Prepared for: Prepared by: 

CalPortland Company AECOM 

Rillito, AZ Chelmsford, MA 

60282724 

May 2013

Environment

Reasonable Progress Analysis for 

CalPortland Company Rillito Cement 

Plant Kilns 
Prepared for: Prepared by: 

CalPortland Company AECOM 

Rillito, AZ Chelmsford, MA 

60282724 

May 2013

Environment

Reasonable Progress Analysis for 

CalPortland Company Rillito Cement 

Plant Kilns 

_________________________________ 

Prepared By: Robert R. Hall 

_________________________________ 

Prepared By: Robert J. Paine 

_________________________________ 

Reviewed By: Steven L. Heisler 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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Contents 

Executive Summary ............................................................................................... ES-1 

1.0 Introduction ............................................................................................................... 1-1

2.0 Facility Description and Baseline Emissions ........................................................... 2-1

2.1 Facility Description ......................................................................................................2-1

2.2 Kiln NOx Emissions .....................................................................................................2-2

3.0 Reasonable Progress Analysis (Steps 1-3) .............................................................. 3-1

3.1 Identification of Technologies (Step 1) and Technical Feasibility (Step 2) ......................3-1

3.1.1 Low NOx Burners with Indirect Firing Systems ...............................................3-1

3.1.2 Mid-Kiln Firing ...............................................................................................3-1

3.1.3 Mixing Air Technologies.................................................................................3-1

3.1.4 Preheater Riser Duct Firing............................................................................3-2

3.1.5 Low NOx Calciner .........................................................................................3-2

3.1.6 Selective Non-Catalytic Reduction .................................................................3-2

3.1.7 Selective Catalytic Reduction .........................................................................3-3

3.1.8 Conclusion ....................................................................................................3-3

3.2 Emission Control Effectiveness (Step 3) .......................................................................3-3

3.2.1 Kilns 1, 2, and 3 ............................................................................................3-3

3.2.2 Kiln 4 ............................................................................................................3-4

4.0 Four Factor Impact Analysis (Step 4) ....................................................................... 4-1

4.1 Factor One: Costs of Compliance ...............................................................................4-1

4.1.1 Kilns 1-3 .......................................................................................................4-1

4.1.2 Kiln 4 ............................................................................................................4-1

4.2 Cost of Compliance Summary (Factor 1) .................................................................... 4-11

4.3 Time Necessary for Compliance (Factor 2) ................................................................ 4-11

4.4 Energy and Non-Air Quality Environmental Impacts (Factor 3) .................................... 4-11

4.5 Remaining Useful Life (Factor 4) ................................................................................ 4-11

4.6 Preliminary Conclusions for Step 4 ............................................................................ 4-12

5.0 CALPUFF Modeling Procedures ............................................................................... 5-1

5.1 CALMET Processing ...................................................................................................5-1

5.2 CALPUFF Model Formulation for Predicting Visibility Impairment ..................................5-3

5.3 Ammonia Background Concentrations .........................................................................5-3
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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5.4 CALPUFF Modeling Procedures ..................................................................................5-6

5.5 Modeled Control Scenarios .........................................................................................5-8

5.6 POSTUTIL Post-Processing ...................................................................................... 5-11

5.7 CALPOST Post-Processing ....................................................................................... 5-11

6.0 CALPUFF Modeling Results ..................................................................................... 6-1

7.0 Conclusions for Visibility Improvement Analysis .................................................... 7-1

Appendix A CALMET/CALPUFF Processing Refinements 

List of Tables 

Table 2-1: CalPortland Cement Plant Kiln Descriptions................................................................2-1

Table 2-2: Kilns 1, 2, and 3 NOx Emissions* ...............................................................................2-2

Table 2-3: Kiln 4 NOx Emissions ................................................................................................2-2

Table 3-1: NOx Control Technologies and Potential Application for Rillito Cement Kilns ................3-3

Table 4-1: Low NOx Burner with Indirect Firing System Kiln 1, 2, or 3 ..........................................4-3

Table 4-2: Mid-Kiln Firing for Kiln 1, 2, or 3 ..................................................................................4-5

Table 4-3: SNCR with Mixing Air Technologies for Kiln 1, 2, or 3 ..................................................4-7

Table 4-4: SNCR for Kiln 4 .........................................................................................................4-9

Table 4-5: Cost of Compliance ................................................................................................. 4-11

Table 5-1: Background Monthly Ammonia Concentrations Used in the Modeling (ppb) .................5-5

Table 5-2: Modeled Stack Parameters for Kilns 1-3 and Kiln 4 .....................................................5-8

Table 5-3: Emissions Modeled for Base Case and Three Control Scenarios for Kilns 1-3 ............ 5-10

Table 5-4: Emissions Modeled for Base Case and Three Control Scenarios for Kiln 4 ................ 5-10

Table 6-1: 98th Percentile Visibility Impairment for Base Case Scenario and Three RP Control 

Case Scenarios (delta-dv) ..........................................................................................6-1

Table 6-2: Visibility Improvement for the Three RP Control Case Scenarios Relative to the Base 

Case Scenario (deciviews) .........................................................................................6-2

List of Figures 

Figure 2-1: CalPortland Company – Rillito Plant ...........................................................................2-1

Figure 5-1: Rillito Kiln Modeling Domain .......................................................................................5-2
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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Figure 5-2: IMPROVE NHx Concentrations from April 2011 to January 2012 .................................5-5

Figure 5-3: 2009 IMPROVE Composition Data for Saguaro East National Park .............................5-5

Figure 5-4: Class I Areas Within 300 km of the Rillito Facility ........................................................5-7

Figure 6-1: 22nd Highest Visibility Impacts Averaged Over 3 Years for the Base Case Scenario and 

Three RP Control Case Scenarios (delta-dv) ..............................................................6-3

Figure 6-2: Visibility Improvements of the Three RP Control Case Scenarios Relative to the Base 

Case Scenario (deciviews) .........................................................................................6-4
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

ES-1

Executive Summary 

A Reasonable Progress (RP) Analysis has been conducted for the Rillito cement plant, located in 

Rillito, Arizona, which is owned and operated by CalPortland Company (CPC). The cement plant has 

four kilns. Kilns 1-3, which are long dry kilns, are not BART-eligible. Kiln 4 is a preheater/precalciner 

kiln that ADEQ has determined, and EPA has proposed to concur, is BART-exempt because it does 

not contribute to visibility impacts. 

The key pollutant at issue is nitrogen oxides (NOx) emissions. The RP analysis presented in this 

report was conducted using a similar analytical framework used by EPA in its RP analysis for its 

Regional Haze Federal Implementation Plan for Montana (Federal Register, Volume 77, No. 96, 

Page 23988, April 20, 2012)1.. The steps considered were as follows: 

Step 1 – Identify all available retrofit control technologies with a practical potential for application to the 

emissions unit and pollutant under evaluation. 

Step 2 – Eliminate technically infeasible options considering whether or not they have been installed 

and operated successfully on the type of source under review, could be applied to the source under 

review and the commercial availability of the technology. 

Step 3 – Evaluate the control effectiveness of the remaining technologies. 

Step 4 – Evaluate impacts: of total annual and incremental costs, time necessary for compliance, 

energy and non-air quality environmental impacts, remaining useful life and visibility, as needed. 

Step 5 – Select Reasonable Progress controls based upon the analysis of the Step 4 factors. 

The available NOx emission controls, their expected performance, and costs are summarized in Table 

ES-1. 

Table ES-2 presents a summary of the Step 4 four-factor RP Analysis for Kilns 1, 2, and 3. The 

results of the RP Analysis for Kiln 4 are presented in Table ES-3. 

As part of the Reasonable Progress analysis, a visibility improvement modeling review was conducted 

for all Prevention of Significant Deterioration Class I areas within 300 km of the plant, using the 

CALPUFF model. The modeling overstates visibility benefits because it does not account for excess 

ammonia emissions that would be associated with SNCR controls. 

The results of this analysis indicate that all candidate controls result in levels of visibility improvement 

that are far too low to be measured by the available technology for particulate monitors (much less 

than 0.3 delta-deciview) and less than 12 percent of the perceptible levels that can be visually 

detected (1 deciview). The visibility improvement associated with SNCR controls on the active Kiln 4, 

which is BART-exempt due to its low impacts, is about 0.1 delta-deciview, a level which is mentioned 

in the 1999 Regional Haze Rule as being associated with “no degradation” of visibility. Accordingly, 

we conclude that none of these Reasonable Progress options is sufficiently effective to replace the 

current NOx emission controls on the CalPortland kilns in Rillito, AZ. 

 

1

 Like EPA’s RP analysis for Montana, CalPortland’s RP analysis follows the analytical framework for determining 

case-by-case BART set forth in 40 CFR Part 51, Appendix Y. 
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

ES-2

Table ES- 1: Available NOx Emission Controls, Performance, and Cost 

Table ES- 2: NOx Reasonable Progress Analysis for Rillito Kilns 1, 2, and 3 

Cost of Compliance 

Kilns 1, 2, and 3 are very small, long dry kilns with good combustion 

practices used for NOx control. The effectiveness of available NOx 

controls is low and the cost effectiveness is high, in the $7,137 to 

$7,988 per ton range. 

Time Necessary for 

Compliance 

Several years would be required to design, permit and then construct 

any control equipment. 

Energy and Non-Air Quality 

Environmental Impacts of 

Compliance 

All technically feasible controls (low NOx burners, mid-kiln firing, 

mixing air technologies, and SNCR) would increase energy usage. 

With respect to SNCR, the storage, transport, and use of urea or 

ammonia create the potential for hazardous spills and ammonia slip. 

Remaining useful life 

The remaining useful life is unknown and unknowable at this time. 

CalPortland has an application pending to modernize its facility and 

permanently shutdown these kilns. Whether CalPortland moves 

forward with this modernization once the application is processed will 

depend on the state of the economy at that time. For the purposes 

of this analysis, we conservatively assumed a 20 year useful life 

Conclusion 

Given that the cost effectiveness for NOx emission reductions at 

these non-BART, units which have not operated for several years, is 

greater than $7,000/ton and that the visibility benefits of emissions 

reductions would be imperceptible and insignificant, CalPortland 

proposes no new NOx emission controls for these kilns. 
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

ES-3

Table ES- 3: NOx Reasonable Progress Analysis for Rillito Kiln 4 

Cost of Compliance 

Kiln 4 is a preheater/precalciner unit with NOx emissions already 

controlled by low NOx burners and preheater riser duct firing. The 

effectiveness of additional available NOx controls is low and the cost 

effectiveness is $2,464/ton. 

Time Necessary for 

Compliance 

Several years would be required to design, permit, and then construct 

SNCR.NOx emission controls could be installed by 2018. 

Energy and Non-Air 

Quality Environmental 

Impacts of Compliance 

SNCR would increase energy usage. Storage, transport, and use of 

urea or ammonia create the potential for hazardous spills and 

ammonia slip. 

Remaining useful life The remaining useful life may be in excess of 20 years. 

Conclusion 

Given that the cost effectiveness for NOx emission reductions at this 

non-BART unit is $2,464/ton and that the visibility benefits of 

emissions reductions would be very small, CalPortland proposes no 

additional NOx emission controls for this kiln. 
AECOM 

Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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1.0 Introduction 

A Reasonable Progress (RP) Analysis has been conducted for the Rillito cement plant, located in 

Rillito, Arizona, which is owned and operated by CalPortland Company (CPC). This document 

describes the procedures by which a Reasonable Progress engineering review and visibility 

improvement analysis has been conducted. 

The focus of this analysis is limited to nitrogen oxides (NOx) emissions for two reasons. First, 

particulate matter (PM) and sulfur dioxide (SO2) emissions are very low. Second, emissions of PM 

and acid gases are subject to the Portland Cement MACT rule (40 CFR Part 63 Subpart LLL) which 

was finalized on February 12, 2013 with a September 15, 2015 compliance date. As the name 

indicates, this rule requires the use of maximum achievable control technology to control emissions of 

PM and acid gases. Because compliance with MACT requirements is generally considered sufficient 

for BART2, it is sufficient for RP as well. 

The RP analysis presented in this report follows the procedures used by US EPA in its Regional Haze 

Federal Implementation Plan for Montana (Federal Register, Volume 77, No. 96, Page 23988, April 

20, 2012). US EPA’s RP analysis includes four specific steps as listed below: 

x Step 1: Identify all available technologies 

x Step 2: Eliminate technically infeasible options 

x Step 3: Evaluate control effectiveness of the feasible control technologies 

x Step 4: Evaluate impacts and document results 

The factors considered by US EPA in the Montana analysis for the Step 4 RP analysis were: 

x Factor 1: Costs of compliance 

x Factor 2: Time necessary for compliance 

x Factor 3: Energy and non-air quality environmental impacts of compliance 

x Factor 4: Remaining useful life 

x Factor 5: Modeled visibility impacts 

Before any RP controls are proposed, “the projected visibility benefit of the controls should be taken 

into account when determining if the controls are needed to make reasonable progress.” See EPA’s 

proposed action on Arizona’s SIP (Federal Register, Volume 77, No. 246, Page 75704, December 21, 

2012). Accordingly, CalPortland has elected to provide such an analysis, using the EPA-approved 

CALPUFF model. 

 

2

The US Environmental Protection Agency’s (EPA) July 6, 2005 Best Available Retrofit Technology (BART) Guideline (Federal 

Register Volume 70, No. 128) states: “Unless there are new technologies subsequent to the MACT standards which would 

lead to cost effective increases in the level of control, you may rely on the MACT standards for purposes of BART.”
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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This report documents the RP analysis conducted for NOx emissions from the Rillito cement kilns. 

Section 2 provides a description of the kilns and their baseline emissions. Section 3 provides Steps 1-

3. Section 4 provides a discussion of four of the RP analysis factors, focusing upon conclusions 

based upon the engineering analysis (not including the visibility benefit analysis, which is described in 

later sections). Section 5 provides an explanation of the CALPUFF visibility modeling. Section 6 

provides the results of the CALPUFF visibility modeling. Further Reasonable Progress conclusions 

based upon the visibility improvement analysis are presented in Section 7.
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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2.0 Facility Description and Baseline Emissions 

2.1 Facility Description 

The CalPortland facility, shown in Figure 2-1 has three long dry kilns and one preheater/precalciner 

kiln. The years that the kilns came on-line and the rated production capacities are shown in Table 2-1. 

The three long dry kilns, Kilns 1-3, are very small, non-BART kilns that are more than 50 years old 

and have not been operated since January 2008. Kiln 4 is BART-exempt due to its lack of visibility 

impacts. All four kilns have baghouses for control of particulate emissions. 

Figure 2-1: CalPortland Company – Rillito Plant 

Table 2-1: CalPortland Cement Plant Kiln Descriptions 

Year on Line Primary Fuel Type Capacity, ton/day

1949 Coal Long DRY 415

1951 Coal Long DRY 415

1955 Coal Long DRY 415

2002 Coal Precalciner 3233
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2.2 Kiln NOx Emissions 

Kilns 1, 2, and 3 do rely on good combustion practices to control NOx emissions. NOx emissions 

from Kiln 4 are controlled by low NOx burners with indirect firing and preheater riser duct firing. Table 

2-2 summarizes NOx emissions data for Kilns 1, 2, and 3, while Table 2-3 summarizes NOx 

emissions for Kiln 4. The recent relatively high pounds per ton (lb/ton) of clinker emission rates for 

Kiln 4 are attributable to operation at low clinker production rates. 

Table 2-2: Kilns 1, 2, and 3 NOx Emissions* 

*Note that 2003 data is for a partial year of operation 

Table 2-3: Kiln 4 NOx Emissions 

Clinker 

Produced

Clinker /day 

Average

Clinker 

Produced

Clinker /day 

Average

Clinker 

Produced Clinker /day Clinker Produced

Clinker /day 

Average

NOx 

Produced

NOx / 

Clinker

Tons Tons Tons Tons Tons Tons Tons Tons Tons lb/Ton

2003 63,949 328 64,790 339 70,705 361 199,443 987 956 9.65 

2004 105,410 313 117,571 334 133,483 378 356,464 977 1,836 10.36 

2005 102,311 308 121,411 355 119,278 360 342,999 945 1,939 11.35 

2006 116,483 322 118,053 345 133,779 367 368,314 1,009 1,933 10.58 

2007 127,867 374 116,576 354 113,428 349 357,871 994 1,758 10.04 

2008 6,836 263 17,210 366 6,475 341 30,521 649 148 9.54 

2009 - - - - - - - - - - 

2010 - - - - - - - - - - 

2011 - - - - - - - - - - 

2012 - - - - - - - - - - 

Year

Kiln 1 Kiln 2 Kiln 3 Kilns 1, 2, 3

Clinker 

Produced

Clinker /day 

Average

NOx 

Produced

NOx / 

Clinker

Tons Tons Tons lb/Ton

2003 585,813 2,914 1,311 4.51 Last 1/2 of the year

2004 1,062,124 3,009 2,128 3.99 

2005 991,769 2,875 1,714 3.47 

2006 1,025,652 3,034 1,862 3.65 

2007 1,033,261 3,021 1,748 3.57 

2008 1,031,530 3,043 1,932 3.76 Kilns 1, 2, 3 shutdown 

after first 2 months

2009 466,445 2,549 1,085 4.73 

2010 681,963 2,024 1,947 5.75 

2011 606,935 2,003 1,630 5.44 

2012 652,774 2,382 1,586 5.86 First 10 months of the 

year

Kiln 4

Comments Year
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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3.0 Reasonable Progress Analysis (Steps 1-3) 

3.1 Identification of Technologies (Step 1) and Technical Feasibility (Step 2) 

The following options have been identified as possible retrofit NOx emission control technologies for 

cement kilns: 

x Low NOx burner with an indirect firing system; 

x Mid kiln firing; 

x Mixing air technologies; 

x Preheater riser duct firing; 

x Low NOx calciner; 

x Selective non-catalytic reduction; and 

x Selective catalytic reduction. 

3.1.1 Low NOx Burners with Indirect Firing Systems 

Low NOx burner designs reduce NOx emissions by reducing the peak burner flame temperature 

though the use of staged combustion. Typically, these burners introduce primary air at substoichiometric or near-stoichiometric ratios at the primary burner inlet, creating an oxygen starved 

flame resulting in a longer, less intense flame and a lower peak flame temperature. Secondary air 

inlets are used to complete the combustion process. In order to be reasonably effective, an indirect 

firing system is required. This technology is technically feasible for Kilns 1, 2, and 3 which are long 

dry kilns. Kiln 4 already uses low NOx burner technology with indirect firing. 

3.1.2 Mid-Kiln Firing 

Mid-kiln firing reduces NOx emissions by allowing less intense firing at the primary burner. Typically, 

whole tires, which burn at a relatively slow rate, are introduced at a mid-kiln location. This technology 

is technically feasible for Kilns 1, 2, and 3, which are long dry kilns. This specific technology cannot 

be applied to Kiln 4, because Kiln 4, like all preheater/precalciner kilns, uses a form of mid-kiln firing 

by adding supplemental fuel to the calciner (see riser duct firing). 

3.1.3 Mixing Air Technologies 

In long dry kilns, higher temperature oxygen-rich gases tend to travel along the top of the kiln while 

cooler, carbon dioxide-rich gases tend to travel along the bottom. When Mixing Air Technology is 

added, stratified kiln gases begin to rotate and mix. This technology is technically feasible for Kilns 1, 

2, and 3 which are long dry kilns. In preheater/precalciner kilns the stratified air can occur in the 

calciner after the riser duct firing. This results in areas of incomplete combustion. Mixing Air 

Technology is typically applied to the calciner with the goal to improve combustion air mixing and 

therefore reducing emissions. CPC has tried this technology on the Kiln 4 calciner using compressed 

air and nozzles as is typically done. However, the technology was found ineffective at reducing 

emissions from Kiln 4. 
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3.1.4 Preheater Riser Duct Firing 

Preheater riser duct firing is applicable to preheater/pre-calciner kilns. NOx formation occurs in the 

rotary kiln under oxidizing conditions. Fuel is then added to the kiln exhaust gas, in the kiln inlet, or in 

the kiln riser duct so that a reducing zone (a zone where less air is available than would be required 

for complete combustion) is created. This promotes the reduction of NOx to molecular oxygen. 

Finally, air is added in the upper part of the calciner, which completes fuel combustion. This 

technology is not technically feasible for Kilns 1, 2, and 3, which are long dry kilns. This technology is 

already applied to Kiln 4, which is a pre-calciner. 

3.1.5 Low NOx Calciner 

In a low NOx calciner, the fuel is injected into the kiln riser below where the tertiary air enters at the 

base of the calciner. This so-called reduction zone, sized for a particular gas retention time, has an 

oxygen deficient atmosphere that promotes NOx reduction. The optimum temperature in the zone is 

controlled by a material split from the second lowest stage between the calciner and the kiln riser. 

Above the reduction zone is the main calciner vessel, which is divided into two or more sections 

separated by a notch. The changes in cross-sectional areas create turbulence that ensures effective 

mixing of fuel, raw meal and gas, improving heat transfer and combustion. This technology is not 

technically feasible for Kilns 1, 2, and 3, which are long dry kilns. The application of this technology to 

Kiln 4 would require a complete rebuild of the calciner due in part to the height requirement of this 

technology and local seismic requirements that would be equivalent to redesigning the source. US 

EPA’s July 6, 2005 BART Guidelines (Federal Register, July 6, 2005, Volume 70, No. 128, Page 

39164) states that EPA does not consider BART as a requirement to re-design the source when 

considering available control alternatives. Therefore, this technology is not an available technology for 

Kiln 4. 

3.1.6 Selective Non-Catalytic Reduction 

Selective non-catalytic reduction (SNCR) is an add-on control technology that involves injection of 

aqueous or anhydrous ammonia (NH3), or urea, into a hot flue gas stream. The optimum temperature 

range for this reaction is 1,600oF to 1,900oF. Above 1,900oF, the amount of NH3 that oxidizes to NOx 

increases, and, in turn, the NOx reduction performance deteriorates. At temperatures at or below 

1,600oF, unreacted NH3 emissions may rapidly increase. The following factors influence the control 

effectiveness of SNCR: 

x Temperature and oxygen availability (i.e., the NH3 injection location); 

x The baseline, or uncontrolled NOx concentration; 

x Mixing; 

x Reagent Ratio (i.e., the NH3 to NOx molar ratio at the injection point); 

x NH3 accumulation; 

x Excess ammonia emissions; and 

x Ammonium salt formation. 

For SNCR to work effectively, the gas stream being treated must have a relatively high concentration 

of NOx as opposed to other potential reactants with which NOx would compete to react with NH3. The 

presence of competing reactants in the gas stream may result in less NH3 to convert NOx to its nonpolluting forms. This would reduce the effectiveness of the SNCR process. SNCR requires an 

oxidizing, or fuel-lean, atmosphere to effectively reduce NOx emissions. In a fuel-rich, or reducing 

environment, partially oxidized fuel (e.g., CO) competes with NH3 for OH* radicals, thus reducing NOx 

control effectiveness. SNCR is technically feasible for Kilns 1, 2, 3, and 4. 
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3.1.7 Selective Catalytic Reduction 

Like SNCR, Selective Catalytic Reduction (SCR) systems use NH3 to chemically convert NOx to 

molecular nitrogen (N2). SCR uses a catalyst to promote the selective reaction of NOx and ammonia. 

Ammonia injected into the gas stream reacts with NOx, and the SCR catalyst enables these reactions 

to occur at lower temperatures than are possible with SNCR and at nearly 100% ammonia utilization. 

While catalysts can operate over a range of temperatures, the optimal temperature range for SCR 

applications is between 570o to 750oF, well below the 1,600oF to 1,900oF temperature range for 

SNCR reactions discussed previously. SCR has been widely applied to gas turbines and boilers, but 

not to cement plants. The only known application of SCR to cement kilns is in Europe. Experience 

has shown SCR operating problems primarily due to dust poisoning of the catalysts and did not 

demonstrate that SCR was more effective than SNCR.3 Therefore, SCR is not considered to be 

technically feasible for Kilns 1, 2, 3, or 4. 

3.1.8 Conclusion 

Table 3-1 summarizes the available control technologies and their potential application for 

CalPortland’s cement kilns: 

Table 3-1: NOx Control Technologies and Potential Application for Rillito Cement Kilns 

Control Technology Kilns 1 through 3 Kiln 4 

Low NOx burner with an indirect 

firing system 

Technically Feasible In Use 

Mid-kiln firing Technically Feasible Infeasible 

Mixing air technologies Technically Feasible Ineffective 

Preheater riser duct firing Not Applicable In Use 

Low NOx calciner Not Applicable Infeasible 

Selective non-catalytic reduction Technically Feasible Technically Feasible 

Selective catalytic reduction Infeasible Infeasible 

3.2 Emission Control Effectiveness (Step 3) 

3.2.1 Kilns 1, 2, and 3 

Performance estimates for emission control options were based on CPC experience at implementing 

these controls on the two long dry kilns at its Colton plant and site-specific details for Kilns 1, 2, and 3. 

The estimated NOx control efficiencies are: 

x 20 percent for low NOx burner with indirect firing for Kilns 1, 2, and 3; 

 

3

 Schreiber, R. J., The Experience of SCR at Solnhofen and its Applicability to US Cement Plants, June 6, 2006. 
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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x 20 percent for mid-kiln firing with mixing air technologies for Kilns 1, 2, and 3; 

x 25 percent for SNCR with mixing air technologies for Kilns 1, 2, and 3; 

3.2.2 Kiln 4 

CalPortland estimates 30 percent NOx emission control based on its experience implementing SNCR 

for its similar preheater/precalciner kiln in Mohave, California. 
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4.0 Four Factor Impact Analysis (Step 4) 

This section discusses the four factors (other than the visibility impact analysis) considered in the 

Reasonable Progress impact (Step 4) analysis. 

4.1 Factor One: Costs of Compliance 

4.1.1 Kilns 1-3 

Capital costs were based on CPC’s experience at its other facilities, adjusted for Kiln 1, 2, and 3 

capacities and complexity, and factors from US EPA’s Air Pollution Control Cost Manual, Sixth Edition 

EPA/452/B-02-001, and January 2002. Total capital costs were estimated to be: 

x $2.4 million for low NOx burner with indirect firing for each kiln, 

x $1.4 million for mid-kiln firing with mixing air technologies for each kiln, and 

x $1.1 million for SNCR with mixing air technologies for each kiln. 

Direct operating costs and annual maintenance costs were based on CPC’s experience at its other 

facilities, adjusted for site specific factors. Electricity requirements were based on power for increased 

exhaust flow from the kilns as well as SNCR heating and pumping requirements. Electricity cost at 

Rillito is approximately $100/MWh. The reagent for SNCR was assumed to be 19 percent aqueous 

ammonia for safety reasons and because ammonia has been shown to be the most effective reagent. 

The delivered cost to Rillito of 19 percent aqueous ammonia was based on current pricing in the Los 

Angeles area, taxes, and freight charges. 

Indirect operating costs were based on the EPA Air Pollution Control Cost Manual. 

Total annualized costs were conservatively based on a 7 percent interest rate and 20 years as cited in 

the EPA Air Pollution Control Cost. For Kilns 1, 2, and 3, no limitation on the remaining useful life was 

assumed. 

The estimated cost effectiveness results are: 

x $7,137 per ton of NOx controlled for low NOx burner with indirect firing for each 

kiln; 

x $7,988 per ton of NOx controlled for mid-kiln firing with mixing air technologies for 

each kiln; 

x $7,946 per ton of NOx controlled for SNCR with mixing air technologies for each 

kiln. 

Detailed cost analyses are presented in Tables 4-1a, 4-1b, 4-2a, 4-2b, 4-3a, and 4-3b. 

4.1.2 Kiln 4 

The methodologies that were used for Kilns 1, 2, and 3 were also applied to Kiln 4. Specifically, 

CalPortland relied on its experience at its Mohave Facility, adjusted to reflect site-specific factors 

associated with Kiln 4. For the application of SNCR to Kiln 4, the results are: 
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Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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x 30 percent NOx emission control; 

x $1.34 million capital cost; 

x $2,464 per ton of NOx controlled. 

A detailed cost analysis is presented in Tables 4-4a and 4-4b. 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-3

Table 4-1: Low NOx Burner with Indirect Firing System Kiln 1, 2, or 3 

Table 4-1a: Capital Cost Basis 

DIRECT COSTS: 

PURCHASED EQUIPMENT 

 (a) Basic Equipment (BE) $1,533,333 

Includes indirect firing modifications and burner upgrade. Based on 

CalPortland Company’s Colton system escalated to 2013$ and adjusted for 

coal system capacity and complexity. 

 (b) Instrumentation & Controls $153,333 10% of BE, EPA Cost Control Manual 

 € Sales Tax $46,000 3% of BE, EPA Cost Control Manual 

 (d) Freight $76,667 5% of BE, EPA Cost Control Manual 

TOTAL PURCHASED EQUIPMENT (PE): $1,809,300 

DIRECT INSTALLATION 

 (a) Foundations and Support $144,744 8% of PE, EPA Cost Control Manual 

 (b) Handling and Erection $253,302 14% of PE, EPA Cost Control Manual 

 € Electrical $72,372 4% of PE, EPA Cost Control Manual 

 (d) Piping $36,186 2% of PE, EPA Cost Control Manual 

 € Insulation for Piping $18,093 1% of PE, EPA Cost Control Manual 

 (f) Painting $18,093 1% of PE, EPA Cost Control Manual 

TOTAL DIRECT INSTALLATION (DI): $542,790 

 Site Preparation $0 none required 

 Buildings $0 none required 

TOTAL DIRECT COST (TDC): $2,352,100 PE + DI + site preparation + buildings 

INDIRECT COSTS: 

INDIRECT INSTALLATION 

 (a) Engineering and Project Management $235,210 10% of TDC, EPA Cost Control Manual 

 (b) Construction & Field Expenses $117,605 5% of TDC, EPA Cost Control Manual 

 € Contractor Fees $235,210 10% of TDC, EPA Cost Control Manual 

 (d) Startup & Performance Tests $47,042 2% of TDC, EPA Cost Control Manual 

 € Downtime $0 

 (f) Contingencies $235,210 10% of TDC, CalPortland Company engineering judgment based on experience 

OTHER INDIRECT COSTS 

TOTAL INDIRECT COST: $870,300 

TOTAL CAPITAL COST: $3,222,400 

 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-4

 

Table 4-1b: Annualized Cost and Cost Effectiveness 

Low NOx Burner with Indirect Firing System Basis 

TOTAL CAPITAL COST: $3,222,400 

DIRECT OPERATING COSTS: 

Operating Labor $43,800 1.0 hr/shift at $40 per hour, CalPortland Company 

Maintenance Labor $64,400 2% of total capital cost, CalPortland Company 

Maintenance Materials $64,400 2% of total capital cost, CalPortland Company 

Electricity $300 kW for increased coal system exhaust & primary air power, CalPortland 

Company 

Electricity Annual Cost $236,520 $100/MWh, CalPortland Company 

Indirect Operating Costs 

Overhead $77,280 60% of Total Maintenance and Labor, EPA Cost Control Manual 

Property Tax $32,200 1% of Total Capital Cost, EPA Cost Control Manual 

Insurance $32,200 1% of Total Capital Cost, EPA Cost Control Manual 

Administration $64,400 2% of Total Capital Cost, EPA Cost Control Manual 

Capital Recovery $304,200 20 yr life, 7% interest rate, EPA Cost Control Manual 

TOTAL ANNUALIZED COST: $919,400 

Capacity, ton/day 415 

Annual Capacity Factor 90% 

NOx Emission Rate, lb/ton 9.45 

Maximum NOx Emissions before Control, ton/yr 644 

Control Efficiency, % 20% 

Controlled NOx Emission Rate, lb/ton 7.56 

NOx Emissions after Control, ton/yr 515 

NOx Emission Reduction, ton/yr 129 

COST EFFECTIVENESS ($/ton): $7,137 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-5

Table 4-2: Mid-Kiln Firing for Kiln 1, 2, or 3 

Table 4-2a: Capital Cost Basis 

DIRECT COSTS: 

PURCHASED EQUIPMENT 

 (a) Basic Equipment (BE) $666,667

Includes tire infeed and firing system and mixing air system. Based on 

CalPortland Company’s Colton system escalated to 2013$ and adjusted for 

tire system capacity and complexity. 

 (b) Instrumentation & Controls $66,667 10% of BE, EPA Cost Control Manual 

 (c) Sales Tax $20,000 3% of BE, EPA Cost Control Manual 

 (d) Freight $33,333 5% of BE, EPA Cost Control Manual 

TOTAL PURCHASED EQUIPMENT (PE): $786,700 

DIRECT INSTALLATION 

 (a) Foundations and Support $62,936 8% of PE, EPA Cost Control Manual 

 (b) Handling and Erection $110,138 14% of PE, EPA Cost Control Manual 

 (c) Electrical $31,468 4% of PE, EPA Cost Control Manual 

 (d) Piping $15,734 2% of PE, EPA Cost Control Manual 

 (e) Insulation for Piping $7,867 1% of PE, EPA Cost Control Manual 

 (f) Painting $7,867 1% of PE, EPA Cost Control Manual 

TOTAL DIRECT INSTALLATION (DI): $236,010 

 Site Preparation $0 none required 

 Buildings $0 none required 

TOTAL DIRECT COST (TDC): $1,022,700 PE + DI + site preparation + buildings 

INDIRECT COSTS: 

INDIRECT INSTALLATION 

 (a) Engineering and Project Management $102,270 10% of TDC, EPA Cost Control Manual 

 (b) Construction & Field Expenses $51,135 5% of TDC, EPA Cost Control Manual 

 (c) Contractor Fees $102,270 10% of TDC, EPA Cost Control Manual 

 (d) Startup & Performance Tests $20,454 2% of TDC, EPA Cost Control Manual 

 (e) Downtime $0 

 (f) Contingencies $102,270 10% 

OTHER INDIRECT COSTS 

TOTAL INDIRECT COST: $378,400 

TOTAL CAPITAL COST: $1,401,100 

 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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Table 4-2b: Annualized Cost and Cost Effectiveness

Mid-Kiln Firing for Kiln 1, 2, or 3 Basis 

TOTAL CAPITAL COST: $1,401,100 

DIRECT OPERATING COSTS: 

Operating Labor $43,800 1.0 hr/shift at $40 per hour, CalPortland Company 

Maintenance Labor $140,100 10% of total capital cost, CalPortland Company 

Maintenance Materials $210,200 15% of total capital cost, CalPortland Company 

Electricity 300 kW for increased coal system exhaust & primary air power, CalPortland 

Company 

Electricity Annual Cost $236,520 $100/MWh, CalPortland Company

Indirect Operating Costs 

Overhead $210,180 60% of Total Maintenance and Labor, EPA Cost Control Manual 

Property Tax $14,000 1% of Total Capital Cost, EPA Cost Control Manual 

Insurance $14,000 1% of Total Capital Cost, EPA Cost Control Manual 

Administration $28,000 2% of Total Capital Cost, EPA Cost Control Manual 

Capital Recovery $132,300 20 yr life, 7% interest rate, EPA Cost Control Manual 

TOTAL ANNUALIZED COST: $1,029,100 

Capacity, ton/day 415 

Annual Capacity Factor 90% 

NOx Emission Rate, lb/ton 9.45 

Current NOx Emissions, ton/yr 644 

Control Efficiency, % 20% 

Controlled NOx Emission Rate, lb/ton 7.56 

NOx Emissions after Control, ton/yr 515 

NOx Emission Reduction, ton/yr 129 

COST EFFECTIVENESS ($/ton): $7,988 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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Table 4-3: SNCR with Mixing Air Technologies for Kiln 1, 2, or 3 

Table 4-3a: Capital Cost Basis 

DIRECT COSTS: 

PURCHASED EQUIPMENT 

 (a) Basic Equipment (BE) $500,000

Includes mixing air system, plenum heater ammonia evaporation system, 

and injection system. Based on CalPortland Company’s Colton system 

escalated to 2013$. 

 (b) Instrumentation & Controls $50,000 10% of BE, EPA Cost Control Manual 

 (c) Sales Tax $15,000 3% of BE, EPA Cost Control Manual 

 (d) Freight $25,000 5% of BE, EPA Cost Control Manual 

TOTAL PURCHASED EQUIPMENT (PE): $590,000 

DIRECT INSTALLATION 

 (a) Foundations and Support $47,200 8% of PE, EPA Cost Control Manual 

 (b) Handling and Erection $82,600 14% of PE, EPA Cost Control Manual 

 (c) Electrical $23,600 4% of PE, EPA Cost Control Manual 

 (d) Piping $11,800 2% of PE, EPA Cost Control Manual 

 (e) Insulation for Piping $5,900 1% of PE, EPA Cost Control Manual 

 (f) Painting $5,900 1% of PE, EPA Cost Control Manual 

TOTAL DIRECT INSTALLATION (DI): $177,000 

 Site Preparation $0 none required 

 Buildings $0 none required 

TOTAL DIRECT COST (TDC): $767,000 PE + DI + site preparation + buildings 

INDIRECT COSTS: 

INDIRECT INSTALLATION 

 (a) Engineering and Project Management $76,700 10% of TDC, EPA Cost Control Manual 

 (b) Construction & Field Expenses $38,350 5% of TDC, EPA Cost Control Manual 

 (c) Contractor Fees $76,700 10% of TDC, EPA Cost Control Manual 

 (d) Startup & Performance Tests $15,340 2% of TDC, EPA Cost Control Manual 

 (e) Downtime $0 

 (f) Contingencies $76,700 10% 

OTHER INDIRECT COSTS 

TOTAL INDIRECT COST: $283,800 

TOTAL CAPITAL COST: $1,050,800 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-8

 

Table 4-3b: Annualized Cost and Cost Effectiveness

SNCR with Mixing Air Technologies for Kilns 1, 2, or 3 Basis 

TOTAL CAPITAL COST: $1,050,800 

DIRECT OPERATING COSTS: 

Operating Labor $43,800 1.0 hr/shift at $40 per hour, CalPortland Company 

Maintenance Labor $105,100 10% of total capital cost, CalPortland Company 

Maintenance Materials $157,600 15% of total capital cost, CalPortland Company 

Ammonia 238.1 1.00 mole NH3/mole NOx emissions, CalPortland Company 

Ammonia Annual Cost $390,409 $1640/ton, CalPortland Company 

Electricity 360 kW for increased exhaust gas volume, heaters and pumping 

Electricity Annual Cost $283,824 $100/MWh, CalPortland Company

Indirect Operating Costs 

Overhead $157,620 60% of Total Maintenance and Labor, EPA Cost Control Manual 

Property Tax $10,500 1% of Total Capital Cost, EPA Cost Control Manual 

Insurance $10,500 1% of Total Capital Cost, EPA Cost Control Manual 

Administration $21,000 2% of Total Capital Cost, EPA Cost Control Manual 

Capital Recovery $99,200 20 yr life, 7% interest rate, EPA Cost Control Manual 

TOTAL ANNUALIZED COST: $1,279,600 

Capacity, ton/day 415 

Annual Capacity Factor 90% 

NOx Emission Rate, lb/ton 9.45 

Current NOx Emissions, ton/yr 644 

Control Efficiency, % 25% 

Controlled NOx Emission Rate, lb/ton 7.09 

NOx Emissions after Control, ton/yr 483 

NOx Emission Reduction, ton/yr 161 

COST EFFECTIVENESS ($/ton): $7,946 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-9

Table 4-4: SNCR for Kiln 4

Table 4-4a: Capital Cost Basis 

DIRECT COSTS: 

PURCHASED EQUIPMENT 

 (a) Basic Equipment (BE) $650,000 Based on CalPortland’s Mojave system escalated to 2013$ and adjusted 

for Rillito site conditions. 

 (b) Instrumentation & Controls $65,000 10% of BE, EPA Cost Control Manual 

 (c) Sales Tax $19,500 3% of BE, EPA Cost Control Manual 

 (d) Freight $32,500 5% of BE, EPA Cost Control Manual 

TOTAL PURCHASED EQUIPMENT (PE): $767,000 

DIRECT INSTALLATION 

 (a) Foundations and Support $61,360 8% of PE, EPA Cost Control Manual 

 (b) Handling and Erection $107,380 14% of PE, EPA Cost Control Manual 

 (c) Electrical $30,680 4% of PE, EPA Cost Control Manual 

 (d) Piping $15,340 2% of PE, EPA Cost Control Manual 

 (e) Insulation for Piping $7,670 1% of PE, EPA Cost Control Manual 

 (f) Painting $7,670 1% of PE, EPA Cost Control Manual 

TOTAL DIRECT INSTALLATION (DI): $230,100 

 Site Preparation $0 none required 

 Buildings $0 none required 

TOTAL DIRECT COST (TDC): $997,100 PE + DI + site preparation + buildings 

INDIRECT COSTS: 

INDIRECT INSTALLATION 

 (a) Engineering and Project Management $99,710 10% of TDC, EPA Cost Control Manual 

 (b) Construction & Field Expenses $49,855 5% of TDC, EPA Cost Control Manual 

 (c) Contractor Fees $99,710 10% of TDC, EPA Cost Control Manual 

 (d) Startup & Performance Tests $19,942 2% of TDC, EPA Cost Control Manual 

 (e) Downtime $0 

 (f) Contingencies $99,710 10% 

OTHER INDIRECT COSTS 

TOTAL INDIRECT COST: $368,900 

TOTAL CAPITAL COST: $1,366,000 

 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

4-10

 

Table 4-4b: Annualized Cost and Cost Effectiveness

SNCR for Kiln 4 Basis 

TOTAL CAPITAL COST: $1,366,000 

DIRECT OPERATING COSTS: 

Operating Labor $43,800 

Maintenance Labor $27,300 2% of total capital cost, CalPortland Company 

Maintenance Materials $27,300 2%, CalPortland Company 

Ammonia 786.9 1.00 mole NH3/mole NOx emissions, CalPortland Company 

Ammonia Annual Cost $1,290,596 $1640/ton, CalPortland Company 

Electricity 15.00 kW for increased exhaust gas volume, heaters and pumping, 

CalPortland Company 

Electricity Annual Cost $11,826 $100/MWh, CalPortland Company 

Indirect Operating Costs 

Overhead $32,760 60% of Total Maintenance and Labor 

Property Tax $13,700 1% of Total Capital Cost 

Insurance $13,700 1% of Total Capital Cost 

Administration $27,300 2% of Total Capital Cost 

Capital Recovery $128,900 20 yr life, 7% interest rate 

TOTAL ANNUALIZED COST: $1,574,200 

Capacity, ton/day 3,233 

Annual Capacity Factor 90% 

NOx Emission Rate, lb/ton 4.01 

Current NOx Emissions, ton/yr 2,129 

Control Efficiency, % 30% 

Controlled NOx Emission Rate, lb/ton 2.81 

NOx Emissions after Control, ton/yr 1,491 

NOx Emission Reduction, ton/yr 639 

COST EFFECTIVENESS ($/ton): $2,464 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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4.2 Cost of Compliance Summary (Factor 1) 

Detailed information on the cost of compliance was presented in Section 4.1. Compliance costs are 

summarized in Table 4-5. 

Table 4-5: Cost of Compliance 

4.3 Time Necessary for Compliance (Factor 2) 

Several years would be required to design, permit and then construct any control equipment 

The time needed to install emission controls is approximately 3 years. 

4.4 Energy and Non-Air Quality Environmental Impacts (Factor 3) 

Increased energy use for Kilns 1, 2, and 3 would be approximately 2,838 MWh per year per kiln at a 

90 percent capacity factor. Increased energy use for Kiln 4 would be approximately 118 MWh per 

year at a 90 percent capacity factor. The use of SNCR at the specified emission control efficiencies 

would result in a modest increase of ammonia emissions. However, it should be noted that higher 

SNCR control efficiencies may result in higher ammonia emissions and significant adverse 

environmental air quality impacts. These increased ammonia emissions were not accounted for in 

the visibility improvement modeling discussion in Sections 5 and 6, so the modeling results overstate 

the visibility benefits of SNCR controls. Ammonia transport to the site will create the potential for 

accidents and spills and will cause increased air emissions. Storage of ammonia creates potential 

risks for spills. 

4.5 Remaining Useful Life (Factor 4) 

The remaining useful life of the kilns is unknown and unknowable at this time. CalPortland has an 

application pending to modernize its facility and permanently shutdown these kilns. Whether 

CalPortland moves forward with this modernization once the application is processed will depend on 

the state of the economy at that time. For the purposes of this analysis, we conservatively assumed 

a 20 year useful life 

Capital Cost Annual 

Cost

Cost 

Effectiveness

% ton/yr $ $/yr $ per ton NOx 

Controlled

Low NOx burner with indirect firing for 

Kilns 1, 2, and 3 (total for 3 kilns) 20% 386.5 $9,667,200 $2,758,200 $7,137 

Mid-kiln firing with mixing air technologies 

for Kilns 1, 2, and 3 (total for 3 kilns) 20% 386.5 $4,203,300 $3,087,300 $7,988 

SNCR with mixing air technologies for 

Kilns 1, 2, and 3 (total for 3 kilns) 25% 483.1 $3,152,400 $3,838,800 $7,946 

SNCR for Kiln 4. 30% 638.8 $1,366,000 $1,574,200 $2,464 

Emission Control Option

NOx Emission 

Reduction
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Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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4.6 Preliminary Conclusions for Step 4 

Given the nearby Class I area is on track to demonstrate a uniform rate of progress without any 

additional controls on the kilns, the relatively low NOx emissions (especially from Kilns 1 through 3, 

which have been inactive for several years), the high costs of compliance associated with the 

technically feasible control measures, and the uncertain future of the existing kilns, it is reasonable to 

not require additional NOx controls for this planning period for the Rillito kilns. Further consideration 

of impacts due to the expected visibility improvement from these controls, if they were to be 

implemented, is provided in the following sections. 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

5-1

5.0 CALPUFF Modeling Procedures 

The CALPUFF visibility modeling analysis portion of RP Step 4 followed the Western Regional Air 

Partnership (WRAP) common BART modeling protocol with the exception of the model version and a 

few refinements to CALMET settings. These differences are discussed in the sections below and in 

Appendix A. 

5.1 CALMET Processing 

The WRAP has developed six 4-km CALMET meteorological databases for three years (2001-2003). 

The CALMET modeling domains are strategically designed to cover all potential BART eligible 

sources within WRAP states and all PSD Class I areas within 300 km of those sources. The 

boundaries of the six domains are shown in Figure 3-a through Figure 3-1f of the WRAP common 

BART modeling protocol, available at 

http://pah.cert.ucr.edu/aqm/308/bart/WRAP_RMC_BART_Protocol_Aug15_2006.pdf. The RP 

CALPUFF modeling for the Rillito kilns was done using the Arizona 4-km domain, as shown in Figure 

5-1. The WRAP CALMET meteorological inputs, technical options, and processing steps are 

described in Sections 2 and 3 of the WRAP protocol. 

USGS 3 arc-second Digital Elevation Model (DEM) files were used by WRAP to generate the 

terrain data at 4-km resolution for input to the six CALMET runs. Likewise, the Composite Theme 

Grid format (CTG) files using Level I USGS land use categories were used by WRAP to generate 

the land use data at 4-km resolution for input to the six CALMET runs. See Sections 3.1.1.3 and 

3.1.1.4 of the WRAP common BART modeling protocol for more details on the data processing. 

Three years of 36-km MM5 data (2001-2003) were used by WRAP to generate the 4-km subregional meteorological data sets. Section 2 of the WRAP protocol discusses MM5 data 

extraction. Application-specific modifications approved by EPA for the CALPUFF modeling are 

described in Appendix A. 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

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Figure 5-1: Rillito Kiln Modeling Domain 
AECOM Environment 

Reasonable Progress Analysis – CalPortland’s Rillito Kilns May 2013

5-3

5.2 CALPUFF Model Formulation for Predicting Visibility Impairment 

In July 2005, EPA issued BART Guidelines that provide guidance to the States in making BART 

determinations for large power plants and other BART-eligible sources4. The BART Guideline states 

that modeling may be necessary to support a decision by the States about which BART-eligible 

sources “cause or contribute” to visibility impairment and are subject to BART. 

EPA guidance recommends CALPUFF for modeling single source visibility impacts at Class I areas. 

The model developer website describes CALPUFF as “...an advanced non-steady-state 

meteorological and air quality modeling system... It is maintained by the model developers and 

distributed by TRC. The model has been adopted by the U.S. Environmental Protection Agency 

(U.S. EPA) in its Guideline on Air Quality Models as the preferred model for assessing long range 

transport of pollutants and their impacts on Federal Class I areas and on a case-by-case basis for 

certain near-field applications involving complex meteorological conditions. The modeling system 

consists of three main components and a set of pre-processing and post-processing programs. The 

main components of the modeling system are CALMET (a diagnostic 3-dimensional meteorological 

model), CALPUFF (an air quality dispersion model), and CALPOST (a post-processing package)”.

CALPUFF offers three options for dealing with chemical transformations: 

x A pseudo-first-order chemical reaction mechanism for the conversion of SO2 to sulfate 

(SO4) and NOx to nitrate (NO3). This mechanism is based on the chemical transformation 

scheme used in the MESOPUFF-II5 model and incorporates the most significant 

dependencies of spatially and temporally varying environmental conditions of the 

transformation rates. 

x The RIVAD/ARM3 scheme6, which treats nitric oxide (NO) and nitrogen dioxide (NO2) 

conversion processes in addition to the NO2 to NO3 and SO2 to SO4 conversions, with 

equilibrium between gaseous nitric acid (HNO3) and ammonium nitrate aerosol. 

x User-specified 24-hour cycles of transformation rates. 

The Interagency Workgroup on Air Quality Modeling (IWAQM) recommends using the 

MESOPUFF-II system with CALPUFF. The MESOPUFF-II chemistry option is also the model 

default recommended by EPA. 

5.3 Ammonia Background Concentrations 

In the CALPUFF model, the oxidation of NOx to HNO3 depends on the NOx concentration, ambient 

ozone concentration, and atmospheric stability. Some of the nitric acid is then combined with 

available ammonia in the atmosphere to form ammonium nitrate. The ambient ammonia 

concentration is a critical input to the CALPUFF model for nitrate formation, especially with the use of 

the MESOPUFF II chemistry. It is important to note that that only particulate nitrate will impact 

visibility; nitric acid would not. 

 

4

 US EPA, 2005. BART guidelines, Federal Register update: June 24, 2005. 

5

 Scire et. al.,1984. User’s Guide to the MESOPUFF II Model and Related Processor Programs, 1984. EPA-600 S8-84-013. 

May 1984. 

6

 Morris et. al.,1988. Rocky Mountain Acid Deposition Model Assessment: Acid Rain Mountain Mesoscale Model (ARM3), EPA 

1988.
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Morris et al.7 reported that the EPA-approved version of CALPUFF with the MESOPUFF II chemistry 

(Version 5.8) was developed from field data limited to ambient temperatures no lower than 50°F. 

Therefore, the use of CALPUFF for much lower temperatures for the critical winter season represents 

an extension of the model to untested conditions. Morris et al. found that the limitations of the 

ambient temperatures in the field data used in development of the model could result in 

overestimating sulfate and nitrate formation in colder conditions. These investigators found that 

CALPUFF (version 5.8) tended to over-predict nitrate concentrations during winter by a factor of 

about 3 with high ammonia background concentrations. 

Recently, the IMPROVE monitoring network began to incorporate routine measurements of gaseous 

ammonia at specific sites. A recently issued technical paper8 on this subject showed monthly 

ammonia measurements at these sites, including one in southern Arizona (Chiricahua) that was 

modeled for this study. A review of the measurements taken to date at these sites (see Figure 5-2) 

indicates that ammonia concentrations less than 1 part-per-billion (ppb) (e.g., 0.5 ppb) are present at 

this site in winter. Note that EPA used a constant value ammonia background level of 1 ppb for all 12 

months, but without the benefit of the recent IMPROVE measurements. 

In an independent analysis, the Colorado Department of Public Health and Environment (CDPHE) 

performed a sensitivity modeling analysis to explore the effect of the ammonia concentration input to 

CALPUFF on the predicted visibility impacts for a source with high NOX emissions relative to SO2

emissions.9 It is noteworthy that the largest sensitivity occurs for ammonia input values between 1 

and 0.1 ppb. In that range, the difference in the peak visibility impacts predicted by CALPUFF is 

slightly more than a factor of 3 between ammonia concentration input values of 1 and 0.1 ppb. This 

sensitivity analysis shows that the choice of background ammonia is very important in terms of the 

magnitude of visibility impacts predicted by CALPUFF, and that the assumption of 1 ppb for winter 

likely introduces another level of over-predictive conservatism in the modeling results for NOx effects 

upon haze. 

The visibility composition plots depicted in Figure 5-3 from two IMPROVE monitors located in 

Saguaro East National Monument show that the majority of nitrate (shown by the red portions of the 

composition columns) forms during cold temperature (in the modeled predictions and in the real 

world) and, therefore, the model is not sensitive to the selected ammonia values in summer, but 

would be highly sensitive to values in winter months. 

Based upon this newly available ammonia measurement information (which conservatively includes 

both gaseous and particulate form concentration contributions), AECOM has developed a set of 

monthly-varying ammonia background concentrations (see Table 5-1) that correspond to the actual 

measured values noted above. Consistent with the EPA values, an ammonia background of 1 ppb is 

used for many of the non-winter months. 

 

7

 Morris, R., Steven Lau and Bonyoung Koo, 2005. Evaluation of the CALPUFF Chemistry Algorithms. Presented at A&WMA 

98th Annual Conference and Exhibition, June 21-25, 2005 Minneapolis, Minnesota. 

8

Chen, X., D. Day, B. Schichtel, W. Malm, J. Mojica, C. McDade, E. Hardison, S. Kreidenweis, and J. Collett, 2012. A Pilot 

Monitoring Study of Atmospheric NHx at Selected IMPROVE Sites. Extended Abstract # 19. Presented at the 2012 Aerosol 

and Atmospheric Optics: Visibility & Air Pollution Specialty Conference, held September 25-28th, 2012 in Whitefish, MT. Air & 

Waste Management Association, Pittsburgh, PA. 

9

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

(DRAFT), revised June 25, 2010, available at http://www.colorado.gov/airquality/documents/DraftColoradoSupplementalBARTAnalysisCALPUFFProtocol-25June2010.pdf. 
AECOM Environment 

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Figure 5-2: IMPROVE NHx Concentrations from April 2011 to January 2012 

Figure 5-3: 2009 IMPROVE Composition Data for Saguaro East National Park 

Table 5-1: Background Monthly Ammonia Concentrations Used in the Modeling (ppb) 

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 

0.5 0.5 0.6 0.7 1.0 1.0 1.0 1.0 1.0 1.0 1.0 0.8 
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5.4 CALPUFF Modeling Procedures 

AECOM used the EPA-approved version of CALPUFF (Version 5.8, Level 070623) that has been 

posted at http://www.src.com/calpuff/download/download.htm#EPA_VERSION. Although the 

WRAP BART protocol mentions the use of CALPUFF version 6, EPA’s Office of Air Quality 

Planning and Standards indicates that this use is a non-guideline application requiring EPA 

approval on a case-by-case basis. It is clear from the discussion provided in Appendix A that 

CALPUFF version 6 is not approvable by EPA at this time without a significant effort to show that it 

is technically superior. To avoid the need for the justification and documentation required to use a 

non-guideline version of the model, AECOM used the official EPA version 5.8. 

The area considered in the modeling is shown in Figure 5-3. The Reasonable Progress CALPUFF 

modeling for the Rillito kilns was conducted using a computational grid that included the entire 

domain. This domain includes 12 Class I areas within 300 km of the source, plus a 50-km buffer 

around each Class I area and a 100-km buffer around the source to assure puffs recirculation. The 

receptors used for each of the Class I areas are based on the National Park Service database of 

Class I receptors. The Class I areas included in the modeling are: 

1. Chiricahua National Monument 

2. Chiricahua Wilderness 

3. Galiuro Wilderness 

4. Gila Wilderness 

5. Mazatzal Wilderness 

6. Mount Baldy Wilderness 

7. Petrified Forest National Park 

8. Pine Mountain Wilderness 

9. Saguaro National Park (Eastern Portion) 

10. Sierra Ancha Wilderness 

11. Superstition Wilderness 

12. Sycamore Canyon Wilderness 

The Saguaro West area was not modeled by EPA or AECOM because it is too close to the source to 

have regional haze effects. This list of Class I areas modeled is consistent with the modeling 

conducted by the EPA for its Task 9 report. 

For CALPUFF model technical options, inputs, and processing steps, AECOM followed the WRAP 

common BART protocol, except for the model version, as discussed above. Due to the long distance 

to the nearest Class I area, building downwash effects were not included in the CALPUFF modeling. 

WRAP has developed hourly ozone measurement files for three years (2001-2003), available at 

http://pah.cert.ucr.edu/aqm/308/bart/calpuff/ozone_dat/. Data collection and processing are 

described in Section 3.1.2.7 of the WRAP protocol. The ozone data was used as input to CALPUFF. 

The stack parameters modeled were taken from EPA’s Task 9 report, Table 30. Kilns 1-3 were 

modeled together and Kiln 4 was modeled separately. The stack parameters are listed in Table 5-2. 

Section 5.5 discusses the emissions modeled for the base case and the three control scenarios.
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Figure 5-4: Class I Areas Within 300 km of the Rillito Facility 
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Table 5-2: Modeled Stack Parameters for Kilns 1-3 and Kiln 4 

 Units Kilns 1-3 Kiln 4 

Latitude Deg 32.4077 32.4076 

Longitude Deg -111.1497 -111.1498 

Stack Height Ft 75.00 75.00 

Base Elevation Ft 2060.00 2060.00 

Diameter Ft 10.00 16.00 

Gas Exit Velocity ft/s 52.70 47.83 

Stack Gas Exit 

Temperature Deg F 425.00 400.00 

 

Lambert Conformal X (1) Km -1324.2247 -1324.2374 

Lambert Conformal Y (1) Km -737.8118 -737.8177 

Stack Height M 22.86 39.62 

Base Elevation M 627.89 627.89 

Diameter M 3.05 4.88 

Gas Exit Velocity m/s 16.06 14.58 

Stack Gas Exit 

Temperature Deg K 491.48 477.59 

 

Lambert Conformal coordinate system is based on 40 deg N/97 deg 

W projection origin, 33 deg N/45 deg N standard parallels and NWS84 datum. 

5.5 Modeled Control Scenarios 

The emissions rates for Kilns 1-3 for the baseline case and the three control cases are presented in 

Table 5-3. The emissions rates for Kiln 4 for the baseline case and the three control cases are 

presented in Table 5-4. The SO2 emission rates were taken from EPA’s Task 9 report. The 

speciated PM emission rates were also taken from Task 9 report, but corrected (reduced by a factor 

of 3) for each stack due to an error in the Task 9 report’s calculations of the PM emissions. NOx 

emission rates were calculated by AECOM based on the NOx control options discussed in Section 3. 

A description of the cases modeled is as follows: 

x Base Case: No control options are implemented for any of the kilns. 

x Control Case 1: LNB and indirect firing or mid-kiln firing is implemented on Kilns 1-3. No 

controls are implemented for Kiln 4. 

x Control Case 2: SNCR is implemented on Kilns 1-3. No control options are implemented for 

Kiln 4. 
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x Control Case 3: SNCR is implemented on Kiln 4. No control options are implemented for 

Kilns 1-3. 

It is noteworthy to consider that excess ammonia emissions due to SNCR operation were not 

considered in the modeling. Such emissions can combine with gaseous SO2 or NOx emissions that 

are not visibility impairing and result in formation of secondary particulate (ammonium sulfate or 

ammonium nitrate). Therefore, the stated visibility benefits for all SNCR controls are overestimates 

of their actual benefits.
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Table 5-3: Emissions Modeled for Base Case and Three Control Scenarios for Kilns 1-3 

Table 5-4: Emissions Modeled for Base Case and Three Control Scenarios for Kiln 4 

SO2 SO4 NOx PMF PMC EC SOA SO2 SO4 NOx PMF PMC EC SOA

Base Case - No Controls 10.643 22.619 490.200 0.772 0.669 0.000 1.029 1.341 2.850 61.765 0.097 0.084 0.000 0.130

Case 1 - LNB and Indirect 

firing or Mid-Kiln Firing 

Kilns 1, 2, 3; Kiln 4 is at 

Baseline 10.643 22.619 392.200 0.772 0.669 0.000 1.029 1.341 2.850 49.417 0.097 0.084 0.000 0.130

Case 2 - SNCR Kilns 1, 2, 3; 

Kiln 4 is at Baseline 10.643 22.619 367.700 0.772 0.669 0.000 1.029 1.341 2.850 46.330 0.097 0.084 0.000 0.130

Case 3 - SNCR Kiln 4; Kilns 

1,2,3 are at Baseline 10.643 22.619 490.200 0.772 0.669 0.000 1.029 1.341 2.850 61.765 0.097 0.084 0.000 0.130

Case

Emissions (lb/hr) for Kilns 1-3 Emissions (g/s) for Kilns 1-3

SO2 SO4 NOx PMF PMC EC SOA SO2 SO4 NOx PMF PMC EC SOA

Base Case - No Controls 2.643 4.246 540.200 2.444 2.198 0.095 0.579 0.333 0.535 68.065 0.308 0.277 0.012 0.073

Case 1 - LNB and Indirect 

firing or Mid-Kiln Firing 

Kilns 1, 2, 3; Kiln 4 is at 

Baseline 2.643 4.246 540.200 2.444 2.198 0.095 0.579 0.333 0.535 68.065 0.308 0.277 0.012 0.073

Case 2 - SNCR Kilns 1, 2, 3; 

Kiln 4 is at Baseline 2.643 4.246 540.200 2.444 2.198 0.095 0.579 0.333 0.535 68.065 0.308 0.277 0.012 0.073

Case 3 - SNCR Kiln 4; Kilns 

1,2,3 are at Baseline 2.643 4.246 378.100 2.444 2.198 0.095 0.579 0.333 0.535 47.641 0.308 0.277 0.012 0.073

Case

Emissions (lb/hr) for Kiln 4 Emissions (g/s) for Kiln 4
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5.6 POSTUTIL Post-Processing 

The EPA-approved version of POSTUTIL was used to repartition the nitrate concentrations between the gas and 

particle phases and CALPOST was used to process the regional haze impacts with Method 6. POSTUTIL Version 

1.56, Level 070627, and CALPOST Version 6.221, Level 080724, were used. To be consistent with the EPA Task 9 

report, AECOM used the APPEND program (Version 2.33, Level 040623) to append the POSTUTIL binary output 

for the three years modeled into one continuous file prior to running CALPOST. 

These programs are available for download from the TRC website http://www.src.com/calpuff/calpuff1.htm. 

5.7 CALPOST Post-Processing 

CALPUFF uses predictions of various particulate species to compute the visibility extinction using the Interagency 

Monitoring of Protected Visual Environments (IMPROVE) equation (both original10 and “new”11 versions as 

documented in the Federal Land Managers’ Air Quality Related Values Workgroup (FLAG) reports. The update to 

the IMPROVE equation, adopted in the FLAG 2010 version, is based upon a re-evaluation of the comparison 

between particulate species concentrations, relative humidity, and directly-observed light scattering. During most of 

the BART analysis period between 2005 and 2010, EPA has relied upon the original IMPROVE equation. 

The model user provides specific inputs for the CALPOST post-processor as noted in FLAG reports regarding the 

use of the original and new IMPROVE equations. In addition to the choice between these equations, the CALPOST 

user needs to define the natural background particulate concentrations. The BART Rule specifies that the visibility 

improvement for various emission cases needs to be referenced to “clean” natural conditions, which can be defined 

in two alternate ways: the annual average natural conditions (referred to as option “a”) and the conditions 

associated with the 20% best days (referred to as option “b”). 

EPA guidance provides each state the option to choose between the two definitions of natural conditions. As EPA 

noted in its July 20, 2012 proposed rule, Arizona selected the annual average natural background and the original 

IMPROVE equation (also termed “Method 6”) for use in the State’s BART analyses. These selections correspond to 

“Method 6a” in the terminology adopted in EPA’s proposed rule. 

The modeling results presented in this document were based on Method 6a. 

 

10 Federal Land Managers, 2001. Federal Land Managers’ Air Quality Related Values Workgroup (FLAG) Phase I Report. 

http://www2.nature.nps.gov/ard/flagfree/index.htm. 

11 Federal Land Managers, 2010. Federal Land Managers’ Air Quality Related Values Work Group (FLAG) Phase I Report—

Revised (2010). Natural Resource Report NPS/NRPC/NRR—2010/232. 

http://nature.nps.gov/air/pubs/pdf/flag/FLAG_2010.pdf. 
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6.0 CALPUFF Modeling Results 

The results of the RP control options visibility modeling are presented in Tables 6-1 and 6-2 and are graphically 

plotted in Figure 6-1. Results presented in Table 6-1 are the 3-year average of the 98th percentile delta-deciviews 

(delta-dv) predicted impacts for each Class I area due to installation of the candidate RP controls on the Rillito kilns, 

which is represented by the 22nd highest modeled delta-dv value. Table 6-2 shows the improvements in the visibility 

impairment for each of the RP control options relative to the base case for each modeled Class I areas. Figure 6-1 

compares the total visibility impairment (expressed in deciviews) for the modeled results with output from the three 

modeled years averaged for each case and Class I area. Figure 6-2 compares the improvements in the visibility 

impairment for the RP control cases relative to the base case. 

Table 6-1: 98th Percentile Visibility Impairment for Base Case Scenario and Three RP Control Case Scenarios 

(delta-dv) 

Baseline Control Case 1 Control Case 2 Control Case 3

No Controls

LNB and Indirect 

Firing or Mid-Kiln 

Firing on Kilns 1-3; 

No controls on Kiln 4

SNCR on Kilns 1-3; 

No control on Kiln 4

SNCR on Kiln 4; No 

controls on Kilns 1-3

Chiricahua NM 0.201 0.184 0.180 0.173

Chiricahua W 0.218 0.200 0.195 0.189

Galiuro 0.856 0.797 0.784 0.759

Gila 0.902 0.846 0.832 0.786

Mazatzal 0.102 0.095 0.094 0.090

Mount Baldy 0.073 0.067 0.066 0.063

Petrified Forest 0.080 0.073 0.071 0.068

Pine Mountain 0.091 0.084 0.081 0.077

Saguaro (East Only) 1.067 1.001 0.985 0.955

Sierra Ancha 0.102 0.095 0.093 0.089

Superstition 0.251 0.235 0.230 0.232

Sycamore Canyon 0.072 0.067 0.066 0.063

Class I Areas
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Table 6-2: Visibility Improvement for the Three RP Control Case Scenarios Relative to the Base Case Scenario 

(deciviews) 

Control Case 1 Control Case 2 Control Case 3

LNB and Indirect 

Firing or Mid-Kiln 

Firing on Kilns 1-3; 

No controls on Kiln 4

SNCR on Kilns 1-3; 

No control on Kiln 4

SNCR on Kiln 4; No 

controls on Kilns 1-3

Chiricahua NM 0.017 0.021 0.028

Chiricahua W 0.018 0.023 0.029

Galiuro 0.059 0.072 0.097

Gila 0.056 0.070 0.116

Mazatzal 0.007 0.008 0.012

Mount Baldy 0.006 0.007 0.010

Petrified Forest 0.007 0.009 0.012

Pine Mountain 0.007 0.010 0.014

Saguaro (East Only) 0.066 0.082 0.112

Sierra Ancha 0.007 0.009 0.013

Superstition 0.016 0.021 0.019

Sycamore Canyon 0.005 0.006 0.009

Max 0.066 0.082 0.116

Class I Areas
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Figure 6-1: 22nd Highest Visibility Impacts Averaged Over 3 Years for the Base Case Scenario and Three RP Control 

Case Scenarios (delta-dv) 

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

Chiricahua 

NM

Chiricahua 

W

Galiuro Gila Mazatzal Mount Baldy Petrified 

Forest

Pine 

Mountain

Saguaro 

(East Only)

Sierra 

Ancha

Superstition Sycamore 

Canyon

22nd Highest (delta-deciview)

Class I Area

Baseline - No Controls

Control Case 1 - Kilns 1-3: LNB; Kiln 4: No Controls

Control Case 2 - Kilns 1-3: SNCR; Kiln 4: No Controls

Control Case 3 - Kilns 1-3: No Controls; Kiln 4: SNCR
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Figure 6-2: Visibility Improvements of the Three RP Control Case Scenarios Relative to the Base Case Scenario 

(deciviews) 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

Chiricahua 

NM

Chiricahua 

W

Galiuro Gila Mazatzal Mount Baldy Petrified 

Forest

Pine 

Mountain

Saguaro 

(East Only)

Sierra 

Ancha

Superstition Sycamore 

Canyon

Visibility Improvement (deciview)

Class I Area

Control Case 1 - Kilns 1-3: LNB; Kiln 4: No Controls

Control Case 2 - Kilns 1-3: SNCR; Kiln 4: No Controls

Control Case 3 - Kilns 1-3: No Controls; Kiln 4: SNCR
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7.0 Conclusions for Visibility Improvement Analysis 

One aspect of the 4th Reasonable Progress factor is the expected visibility improvement from 

candidate control options. Several cases were evaluated with the EPA-approved CALPUFF model at 

Class I areas within 300 km of the Rillito plant. 

x Base Case: No control options are implemented for any of the kilns. 

x Control Case 1: LNB and indirect firing or mid-kiln firing is implemented on Kilns 1-3. No 

controls are implemented for Kiln 4. 

x Control Case 2: SNCR is implemented on Kilns 1-3. No control options are implemented for 

Kiln 4. 

x Control Case 3: SNCR is implemented on Kiln 4. No control options are implemented for 

Kilns 1-3. 

The results of this analysis indicate that all candidate controls result in levels of visibility improvement 

that are too low to be detected by the available technology for particulate monitors (much less than 

0.3 delta-deciview) and less than 12 percent of the perceptible levels that can be visually detected (1 

deciview). The visibility improvement associated with SNCR controls on the active Kiln 4 is about 0.1 

delta-deciview, a level which is mentioned in the 1999 Regional Haze Rule as being associated with 

“no degradation” of visibility. Accordingly, we conclude that none of these Reasonable Progress 

options is sufficiently effective to replace the current NOx emission controls on the CalPortland kilns 

in Rillito, AZ.
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Appendix A 

CALMET/CALPUFF Processing 

Refinements 
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Enhancements to the WRAP CALMET Database 

AECOM suggested two modifications/enhancements to the 4-km Arizona CALMET WRAP database. 

They are as follows: 

The 4-km Arizona CALMET database has been produced by AECOM using the downloaded 

CALMET inputs from the WRAP website 

http://pah.cert.ucr.edu/aqm/308/bart/calpuff/calmet_inputs/az/. AECOM initially ran CALMET with the 

setting suggested in the WRAP BART modeling protocol. As part of AECOM’s internal quality 

assurance procedure, we displayed and examined the 4-km Arizona WRAP CALMET wind fields in 

the visualization software CALDESK. Figure A-1 graphically shows wind fields with the WRAP 

settings for a typical hour. Arrows represent wind direction and wind speed for that hour at 10 meter 

height. Circular areas in these figures with common winds and abrupt transitions at the edge of the 

circles indicate a radius of influence of surface stations, R1, which was set to 100 km, as suggested 

in the WRAP BART protocol. The R1 value was coupled with R1MAX = 50 km so that the influence 

of the surface stations is established out to 50 km and then it abruptly ends beyond that distance. 

Setting R1 and R1MAX to such high values is not recommended by the model developer and 

Federal Land Managers, especially with MM5 data resolution of 36 km with areas of complex terrain. 

Typically, R1 is set to a fairly small value, generally not exceeding half of the MM5 data resolution (18 

km), according to recent guidance on multiple PSD projects involving CALPUFF modeling in the 

WRAP region from John Notar of the National Park Service (personal correspondence between John 

Notar of the NPS and Bob Paine of AECOM). A large R1 value results in wind fields surrounding 

surface stations that overwrite the MM5 wind fields, which do have terrain influences incorporated 

into them. In many instances, the extended extrapolation of the surface station data with an abrupt 

transition at 50 km produces opposing wind directions in adjacent grid squares at the 50 km distance. 

To avoid this problematic wind field result, AECOM used a smaller R1 value of 18 km and R1MAX 

value of 30 km. The resulting wind fields for the same hour and height are depicted in Figure A-2. 

The adjusted R1 and R1MAX values blend the surface observations into the MM5 observations 

much better, creating a more uniform wind field throughout the domain. Therefore, AECOM used the 

smaller R1 and R1MAX values to be more consistent with FLM guidance and due to the better 

performance in the wind field depiction associated with the smaller values. 

When rerunning CALMET, AECOM used the "official" EPA-approved version of CALPUFF modeling 

system CALMET Version 5.8 instead of Version 6.211 that was used by WRAP, available at 

http://www.src.com/calpuff/download/download.htm#EPA_VERSION. 

In accordance with recent CALPUFF modeling guidance from the EPA Region IX and National Park 

Service, AECOM used the technical options listed below. 

x Included upper air soundings in a Step 2 analysis; the WRAP BART protocol does not 

include these observations. Figure A-3 shows upper air and surface station locations. 

x Set NOOBS = 0, to use both surface and upper air observations. 

x Set IEXTRP = -4, to extrapolate surface wind observations to the upper layers using 

similarity theory, and ignore layer 1 from the upper air soundings. 

x Set ITPROG = 1, to use surface station temperature and the MM5 for upper air 

temperature interpolation. 
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A summary of the specific CALMET options selected by AECOM are listed in Table A-1. 

Table A-1 CALMET Options Comparison 

Variable Description WRAP Value ENSR Value 

RMAX1 Maximum radius of influence over land 

in the surface layer 

50 30 

R1 Relative weighting of the first-guess 

field and observations in the surface 

layer

100 18 

R2 Relative weighting of the first-guess 

field and observations in the layers 

aloft 

200 20 
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Figure A-1 CALMET Windfields with WRAP Settings 
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Figure A-2 CALMET Windfields with AECOM Settings 
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Figure A-3 Location of Surface and Upper Air Stations used for Arizona CALMET Domain