasonable Attribution Study of Visibility Impairment. Volume II: Results of Data Analysis and Modeling - Final Report,”
The CALPUFF chemical module is formul ated around linear transformation rates for SO 2 to sulfate and NO X to total nitrate. There are two options for specifying these transformation rates:

Option 1: An internal calculation of rates based on local values for several controlling variables (e.g., solar radi ation, background ozone, relative humidity, and plume NO X ) as used in MESOPUFF-II. The parametric transformation rate relationships empl oyed were derived from box model calculations using the mechanism of Atkinson et al. (1982).

Option 2: A user-specified input file of diurnally varying but spatially uniform conversion rates.

Morris et al. (1987) reviewed the MESOPUFF-II mechanism as part of the U.S. EPA Rocky Mountain Acid Depositi on Model Assessment study. They found that it provided physically plausib le responses to many of the controlling environmental parameters. However, the mechanism had no temperature dependence, which is an important factor in the Rocky Mountain region where there are wide variations in tempera ture. Furthermore, the MESOPUFF-II transformation scheme was based on box model simulations for conditions more representative of th e Eastern U.S. than of the Rocky Mountains.

The largest deficiency in the ME SOPUFF-II chemical transformation algorithm is the lack of explicit treatment for in-cloud (aqueous-phase) enhanced oxidation of SO 2 to sulfate. The MESOPUFF-II chemical transformation algorithm includes a surrogate reaction rate to account for aqueous-phase oxidation of SO2 to sulfate as follows:

K aq = 3 × 10 -8 × RH 4 (%/hr) (B.2-1)

Thus, at 100% relative humidity (RH), the MESOPUFF-II aqueous-phase surrogate SO 2 oxidation rate will be 3% per hour. Measurements in generating station plumes suggest s patially- and temporally-integrated SO 2 oxidation rates due to oxidants in cl ouds to be 10 times this value.

Another issue is the amount of ammonia av ailable for nitrate chemistry. According to a paper by EarthTech (Escoffier-Czaja and Scire, 2002), “In the CALPUFF model, total ni trate (TNO3 = HNO3 + NO3) is partitioned into each species according to the equilibrium relationship between HNO3 and NO3. This equilibriu m varies as a function of time and space, in response to both the ambient temperature and relative humidity. In addition, the formation of nitrate is subj ect to the availability of NH3 to form ammonium nitrate (NH4NO3), th e assumed form of nitrate in the model. In CALPUFF, a continuous plume is simulated as a series of puffs, or discrete plume elements. The tota l concentration at any point in the model is the sum of the c ontribution of all nearby puffs from each source.

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Because CALPUFF allows the full amount of the specified background concentration of ammonia to be avail able to each puff for forming nitrate, the same ammonia may be used multiple times in forming nitrate, resulting in an overestimate of nitrate formati on. In order to properly account for ammonia consumption, a program called POSTUTIL was introduced into the CALPUFF modeling system in 1999. PO STUTIL allows total nitrate to be repartitioned in a post-processing st ep to account for the total amount of sulfate scavenging ammonia from all sources (both project and background sources) and the total amount of TNO3 competing for the remaining ammonia. In POSTUTIL, ammonia ava ilability is computed based on receptor concentrations of total su lfate and TNO3, not on a puff-by-puff basis.”

Ammonia-limiting methods are used for re partitioning nitric acid and nitrate on a receptor-by-receptor and hour-by-hour basis to account for over prediction due to overlapping puffs in CALPUFF. Specifical ly, the use of the MNIRATE=1 option in POSTUTIL is acceptable. At this time , other ammonia-limiting methods, including iterative techniques that use observati onal data to resolve backward the thermodynamic equilibrium equation between NO3/HNO 3 for each hour to minimize available ammonia, are not acceptable. Generally, for regulatory CALPUFF modeling in Colorado, techniques that assu me the atmosphere is always ammonia poor are not acceptable, particul arly in eastern Colorado.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 25Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.2.6. Chemical Mechanism – Ammonia Sensitivity Tests In 2005, to better understand the response of the modeling system to background ammonia when a single point source with significant emissions of SO 2 and NOx is modeled, the Division performed sensitivity tests for a source in northeast Colorado and a source in northwest Colorado using the 2002 MM5/CALMET meteorology. These tests have not been revised for this supplemental BART modeling, but they are provided here for informational purposes. In the test case, SO 2 , NOx, and filterable PM10 emissions were modeled. The ammonia background value was varied from 0 to 100 ppb. In the northeast Colorado test case, the SO 2 emission rate is about 3 times higher than the NOx emission rate. In the northwest Colorado test case, the modeled NOx emission rate is a bout 4.4 times higher than the SO 2 rate.

In both cases, when the background ammoni a concentration is zero, the model produces no nitrate, as expected; however, it produces sulfate.

For the northeast Colorado sensitivity test (see Figure 8 ), where the modeled SO 2 emission rate is significantly higher than the NOx emission rate, the change in visibility (delta-deciview) is not very sensitive to the background ammonia concentration across the range from 1.0 ppb to 100.0 ppb because of the high SO 2 emission rates relative to NOx and the way sulfate is produced in the MESOPUFF II chemical mechanism. Visibility impact s drop significantly when the ammonia background is less than 1.0 ppb, but even at 0.0 ppb of ammonia, sulfate impacts remain relative high.

Figure 8. Sensitivity of CALPUFF visibi lity impacts (delta-deciview) to ammonia backgrounds from 0 ppb to 100 ppb from a source with high SO 2 emissions relative to NOx.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 26Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

For the northeast Colorado case, on days with the highest visibility impacts, the relative contribution of nitr ate and sulfate vary (see Figure 9 and Figure 10 ), but most of the modeled visibility impairment is due to sulfate. When comparing these figures, be aware the relative rank for some days is different. For example, day 85 is the 2 nd worst day for the 0.1 ppb ammonia case, but it’s the 3rd worst day for the 100 ppb case. On the day with the highest impact (d ay 84), the contribution from sulfate is 98.8% for the 0.1 ppb ammonia case and 72.7% for the 100 ppb ammonia case. For the 8 th high delta-deciview value, the contri bution from sulfate is 86.3% for the 0.1 ppb case and 67.9% for the 100 ppb case.

Figure 9. Contribution of sulfate and nitrate to the modeled change in deciviews, assuming a background ammonia of 0.1 ppb in CALPUFF.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 27Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Figure 10. Contribution of sulfate and nitrate to the modeled change in deciviews, assuming a background ammonia of 100 ppb.

For the northwest Colorado sensitivity test (see Figure 11 ), where the modeled NOx emission rate is significantly higher than the SO 2 emission rate, the change in visibility (delta-deciview) is not sensitive to the background a mmonia concentration across the range from 10 ppb to 100 ppb. While there is a moderate drop in impacts when ammonia is dropped from 10 ppb to 1.0 ppb, the model is very sensitive to ammonia when the background ammoni a level is less than 1.0 ppb.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 28Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Figure 11. Sensitivity of CALPUFF visibility impact s (delta-deciview) to ammonia backgrounds from 0 ppb to 100 ppb from a source with high NOx emissions relative to SO 2 .

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 29Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

For the northwest Colorado test case, according to CALPUFF as implemented here, impairment is primarily due to nitrate (see Figure 12 and Figure 13 ), but the contribution due to nitrate varies significantly depending on the assumed ammonia background level. For the 100 ppb background case, the nitrate contribution is greater than 90% for the top 20 days. Ho wever, for the 0.1 ppb case, the nitrate contribution varies from 43% to 81% for the top 20 days.

Figure 12. Contribution of sulfate and nitrate to the modeled change in deciviews, assuming a background ammonia of 0.1 ppb in CALPUFF.

Figure 13. Contribution of sulfate and nitrate to the modeled change in deciviews, assuming a background ammonia of 100 ppb in CALPUFF. Caution should be used when extrapolat ing the results of these tests to other CALPUFF applications.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 30Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Since the MESOPUFF II chemical mechanis m used in this analysis depends on several parameters, including ozone and ammonia background concentrations, the methods for determining the background ozone and ammonia concentration fields are discussed in more detail in the next two sections.

3.1.2.7. Ammonia Assumptions - Discussion In CALPUFF, as used in this application, the background ammonia concentration is temporally and spatially uniform. It is likely that some portions of the modeling domain are ammonia poor and some are am monia rich. Thus, setting a domain-wide background is problematic. As discussed in the previous section, when modeling a single large source with high SO 2 emission rates relative to NOx, the assumed background ammonia concentration is not a critical parameter for determining visibility impacts.

According to the IWAQM Phase 2 Report, A further complication is that the fo rmation of particulate nitrate is dependent on the ambient concentra tion of ammonia, which preferentially reacts with sulfate. The ambient ammoni a concentration is an input to the model. Accurate specification of this parameter is critical to the accurate estimation of particulate nitrate c oncentrations. Based on a review of available data, Langford et al. (1992) sugge st that typical (within a factor of 2) background values of ammonia are: 10 ppb for grasslands, 0.5 ppb for forest, and 1 ppb for arid lands at 20 C. Langford et al. (1992) provide strong evidence that background levels of ammonia show strong dependence with ambient temperature (var iations of a factor of 3 or 4) and a strong dependence on the soil pH. How ever, given all the uncertainties in ammonia data, IWAQM recommends use of the background levels provided above, unless specific data are ava ilable for the modeling domain that would discredit the values cited. It should be noted, however, that in areas where there are high ambient levels of sulfate, values such as 10 ppb might overestimate the formation of particulate nitrate from a given source, for these polluted conditions. Furthermore, ar eas in the vicinity of strong point sources of ammonia, such as feedlots or other agricultural areas, may experience locally high levels of background ammonia.

The Northern Front Range is assumed to be ammonia rich. “Sulfate along the Northern Front Range is completely ne utralized by available ammonium and is present in the form of a mmonium sulfate.... The Northern Front Range is ammonia rich. There was sufficient ammonia, on mo st days during winter, to completely neutralize available nitr ic acid (NFRAQS, 1998).”

For northeast Colorado, a background ammonia concentration of 30.4 μg/m 3 (about 44 ppb) or less appears to be reasonable based on measurements for this modeling study. According to monitoring conducted for NFRAQS,

• "With respect to gaseous measurements, only ammonia was acquired at all nine sites with the denuder difference met hod at the Brighton and Welby sites and

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 31Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

with the filter-pack method (i.e., impregnated cellul ose-fiber filters behind Teflon-membrane filters) at the other s ites. Average ammonia concentrations were 30.4 ± 53.4 μg/m3 at the core site s and 10.3 ±12.6 μg/m3 at the satellite sites. The large standard deviation is mainly due to elevated ammonia concentrations found at the Evans site. Maximum 24-hour ammonia concentrations were 187.0 ± 5.4 μg/m3 at the Evans core site on 01/17/97 and 66.7 ± 3.5 μg/m3 at the Masters site on 01/20/97. Figure 6.3-5 shows that during the mid-January episode, 24-hour ammonia concentrations varied by orders of magnitude at the nine NFRAQS sites."

• "For the 6- and 12-hour samples, Figure 6.4-3 [not included in this report] ammonia concentrations were rather consistent throughout the day, with apparent site -to-site and season-to -season variation. Average ammonia concentrations at the Brighton site we re double those at the Welby site during Winter 97. Summertime ammonia concentrations were ~1 to 2 μg/m3 higher than the wintertime at the Welby site. Since ammonia concentrations closely reflect the vicinity of the sampling are a, site-to-site variations were more pronounced than seasonal or diurnal variat ions. This is evidenced by the graph in Figure 6.4-4 [not included in this report] , which shows ammonia concentrations were factors of 10 to 20 hi gher at the Evans site than at most of the other sites during Winter 97. Elevated concentrations exceeded 50 μg/m3 on 20% of the days at the Evans site. Twen ty-four hour ammonia concentrations at the Masters and Longmont sites were also factors of 5 to 10 higher than at the other sites."

For other areas like northwest Colorado, an annual background ammonia concentration of about 1 ppb or less is probably more re asonable, based on ammonia measurements from the Mt. Zirkel Visibility Study.

In the Aerosol Evolution Model (AEM) simulations done for the Mt Zirkel Study for a specific period, “ base case background air concentr ations for ammonia were assumed to be 0.5 μ g/m 3 and 30 ppb v for ozone, consistent with me asured values at the Hayden VOR site .” An ammonia co ncentration of 0.5 μ g/m 3 is about 0.7 ppb.

In the CALPUFF modeling section of the Mt Zirkel Study report, “The CALPUFF default value for backg round ammonia concentrations of 10 ppb was also considered far too high as a representative area-average. Measurements from the Buffalo Pass and Gilpin Creek sites were used to adjust ammonia concentration to episode and site-mean values.”

Based on a review of CALUFF files used for the Mt. Zirkel Study, for the August simulations, the assumed ammonia b ackground (BCKNH3) was 1.6 ppb; for the October simulation, the assumed background was 0.5 ppb; and for the September simulation, the assumed background was 0.8 ppb.

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3.1.2.8. Ammonia Assumptions To help provide consistency with the Division’s original BART modeling, the Division has not determined if more recen t ammonia measurements would change the assumptions below. The assumptions below are assumed to be reasonable for purposes of comparing control technologies.

Based on information in the previous s ection, for sources lo cated in northeast Colorado (e.g., Pawnee) and along the South Platte River, a domain-wide ammonia background value of 44 ppb is used. For CENC near Golden and CEMEX near Lyons, a background of 5 ppb is used, as justif ied by the source operators and approved by the Division in 2006 during the original BART Analysis process. For sources located in northwest Colorado (e.g., Craig and Hayden), a background ammonia concentration of 1.0 ppb is used. For s ources located in Colorado Springs (e.g., Drake), southeastern Colorado along the Arkansas River (e.g., Comanche), a background value of 10 ppb is used.

3.1.2.9. Ozone Assumptions According to the IWAQM Phase 2 Report, CALPUFF provides two options for providing the ozone background data: (1) a single, typical background value appropriate for the modeling region, or (2) hourly ozone data from one or more ozone monitoring stations. The second and preferred option requires the creation of the OZONE.DAT file containing the necessary data. For the Demonstration Assessment, the domain was large (700 km by 1000 km) such that the second option was necessary. The IWAQM does not anticipat e such large domains as being the typical application. Rather, it is ant icipated that the more typical application will involve domains of orde r 400 km by 400 km or smaller. But even for smaller domains, the ability to provide at least monthly background values of ozone is deemed desirable. The problem in developing time (and perhaps spatial) varying background ozone values is having access to representative background ozone dat a. Ozone data are available from EPA’s Aerometric Information Retri eval System (AIRS); however, AIRS data must be used with caution. Many ozone sites are located in urban and suburban centers and are not representati ve of oxidant levels experienced by plumes undergoing long range transport.

In this study, the following ozone stations were used:

• Welby

• Rocky Mountain National Park

• Greeley

• Highland

• S. Boulder Creek

• Carriage

• Chatfield

• USAF Academy

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• Arvada

• Welch

• Rocky Flats North

• NREL

• Ignacio (S. Ute)

• Hwy. 550 (S. Ute)

• Ft. Collins S. Mason-CSU

• Mesa Verde

• Bloomfield-Hyw. Dept. Yard

• USBR-Shiprock Substation (Farmington)

3.1.3. CALPOST Settings and Visibility Post-Processing To maintain consistency with previous BA RT modeling in Colorado, to expedite this analysis, and as approved by EPA Region 8, th e old IMPROVE equation is used for this CALPUFF analysis. As of the date of this report, the regulatory version of CALPUFF relies on the old IMPROVE equation.

The CALPUFF results are post-processed with the regulatory version of CALPOST and POSTUTIL.

For the Division’s original subject-to-BART modeling analysis, all PM10 was assumed to have a extinction efficiency of 1.0 since th e contribution of direct PM10 emissions was expected to be relatively small compared to visibility impairment caused by SO 2 and NOx emissions. This same approach is used for this supplemental BART analysis modeling. However, if it is reasonable to believe that the inclusion of conde nsable and filterable PM10 emissions and speciation would change th e outcome of a BART analysis decision, the Division may consider incl uding these factors. If speciated PM emissions are modeled, the following species are considered: fine part iculates (PMF), coarse particulates (PMC), elemental carbon (EC), organic carbon (SOA), and sulfate (SO4) along with appropriate particle size and deposition parameters for the source type and emission control technology.

To calculate background light extinction, MVISBK = 6 is used. That is, monthly RH adjustment factors are applied directly to the background and modeled sulfate and nitrate concentrations, as recommended by the BART guideline. The RHMAX parameter, which is the maximum relative humidity factor used in the particle growth equation for visibility processing, is not used when method 6 is selected. Similarly, the relative humidity adjustment factor (f(RH)) curves in CA LPOST (e.g., IWAQM growth curve and the 1996 IMPROVE curve) are not used wh en MVISBK is equal to 6.

EPA allows use of either the 20% best visibility days or annual average to calculate natural background for purposes of BART. In 2005, pr ior to the Utility Air Regulatory Group (UARG) settlement, the Division based natura l background on the 20% best visibility days, as recommended by th e BART guideline preamble:

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Finally, these BART guidelines use the natural visibility baseline for the 20 percent best visibility days for comparison to the "cause or contribute" applicability thresholds. We believe this estimate d baseline is likely to be reasonably conservative and consistent with the goal of natural conditions (70 FR 39125). This assumption was revisited in 2006 after the UARG settlement. The Division decided to continue using 20% best days for BART natural background. For this supplemental modeling analysis, 20% best days for natural background is used.

The method for estimating natural ba ckground is presented in section 3.1.3.1 . Specifically, for hygroscopic components, BKSO4 in CALP OST is set to 0.0893 for all months. For non-hygroscopic components, BKSOIL should be set to 1.620 for a ll months. The BKSO4 and BKSOIL values have been computed specif ically for the Colorado Class I areas used in this analysis.

The extinction due to Rayleigh scattering (i.e., the scattering of light by natural particles much smaller than the wavelength of the light) is set to 10 Mm -1 (BEXTRAY = 10.0).

As part of the protocol development process, previous analyses performed by the Division were reviewed regarding comparison’s betw een the natural background assumptions used in this analysis (see next section) and newer methods such as those presented in the draft FLAG 2008 report. For Rocky Mount ain National Park, the appr oach specified in this analysis uses a natural background that ha s a monthly background extinction of about 12 Mm -1 whereas the FLAG 2008 “20% best days” value is about 14 Mm -1 and the FLAG 2008 “annual average best days ” value is about 10 Mm -1 . A directionally similar trend exists for the other Class I areas in Colorado. That is, th e Division’s “20% best days” natural background assumption is be tween the FLAG 2008 recommendations. Consequently, as mentioned earlier, to help maintain consistency with previous BART modeling and to streamline this supplemental BA RT analysis process, the Division retained its original approach, as de scribed in the next section.

3.1.3.1. Natural Conditions - Determining Hygroscopic And NonHygroscopic Values For the Best 20% Visibility Days

3.1.3.1.1. Natural Background - Objective The spreadsheet shown in Figure 14 was created to determine the hygroscopic (3[BKSO4]) and non-hygroscopic (equivale nt to [BKSOIL]) portions of natural background for the best 20% vi sibility days (Best Days) at all Class I areas in Colorado's BART modeling. These concen trations, [BKSO4] and [BKSOIL], are used in CALPOST with monthly relative humidity adjustment factors (f(RH)) to determine monthly natural background visibi lity that would, on average, represent the average natural background visibility for the best 20% days in EPA's “Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program” (EPA, 2003).

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3.1.3.1.2. Natural Background - Discussion “Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Program” (EPA, 2003), section 2.4, describes the calculation of the annual average background extinction (in 1/Mm) for a Cla ss I area using the area's annual f(RH) and average natural concentrations base d on the area's geographic location (east versus west). Annual average back ground extinction values (in 1/Mm) are converted to annual average Haze Index (HI) values (in deciview or dv). Then, the average HI value for the 20% best visibility days (Best Days (dv)) is estimated from 10th percentile of the annual average HI value for a Class I area assuming normal distribution. Thus, no average natural con centrations are provided for determining extinction for the 20% best visibility days.

For background extinction computati on methods 2, 3, and 6 in CALPOST, background extinction is calcula ted with user-supplied m onthly concentrations of SO4, NO3, PM coarse, organic carbon, soil, and elemental carbon species. In practice, concentrations for only 2 speci es, SO4 ([BKSO4]) and soil ([BKSOIL]), are supplied in the CALPOST input file to represent hygroscopic and nonhygroscopic portions of backgr ound extinction, respectively.

To determine background extinction for the BART analysis with CALPOST, average natural concentrations that repr esent average natural background visibility for the best 20% days need to be determined.

3.1.3.1.3. Natural Background - Method Following EPA's approach of using regional average natural concentrations and the concept of using simplified inputs in CA LPOST, the same hygroscopic (3[BKSO4]

best20 ) and non-hygroscopic ([BKSOIL] best20 ) values would be used in CALPOST for all Class I areas in Colorado's BART modeling.

The spreadsheet calculates an aver age background (dv) based on monthly background extinction (1/Mm) for each Cla ss I area in Colorado's BART modeling using the following equations:

1. Monthly background extinction in 1/Mm (bext month ) = 3[BKSO4] best20 f(RH) + [BKSOIL] best20 + Rayleigh 2. Annual average background extinction in 1/Mm (bext annual_ave ) = (bext Jan + bext Feb + ... + bext Dec )/12 3. Calculated Best Da ys in dv = 10ln(bext annual_ave /10)

EPA guidance provides f(RH) values based on the centroid of the Class I area (see Appendix B – Monthly f(RH) Values ) and a Best Days (dv) value for each of the Class I areas (see Appendix A – Natural Background Values ).

The hygroscopic (3[BKSO4]) and non-hygrosco pic ([BKSOIL]) values determined yielded the lowest sum of the absolute di fferences between the published Best Days (dv) and calculated Best Days (dv) for all Class I areas in the analysis:

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 36Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



## ) ( ) ( 

## ∑

= 11

1n n n DaysBest calculated - DaysBest published Minimize

where: n = number of Cl ass I areas in analysis

The "hygro (3[BKSO4])” and "non-hygro ([BKSOIL])" values of 0.268 and 1.620 were calculated in Microsoft Excel using the "solver add-in" tool for optimization and equation solving ( Figure 14 ). As can be seen from the “difference” values in Figure 14 , the annual 20% best visibility days background concentrations for each Class I area calculated with this method are within 0.01 decivi ews or less of the annual 20% best visibility days back ground values recommended by EPA. For CALPOST, the hygroscopic component of ex tinction is divided by 3 (the extinction coefficient of sulfate and nitrate) a nd input as BKSO4 (i.e., BKSO4 = 0.268/3 = 0.0893). The non-hygroscopic component is us ed directly (i.e., BKSOIL = 1.620).

Figure 14. Spreadsheet showing the "hygro (3[BKSO4])" (0.268)and "nonhygro ([BKSOIL])" (1.620) values calc ulated in Microsoft Excel using the "solver add-in" tool for optimi zation and equation solving.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 37Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

3.1.3.2. CALPOST and POSTUTIL Parameters Two post-processing examples are provi ded. In example #1, fine particulate emissions are speciated into PMF, PMC, EC, SOA, and SO4 and explicitly included as species in CALPUFF. Emission rates fo r each species are included in CALPUFF. Figure 15 summarizes some of the key CALP OST settings. The monthly f(RH) values (RHFAC), which are different for each Class I area, are from Appendix B – Monthly f(RH) Values

.

Figure 15. CALPOST - key parame ters (example #1 setup).

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 38Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

In example #1, POSTUTIL is used to compute the partition for the total concentration fields with MNITRATE=1 and the appropriate ammonia background concentration. The ammonia background c oncentration, BCKNH3, in POSTUTIL is the same as the background value presented in section 3.1.2.8 . In POSTUIL, the input species include SO2, SO4, NOX, HN O3, NO3, SOA, PMF, PMC, and EC and the output species include SO4, HNO3, NO3, SOA, PMF, PMC, and EC. Key POSTUTIL parameters are shown in Figure 16

.

Figure 16. POSTUTIL - key pa rameters for cases with nitrate partitioning and speciated PM10 concentrat ions (example #1 setup).

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 39Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

In example #2, PM10 is included as a speci es in CALPUFF and ammonia limiting is performed with POSTUTIL. The example #2 CALPOST setup is the same as shown in example #1 (see Figure 15 ) except LVPMC=F, since there are is no coarse PM, and SPECPMF=SOIL because the PM10 emi ssions from CALPUFF are reallocated to the species SOIL and EC in the first of two POSTUTIL runs. The first POSTUTIL setup for example #2 (see Figure 17 ) is intended to provide a post-processing opportunity to divide the PM10 concentra tions into SOIL and EC components; however, in the setup example shown in Figure 17 , all of the PM10 is allocated to SOIL and none is allocated to EC.

Figure 17. POSTUTIL setup for simulati ons where PM10 is divided into SOIL and EC species (example #2 setup).

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 40Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

In the second POSTUTIL setup for exampl e #2, POSTUTIL is used to compute the partition for the total concentration fiel ds with MNITRATE=1 and the appropriate ammonia background concentration. The ammonia background concentration, BCKNH3, in POSTUTIL is the same as th e background value presented in section 3.1.2.8 . In this POSTUIL setup, the input species include SO4, NO3, HNO3, EC, SOIL, and SOA and the output species include SO4, NO3, HNO3, EC, SOIL, and SOA. Key POSTUTIL parameters are shown in Figure 16

.

Figure 18. POSTUTIL setup for simu lations where ammonia limiting is performed using the output file generated from the POSTUTIL setup in Figure 17 (example #2 setup).

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 41Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# 4. BART Analysis Modeling Process

The Division’s modeling approach mode ls all pollutants (i.e., direct PM, SO 2 , and NOx) from all BART-eligible units at a source in each CALPUFF run. The Division is not modeling unitby-unit and pollutant-by-pollutant impacts because looking at results from individual units and pollutants can, in some cases, provide misleading results.

Judicious selection of “pre-contr ol” and “post-control” scenarios is used to isolate specific units or pollutants.

For example: 1. Consider a source with one unit where a decision has already been made on SO 2 BART and only NOx BART controls are under ev aluation. In this case, it would be appropriate to compare the following two scenarios:

• Scenario #1 = Model pre-control emi ssions for NOx, pre-control emissions direct PM, and post-control (BART) emissions for SO 2

. • Scenario #2 = keep everything consta nt from Scenario #1 but model a NOx BART control scenario.

Impacts from the two scenario s above would then be compar ed to provide “degree of visibility improvement” results for the specified NOx control.

2. The situation becomes more complicated when a source has more than one unit. However, the same isolation method would be used. For example, consider a source with 3 units:

• Scenario #1

o Pre-control emissions for NOx and direct PM; SO 2 BART post-control emissions on unit 1

o Pre-control emissions for NOx and di rect PM; SO2 BART post-control emissions on unit 2

o Pre-control emissions fo r NOx, direct PM, and SO 2 on unit 3

• Scenario #2 = keep everything consta nt from Scenario #1 but add a NOx control for unit 2.

Impacts from the two scenarios above w ould isolate the degree of visibility improvement from the addition of NOx controls to unit 2.

A matrix of BART scenarios is established and the effects of BA RT controls are estimated for individual pollutants and individual units by us ing the isolation technique above. In addition, the cumulative impact for a given source fr om the total BART control strategy (e.g., SO 2 controls and NOx controls), as compared to pr e-control emissions, is ev aluated as appropriate.

The BART modeling process is summ arized in the following steps:

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 42Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Step A

. Model the pre-control emission rates for SO 2 , NOx, and direct PM emissions (e.g., filterable and condensable PM2.5 and PM10) from all BART-e ligible units at the s ource. This scenario becomes the pre-control “base case.”

Step B

. Model as many pre- and post-control scenarios as necessary to isolat e the desired units, pollutants, and BART scenarios. (Note: For each control scenario/str ategy evaluated, model SO 2 , NOx, and direct PM emissions together from all BART-eligible units at the facility.)

Step C

. As appropriate to complete the BART analysis , compare the pre-control (step A) with postcontrol (step B) results and/or compare various permutations to isolate specific units and specific pollutants.

There could be a large number of combinati ons if every unit, every pollutant, and every potential BART control is isolated with the steps above. Consequentl y, the Division may not conduct an exhaustive set of modeling analyses that examine every possible combination of potential BART controls if it is clear that the ev aluation of certain combin ations of controls are solely academic exercises. The Division will ex ercise reasonable professional judgment when deciding how many modeling analys es are necessary to character ize the degree of visibility improvement from the realistically viable BART scenarios. In additi on, the actual number of modeling analyses depends on how the modeli ng results are factored into the BART determination process. In cases where the weight given to modeling is relatively low compared to the weight given to other factors, a limited nu mber of modeling analyses may be adequate to satisfactorily complete the BART analysis process.



# 5. Reporting of Results for the Degree of Visibility Change

The metrics discussed in this section are in tended to help provide a common framework for quantifying the degree of change from control sc enarios/strategies. The BART analysis should discuss the recommended metrics in this section (plus others, as appropria te) and how the results have been factored into the BART determination process.

For this analysis, the magnitude (e.g., 98 th percentile delta-deciview impact) and frequency (e.g., days per year with impacts above 0.5 dv and 1.0 dv) for the pre-control and post-control scenario under evaluated are presented.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 43Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



### 5.1. 1 st 

### -High and 98 th 

### Percentile Metrics The BART guideline provided spec ific guidance on the use of 98 th percentile values for the subject-to-BART modeling:

... you should compare your “contribution” threshol d against the 98th percentile of values. If the 98 th percentile value from your modeling is less than your cont ribution threshold, then you may conclude that the source does not contribute to visibility impairment and is not subject to BART. (70 FR 39162)

The BART guideline did not recommend the use of a specific set of metrics for determining the degree of visibility improvement from BART.

As explained in more detail later, to dete rmine the degree of visi bility improvement from various BART scenarios, the Division will report the 98 th percentile value, as well as the number of days over 0.5 dv and the number of days over 1.0 dv.

For a 365-day simulation, the 98 th percentile value is the 8 th highest modeled delta-deciview value from the list of ranked delta-deciview va lues. That is, the top 7 days are ignored, even though the values being ignored may be at different receptors.

The use of the 8 th high value for a given year to represent the 98 th percentile value, as recommended by U.S. EPA, is consistent with the values that would be generated from the equations in 40 CFR 50 Appendix N - “Interpret ation of the National Ambient Air Quality Standards for PM2.5” – for determining 98 th percentile values for PM2.5 monitoring.



### 5.2. Metrics for Characterizing the Change in Visibility Impacts According to U.S. EPA Region 8, “to show th e change in visibility impact between scenarios the most important metric to provi de would be the delta -deciview between pre and post control 98th percentile impacts for each scenario in the thre e modeling years. Also provide the number of days exceeding .5 and 1 deciview.”

In addition to the approach recommended by U.S. EPA, the Division may use other metrics, if appropriate, to describe the exp ected degree of visibility change from each BART scenario.



### 5.3. Postprocessor for Generating Metrics The Division’s BART postprocessor from 2005 and 2006, which was described in the April 15, 2010 draft protocol, was not used because the newer versions of CALPOST provide results in a more convenient format than older versions of the postprocessor.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 44Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# 6. References

Escoffier-Czaja, Christelle and J. Scire, 2002. “The Effects of Ammoni a Limitation on Nitrate Aerosol Formation and Visibility Impacts in Class I Areas.” Earth Tech, Inc., Extended abstract. 12th Joint Conference on the A pplications of Air Polluti on Meteorology with the Air and Waste Management Association , Norfolk, VA, Amer. Meteor. Soc, J5.13.

Douglas, S. and R. Kessler, 1988. User's Guide to the Diagnostic Wind Model (Version 1.0). Systems Applications, Inc., San Rafael, CA.

“Federal Land Manager’s Air Quality Relate d Values Workgroup (FLAG): Phase I Report,” U.S. Forest Service, National Park Service, U.S. Fish and Wildlife Service, December 2000.

“Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule.” EPA454/B-03-005. September 2003.

“Guidance for Tracking Progress Under the Re gional Haze Rule.” U.S. EPA, EPA-454/B-03- 004. September 2003.

“Interagency Workgroup on Air Quality M odeling (IWAQM) Phase 2 Summary Report and Recommendations for Modeling Long Range Transport Impacts.” EPA-454/R-98-019, December 1998.

“Mt. Zirkel Wilderness Area Reasonable Attrib ution Study of Visibility Impairment. Volume II: Results of Data Analysis and Modeling - Final Report.” Prep ared by John G. Watson, et al, Prepared for Colorado Department of Public Health and Environment, 1996.

“Northern Front Range Air Qu ality Study Final Report.” Pr epared for Colorado State University, Prepared by John G. Watson, Eric Fujita, Judith C. C how Barbara Zielinska (Desert Research Institute), L. Willard Richards (Sonoma Technology, Inc.), William Neff (NOAA), David Dietrich (Air Reso urce Specialists, Inc.), 1998.

Scire J.S., D.G. Strimaitis, R.J. Yamartino. “A User's Guide for the CALPUFF Dispersion Model.” Earth Tech, Concord, MA, January 2000.

Scire J.S., F. Robe, F.E.. Fernau, R.J. Yamartino. “A User's Guide for the CALMET Meteorological Model.” Earth Tech, Concord, MA, January 2000.

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 45Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# Appendix A – Natural Background Values

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 46Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 47Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 48Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 49Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 50Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 51Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 52Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 53Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# Appendix B – Monthly f(RH) Values

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 54Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 55Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling (DRAFT)Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services ProgramApril 15, 2010 (revised June 25, 2010 and August 19, 2010) 56Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling (DRAFT)Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services ProgramApril 15, 2010 (revised June 25, 2010 and August 19, 2010) 57Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling (DRAFT)Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services ProgramApril 15, 2010 (revised June 25, 2010 and August 19, 2010) 58Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling (DRAFT)Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services ProgramApril 15, 2010 (revised June 25, 2010 and August 19, 2010) 59Supplemental BART Analysis CALPUFF Protocol for Class I Federal Area Visibility Improvement Modeling (DRAFT)Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services ProgramApril 15, 2010 (revised June 25, 2010 and August 19, 2010) 60Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)



# Appendix C – Sample CALMET File

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 61Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Sample CALMET file ---------------- Run title (3 lines) ------------------------------------------

CALMET MODEL CONTROL FILE

--------------------------

-------------------------------------------------------------------------------

INPUT GROUP: 0 -- Input and Output File Names

Subgroup (a)

------------ Default Name Type File Name

------------ ---- --------- GEO.DAT input ! GEODAT= geo4km.DAT ! SURF.DAT input ! SRFDAT= surf01.DAT ! CLOUD.DAT input * CLDDAT= * PRECIP.DAT input ! PRCDAT= PRECIP01.DAT ! WT.DAT input * WTDAT= *

CALMET.LST output ! METLST= APR01.LST ! CALMET.DAT output ! METDAT= APR01.DAT ! PACOUT.DAT output * PACDAT= *

All file names will be converted to lower case if LCFILES = T Otherwise, if LCFILES = F, file names will be converted to UPPER CASE T = lower case ! LCFILES = T !

F = UPPER CASE

NUMBER OF UPPER AIR & OVERWATER STATIONS:

Number of upper air stations (NUSTA) No default ! NUSTA = 1 ! Number of overwater met stations (NOWSTA) No default ! NOWSTA = 0 !

NUMBER OF PROGNOSTIC and IGF-CALMET FILEs:

Number of MM4/MM5/3D.DAT files (NM3D) No default ! NM3D = 1 !

Number of IGF-CALMET.DAT files (NIGF) No default ! NIGF = 0 !

!END!

-------------------------------------------------------------------------------

- Subgroup (b)

--------------------------------- Upper air files (one per station)

--------------------------------- Default Name Type File Name

------------ ---- --------- UP1.DAT input 1 ! UPDAT= UPden01.DAT! !END!

-------------------------------------------------------------------------------

-

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 62Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Subgroup (c)

----------------------------------------- Overwater station files (one per station)

----------------------------------------- Default Name Type File Name

------------ ---- ---------

-------------------------------------------------------------------------------

- Subgroup (d)

------------------------------------------------ MM4/MM5/3D.DAT files (consecutive or overlapping)

------------------------------------------------ Default Name Type File Name

------------ ---- --------- MM51.DAT input 1 ! M3DDAT= APR01.MM5 ! !END!

-------------------------------------------------------------------------------

- Subgroup (e)

------------------------------------------------- IGF-CALMET.DAT files (consecutive or overlapping)

------------------------------------------------- Default Name Type File Name

------------ ---- --------- IGFn.DAT input 1 * IGFDAT=CALMET0.DAT * *END*

-------------------------------------------------------------------------------

- Subgroup (f)

---------------- Other file names

----------------

Default Name Type File Name

------------ ---- --------- DIAG.DAT input * DIADAT= * PROG.DAT input * PRGDAT= *

TEST.PRT output * TSTPRT= * TEST.OUT output * TSTOUT= * TEST.KIN output * TSTKIN= * TEST.FRD output * TSTFRD= * TEST.SLP output * TSTSLP= * DCST.GRD output * DCSTGD= *

-------------------------------------------------------------------------------

- NOTES: (1) File/path names can be up to 70 characters in length (2) Subgroups (a) and (f) must have ONE 'END' (surrounded by delimiters) at the end of the group (3) Subgroups (b) through (e) are included ONLY if the corresponding number of files (NUSTA, NOWSTA, NM3D, NIGF) is not 0, and each must have an 'END' (surround by delimiters) at the end of EACH LINE

!END!

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 63Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

-------------------------------------------------------------------------------

INPUT GROUP: 1 -- General run control parameters

--------------

Starting date: Year (IBYR) -- No default ! IBYR= 2001 ! Month (IBMO) -- No default ! IBMO= 4 ! Day (IBDY) -- No default ! IBDY= 1 ! Hour (IBHR) -- No default ! IBHR= 0 !

Note: IBHR is the time at the END of the first hour of the simulation (IBHR=1, the first hour of a day, runs from 00:00 to 01:00)

Base time zone (IBTZ) -- No default ! IBTZ= 7 ! PST = 08, MST = 07 CST = 06, EST = 05

Length of run (hours) (IRLG) -- No default ! IRLG= 720 !

Run type (IRTYPE) -- Default: 1 ! IRTYPE= 1 !

0 = Computes wind fields only 1 = Computes wind fields and micrometeorological variables (u*, w*, L, zi, etc.) (IRTYPE must be 1 to run CALPUFF or CALGRID)

Compute special data fields required by CALGRID (i.e., 3-D fields of W wind components and temperature) in additional to regular Default: T ! LCALGRD = T ! fields ? (LCALGRD) (LCALGRD must be T to run CALGRID)

Flag to stop run after SETUP phase (ITEST) Default: 2 ! ITEST= 2 ! (Used to allow checking of the model inputs, files, etc.) ITEST = 1 - STOPS program after SETUP phase ITEST = 2 - Continues with execution of COMPUTATIONAL phase after SETUP

Test options specified to see if they conform to regulatory values? (MREG) No Default ! MREG = 1 !

0 = NO checks are made 1 = Technical options must conform to USEPA guidance IMIXH -1 Maul-Carson convective mixing height over land; OCD mixing height overwater ICOARE 0 OCD deltaT method for overwater fluxes THRESHL 0.0 Threshold buoyancy flux over land needed to sustain convective mixing height growth

!END!

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 64Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

-------------------------------------------------------------------------------

INPUT GROUP: 2 -- Map Projection and Grid control parameters

--------------

Projection for all (X,Y):

-------------------------

Map projection (PMAP) Default: UTM ! PMAP = LCC !

UTM : Universal Transverse Mercator TTM : Tangential Transverse Mercator LCC : Lambert Conformal Conic PS : Polar Stereographic EM : Equatorial Mercator LAZA : Lambert Azimuthal Equal Area

False Easting and Northing (km) at the projection origin (Used only if PMAP= TTM, LCC, or LAZA) (FEAST) Default=0.0 ! FEAST = 0.000 ! (FNORTH) Default=0.0 ! FNORTH = 0.000 !

UTM zone (1 to 60) (Used only if PMAP=UTM) (IUTMZN) No Default ! IUTMZN = -999 !

Hemisphere for UTM projection? (Used only if PMAP=UTM) (UTMHEM) Default: N ! UTMHEM = N ! N : Northern hemisphere projection S : Southern hemisphere projection

Latitude and Longitude (decimal degrees) of projection origin (Used only if PMAP= TTM, LCC, PS, EM, or LAZA) (RLAT0) No Default ! RLAT0 = 38.4N ! (RLON0) No Default ! RLON0 = 105.5W !

TTM : RLON0 identifies central (true N/S) meridian of projection RLAT0 selected for convenience LCC : RLON0 identifies central (true N/S) meridian of projection RLAT0 selected for convenience PS : RLON0 identifies central (grid N/S) meridian of projection RLAT0 selected for convenience EM : RLON0 identifies central meridian of projection RLAT0 is REPLACED by 0.0N (Equator) LAZA: RLON0 identifies longitude of tangent-point of mapping plane RLAT0 identifies latitude of tangent-point of mapping plane

Matching parallel(s) of latitude (decimal degrees) for projection (Used only if PMAP= LCC or PS) (XLAT1) No Default ! XLAT1 = 36.4N ! (XLAT2) No Default ! XLAT2 = 40.5N !

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 65Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

LCC : Projection cone slices through Earth's surface at XLAT1 and
XLAT2 PS : Projection plane slices through Earth at XLAT1 (XLAT2 is not used)

---------- Note: Latitudes and longitudes should be positive, and include a letter N,S,E, or W indicating north or south latitude, and east or west longitude. For example, 35.9 N Latitude = 35.9N 118.7 E Longitude = 118.7E

Datum-region

------------

The Datum-Region for the coordinates is identified by a character string. Many mapping products currently available use the model of the Earth known as the World Geodetic System 1984 (WGS-84). Other local models may be in use, and their selection in CALMET will make its output consistent with local mapping products. The list of Datum-Regions with official transformation parameters is provided by the National Imagery and Mapping Agency (NIMA).

NIMA Datum - Regions(Examples)

--------------------------------------------------------------------------

---- WGS-84 WGS-84 Reference Ellipsoid and Geoid, Global coverage (WGS84) NAS-C NORTH AMERICAN 1927 Clarke 1866 Spheroid, MEAN FOR CONUS (NAD27) NAR-C NORTH AMERICAN 1983 GRS 80 Spheroid, MEAN FOR CONUS (NAD83) NWS-84 NWS 6370KM Radius, Sphere ESR-S ESRI REFERENCE 6371KM Radius, Sphere

Datum-region for output coordinates (DATUM) Default: WGS-84 ! DATUM = NAR-C !

Horizontal grid definition:

---------------------------

Rectangular grid defined for projection PMAP, with X the Easting and Y the Northing coordinate

No. X grid cells (NX) No default ! NX = 127 ! No. Y grid cells (NY) No default ! NY = 172 !

Grid spacing (DGRIDKM) No default ! DGRIDKM = 4. ! Units: km

Reference grid coordinate of SOUTHWEST corner of grid cell (1,1)

X coordinate (XORIGKM) No default ! XORIGKM = -253.0 ! Y coordinate (YORIGKM) No default ! YORIGKM = -348.0 ! Units: km

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 66Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Vertical grid definition:

-------------------------

No. of vertical layers (NZ) No default ! NZ = 11 !

Cell face heights in arbitrary vertical grid (ZFACE(NZ+1)) No defaults Units: m ! ZFACE = 0.,20.,40.,80.,160.,320.,640.,1200.,2000.,3000.,4000.,5000. !

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 3 -- Output Options

--------------

DISK OUTPUT OPTION

Save met. fields in an unformatted output file ? (LSAVE) Default: T ! LSAVE = T ! (F = Do not save, T = Save)

Type of unformatted output file: (IFORMO) Default: 1 ! IFORMO = 1 !

1 = CALPUFF/CALGRID type file (CALMET.DAT) 2 = MESOPUFF-II type file (PACOUT.DAT)

LINE PRINTER OUTPUT OPTIONS:

Print met. fields ? (LPRINT) Default: F ! LPRINT = F ! (F = Do not print, T = Print) (NOTE: parameters below control which met. variables are printed)

Print interval (IPRINF) in hours Default: 1 ! IPRINF = 1 ! (Meteorological fields are printed every 1 hours)

Specify which layers of U, V wind component to print (IUVOUT(NZ)) -- NOTE: NZ values must be entered (0=Do not print, 1=Print) (used only if LPRINT=T) Defaults: NZ*0 ! IUVOUT = 11*0 !

-----------------------

Specify which levels of the W wind component to print (NOTE: W defined at TOP cell face -- 10 values) (IWOUT(NZ)) -- NOTE: NZ values must be entered

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 67Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

(0=Do not print, 1=Print) (used only if LPRINT=T & LCALGRD=T)

----------------------------------- Defaults: NZ*0 ! IWOUT = 11*0 !

Specify which levels of the 3-D temperature field to print (ITOUT(NZ)) -- NOTE: NZ values must be entered (0=Do not print, 1=Print) (used only if LPRINT=T & LCALGRD=T)

----------------------------------- Defaults: NZ*0 ! ITOUT = 11*0 !

Specify which meteorological fields to print (used only if LPRINT=T) Defaults: 0 (all variables)

-----------------------

Variable Print ? (0 = do not print, 1 = print)

-------- ------------------

! STABILITY = 0 ! - PGT stability class ! USTAR = 0 ! - Friction velocity ! MONIN = 0 ! - Monin-Obukhov length ! MIXHT = 0 ! - Mixing height ! WSTAR = 0 ! - Convective velocity scale ! PRECIP = 0 ! - Precipitation rate ! SENSHEAT = 0 ! - Sensible heat flux ! CONVZI = 0 ! - Convective mixing ht.

Testing and debug print options for micrometeorological module

Print input meteorological data and internal variables (LDB) Default: F ! LDB = F ! (F = Do not print, T = print) (NOTE: this option produces large amounts of output)

First time step for which debug data are printed (NN1) Default: 1 ! NN1 = 1 !

Last time step for which debug data are printed (NN2) Default: 1 ! NN2 = 1 !

Print distance to land internal variables (LDBCST) Default: F ! LDBCST = F ! (F = Do not print, T = print) (Output in .GRD file DCST.GRD, defined in input group 0)

Testing and debug print options for wind field module (all of the following print options control output to

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wind field module's output files: TEST.PRT, TEST.OUT, TEST.KIN, TEST.FRD, and TEST.SLP)

Control variable for writing the test/debug wind fields to disk files (IOUTD) (0=Do not write, 1=write) Default: 0 ! IOUTD = 0 !

Number of levels, starting at the surface, to print (NZPRN2) Default: 1 ! NZPRN2 = 0 !

Print the INTERPOLATED wind components ? (IPR0) (0=no, 1=yes) Default: 0 ! IPR0 = 0 !

Print the TERRAIN ADJUSTED surface wind components ? (IPR1) (0=no, 1=yes) Default: 0 ! IPR1 = 0 !

Print the SMOOTHED wind components and the INITIAL DIVERGENCE fields ? (IPR2) (0=no, 1=yes) Default: 0 ! IPR2 = 0 !

Print the FINAL wind speed and direction fields ? (IPR3) (0=no, 1=yes) Default: 0 ! IPR3 = 0 !

Print the FINAL DIVERGENCE fields ? (IPR4) (0=no, 1=yes) Default: 0 ! IPR4 = 0 !

Print the winds after KINEMATIC effects are added ? (IPR5) (0=no, 1=yes) Default: 0 ! IPR5 = 0 !

Print the winds after the FROUDE NUMBER adjustment is made ? (IPR6) (0=no, 1=yes) Default: 0 ! IPR6 = 0 !

Print the winds after SLOPE FLOWS are added ? (IPR7) (0=no, 1=yes) Default: 0 ! IPR7 = 0 !

Print the FINAL wind field components ? (IPR8) (0=no, 1=yes) Default: 0 ! IPR8 = 0 !

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 4 -- Meteorological data options

--------------

NO OBSERVATION MODE (NOOBS) Default: 0 ! NOOBS = 0 ! 0 = Use surface, overwater, and upper air stations 1 = Use surface and overwater stations (no upper air observations) Use MM4/MM5/3D for upper air data 2 = No surface, overwater, or upper air observations

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 69Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Use MM4/MM5/3D for surface, overwater, and upper air data

NUMBER OF SURFACE & PRECIP. METEOROLOGICAL STATIONS

Number of surface stations (NSSTA) No default ! NSSTA = 25 !

Number of precipitation stations (NPSTA=-1: flag for use of MM5/3D precip data) (NPSTA) No default ! NPSTA = 91 !

CLOUD DATA OPTIONS Gridded cloud fields: (ICLOUD) Default: 0 ! ICLOUD = 0 ! ICLOUD = 0 - Gridded clouds not used ICLOUD = 1 - Gridded CLOUD.DAT generated as OUTPUT ICLOUD = 2 - Gridded CLOUD.DAT read as INPUT ICLOUD = 3 - Gridded cloud cover computed from prognostic fields

FILE FORMATS

Surface meteorological data file format (IFORMS) Default: 2 ! IFORMS = 2 ! (1 = unformatted (e.g., SMERGE output)) (2 = formatted (free-formatted user input))

Precipitation data file format (IFORMP) Default: 2 ! IFORMP = 2 ! (1 = unformatted (e.g., PMERGE output)) (2 = formatted (free-formatted user input))

Cloud data file format (IFORMC) Default: 2 ! IFORMC = 2 ! (1 = unformatted - CALMET unformatted output) (2 = formatted - free-formatted CALMET output or user input)

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 5 -- Wind Field Options and Parameters

--------------

WIND FIELD MODEL OPTIONS Model selection variable (IWFCOD) Default: 1 ! IWFCOD = 1 ! 0 = Objective analysis only 1 = Diagnostic wind module

Compute Froude number adjustment effects ? (IFRADJ) Default: 1 ! IFRADJ = 1 ! (0 = NO, 1 = YES)

Compute kinematic effects ? (IKINE) Default: 0 ! IKINE = 0 ! (0 = NO, 1 = YES)

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Use O'Brien procedure for adjustment of the vertical velocity ? (IOBR) Default: 0 ! IOBR = 0 ! (0 = NO, 1 = YES)

Compute slope flow effects ? (ISLOPE) Default: 1 ! ISLOPE = 1 ! (0 = NO, 1 = YES)

Extrapolate surface wind observations to upper layers ? (IEXTRP) Default: -4 ! IEXTRP = -4 ! (1 = no extrapolation is done, 2 = power law extrapolation used, 3 = user input multiplicative factors for layers 2 - NZ used (see FEXTRP array) 4 = similarity theory used -1, -2, -3, -4 = same as above except layer 1 data at upper air stations are ignored

Extrapolate surface winds even if calm? (ICALM) Default: 0 ! ICALM = 0 ! (0 = NO, 1 = YES)

Layer-dependent biases modifying the weights of surface and upper air stations (BIAS(NZ)) -1<=BIAS<=1 Negative BIAS reduces the weight of upper air stations (e.g. BIAS=-0.1 reduces the weight of upper air stations by 10%; BIAS= -1, reduces their weight by 100 %) Positive BIAS reduces the weight of surface stations (e.g. BIAS= 0.2 reduces the weight of surface stations by 20%; BIAS=1 reduces their weight by 100%) Zero BIAS leaves weights unchanged (1/R**2 interpolation) Default: NZ*0 ! BIAS = 11*0 !

Minimum distance from nearest upper air station to surface station for which extrapolation of surface winds at surface station will be allowed (RMIN2: Set to -1 for IEXTRP = 4 or other situations where all surface stations should be extrapolated) Default: 4. ! RMIN2 = -1 !

Use gridded prognostic wind field model output fields as input to the diagnostic wind field model (IPROG) Default: 0 ! IPROG = 14 ! (0 = No, [IWFCOD = 0 or 1] 1 = Yes, use CSUMM prog. winds as Step 1 field, [IWFCOD = 0] 2 = Yes, use CSUMM prog. winds as initial guess field [IWFCOD = 1] 3 = Yes, use winds from MM4.DAT file as Step 1 field [IWFCOD = 0] 4 = Yes, use winds from MM4.DAT file as initial guess field [IWFCOD = 1] 5 = Yes, use winds from MM4.DAT file as observations [IWFCOD = 1] 13 = Yes, use winds from MM5/3D.DAT file as Step 1 field [IWFCOD = 0] 14 = Yes, use winds from MM5/3D.DAT file as initial guess field [IWFCOD = 1] 15 = Yes, use winds from MM5/3D.DAT file as observations [IWFCOD = 1]

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 71Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Timestep (hours) of the prognostic model input data (ISTEPPG) Default: 1 ! ISTEPPG = 1 !

Use coarse CALMET fields as initial guess fields (IGFMET) (overwrites IGF based on prognostic wind fields if any) Default: 0 ! IGFMET = 0 !

RADIUS OF INFLUENCE PARAMETERS

Use varying radius of influence Default: F ! LVARY = F! (if no stations are found within RMAX1,RMAX2, or RMAX3, then the closest station will be used)

Maximum radius of influence over land in the surface layer (RMAX1) No default ! RMAX1 = 100. ! Units: km Maximum radius of influence over land aloft (RMAX2) No default ! RMAX2 = 200. ! Units: km Maximum radius of influence over water (RMAX3) No default ! RMAX3 = 200. ! Units: km

OTHER WIND FIELD INPUT PARAMETERS

Minimum radius of influence used in the wind field interpolation (RMIN) Default: 0.1 ! RMIN = 0.1 ! Units: km Radius of influence of terrain features (TERRAD) No default ! TERRAD = 15. !

Units: km Relative weighting of the first guess field and observations in the SURFACE layer (R1) No default ! R1 = 50. ! (R1 is the distance from an Units: km observational station at which the observation and first guess field are equally weighted)

Relative weighting of the first guess field and observations in the layers ALOFT (R2) No default ! R2 = 100. ! (R2 is applied in the upper layers Units: km in the same manner as R1 is used in the surface layer).

Relative weighting parameter of the prognostic wind field data (RPROG) No default ! RPROG = 0. ! (Used only if IPROG = 1) Units: km

------------------------

Maximum acceptable divergence in the divergence minimization procedure

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 72Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

(DIVLIM) Default: 5.E-6 ! DIVLIM= 5.0E-06

!

Maximum number of iterations in the divergence min. procedure (NITER) Default: 50 ! NITER = 50 !

Number of passes in the smoothing procedure (NSMTH(NZ)) NOTE: NZ values must be entered Default: 2,(mxnz-1)*4 ! NSMTH = 2, 10*4 !

Maximum number of stations used in each layer for the interpolation of data to a grid point (NINTR2(NZ)) NOTE: NZ values must be entered Default: 99. ! NINTR2 = 11*99

!

Critical Froude number (CRITFN) Default: 1.0 ! CRITFN = 1. !

Empirical factor controlling the influence of kinematic effects (ALPHA) Default: 0.1 ! ALPHA = 0.1 !

Multiplicative scaling factor for extrapolation of surface observations to upper layers (FEXTR2(NZ)) Default: NZ*0.0 ! FEXTR2 = 11*0. ! (Used only if IEXTRP = 3 or -3)

BARRIER INFORMATION

Number of barriers to interpolation of the wind fields (NBAR) Default: 0 ! NBAR = 0 !

Level (1 to NZ) up to which barriers apply (KBAR) Default: NZ ! KBAR = 11 !

THE FOLLOWING 4 VARIABLES ARE INCLUDED ONLY IF NBAR > 0 NOTE: NBAR values must be entered No defaults for each variable Units: km

X coordinate of BEGINNING of each barrier (XBBAR(NBAR)) ! XBBAR = 0. ! Y coordinate of BEGINNING of each barrier (YBBAR(NBAR)) ! YBBAR = 0. !

X coordinate of ENDING of each barrier (XEBAR(NBAR)) ! XEBAR = 0. ! Y coordinate of ENDING of each barrier (YEBAR(NBAR)) ! YEBAR = 0. !

DIAGNOSTIC MODULE DATA INPUT OPTIONS

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 73Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Surface temperature (IDIOPT1) Default: 0 ! IDIOPT1 = 0 ! 0 = Compute internally from hourly surface observations 1 = Read preprocessed values from a data file (DIAG.DAT)

Surface met. station to use for the surface temperature (ISURFT) No default ! ISURFT = 9 !
*DEN* (Must be a value from 1 to NSSTA) (Used only if IDIOPT1 = 0)

--------------------------

Domain-averaged temperature lapse rate (IDIOPT2) Default: 0 ! IDIOPT2 = 0 ! 0 = Compute internally from twice-daily upper air observations 1 = Read hourly preprocessed values from a data file (DIAG.DAT)

Upper air station to use for the domain-scale lapse rate (IUPT) No default ! IUPT = 1 ! (Must be a value from 1 to NUSTA) (Used only if IDIOPT2 = 0)

--------------------------

Depth through which the domain-scale lapse rate is computed (ZUPT) Default: 200. ! ZUPT = 200. ! (Used only if IDIOPT2 = 0) Units: meters

--------------------------

Domain-averaged wind components (IDIOPT3) Default: 0 ! IDIOPT3 = 0 ! 0 = Compute internally from twice-daily upper air observations 1 = Read hourly preprocessed values a data file (DIAG.DAT)

Upper air station to use for the domain-scale winds (IUPWND) Default: -1 ! IUPWND = -1 ! (Must be a value from -1 to NUSTA) (Used only if IDIOPT3 = 0)

--------------------------

Bottom and top of layer through which the domain-scale winds are computed (ZUPWND(1), ZUPWND(2)) Defaults: 1., 1000. ! ZUPWND= 1., 1000.

! (Used only if IDIOPT3 = 0) Units: meters

--------------------------

Observed surface wind components for wind field module (IDIOPT4) Default: 0 ! IDIOPT4 = 0 ! 0 = Read WS, WD from a surface data file (SURF.DAT)

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 74Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

1 = Read hourly preprocessed U, V from a data file (DIAG.DAT)

Observed upper air wind components for wind field module (IDIOPT5) Default: 0 ! IDIOPT5 = 0 ! 0 = Read WS, WD from an upper air data file (UP1.DAT, UP2.DAT, etc.) 1 = Read hourly preprocessed U, V from a data file (DIAG.DAT)

LAKE BREEZE INFORMATION

Use Lake Breeze Module (LLBREZE) Default: F ! LLBREZE = F !

Number of lake breeze regions (NBOX) ! NBOX = 0 !

X Grid line 1 defining the region of interest ! XG1 = 0. ! X Grid line 2 defining the region of interest ! XG2 = 0. ! Y Grid line 1 defining the region of interest ! YG1 = 0. ! Y Grid line 2 defining the region of interest ! YG2 = 0. !

X Point defining the coastline (Straight line) (XBCST) (KM) Default: none ! XBCST = 0. !

Y Point defining the coastline (Straight line) (YBCST) (KM) Default: none ! YBCST = 0. !

X Point defining the coastline (Straight line) (XECST) (KM) Default: none ! XECST = 0. !

Y Point defining the coastline (Straight line) (YECST) (KM) Default: none ! YECST = 0. !

Number of stations in the region Default: none ! NLB = 0 ! (Surface stations + upper air stations)

Station ID's in the region (METBXID(NLB)) (Surface stations first, then upper air stations) ! METBXID = 0 !

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 6 -- Mixing Height, Temperature and Precipitation Parameters

--------------

EMPIRICAL MIXING HEIGHT CONSTANTS

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 75Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

Neutral, mechanical equation (CONSTB) Default: 1.41 ! CONSTB = 1.41 ! Convective mixing ht. equation (CONSTE) Default: 0.15 ! CONSTE = 0.15 ! Stable mixing ht. equation (CONSTN) Default: 2400. ! CONSTN = 2400.! Overwater mixing ht. equation (CONSTW) Default: 0.16 ! CONSTW = 0.16 ! Absolute value of Coriolisparameter (FCORIOL) Default: 1.E-4 ! FCORIOL = 1.0E04! Units: (1/s)

SPATIAL AVERAGING OF MIXING HEIGHTS

Conduct spatial averaging (IAVEZI) (0=no, 1=yes) Default: 1 ! IAVEZI = 1 !

Max. search radius in averaging process (MNMDAV) Default: 1 ! MNMDAV = 1 ! Units: Grid cells Half-angle of upwind looking cone for averaging (HAFANG) Default: 30. ! HAFANG = 30. ! Units: deg. Layer of winds used in upwind averaging (ILEVZI) Default: 1 ! ILEVZI = 1 ! (must be between 1 and NZ)

CONVECTIVE MIXING HEIGHT OPTIONS: Method to compute the convective mixing height(IMIHXH) Default: 1 ! IMIXH = -1 ! 1: Maul-Carson for land and water cells -1: Maul-Carson for land cells only - OCD mixing height overwater 2: Batchvarova and Gryning for land and water cells -2: Batchvarova and Gryning for land cells only OCD mixing height overwater

Threshold buoyancy flux required to sustain convective mixing height growth overland (THRESHL) Default: 0.05 ! THRESHL = 0. ! (expressed as a heat flux units: W/m3 per meter of boundary layer)

Threshold buoyancy flux required to sustain convective mixing height growth overwater (THRESHW) Default: 0.05 ! THRESHW = 0.05 ! (expressed as a heat flux units: W/m3 per meter of boundary layer)

Option for overwater lapse rates used in convective mixing height growth

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 76Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

(ITWPROG) Default: 0 ! ITWPROG = 0 ! 0 : use SEA.DAT lapse rates and deltaT (or assume neutral conditions if missing) 1 : use prognostic lapse rates (only if IPROG>2) and SEA.DAT deltaT (or neutral if missing) 2 : use prognostic lapse rates and prognostic delta T (only if iprog>12 and 3D.DAT version# 2.0 or higher)

Land Use category ocean in 3D.DAT datasets (ILUOC3D) Default: 16 ! ILUOC3D = 16 ! Note: if 3D.DAT from MM5 version 3.0, iluoc3d = 16 if MM4.DAT, typically iluoc3d = 7

OTHER MIXING HEIGHT VARIABLES

Minimum potential temperature lapse rate in the stable layer above the current convective mixing ht. Default: 0.001 ! DPTMIN = 0.001 ! (DPTMIN) Units: deg. K/m Depth of layer above current conv. mixing height through which lapse Default: 200. ! DZZI = 200. ! rate is computed (DZZI) Units: meters

Minimum overland mixing height Default: 50. ! ZIMIN = 50. ! (ZIMIN) Units: meters Maximum overland mixing height Default: 3000. ! ZIMAX = 4500. ! (ZIMAX) Units: meters Minimum overwater mixing height Default: 50. ! ZIMINW = 50. ! (ZIMINW) -- (Not used if observed Units: meters overwater mixing hts. are used) Maximum overwater mixing height Default: 3000. ! ZIMAXW = 4500. ! (ZIMAXW) -- (Not used if observed Units: meters overwater mixing hts. are used)

OVERWATER SURFACE FLUXES METHOD and PARAMETERS (ICOARE) Default: 10 ! ICOARE = 0 ! 0: original deltaT method (OCD) 10: COARE with no wave parameterization (jwave=0, Charnock) 11: COARE with wave option jwave=1 (Oost et al.) and default wave properties -11: COARE with wave option jwave=1 (Oost et al.) and observed wave properties (must be in SEA.DAT files) 12: COARE with wave option 2 (Taylor and Yelland) and default wave properties -12: COARE with wave option 2 (Taylor and Yelland) and observed wave properties (must be in SEA.DAT files)

Coastal/Shallow water length scale (DSHELF) (for modified z0 in shallow water) ( COARE fluxes only) Default : 0. ! DSHELF = 0. ! units: km

COARE warm layer computation (IWARM) ! IWARM = 0 !

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 77Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

1: on - 0: off (must be off if SST measured with IR radiometer) Default: 0

COARE cool skin layer computation (ICOOL) ! ICOOL = 0 ! 1: on - 0: off (must be off if SST measured with IR radiometer) Default: 0

TEMPERATURE PARAMETERS

3D temperature from observations or from prognostic data? (ITPROG) Default:0 ! ITPROG = 0 !

0 = Use Surface and upper air stations (only if NOOBS = 0) 1 = Use Surface stations (no upper air observations) Use MM5/3D for upper air data (only if NOOBS = 0,1) 2 = No surface or upper air observations Use MM5/3D for surface and upper air data (only if NOOBS = 0,1,2)

Interpolation type (1 = 1/R ; 2 = 1/R**2) Default:1 ! IRAD = 1 !

Radius of influence for temperature interpolation (TRADKM) Default: 500. ! TRADKM = 500.

! Units: km

Maximum Number of stations to include in temperature interpolation (NUMTS) Default: 5 ! NUMTS = 5 !

Conduct spatial averaging of temp- eratures (IAVET) (0=no, 1=yes) Default: 1 ! IAVET = 1 ! (will use mixing ht MNMDAV,HAFANG so make sure they are correct)

Default temperature gradient Default: -.0098 ! TGDEFB = - 0.0098 ! below the mixing height over Units: K/m water (TGDEFB)

Default temperature gradient Default: -.0045 ! TGDEFA = - 0.0045 ! above the mixing height over Units: K/m water (TGDEFA)

Beginning (JWAT1) and ending (JWAT2) land use categories for temperature ! JWAT1 = 55 ! interpolation over water -- Make ! JWAT2 = 55 ! bigger than largest land use to disable

PRECIP INTERPOLATION PARAMETERS

Method of interpolation (NFLAGP) Default: 2 ! NFLAGP = 2 !

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 78Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

(1=1/R,2=1/R**2,3=EXP/R**2) Radius of Influence (SIGMAP) Default: 100.0 ! SIGMAP = 100. ! (0.0 => use half dist. btwn Units: km nearest stns w & w/out precip when NFLAGP = 3) Minimum Precip. Rate Cutoff (CUTP) Default: 0.01 ! CUTP = 0.01 ! (values < CUTP = 0.0 mm/hr) Units: mm/hr

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 7 -- Surface meteorological station parameters

--------------

SURFACE STATION VARIABLES (One record per station -- 25 records in all)

1 2 Name ID X coord. Y coord. Time Anem. (km) (km) zone Ht.(m)

---------------------------------------------------------- ! SS1 ='AKO ' 24698 193.159 198.973 7 10 ! ! SS2 ='ALS ' 24620 -32.336 -106.860 7 10 ! ! SS3 ='APA ' 24666 55.922 130.041 7 10 ! ! SS4 ='ASE ' 24676 -118.091 92.190 7 10 ! ! SS5 ='CAG ' 25700 -171.322 234.404 7 10 ! ! SS6 ='CAO ' 23600 210.283 -214.114 7 10 ! ! SS7 ='COS ' 24660 68.475 45.993 7 10 ! ! SS8 ='CYS ' 25640 58.198 306.332 7 10 ! ! SS9 ='DEN ' 25650 72.093 159.306 7 10 ! ! SS10 ='DHT ' 22636 266.176 -259.412 7 10 ! ! SS11 ='DRO ' 24625 -200.668 -136.973 7 10 ! ! SS12 ='EOO ' 24674 -203.468 185.599 7 10 ! ! SS13 ='FMN ' 23658 -243.657 -180.141 7 10 ! ! SS14 ='LAA ' 24636 246.555 -32.844 7 10 ! ! SS15 ='LAR ' 25645 -14.616 323.319 7 10 ! ! SS16 ='LHX ' 24635 173.058 -36.818 7 10 ! ! SS17 ='LIC ' 24665 154.047 89.075 7 10 ! ! SS18 ='LVS ' 23677 32.391 -304.593 7 10 ! ! SS19 ='LXV ' 24673 -70.429 92.179 7 10 ! ! SS20 ='MTJ ' 24765 -208.969 14.367 7 10 ! ! SS21 ='PUB ' 24640 87.574 -11.726 7 10 ! ! SS22 ='RIL ' 25717 -191.319 127.284 7 10 ! ! SS23 ='SAF ' 23656 -53.382 -308.617 7 10 ! ! SS24 ='SNY ' 25610 211.364 302.733 7 10 ! ! SS25 ='TAD ' 24645 102.806 -125.906 7 10 !

------------------- 1 Four character string for station name (MUST START IN COLUMN 9)

2 Six digit integer for station ID

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 79Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 8 -- Upper air meteorological station parameters

--------------

UPPER AIR STATION VARIABLES (One record per station -- 1 records in all)

1 2 Name ID X coord. Y coord. Time zone (km) (km)

----------------------------------------------- ! US1 ='DEN ' 23062 59.101 152.186 7 !

------------------- 1 Four character string for station name (MUST START IN COLUMN 9)

2 Five digit integer for station ID

!END!

-------------------------------------------------------------------------------

INPUT GROUP: 9 -- Precipitation station parameters

--------------

PRECIPITATION STATION VARIABLES (One record per station -- 91 records in all) (NOT INCLUDED IF NPSTA = 0)

1 2 Name Station X coord. Y coord. Code (km) (km)

------------------------------------

! PS1 ='WY01' 481675 85.74 299.06 ! ! PS2 ='WY02' 483050 -81.49 303.46 ! ! PS3 ='WY03' 484930 -42.89 294.26 ! ! PS4 ='WY04' 485420 10.07 308.59 ! ! PS5 ='WY05' 487200 100.45 331.46 ! ! PS6 ='WY06' 487240 118.50 300.60 ! ! PS7 ='WY07' 487995 -81.29 322.34 ! ! PS8 ='NM01' 290041 -68.41 -250.45 ! ! PS9 ='NM02' 290407 27.86 -236.26 ! ! PS10 ='NM03' 291887 216.54 -233.47 ! ! PS11 ='NM04' 291982 -63.65 -334.85 ! ! PS12 ='NM05' 292030 126.63 -349.69 ! ! PS13 ='NM06' 292241 -97.39 -264.59 ! ! PS14 ='NM07' 292700 30.57 -240.69 !

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 80Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

! PS15 ='NM08' 292837 -84.37 -225.89 ! ! PS16 ='NM09' 293142 -237.62 -216.24 ! ! PS17 ='NM10' 294862 34.58 -341.69 ! ! PS18 ='NM11' 296275 41.42 -252.85 ! ! PS19 ='NM12' 297279 111.01 -204.49 ! ! PS20 ='NM13' 297638 125.17 -313.06 ! ! PS21 ='NM14' 298085 -8.19 -336.20 ! ! PS22 ='NM15' 298501 102.51 -241.22 ! ! PS23 ='NM16' 299031 -146.20 -322.71 ! ! PS24 ='NE01' 257827 245.44 301.36 ! ! PS25 ='CO01' 050109 205.46 190.22 ! ! PS26 ='CO02' 050130 -1.77 -126.46 ! ! PS27 ='CO03' 050183 15.34 191.98 ! ! PS28 ='CO04' 050263 -3.46 66.56 ! ! PS29 ='CO05' 050372 -86.44 79.24 ! ! PS30 ='CO06' 050843 28.16 179.81 ! ! PS31 ='CO07' 051179 122.18 116.33 ! ! PS32 ='CO08' 051401 86.31 91.44 ! ! PS33 ='CO09' 051443 -177.73 17.50 ! ! PS34 ='CO10' 051539 192.94 -35.41 ! ! PS35 ='CO11' 051547 86.12 109.20 ! ! PS36 ='CO12' 051713 -83.95 -13.98 ! ! PS37 ='CO13' 051778 93.29 10.53 ! ! PS38 ='CO14' 051959 -94.98 14.98 ! ! PS39 ='CO15' 052162 126.59 109.74 ! ! PS40 ='CO16' 052211 84.30 118.05 ! ! PS41 ='CO17' 052220 84.30 118.05 ! ! PS42 ='CO18' 052354 25.52 206.44 ! ! PS43 ='CO19' 052790 26.70 108.77 ! ! PS44 ='CO20' 052965 28.75 16.69 ! ! PS45 ='CO21' 053005 38.23 216.49 ! ! PS46 ='CO22' 053007 31.41 222.01 ! ! PS47 ='CO23' 053386 30.98 113.23 ! ! PS48 ='CO24' 053500 -1.70 189.75 ! ! PS49 ='CO25' 053553 91.89 204.72 ! ! PS50 ='CO26' 053579 91.69 73.75 ! ! PS51 ='CO27' 053584 91.60 81.51 ! ! PS52 ='CO28' 053662 -94.38 -8.32 ! ! PS53 ='CO29' 054155 123.78 178.51 ! ! PS54 ='CO30' 054172 191.07 78.84 ! ! PS55 ='CO31' 054293 31.88 104.35 ! ! PS56 ='CO32' 054388 257.89 -35.82 ! ! PS57 ='CO33' 054538 204.78 -122.78 ! ! PS58 ='CO34' 054720 191.26 -38.78 ! ! PS59 ='CO35' 054742 19.17 15.55 ! ! PS60 ='CO36' 054877 11.18 117.61 ! ! PS61 ='CO37' 055121 34.93 194.27 ! ! PS62 ='CO38' 055352 81.93 12.62 ! ! PS63 ='CO39' 055484 -177.53 180.65 ! ! PS64 ='CO40' 055706 -54.91 -116.29 ! ! PS65 ='CO41' 055765 32.72 109.91 ! ! PS66 ='CO42' 055881 14.51 179.77 ! ! PS67 ='CO43' 055922 169.01 219.33 ! ! PS68 ='CO44' 055982 -59.29 239.94 ! ! PS69 ='CO45' 056023 87.41 224.66 ! ! PS70 ='CO46' 056136 181.79 -7.93 !

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 81Supplemental BART Analysis CALPUFF Pr otocol for Class I Federal Area Vi sibility Improvement Modeling (DRAFT)

! PS71 ='CO47' 056203 -166.75 -41.54 ! ! PS72 ='CO48' 056740 105.09 -24.83 ! ! PS73 ='CO49' 057031 -170.64 103.90 ! ! PS74 ='CO50' 057296 5.94 224.17 ! ! PS75 ='CO51' 057320 83.01 -92.76 ! ! PS76 ='CO52' 057337 -50.88 -38.67 ! ! PS77 ='CO53' 057428 23.10 -143.07 ! ! PS78 ='CO54' 057519 257.30 90.70 ! ! PS79 ='CO55' 057560 199.88 106.81 ! ! PS80 ='CO56' 057572 31.85 -107.54 ! ! PS81 ='CO57' 057664 125.39 76.43 ! ! PS82 ='CO58' 058064 -62.20 83.45 ! ! PS83 ='CO59' 058204 -178.35 -90.12 ! ! PS84 ='CO60' 058220 41.80 -150.76 ! ! PS85 ='CO61' 058429 107.51 -142.40 ! ! PS86 ='CO62' 058436 103.98 -144.66 ! ! PS87 ='CO63' 058781 92.05 -111.52 ! ! PS88 ='CO64' 058997 126.35 -96.64 ! ! PS89 ='CO65' 059096 -52.91 179.94 ! ! PS90 ='CO66' 059210 37.21 71.09 ! ! PS91 ='CO67' 059285 117.67 13.06 !

------------------- 1 Four character string for station name (MUST START IN COLUMN 9)

2 Six digit station code composed of state code (first 2 digits) and station ID (last 4 digits)

!END!

Colorado Department of Public Health & Environment / Air Pollution Control Division / Technical Services Program April 15, 2010 (revised June 25, 2010 and August 19, 2010) 82