1

Technical Support Document for

Alabama Regional Haze SIP Submittal

January 2012

U.S. EPA – Region 4 

Atlanta, GA
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Technical Support Document (TSD) for 

Alabama Regional Haze SIP Submittal

Table of Contents

I. Background

II. Summary of EPA’s Action

III. Evaluation of State Regional Haze Submittal

A. Identification of Areas

B. Reasonable Progress Goals Development

1. Calculations of Baseline Visibility Conditions

2. Calculations of Natural Visibility Conditions

3. Uniform Rate of Progress (UROP or “Glidepath”) 

for Reasonable Progress

C. Long Term Strategy

1. Technical Basis for Strategy

2. Identification of Sources and Factors to be 

Considered

3. Source or Source Category Specific Analyses for 

Reasonable Progress

4. Enforceability of Reasonable Progress Measures

D. Best Available Retrofit Technology (BART) Requirements

1. Identification of all BART Eligible Sources

2. Modeling or other Demonstrations for BART 

Exempt Sources

3. Identification of Sources Addressed by CAIR Rule

4. Source Specific BART Determinations

5. Enforceability of BART

E. Coordination of Regional Haze and RAVI Requirements

F. Monitoring Strategy and Other Implementation 

Requirements

G. Emission Inventory

IV. Conclusions

__________________________________________________________________

Note: Italicized text in this document that appears under the “State Regional Haze 

Submittal” headings are excerpts from relevant portions of the Alabama regional haze 

submittal as cited. Figure and table citations under these headings reflect the actual 

references as listed in the State’s SIP submittal. Page numbers refer to the SIP Narrative, 

unless otherwise specified.
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TSD for Alabama Regional Haze SIP Submittal

I. Background

In Section 169A of the 1977 Amendments to the Clean Air Act (CAA), Congress set 

forth a program for protecting visibility in Federal Class I areas which calls for the 

“prevention of any future, and the remedying of any existing, impairment of visibility in 

mandatory Federal Class I areas which impairment results from manmade air pollution.” 

Congress adopted the visibility provisions to protect visibility in 156 Federal Class I 

areas, which include certain national parks, memorial parks, and wilderness areas over a 

certain size, and all international parks. These areas are defined at 40 CFR 81.400, and 

listed by state at 40 CFR 81.401-81.437. On December 2, 1980, EPA promulgated 

regulations to address visibility impairment that is “reasonably attributable” to a single 

source or small group of sources. 45 FR 80084. These regulations represented the first 

phase in addressing visibility impairment and deferred action on regional haze that 

emanates from a variety of sources until monitoring, modeling and scientific knowledge 

about the relationships between pollutants and visibility impairment improved. 

In the 1990 Amendments to the CAA, Congress added Section 169B and called on EPA 

to issue regional haze rules. The Regional Haze rule (RHR) that EPA promulgated on 

July 1, 1999 (64 FR 35713) revised the existing visibility regulations to integrate 

provisions addressing regional haze visibility impairment and establish a comprehensive 

visibility protection program for Federal Class I areas. States are required to submit state 

implementation plans (SIPs) to EPA that set out each state’s plan for complying with the 

RHR, including consultation and coordination with other states and with Federal Land 

Managers (FLMs). States must submit a regional haze SIP to EPA within three years 

after the date of designation of areas under the National Ambient Air Quality Standard 

(NAAQS) for fine particulate matter (PM2.5). EPA promulgated PM2.5 designations on 

December 17, 2004, and thus, regional haze SIPs were to be submitted to EPA by 

December 17, 2007, which is also specified at 40 CFR 51.308(b).

The RHR addressed the combined visibility effects of various pollution sources over a 

wide geographic region. Consequently, all 50 states, including those without Class I 

areas, Washington, D.C., and the Virgin Islands, are required to submit regional haze 

SIPs. 40 CFR 51.300(b)(3). EPA designated five Regional Planning Organizations 

(RPOs) to assist with the coordination and cooperation needed to address the visibility 

issue. The RPO that makes up the southeastern portion of the contiguous United States is 

known as VISTAS (Visibility Improvement – State and Tribal Association of the 

Southeast). VISTAS members include: the Eastern Band of the Cherokee Indians, other 

Federally Recognized Tribes and Local Air Programs within the geographic area, and the 

following states: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, 

South Carolina, Tennessee, Virginia, and West Virginia. The Alabama Department of 

Environmental Management (ADEM) chose to participate in VISTAS to develop the 

technical analyses needed to fulfill the requirements of the RHR.
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Figure 1. Geographical Areas of Regional Planning Organizations 

 

 Figure 2. Class I Areas in the VISTAS Region 
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II. Summary of Action

EPA is proposing a limited approval of a revision to the Alabama state implementation 

plan (SIP) submitted by the State of Alabama through the Alabama Department of 

Environmental Management (ADEM), on July 15, 2008, that addresses regional haze for 

the first implementation period. This revision addresses the requirements of the Clean 

Air Act (CAA or Act) and EPA’s rules that require states to prevent any future and 

remedy any existing anthropogenic impairment of visibility in mandatory Class I areas 

(national parks and wilderness areas) caused by emissions of air pollutants from 

numerous sources located over a wide geographic area (also referred to as the “regional 

haze program”). States are required to assure reasonable progress towards the national 

goal of achieving natural visibility conditions in Class I areas. EPA is proposing a 

limited approval of this SIP revision to implement the regional haze requirements for 

Alabama on the basis that the revision, as a whole, strengthens the Alabama SIP. 

Additionally, EPA is proposing to rescind the federal regulations previously approved 

into the Alabama SIP on November 24, 1987, and to rely on the provisions in Alabama’s 

July 15, 2008, SIP submittal to meet the long-term strategy (LTS) requirements for 

reasonably attributable visibility impairment (RAVI). EPA has previously proposed a 

limited disapproval of the Alabama regional haze SIP because of deficiencies in the 

State’s regional haze SIP submittal arising from the remand by the U.S. Court of Appeals 

for the District of Columbia Circuit (D.C. Circuit) to EPA of the Clean Air Interstate 

Rule (CAIR). Consequently, EPA is not proposing to take action in this rulemaking to 

address the State’s reliance on CAIR to meet certain regional haze requirements. 
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III. Evaluation of State Regional Haze Submittal

A. Identification of Areas 

The SIP must identify each mandatory Class I Federal area located within the State and in 

each mandatory Class I Federal area located outside the State that may be affected by 

emissions from within the State. Where a mandatory Class I Federal area is in multiple 

states, a description of how the states have assigned responsibilities for the area needs to 

be included.

State Regional Haze Submittal

AL SIP Narrative, Page 4:

Alabama has one Class I area within its borders, the Sipsey Wilderness area located within 

the Bankhead National Forest in Northeastern Alabama (Figure 1.5-1). The Alabama 

Department of Environmental Management (ADEM) is responsible for developing the 

Regional Haze SIP. This SIP establishes Reasonable Progress Goals (RPGs) for visibility 

improvement at the Sipsey Wilderness, and a Long Term Strategy (LTS) that will achieve 

those RPGs within the first Regional Haze planning period.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. 
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III. Evaluation of Regional Haze Submittal

B. Reasonable Progress Goals Development 

B.1.Calculations of Baseline Visibility Conditions: ((40 CFR 51.308(d)(2)(i))

The period for establishing baseline visibility conditions is 2000 to 2004. For each 

mandatory Class I Federal area located within the State, the State must determine the 

average degree of visibility impairment (expressed in deciviews) for the most impaired 

and least impaired days (i.e. the 20% most impaired days and 20% least impaired days)

for each of these years. Baseline conditions are the average of these annual values. For 

each mandatory Class I Federal area located within the State, the SIP needs to calculate 

the number of deciviews by which baseline conditions exceed natural visibility 

conditions for the most impaired and least impaired days.

Where onsite monitoring is not available, the baseline visibility conditions must be 

established using the most representative monitoring available for the 2000-2004 period 

in consultation with EPA.

State Regional Haze Submittal

AL SIP Narrative, Pages 9-10:

Baseline visibility conditions at the Sipsey Wilderness area are estimated using sampling 

data collected at the IMPROVE monitoring site. A five year average (2000 to 2004) was 

calculated for each of the 20% worst and 20% best visibility days in accordance with 40 CFR 

51.308(d)(2) and the 2003 EPA Guidance. IMPROVE data records for the Sipsey Wilderness 

for the period 2000 to 2004 meet EPA requirements for data completeness (75% for the year 

and 50% for each quarter).

Class 1 area

Average for 

20 percent 

Worst Days 

(deciviews)

Average for 

20 percent 

Best Days 

(deciviews)

Bext (Mm-1) 

Average for 

20 percent 

Worst Days

Bext (Mm-1) 

Average for 

20 percent 

Best Days

Sipsey Wilderness 29.0 15.6 187.3 48.3

Figure 3. Baseline Visibility Conditions – Sipsey Wilderness

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. 
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III. Evaluation of Regional Haze Submittal

B. Reasonable Progress Goals Development 

B.2. Calculations of Natural Visibility Conditions: ((40 CFR 51.308(d)(2)(iii))

For each mandatory Class I Federal area located within the State, natural visibility 

conditions must be calculated by estimating the degree of visibility impairment existing 

under natural conditions for the most impaired and least impaired days, based on 

available monitoring information and appropriate data analysis techniques as specified in 

EPA-454/B-03-005, Guidance for Estimating Natural Visibility Conditions Under the 

Regional Haze Program or an approved alternative technique.

State Regional Haze Submittal

AL SIP Narrative, Pages 8-10:

Natural background visibility, as defined in the 2003 EPA document Guidance for Estimating 

Natural Visibility Conditions Under the Regional Haze Rule, is based on annual average 

concentrations of fine particle components. Natural background visibility for the 20% worst 

days is estimated by assuming that fine particle concentrations for natural background are 

normally distributed and the 90th percentile of the annual distribution represents natural 

background visibility on the 20% worst days. The 20% worst and 20% best days for the 

Sipsey Wilderness can be found in Section 3.0 of Appendix G. 

In the 2003 guidance, EPA also provided that states may use a “refined approach” to 

estimate the values that characterize the natural visibility conditions of the Class I areas. The 

purpose of such a refinement would be to provide more accurate estimates with changes to 

the extinction algorithm that may include the concentration values, factors to calculate 

extinction from a measured particular species and particle size, the extinction coefficients for 

certain compounds, geographical variation (by altitude) of a fixed value, and the addition of 

visibility pollutants. In 2005, the IMPROVE Steering Committee made recommendations for 

a refined equation that modifies the terms of the original equation to account for the most 

recent data. The choice between use of the old or the new equation for calculating the 

visibility metrics for each Class I area is made by the state in which the Class I area is 

located. 

The new IMPROVE equation accounts for the effect of particle size distribution on light 

extinction efficiency of sulfate, nitrate, and organic carbon. The mass multiplier for organic 

carbon (particulate organic matter) is increased from 1.4 to 1.8. New terms are added to the 

equation to account for light extinction by sea salt and light absorption by gaseous nitrogen 

dioxide. Site-specific values are used for Rayleigh scattering to account for the site-specific 

effects of elevation and temperature. Separate relative humidity enhancement factors are 

used for small and large size distributions of ammonium sulfate and ammonium nitrate and 

for sea salt. The elemental carbon (light-absorbing carbon), fine soil, and coarse mass terms 

do not change between the original and new IMPROVE equation. 

The VISTAS states chose to use the new IMPROVE equation as the basis for the conceptual 

description because it takes into account the most recent review of the science and because it 

is recommended by the IMPROVE Steering Committee. For more detailed discussion of the 

two IMPROVE equations, see Appendix B.
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Class 1 area Average for

20% Worst

Days

(deciviews)

Average for

20% Best

Days

(deciviews)

Average for

20% Worst

Days

Bext (Mm-1)

Average for

20% Best

Days

Bext (Mm-1)

Sipsey 

Wilderness

10.9 5.0 30.1 16.6

Figure 4. Natural Background Conditions - Sipsey Wilderness

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision and that he natural background conditions that were used in the reasonable 

progress assessment were developed in an acceptable manner. EPA Region 4 has 

approved the use of the VISTAS methodology for use of the new IMPROVE equation. 

The State used the new IMPROVE equation and developed concentrations for each term 

of the equation consistent with the recommendations and default data from the 

IMPROVE Steering Committee. In a September 27, 2006, Question and Answer (Q&A) 

document (under Miscellaneous #1), EPA stated that it would approve a state’s use of the 

new IMPROVE equation for reasonable progress. That specific Q&A suggested that the 

new equation should be applied consistently in the development of the state’s regional 

haze SIP. The State of Alabama used the new IMPROVE equation in the reasonable 

progress assessment to develop baseline and natural background conditions and in the 

BART modeling. The new IMPROVE equation was used in the reasonable progress

assessment in developing the baseline and natural background conditions and in the 

BART modeling. In the BART evaluations, the new IMPROVE equation was used on a 

case-by-case basis in a hierarchal approach. The equation was only used in the most 

refined of modeling for BART. Of the 35 BART-eligible sources that modeled their 

impacts at less than 0.5 deciview, 33 of the demonstrations relied on the old IMPROVE 

equation. Only two, BP Amoco Chemicals Chemical Lime Co Montevallo, refined their 

modeling further and relied on the new IMPROVE equation to demonstrate that their 

impacts were less than 0.5 deciview.

The concentration data developed for use in the new IMPROVE equation was consistent 

with the recommendations of the Natural Haze Levels II Committee to the RPO 

Monitoring/Data Analysis Workgroup. Alabama chose to use apply the new IMPROVE 

equation in a manner that was consistent with that used by the ten VISTAS RPO states in 

their regional modeling to evaluate reasonable progress with respect to the glidepath. 

References used in the EPA review:

1. Additional Regional Haze Questions, EPA, September 27, 2006 Revision. 

Answers to questions that PA received from various States and Regional Planning 

Organizations (RPOs) related to the submission of regional haze SIPs under the 

program described by 40 CFR 51.308. This document provides guidance to the 
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State air pollution control agencies and the general public on meeting the regional 

haze SIP requirements. 

2. January 18, 2007, e-mail from Marc Pitchford, NOAA - Air Resources 

Laboratory, to Brenda Johnson, EPA. Subject: “Re: December discussions.”

3. Powerpoint presentation: Natural Haze Levels II: Application of the New 

IMPROVE Algorithm to Natural Species Concentration Estimates. Final Report 

of the Natural Haze Levels II Committee to the RPO Monitoring/Data Analysis 

Workgroup.
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III. Evaluation of Regional Haze Submittal

B. Reasonable Progress Goals Development 

B.3. Uniform Rate of Progress (UROP or “Glidepath”) for Reasonable Progress: 

(40 CFR 51.308(d)(1) and (40 CFR 51.308(d)(1)(i)(B))

For each mandatory Class I Federal area located within the State, the State must establish 

goals (expressed in deciviews) that provide for reasonable progress towards achieving 

natural visibility conditions. For each Class I area within the State, the State must 

analyze and determine the rate of progress needed to attain natural visibility conditions 

by the year 2064 and determine the uniform rate of visibility improvement (measured in 

deciviews) that would need to be maintained during each implementation period in order 

to attain natural visibility conditions by 2064. The State must show that the reasonable 

progress goal for each mandatory Class I Federal area represents at least as much 

visibility improvement as is expected to result from implementation of other 

requirements of the CAA during the applicable planning period. 40 CFR 

51.308(d)(1)(vi). The reasonable progress goals must provide for an improvement in 

visibility for the most impaired days over the period of the implementation plan and 

ensure no degradation in visibility for the least impaired days over the same period.

Modeling is not used to determine reasonable progress goals and does not determine 

whether reasonable progress has been met. Modeling is one part of the reasonable 

progress analysis. The modeling results are used to determine if future year visibility at 

Class I areas are estimated to be on a (glide) path towards reaching natural background. 

This is called a uniform rate of progress analysis or “glidepath” analysis. 

State Regional Haze Submittal

AL SIP Narrative, Pages 14-16:

The following glidepaths represent the 20% most impaired days for the Sipsey 

Wilderness, assuming uniform rate of progress toward Regional Haze goals. The first 

glidepath (Figure 3.1-1) represents work prior to January 2008. This work was the basis 

for the majority of the conclusions presented in this SIP. However, the “Best and Final” 

run, incorporating all final known inventory changes and BART and RP controls, was 

completed in late January 2008. This run (Figure 3.1-2) resulted in new 2018 

predictions, and subsequently, revised glidepaths, which are also presented here. Using 

2018 Base G2 emissions, the model projected visibility at the Sipsey Wilderness on the 

20% worst days would be 23.69 dv. Using 2018 Best and Final emissions, the model 

projected visibility at the Sipsey Wilderness on the 20% worst days would be 23.53 dv. 

For the remainder of this narrative, the most recent “Best and Final” glidepaths will be 

included. Due to the lateness of the final run, it was not possible to revise all of the 

figures and tables in this SIP, including those in the Appendices. For this reason, ADEM 

has elected to retain the older figures and tables. The differences may be small had they 

been updated, but ADEM contends that the results of the Best and Final Runs show a 

continued improvement over previous runs that would not change any of the conclusions 

presented. Natural background visibility at the Sipsey Wilderness is predicted to be 

slightly less than 11 dv (10.9)... Note: Method 1 is the EPA method of averaging all 20% 

worst days in 2002 without consideration of model performance. 
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EPA Note: In the Alabama submittal, symbols denoting “Method 1” represent the 

State’s RPG for that area and for that case depicted in the figure (i.e., “best” or “worst” 

20 % days).

AL SIP Narrative, Pages 54-55, 96:

In addition to improving visibility on the 20% worst visibility days, states are also 

required to protect visibility on the 20% best days at Class I areas. As illustrated in 

Figure 7.2.4-3, visibility on the 20% best days is projected to improve in 2018 at all 

VISTAS Class I areas as a result of emissions reductions. Specifically, Figure 7.2.4-4 

demonstrates that no degradation should occur for the Sipsey Wilderness area, and that, 

in fact, visibility should improve beyond that level.
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AL SIP, Appendix G, Pages G-6-10:

2018 Model Assessment of the Uniform Rate of Progress

The purpose of a modeling assessment of the uniform rate of progress is to determine if a 

proposed control strategy will result in uniform rate of progress being met when 

measured concentrations of particulate matter are used to estimate visibility impairment 

at some future date. The modeling is applied in a relative sense. 

The first step involves determining the 20% best and worst days. This involves 

developing model projections to rank visibility (in dv) on each day with observed 

speciated PM2.5 data for each of the 5 years comprising the baseline period (2000-2004) 

for each Class I area. Day-specific observations for mass associated with SO4, NO3, OC, 

EC, Soil, and CM, should be used to calculate bext for each day using climatological 

relative humidity adjustment factor(s) (f(rh)). Total bext for all components are then 

converted to dv for each day to obtain a daily dv value.
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The next step is to use base year and future year modeling results to estimate a relative 

response factor (RRF) for each component of PM2.5 on the 20% best and 20% worst 

monitoring days. Simply put, the RRF is the average modeled future year concentration 

near the monitor divided by the average modeled base year concentration or: Average 

 Modeled Base Year Concentration 

 RRF = Average Modeled Future Year Concentration 

To accomplish this step, concentrations for each component of PM2.5 and coarse matter 

(the difference between PM10 and PM2.5) are extracted from the base year and future year 

modeling output near IMPROVE monitoring sites for the monitored best and worst days. 

The component concentrations are then averaged to develop base and future year 

average component concentrations. The future year average component concentrations 

are then divided by their respective base year component concentrations to develop RRFs 

for each component of PM2.5 and coarse matter.

As an example, consider Table 3.3-1, which has all the pertinent data for the SIPS1 

IMPROVE monitor. Looking at the top table, the first column identifies the 20% best 

days identified in Step 1 (Section 3.1). The next six columns have the 12 km modeled 

base year (2002) concentration values near the monitor corresponding to the 20% best 

days. The next six columns have the 12 km modeled future year (2018) component 

concentrations near the monitor for the same set of days. The final six columns contain 

the daily RRF values for each component species, which is simply the future 

concentration divided by the base year concentration. The bottom row of the table 

contains the average values for the base year components, the future year components, 

and the RRFs for each of the average component values. The bottom table contains the 

same data for the 20% worst days 
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Table 3.3-1: Base year concentrations, future year concentrations, and RRF for SIPS1 

on the monitored 20% best days (top) and 20% worst days (bottom), based on 12 km 

modeling results.

The next step in using model output to estimate future visibility impairment is to multiply 

the RRFs (determined in the previous step, Section 3.3) by the measured species 

concentration data during the baseline period (2000-2004) for the measured 20% best 

and 20% worst days. This results in daily future year species concentrations, where base 

year concentrations, or the current year design value (DVC) is multiplied by the RRF to 

determine the future design value (i.e. DVF = RRF * DVC). For regional haze, this 

calculation is performed for each of the best and worst days for the five-year baseline 

period (calculated in Step 2, Section 3.2) using an RRF for each PM component, for both 
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the best days and the worst days. This produces future concentration estimates for SO4, 

NO3, OC, EC, Soil and CM, for each of the “worst” and “best” visibility days. 

Once future year concentrations are calculated (Section 3.4) the future daily extinction

coefficients (bext) are then calculated for the 20% best and 20% worst visibility days in 

each of the five base years (2000-2004). This is achieved by applying the “new” 

IMPROVE equation: 

bext ≈ 2.2 * fs(RH) * [Small Sulfate] + 4.8 * fL(RH) * [Large Sulfate] 

+ 2.4 * fs(RH) * [Small Nitrate] + 5.1 * fL(RH) * [Large Nitrate] 

+ 2.8 * {Small Organic Mass] + 6.1 * [Large Organic Mass] 

+ 10 * [Elemental Carbon] 

+ 1 * [Fine Soil] 

+ 1.7 * fss(RH) * [Sea Salt] 

+ 0.6 * [Coarse Mass] 

+ Rayleigh Scattering (site specific) 

+ 0.33 * [NO2 (ppb)]

Model estimated daily concentrations are used with the corresponding baseline daily 

relative humidity adjustment factor(s) (f(rh)) identified in Step 1 (Section 3.1). 

The final step is to calculate daily dv values from the total daily extinction calculated in 

the previous step then compute the future average mean dv for the best and worst days 

for each year. The five years are then averaged together to get the final future mean dv 

value for the best and worst days. The first step in this process is to convert the total 

daily bext for each day (calculated in the previous step, Section 3.5) to deciviews (dv). 

This future year daily dv value for each of the best and worst days is then averaged to 

determine the future dv value for the best and worst visibility days for each year. This 

leads to five future estimated mean dv values for the worst and five future estimated mean 

dv values for the best visibility days. The five yearly values for the 20% best and 20% 

worst days are then averaged to produce the final future mean dv value, or dvfuture. Table 

3.6-1 displays the yearly mean dv value for each year in the baseline period for both the

20% worst days (center column) and the 20% best days (right column). The last row in 

the table displays the final future mean dv value, or dvfuture. 

Table 3.6-1: Yearly daily deciview values and final future mean deciview values 

(dvfuture) for SIPS1 based on 12km modeling results.
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the baseline mean dv (dvbaseline) values calculated in Step 2 (Section 3.2). If the resulting 

change in dv is a negative number (future - base), this represents an improvement in 

visibility. Table 3.6-2 summarizes these calculation for the IMPROVE monitor associated 

with the Sipsey Wilderness area. As it can be seen, the Sipsey Wilderness area is showing 

visibility improvement on both the 20% best and 20% worst days.

Table 3.6-2: Comparison of future deciview projections for 2018 compared to 2002 

baseline deciview estimates for the Sipsey Wilderness.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. The glidepath for the Sipsey area was developed through a technical analysis 

that was scientifically and meticulously prepared in an open forum for the RPO and 

stakeholders review and input. Through the application of the modeled LTS, the State 

has demonstrated that progress toward improved visibility and natural conditions on the 

20 percent worst and best days will occur. 
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III. Evaluation of Regional Haze Submittal

C. Long-Term Strategy 

C.1. Technical Basis for Strategy (40 CFR 51.308(d)(3)(iii))

The SIP must document the technical basis, including modeling, monitoring and 

emissions information, on which the State is relying to analyze regional haze. Modeling 

is not used to determine reasonable progress goals and does not determine whether 

reasonable progress has been met. Modeling is one part of the reasonable progress 

analysis. The modeling results are used to determine if future year visibility at Class I 

areas are estimated to be on a (glide) path towards reaching natural background. This is 

called a uniform rate of progress analysis or “glidepath” analysis. The State may meet 

this requirement by relying on technical analyses developed by the regional planning 

organization and approved by all State participants.

Modeling is not used to determine reasonable progress goals and does not determine 

whether reasonable progress has been met. Modeling is one part of the reasonable 

progress analysis. The modeling results are used to compare progress made through 

emission reductions with future year visibility at Class I areas. Note that the emission 

inventory requirements under 40 CFR 51.308(d)(4)(v) are addressed in this section.

State Regional Haze Submittal

The following is taken and/or summarized from Alabama’s July 15, 2008, regional haze 

SIP submittal:

EPA Note: The RHR requires states to establish RPGs for visibility improvement at 

each affected Class I area covering each approximately 10-year period until 2064. 

Alabama’s first set of RPGs will comprise LTS covering the period from the present until 

2018. Appendix H of the Alabama SIP submittal provides an overview of this first LTS. 

Alabama’s LTS contains the following components:

I. Inventory of all controls required or expected under all federal and state regulations by 

2009 and 2018. These controls are referred to as “on the books” or “on the way” 

(OTB/OTW).

II. Modeled expected visibility improvement from OTB/OTW (Base G) controls and 

comparison of Base G results for 2018 to the uniform rate of progress, or “glidepath” for 

the Sipsey Wilderness area. (See also EPA TSD Section III.B.3)

III. Discussion of emissions sensitivity model runs to help determine which pollutants 

and source categories are contributing the most to visibility impairment at Class I areas 

(runs conducted by the Georgia Institute of Technology).

IV. Examination of SO2 Area of Influence (AOIs) projections for the Sipsey Wilderness 

area, and also for any surrounding states’ Class I areas whose AoI includes any Alabama 

sources, to determine which specific sources are most likely to be impairing visibility.

V. Application of the four “statutory factors,” listed in 40 CFR 51.308(d)(1)(i)(A) to 

those sources identified in the previous step. (See also EPA TSD Section III.C.3)
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VI. Using the results of the four factor analyses, identification of control determinations 

for specific sources.

VII. Identification of BART-eligible sources. (See also EPA TSD Section III.D.1)

VIII. BART exemption modeling for BART-eligible sources. (See also EPA TSD 

Section III.D.2)

IX. BART determinations for sources subject to BART. (See also EPA TSD Section 

III.D.3)

X. Modeling demonstration of visibility improvement after inclusion of BART and 

reasonable progress control determinations.

XI. Determination of RPGs based on the visibility improvement expected by 2018.

Excerpted from AL SIP Narrative Pages 22- 30:

5.1 Analysis Methods 

The modeling analysis is a complex technical evaluation that begins by selection of the 

modeling system. VISTAS decided to use the following modeling systems:

Meteorological Model: The Pennsylvania State University/National Center for 

Atmospheric Research (PSU/NCAR) Mesoscale Meteorological Model (MM5) is a 

nonhydrostatic, prognostic meteorological model routinely used for Urban and Regional 

scale photochemical, fine particulate matter, and Regional Haze regulatory modeling 

studies. 

Emissions Model: The Sparse Matrix Operator Kernel Emissions (SMOKE) modeling 

system is an emissions modeling system that generates hourly gridded speciated emission 

Air Quality Model: EPA‟s Models-3/Community Multiscale Air Quality (CMAQ) 

modeling system is an „One-Atmosphere‟ photochemical grid model capable of addressing 

ozone, particulate matter (PM), visibility and acid deposition at Regional scales for periods 

up to one year. 

EPA Modeling Guidance recommends modeling an entire year or, at a minimum, 

several days in each quarter of a year to adequately represent the range of meteorological 

conditions that contribute to elevated levels of fine particulate matter. The year 2002 was 

selected by VISTAS as the modeling year for this demonstration. Meteorological inputs were 

developed for 2002 using MM5. Emission inventories were also developed for 2002 and 

processed through SMOKE. These inputs were used in the air quality model to predict fine 

particle mass and visibility. The model results for 2002 were compared with observed 

meteorological and air quality data to evaluate model performance. Several configurations 

of the meteorological and air quality model were evaluated to select a configuration that 

gave the best overall performance for the VISTAS region. 

Once model performance was deemed acceptable, the current and future year 

emissions were processed through the emissions model. The air quality modeling results are 

used to determine a relative reduction in future visibility impairment, which is used to 

determine reasonable progress. 

The complete modeling protocol used for this analysis can be found in Appendix C.

.....

5.4.1 Horizontal Modeling Domain 
20

EPA‟s modeling guidance recommends a 12-km modeling grid resolution for PM2.5 modeling 

while a 36-km grid is considered acceptable for Regional Haze. For the VISTAS modeling, a 

coarse 36-km grid resolution was used for modeling the entire U.S. and a finer 12-km grid 

was used to model the eastern U.S. 

The CMAQ model was run in one-way nested grid mode. This allowed the larger outer 

domains to feed concentration data to the inner nested domain. Two-way nesting was not 

considered due to the numerical and computational uncertainty associated with the 

technique. 

The horizontal coarse grid modeling domain boundaries were determined through a national 

effort to develop a common grid projection and boundary. A smaller 12-km grid modeling 

domain was selected in an attempt to balance location of areas of interest, such as ozone and 

fine particulate matter nonattainment areas, as well as Class I areas for Regional Haze. 

Processing time was also a factor in choosing a smaller 12-km grid modeling domain. 

The coarse 36-km horizontal grid domain covers the continental U.S. This domain was used 

as the outer grid domain for MM5 modeling with the CMAQ domain nested within the MM5 

domain. Figure 5.4.1-1 shows the MM5 horizontal domain as the outer most, blue grid with 

the CMAQ 36-km domain nested in the MM5 domain. Figure 5.4.1-2 shows the 12-km grid, 

modeling domain for the VISTAS region. 

Figure 5.4.1-1. The MM5 horizontal domain is the outer most, blue grid, with the 

CMAQ 36-km domain nested in the MM5 domain. 
21

Figure 5.4.1-2. A more detailed view of the 12-km grid over the VISTAS region.

Care was taken in the selection of the modeling system used to develop the long-term 

strategy. The VISTAS states tried to ensure that the models selected were scientifically 

appropriate for the intended application and be freely accessible to all stakeholders. 

Scientifically appropriate means that the models address important physical and 

chemical phenomena in sufficient detail, using peer-reviewed methods. Freely accessible 

means that model formulations and coding are freely available for review and that the 

models are available to stakeholders, and their consultants, for execution and verification 

at no or low cost. These criteria were used in selecting the modeling system and are 

documented on pages 22-30 of the SIP Narrative.

EPA Modeling Guidance recommends modeling an entire year or, at a minimum, several 

days in each quarter of a year to adequately represent the range of meteorological 

conditions that contribute to elevated levels of fine particulate matter. The year 2002 was 

selected by VISTAS as the modeling year for this demonstration. Meteorological inputs 

were developed for 2002 using MM5. Emission inventories were also developed for 2002 

and processed through SMOKE. These inputs were used in the air quality model to 

predict fine particle mass and visibility. The model results for 2002 were compared with 

observed meteorological and air quality data to evaluate model performance. Several 

configurations of the meteorological and air quality model were evaluated to select a 

configuration that gave the best overall performance for the VISTAS region.

Emissions Controls Modeled (AL SIP Narrative, Starting at Page 46)

7.2 Expected Visibility Results in 2018 for the Sipsey Wilderness Area under Existing 

and Planned Emissions Controls 

There are significant control programs being implemented both nationally as well as 

across the southeast between the baseline period and 2018. These programs are 

described in more detail below. The impact of programs such as the Clean Air Interstate 

Rule (CAIR) and the NOx SIP Call will be realized regionally. The implementation of 
22

these programs in Alabama will significantly reduce emissions of sources not only within 

the state that these reductions occur, but these reductions will also improve visibility at 

surrounding Class I areas outside Alabama. A case in point is Table 7.6-1 that clearly 

illustrates that overwhelmingly Alabama sources impact the Sipsey Wilderness area. 

These programs will surely benefit visibility and air quality in Alabama. 

7.2.1 Federal and State Control Requirements 

CAIR. CAIR will permanently cap emissions of SO2 and NOx from EGUs in the eastern 

United States by 2015. When fully implemented, CAIR will reduce SO2 emissions from 

EGUs in these states by more than 70%, and NOx emissions by more than 60%, from 

2003 levels. 

NOx SIP Call. Phase I of the NOx SIP call applies to certain EGUs and large non-EGUs, 

including large industrial boilers and turbines, and cement kilns. Those states affected by 

the NOx SIP call in the VISTAS region, including Alabama, have developed rules for the 

control of NOx emissions that have been approved by EPA. The NOx SIP Call has 

resulted in a 68% reduction in NOx emissions from large stationary combustion sources 

in Alabama. For this analysis, emissions were capped for NOx SIP call-affected sources 

at 2007 levels, and carried forward for the 2009 and 2018 future year inventories. 

North Carolina CSA. Under the Act, enacted in 2002, coal-fired power plants in North 

Carolina must achieve a 77% cut in NOx emissions by 2009 and a 73% cut in SO2 

emissions by 2013. This legislation establishes annual caps on both SO2 and NOx 

emissions for the two primary utility companies in North Carolina, Duke Energy and 

Progress Energy. These reductions must be made in North Carolina, and allowances are 

not saleable. 

Consent Agreements (TECO, VEPCO, Gulf Power Crist 7, Santee Cooper, EKPC and 

APCO Plant Miller). 

Under a settlement agreement, by 2008, Tampa Electric Company will install 

permanent emissions-control equipment to meet stringent pollution limits; implement a 

series of interim pollution reduction measures to reduce emissions while the permanent 

controls are designed and installed; and retire pollution emission allowances that Tampa 

Electric or others could use, or sell to others, to emit additional NOx, SO2, and PM. 

• Virginia Electric and Power Co. (VEPCO) agreed to spend $1.2 billion by 2013 to 

eliminate 237,000 tons of SO2 and NOx emissions each year from eight coal-fired 

electricity generating plants in Virginia and West Virginia. VEPCO has installed the 

following controls/fuel switches already. 

o Chesterfield Power Station: 

Unit #4-SCR by 01/01/13; 

Unit #5-SCR by 01/01/12; 

Unit #6 SCR by 01/01/11 & FGD by 01/01/10 

o Chesapeake Power Station: 

Unit #3-SCR by 01/01/13; 

Unit #4-SCR by 01/01/13 

o Clover Power Station: 

Unit #1 and Unit #2: Upgrade of the existing FGD to meet 95% removal. 
23

o Possum Point Power Station 

Unit #3 and Unit #4: Conversion of these coal fired units to natural gas. Coal 

fired operations must cease by 5/1/13. 

• A 2002 voluntary agreement calls for Gulf Power to upgrade its operation to cut 

NOx emission rates by 61% at its Crist generating plant by 2007, with major reductions 

beginning in early 2005. The Crist plant is a significant source of NOx emissions in the 

Pensacola, Florida area. 

• A 2004 consent agreement calls for Santee Cooper to install and commence 

operation of continuous emissions control equipment for PM/SO2/NOx emissions; 

comply with system-wide annual PM/SO2/NOx emissions limits; agree not to buy, sell or 

trade PM/SO2/NOx allowances allocated to Santee Cooper System as a result of said 

agreement; and to comply with emission unit limits of said agreement. Specific 

plants/units were not identified in the consent agreement. 

• A July 2, 2007 consent agreement between the U.S. EPA and East Kentucky 

Power Cooperative (EKPC) requires the utility to reduce its emissions by 62,000 tpy 

(including 54,000 tons of SO2 and 8,000 tons of NOx) by installing/operating selective 

catalytic reduction (SCR) technology; low-NOx burners, and PM and Mercury 

Continuous Emissions Monitoring at the utility‟s Spurlock, Dale and Cooper Plants. 

According to EPA, the plant‟s total emissions will drop from between 50 – 75% from 

2005 levels. As with all Federal Consent Decrees, EKPC is precluded from using 

reductions required under other programs, such as the Clean Air Interstate Rule (CAIR). 

EKPC is expected to spend over $600 million on pollution controls. 

o FGD controls for EKPC Spurlock Units 1 and 2 

o EKPC Cooper Unit 2 

• Alabama Power Company – Plant Miller (Jefferson County) On April 25, 2006, 

the U.S. EPA and the Department of Justice announced a settlement with Alabama Power 

Company (APC) to reduce emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) 

from Boiler Units 3 and 4 at its Plant Miller in Quinton, Alabama. The plant is required 

to reduce SO2 by installing flue gas desulfurization (FGD) and is required to reduce NOx 

by installing selective catalytic reduction (SCR) equipment. The Consent Decree requires 

APC to commence continuous year-round operation of SCR equipment for control of 

NOx emissions by May 1, 2008. APC is also required to begin year-round operation of 

the FGD equipment for control of SO2 emissions by December 31, 2011. The installation 

and operation of these controls are expected to result in the reduction of 4,953 tons per 

year of NOx and 22,788 tons per year of SO2. APC is also required to install and operate 

by December 31, 2008, a mercury continuous emission monitoring system. APC is 

precluded from using the emissions reductions required under other programs, such as 

the Clean Air Interstate Rule (CAIR). In addition, the Consent Decree requires APC to 

purchase and permanently retire $4.9 million worth of 2007 SO2 emissions allowances. 

Cargill, Inc. Consent Decree 

On March 3, 2006, the Federal District Court in Minnesota entered a Consent Decree 

between Cargill, Incorporated, U.S. EPA, the Iowa Department of Natural Resources and 

other participating agencies. Under this agreement, Cargill shall implement a program 

of enforceable emissions reductions of SO2, CO, NOx, and VOCs from its corn 

processing and oilseed processing plants of at least 40,000 tons per year. This includes a 

reduction of SO2 of 15,000 tons per year, CO of 16,000 tons per year, NOx of 2,500 tons 
24

per year, and VOCs of 6,500-11,500 tons per year. The Consent Decree requires permit 

applications to be submitted within three years from entry of the Consent Decree (March 

3, 2009) containing annual limits for boilers and facilities in Appendix B of the Consent 

Decree, which includes Cargill Sweeteners, to less than 15,355 tons per year on a 12-

month rolling sum. This represents a reduction of 15,067 tons of SO2 per year from the 

current allowable emissions from these sources. Also, Cargill is required submit a permit 

application within three years from entry of the Consent Decree that will include 

individual emission limits for boilers at various facilities, including the Cargill 

Sweeteners Stoker Coal-fired boiler, (which was evaluated for reasonable progress (RP)) 

that in aggregate will not exceed a capacity weighted average SO2 emission rate of 1.2 

lb/MMBtu. The Cargill Sweetners Decatur Facility is required by 3/3/09 to control and 

comply with SO2 emissions limitations for its coil fired boilers. 

One-hour Ozone SIPs (Atlanta / Birmingham / Northern Kentucky). SIPs have been 

submitted to EPA to demonstrate attainment of the one-hour ozone National Ambient Air 

Quality Standard (NAAQS). These SIPs require NOx reductions from specific coal fired 

power plants and address transportation plans in these cities. 

Heavy Duty Diesel (2007) Engine Standard (for onroad trucks and buses). EPA set a PM 

emissions standard for new heavy-duty engines of 0.01 grams per brake-horsepowerhour (g/bhp-hr), to take full effect for diesel engines in the 2007 model year. This rule 

also includes standards for NOx and non-methane hydrocarbons (NMHC) of 0.20 g/bhphr and 0.14 g/bhp-hr, respectively. These NOx and NMHC standards will be phased in 

together between 2007 and 2010, for diesel engines. Sulfur in diesel fuel must be lowered 

to enable modern pollution-control technology to be effective on these trucks and buses. 

EPA will require a 97% reduction in the sulfur content of highway diesel fuel from its 

current level of 500 parts per million (low sulfur diesel, or LSD) to 15 parts per million 

(ultra-low sulfur diesel, or ULSD). 

Tier 2 Tailpipe (Onroad vehicles). EPA Mobile rules include the Tier 2 fleet averaging 

program, modeled after the California LEV II standards. Manufacturers can produce 

vehicles with emissions ranging from relatively dirty to zero, but the mix of vehicles a 

manufacturer sells each year must have average NOx emissions below a specified value. 

Tier 2 standards became effective in the 2005 model year. 

Large Spark Ignition and Recreational Vehicle Rule. EPA has adopted new standards for 

emissions of oxides of nitrogen (NOx), hydrocarbons (HC), and carbon monoxide (CO) 

from several groups of previously unregulated nonroad engines. Included in these are 

large industrial spark-ignition engines and recreational vehicles. Nonroad spark-ignition 

engines are those powered by gasoline, liquid propane gas, or compressed natural gas 

rated over 19 kilowatts (kW) (25 horsepower). These engines are used in commercial and 

industrial applications, including forklifts, electric generators, airport baggage transport 

vehicles, and a variety of farm and construction applications. Nonroad recreational 

vehicles include snowmobiles, off highway motorcycles, and all terrain-vehicles. These 

rules were initially effective in 2004 and will be fully phased in by 2012. 

Nonroad Diesel Rule. This rule sets standards that will reduce emissions by more than 

90% from nonroad diesel equipment, and reduce sulfur levels by 99% from current levels 

in nonroad diesel fuel starting in 2007. This rule will apply to most nonroad diesel fuel in 

2010 and to fuel used in locomotives and marine vessels in 2012. 
25

Combustion Turbine MACT. The projection inventories do not include the NOx co-benefit 

effects of the MACT regulations for Gas Turbines or stationary Reciprocating Internal 

Combustion Engines, which EPA estimates to be small compared to the overall inventory. 

VOC 2-, 4-, 7-, and 10-year MACT Standards. Various point source MACTs and 

associated emission reductions were implemented. Reductions occurring before 2002 

were not considered. 

Sources and Pollutants relied on for LTS (AL SIP Narrative, Pages 58-61) 

An important step toward identifying further reasonable progress measures is to identify 

the key pollutants contributing to visibility impairment at the Sipsey Wilderness area. To 

understand the relative benefit of further reducing emissions from different pollutants, 

source sectors, and geographic areas, VISTAS engaged the Georgia Institute of 

Technology to perform emission sensitivity model runs using CMAQ. Emissions 

sensitivities were initially performed for three episodes representing winter and summer 

conditions: January 2002, July 2001, and July 2002. These runs used the initial 2018 

projection inventory and considered 30% reductions from specific pollutants, source 

categories, and geographic areas. Emissions sensitivities were repeated using the 2009 

Base D projection inventory and two month-long episodes from 2002:

SO2 from EGU sources in each VISTAS state, other RPOs in the VISTAS 12 km 

grid, and Boundary Conditions from outside the 12 km domain.

SO2 from non-EGU point sources in each VISTAS state, other RPOs, and 

Boundary Conditions

NOx from ground level sources (on-road plus off-road plus area) in each VISTAS 

state and other RPOs. In the VISTAS states, these reductions were only applied 

to specific counties that were of concern for 8-hour ozone nonattainment.

NOx from point (EGU plus non-EGU) sources in each VISTAS state and other 

RPOs

NH3 from all sources in VISTAS and other RPOs

Volatile Organic Compounds from anthropogenic and biogenic sources in the 12 

km modeling domain

Primary Carbon from all ground level sources in each VISTAS state and other 

RPOs. In the VISTAS states, these reductions were only applied to specific 

counties that were of concern for PM2.5 nonattainment.

Primary Carbon from all point sources in each VISTAS state and other RPOs

Primary Carbon from all fires in each VISTAS state and other RPOs

.....

As Figure 7.4-1 shows, the greatest visibility benefits on the 20% worst days for the 

Sipsey Wilderness area are projected to result from further reducing SO2 from EGUs. 

Reductions in SO2 from Alabama‟s EGUs would have the greatest benefit; contributions 

from other VISTAS states, other RPOs and from the boundary conditions are smaller but 

not insignificant. Additionally, smaller benefits are projected from additional SO2 

emission reductions from non-utility, industrial point sources. 
26

....

The results indicate that sulfate is the dominant contributor to visibility impairment on 

the 20% worst days at all sites, and that ammonium nitrate may be important for sites 

where the 20% worst days occur in the winter. It can be concluded that reducing SO2 

emissions from EGU and non-EGU point sources in the VISTAS states would have the 

greatest visibility benefits for the Sipsey Wilderness area.

Model Performance Evaluation (AL SIP Narrative, Pages 30-45)

The initial modeling effort focused on evaluating previous regional air quality modeling 

applications and testing candidate model configurations for the SMOKE emissions and 

CMAQ model for the VISTAS 36-km and 12-km modeling domains. This effort resulted

in a report recommending the model configuration for the annual emissions and air 

quality modeling, which is included as part of the VISTAS Emissions and Air Quality 

Modeling Protocol. The evaluation of the meteorological modeling configuration can be 

found in Appendix E, with a summary of the final meteorological and air quality 

modeling configuration in the modeling protocol contained in Appendix E and Appendix 

C, respectively. 

Air quality model performance for the 2002 modeling year was initially tested in 2004 

using an early version of the VISTAS emissions inventory. In keeping with the oneatmosphere objective of the CMAQ modeling platform, model performance was 

evaluated based on measured ozone, fine particles, and acid deposition in the Air Quality 

System (AQS), IMPROVE, Speciated Trends Network (STN), Southeastern Aerosol 

Research and Characterization (SEARCH), National Acid Deposition Program (NADP) 

and Clean Air Status and Trends Network (CASTNet) monitoring networks

....

The air quality model‟s performance was evaluated with respect to individual 

components of fine particulate matter (PM2.5), as good model performance of the 

component species will dictate good model performance of total or reconstituted fine 

particulate matter. Model performance of the total fine particulate matter and the 

resulting total light extinction was also provided as a means to discuss the overall model 

performance for the SIP. 

The soccer and bugle plots for the all of the VISTAS IMPROVE monitors are included 

here for summary purposes. The goal and criteria levels used for regional haze model 

performance were 30% and 60%, respectively, for mean fractional bias and 50% and 

75%, respectively, for mean fractional error. Plots were presented for the average 

monthly concentrations and the performance statistics for all of the most significant light 

scattering component species (Sulfate, Nitrate, and Organic Carbon) for the 20% best 

days and 20% worst days. Plots for individual IMPROVE monitors associated with the 

Alabama Class I area are included in Appendix N.

The soccer plots of monthly concentrations (Figures. 6.2-1 and 6.2-2) show that values 

for nitrate generally fall outside of criteria performance thresholds (red box). Sulfates 

and organic carbon generally fall within goal thresholds (green box), with a couple of 
27

months falling just outside the goal thresholds but well within the criteria thresholds. In 

these figures, each point represents a month. Figure 6.2-3 contains separate soccer plots 

for each season. The seasonal plots emphasize poorer nitrate performance in the 

summer (does not even appear on the plots provided because performance is off scale 

with other constituents), when observed nitrate is quite low and predicted nitrate is even 

lower. When concentration is factored into performance criteria, nitrate performance 

improves with respect to mean fractional bias and mean fractional error (Figures 6.2-4 

and 6.2-5) 

Additionally, performance assessed at the “one atmosphere” level was also deemed 

acceptable for ozone and particulate matter at various monitoring sites (STN, FRM, 

CASTNet, etc.). Overall, VISTAS found the Base G2 modeling results to be 

representative and acceptable for use in modeling projection for ozone, particulate 

matter, and regional haze.

....

Comparing the 20 percent best day chart to the 20 percent worst days chart, illustrates 

that the various components of particle pollution play a more prominent role in the 20 

percent best days than with the 20 percent worst days. Also, the species make-up on the 

20 percent best days varies more widely compared to the 20 percent worst days. This 

suggests accurately modeling each species is especially important on the 20 percent best 

days.
28

Overall, ADEM found that model performance fell within the accepted limits. As such, 

ADEM contends that the one atmosphere modeling performed by the VISTAS contractors 

is representative of conditions in Alabama and across the southeastern states and is 

applicable for use as the basis for this SIP. Additional information on model performance 

across the VISTAS region, including the Sipsey Wilderness can be found in Appendix N.

Model Performance Improvements through Emissions Inventory Improvements (AL 

SIP Narrative, Page 21)

Since the initial model performance evaluation, VISTAS has made several improvements 

to the emissions inventory, which in turn improves model performance. These inventory 

improvements are detailed in the VISTAS emissions inventory report and in Appendix D, 

and are summarized here: 

-- For electric generating utilities (EGUs), the Integrated Planning Model (IPM) 

was used to provide estimates of future year utility production and emissions. 

Continuous Emissions Monitoring (CEM) data was used to define seasonal 

variability in production and emissions. For Base G2 emissions, states updated 

IPM model projections from 2005 with control data provided by utility companies 

in 2006 through early 2007. 

-- For on-road vehicle emissions, agencies provided updated MOBILE model 

input and VMT data. 

-- For ammonia emissions from agricultural sources, the Carnegie Mellon 

University ammonia model was used to improve annual and monthly estimates. 
29

-- For fires, the VISTAS states provided fire activity data for 2002 for wildfires, 

prescribed fire, land clearing and agricultural burning and MACTEC developed 

a 2002 fire inventory. Where data allowed, Alpine Geophysics modeled fire events 

as point sources. In 2006, the U.S. Forest Service and Fish and Wildlife Service 

provided projections of increased prescribed burning in 2009 and 2018; these 

data were incorporated in the Base G inventory for all states except Florida. 

-- For non-road engines, the updated EPA NONROAD2005 emissions model was 

used in Base G. 

-- For commercial marine emissions in shipping lanes in the Gulf of Mexico and 

Atlantic Oceans, ENVIRON created gridded emissions for the VISTAS modeling 

domain using inventory data newly developed for EPA by Corbett at the 

University of Delaware. These emissions were incorporated in the Base G 

modeling. 

-- Updated inventories from the neighboring RPOs, Mexico, and Canada were 

incorporated as available.

EPA Note: More detailed discussions of the modeling protocol, quality assurance report, 

procedures, models and data used in the regional haze analysis can be found in 

Appendices C, E, F and G. The archival and acquisition of data and modeling input and 

output files are discussed in Appendix I. 

EPA Findings: In accordance with 40 CFR 51.308(d)(3), the State of Alabama provided 

the appropriate supporting documentation for all required analyses used to determine the 

State’s LTS. EPA believes that the technical analyses and modeling to assess uniform 

rate of progress and to support the LTS were successfully developed consistent with 

EPA’s interim and final modeling guidance. EPA proposes to accept the VISTAS 

technical modeling to support the LTS and determine visibility improvement for uniform 

rate of progress because the modeling system was chosen and simulated according to EPA 

modeling guidance. EPA proposes to agree with the VISTAS model performance 

procedures and results, and that the CMAQ is an appropriate tool for the regional haze 

assessments for the Alabama LTS and regional haze SIP. 

CAIR is also an element of Alabama’s LTS. CAIR rule revisions were approved into the 

Alabama SIP in 2007. See 72 FR 55659 (Oct. 1, 2007). Alabama opted to rely on CAIR 

emission reduction requirements to satisfy the BART requirements for SO2 and NOX

from EGUs. See 40 CFR 51.308(e)(4). Therefore, Alabama only required its BARTeligible EGUs to evaluate PM emissions for determining whether they are subject to 

BART, and if applicable, for performing a BART control assessment. Additionally, 

Alabama concluded that no additional controls beyond CAIR are reasonable for 

reasonable progress for SO2 for its EGUs for this first implementation period. 

Prior to the remand of CAIR, EPA believed the State’s reliance on CAIR for specific 

BART and reasonable progress provisions affecting its EGUs was adequate. The 

regional haze provisions specify that a state may not adopt a RPG that represents less 

visibility improvement than is expected to result from other CAA requirements during the 
30

planning period (40 CFR 51.308(d)(1)(vi)). As such, Alabama took into account 

emissions reductions anticipated from the CAIR in determining its 2018 RPGs. 

The RHR allows states to implement an alternative program in lieu of BART so long as 

the alternative program can be demonstrated to achieve greater reasonable progress 

toward the national visibility goal than would BART. Under regulations issued in 2005 

revising the regional haze program, EPA made just such a demonstration for CAIR. See 

70 FR 39104 (July 6, 2005). EPA’s regulations provide that states participating in the 

CAIR cap-and trade program under 40 CFR part 96 pursuant to an EPA-approved CAIR 

SIP or which remain subject to the CAIR Federal Implementation Plan in 40 CFR part 97 

need not require affected BART-eligible electrical generating (EGUs) to install, operate, 

and maintain BART for emissions of SO2 and NOx. See 40 CFR 51.308(e)(4). Because 

CAIR did not address direct emissions of PM, states were still required to conduct a 

BART analysis for PM emissions from EGUs subject to BART for that pollutant. 

Challenges to CAIR, however, resulted in the remand of the rule to EPA. See North 

Carolina v. EPA, 550 F.3d 1175 (D.C. Cir. 2008). 

EPA issued a new rule in 2011 to address the interstate transport of NOx and SO2 in the 

eastern United States. See 76 FR 48208 (August 8, 2011) (“the Transport Rule,” also 

known as the Cross-State Air Pollution Rule). On December 30, 2011, EPA proposed to 

find that the trading programs in the Transport Rule would achieve greater reasonable 

progress towards the national goal than would BART in the states in which the Transport 

Rule applies. See 76 FR 82219. Based on this proposed finding, EPA also proposed to 

revise the RHR to allow states to substitute participation in the trading programs under 

the Transport Rule for source-specific BART. EPA has not yet taken final action on that 

rule. Also on December 30, 2011, the D.C. Circuit issued an order addressing the status 

of the Transport Rule and CAIR in response to motions filed by numerous parties seeking 

a stay of the Transport Rule pending judicial review. In that order, the D.C. Circuit 

stayed the Transport Rule pending the court’s resolutions of the petitions for review of 

that rule in EME Homer Generation, L.P. v. EPA (No. 11-1302 and consolidated cases). 

The court also indicated that EPA is expected to continue to administer CAIR in the 

interim until the court rules on the petitions for review of the Transport Rule. 

In a separate action, EPA has proposed a limited disapproval of the Alabama regional 

haze SIP because of deficiencies in the State’s regional haze SIP submittal arising from 

the State’s reliance on CAIR to meet certain regional haze requirements. See 76 FR 

82219 (December 30, 2011). EPA is not proposing to take action in this rulemaking on 

issues associated with Alabama’s reliance on CAIR in its regional haze SIP. 

Also, on July 30, 2007, the D.C. Circuit mandated the vacatur and remand of the 

Industrial Boiler MACT Rule. Notwithstanding the vacatur of this rule, the VISTAS 

states, including Alabama, decided to leave these controls in the modeling for their 

regional haze SIPs since it is believed that by 2018, EPA will have re-promulgated an 

industrial boiler MACT rule or the states will have addressed the issue through state-level 

case-by-case MACT reviews in accordance with section 112(j) of the CAA. 
31

EPA proposes to find this approach acceptable for the following reasons. Effective July 

30, 2007, the D.C. Circuit mandated the vacatur and remand of the Industrial Boiler 

MACT Rule.1 This MACT was vacated since it was directly affected by the vacatur and 

remand of the Commercial and Industrial Solid Waste Incinerator Definition Rule. EPA 

proposed a new Industrial Boiler MACT rule to address the vacatur on June 4, 2010, (75 

FR 32006) and issued a final rule on March 21, 2011 (76 FR 15608). The VISTAS 

modeling included emissions reductions from the vacated Industrial Boiler MACT rule, 

and Alabama did not redo its modeling analysis when the rule was re-issued. Even 

though the State’s modeling is based on the vacated Industrial Boiler MACT limits, 

Alabama’s modeling conclusions are unlikely to be affected because the expected 

reductions due to the vacated rule were relatively small compared to the State’s total SO2, 

PM2.5, and coarse particulate matter (PM10) emissions in 2018 (i.e., 0.2 to 0.5 percent,

depending on the pollutant, of the projected 2018 SO2, PM2.5, and PM10 inventory). 

Thus, EPA does not expect that differences between the vacated and final Industrial 

Boiler MACT emission limits would affect the adequacy of the existing Alabama 

regional haze SIP. If there is a need to address discrepancies between projected 

emissions reductions from the vacated Industrial Boiler MACT and the Industrial Boiler 

MACT issued on March 21, 2011 (76 FR 15608), EPA expects Alabama to do so in the 

State’s five-year progress report. 

References used in the EPA review: 

1. EPA’s Guidance on the Use of Models and Other Analyses for Demonstrating 

Attainment of Air Quality Goals for Ozone, PM2.5, and Regional Haze. Located at 

http://www.epa.gov/scram001/guidance/guide/final-03-pm-rh-guidance.pdf (EPA-454/B07-002), April 2007.

2. “(Draft) Guidance for Demonstrating Attainment of Air Quality Goals for PM2.5 and 

Regional Haze”, EPA, 2001. http://www.epa.gov/ttn/scram/guidance_sip.htm.

3. 2002 Base Year Emission Inventory SIP Planning: 8-hr Ozone, PM2.5 and Regional 

Haze, EPA memorandum from Lydia Wegman to Peter Tsirigotis, November 18, 

2002. 

4. CAA §§112(j)(2), (3), (5), and (6). 

5. CAA §505 specifies procedures for notification to the Administrator and affected 

States.

 

1

 See NRDC v. EPA, 489 F.3d 1250 (D.C. Cir. 2007).
32

III. Evaluation of Regional Haze Submittal

C. Long-Term Strategy 

C.2. Identification of Sources and Factors to be Considered for Reasonable 

Progress: (40 CFR 51.308(d)(3)(iv-v)) 

The State must identify all anthropogenic sources of visibility impairment considered by 

the State in developing its long-term strategy. The State should consider major and minor 

stationary sources, mobile sources, and area sources. The State must consider, at a 

minimum, the following factors in developing its long-term strategy: (A) emission 

reductions due to ongoing air pollution control programs, including measures to address 

reasonably attributable visibility impairment; (B) measures to mitigate the impacts of 

construction activities; (C) emissions limitations and schedules for compliance to achieve 

the reasonable progress goal; (D) source retirement and replacement schedules; (E) 

smoke management techniques for agricultural and forestry management purposes 

including plans as currently exist within the State for these purposes; measures to 

mitigate the impacts of construction activities; (F) enforceability of emission limitations 

and control measures; and the (G) anticipated net effect on visibility due to projected 

changes in point, area, and mobile source emissions over the period. 

State Regional Haze Submittal

AL SIP Narrative, Pages 78-81:

ADEM’s Process on Reasonable Progress Assessment 

Step 1: Determine pollutants of concern. 

VISTAS evaluated the species contribution on the 20% worst visibility days and 

concluded that sulfate accounted for the greatest contribution of visibility impairing 

pollution. The VISTAS states concluded that controlling SO2 emissions was the 

appropriate step in addressing the reasonable progress assessment for 2018. The 

findings were consistent with the findings of SAMI where it was confirmed that sulfate 

particles account for the greatest portion of the haze affecting Class I areas in the 

Southern Appalachian region and that these sulfates were produced in large part from 

SO2 emissions from coal combustion. 

Step 2: Determine which source sectors should be evaluated for reasonable progress. 

Since SO2 point source emissions in 2018 are projected to represent the majority of the 

total SO2 emissions inventory, the VISTAS states concluded that the focus should be on 

electric generating unit (EGU) and non-EGU point sources of SO2 emissions. 

Step 3: Determine if the Clean Air Interstate Rule (CAIR) is sufficient for reasonable 

progress. 

“In determining the emissions and visibility improvement achieved during each 

implementation period, states should include all air quality improvements that will be 

achieved by other programs and activities under the CAA and any state air pollution 

control requirements” (64 FR 35733). In keeping with this recommendation, Alabama, as 

part of its long term reasonable progress analysis to consider potential sources 
33

contributing to visibility impairment, examined other CAA requirements such as CAIR. 

ADEM evaluated the amount of expected SO2 reduction from EGUs due to CAIR. Since 

the EGUs will be reducing their SO2 emissions by approximately 70% through these 

programs, ADEM concluded that additional EGU control during this time period 

(between present and 2018) was not reasonable. 

The preceding section (Section 7.6) discusses a general four factor analysis for coal fired 

units. Additionally, for EGUs subject to CAIR, EPA evaluated a number of factors, 

including the cost of compliance and time necessary for compliance. In the CAIR rule, 

EPA determined "that the earliest reasonable deadline for compliance with the final 

highly cost effective control levels for reducing emissions was 2015..." (70 FR 25197-

25198, May 12, 2005) The State believes the cost of compliance and time necessary for 

compliance are the dominant factors for determining if additional reductions would be 

reasonable from CAIR subject EGUs. Based on the detailed analyses in the May 12, 

2005, CAIR rule, the State concludes that CAIR controls satisfy reasonable progress for 

SO2 for the first planning period ending in 2018. 

Under the Rule, each “state must identify the uniform rate of progress over the 60 year 

period that would be needed to attain natural background conditions by the year 2064” 

(64 FR 35732). To calculate the rate of progress represented by each reasonable 

progress goal, Alabama compared baseline visibility conditions to natural visibility 

conditions at the Sipsey Wilderness area and determined the uniform rate of visibility (in 

dv) that would need to be maintained during each implementation period in order to 

attain natural visibility conditions by 2064. SO2 emissions reductions that are predicted 

by the IPM to meet the CAIR requirements are not certain due to the current rule‟s 

reliance on trading and the use of banked Title IV allowances. ADEM intends to review 

the SO2 reductions from CAIR at the time of the periodic report in 2012 to ensure that 

the reductions are in fact taking place. Based on the controls predicted by IPM under 

CAIR, ADEM has concluded that, at this time, these existing regulatory programs 

constitute reasonable measures for Alabama‟s EGUs during this first assessment period 

(baseline to 2018). It is important to note that the IPM model was used extensively by 

EPA when performing analyses for CAIR. 

Step 4: Determine which emission units would be evaluated based on impact. 

ADEM calculated the fractional contribution from all emission units within the SO2 AoI 

for a given Class I area and identified those emission units with a contribution of 1% or 

more to the visibility impairment at that Class I area. 

ADEM recognized that there was neither sufficient time nor resources available to 

evaluate all units within a given AoI. Therefore, a threshold needed to be established to 

determine which units would be evaluated. ADEM chose to adopt 1% as the contribution 

threshold used to consider a source for a four factor analysis of reasonable further 

controls based on the precedence established in other Federal programs that used an 

equal to or higher threshold for evaluation (For a full explanation of the rationale behind 

the selection of the 1% threshold, please refer to Appendix H, Section 5.0). These 

programs are listed below:
34

The BART rule specified that a maximum impact of 0.5 dv is an acceptable 

threshold for establishing source contribution. This threshold is representative of 

a 5% change in visible perception. 

The NOx SIP call established a significance level for 126 petitions (the level at 

which a state‟s contribution to another state‟s ozone was considered significant) 

at 4 parts per billion. This threshold is representative of approximately 3.2% of 

the 1 hour ozone standard of 125 parts per billion, which was the standard at the 

time. 

The CAIR rule established a PM contribution threshold of 0.2 μg/m3 as 

significant. This threshold represents 1.3% of the Annual PM2.5 standard of 15 

μg/m3. 

The NAAQS assign significant impact levels for human health standards based on 

a source‟s contribution to air quality. These significance levels represent a 

percentage of the NAAQS. Those facilities able to demonstrate that a new or 

modified source‟s contribution is less than a particular significance level is 

relieved of further modeling. ADEM examined all the averaging periods for the 

criteria pollutants and determined that the 1% threshold contribution chosen for 

reasonable progress was as stringent as any significant impact level, the most 

restrictive being NO2 at 1 μg/m3 or 1%. (NO2 NAAQS: 100 μg/m3) 

For the Sipsey Wilderness area, six units were determined to have impacts greater than 

1% of the total impact. These included 1 unit at the International Paper- Courtland Mill, 

4 units at the Solutia, Inc. facility and 1 unit at the Cargill, Inc. facility. 

At both the International Paper- Courtland Mill and the Solutia, Inc. facilities, all units 

identified in the Sipsey AoI table were subject to BART and subsequently were evaluated 

for BART controls. It is ADEM‟s contention that, for these units, BART is equivalent to 

Reasonable Progress (RP). 

For the Cargill, Inc, facility, a four factor analysis was performed for the Keeler Stoker 

Boiler (Unit S-407), a summary of which is included in Step 5 below, as well as in 

Appendix O. 

For the Breton Wildlife Refuge, a sulfur recovery unit at the Escambia Operating 

Company- Big Escambia Creek was determined to have impacts greater than 1% of the 

total impact. This unit took a permit limit of approximately 7963 tons of actual SO2 

emissions (equivalent to a ~ 40% reduction in emissions). This limit precluded the source 

from BART subjectivity and a permit was issued enforcing this limit in mid 2006. As such, 

ADEM contends that this unit has, in effect been through the BART process, and that this 

reduction is sufficient for RP. The State of Louisiana used a number of tools including 

CENRAP source apportionment modeling and the VISTAS AOI analyses in developing 

their source list for the Breton Wildlife Refuge. Discussions with the State of Louisiana 

yielded no request for a four factor analysis for this source. For these reasons, ADEM 

contends that no further evaluation is needed for this source. 
35

For the St. Marks Wilderness area, two units at the Sanders Lead Company were 

determined to have impacts greater than 1% of the total impact. The Florida reasonable 

progress methodology used to identify sources for a four factor analysis for the St. Marks 

Wilderness Area involved assessing emissions units having sulfur dioxides (SO2) 

emissions of at least 250 tons per year, and emissions (Q) to distance ratio of greater 

than or equal to 50 (Q/d>=50), and being within 300 km of the Class I area. Although 

the States of Alabama and Florida are using different methodologies, ADEM feels it is 

the responsibility of the state in which the Class I area resides to establish procedures for 

evaluating reasonable progress for that Class I area. In consultation with the Florida 

Department of Environmental Protection, Florida did not request a four factor analysis 

of these units. For this reason, ADEM contends that no further evaluation is needed for 

these sources. 

AL SIP Narrative, Pages 69-73:
36
37

AL SIP Narrative,Pages 91-92:

Section 308(d)(3)(v) of the Rule addresses several factors, including the role of fire at 

Class I areas and status of state planning for smoke management, the role of dust and 

fine soil at Class I areas and status of state plans to mitigate emissions from construction 

activities and the role of NH3 and potential benefits if emissions from agricultural 

sources are mitigated. 

As discussed in Section 2.4, elemental carbon (sources include agriculture, prescribed 

wildland fires, and wildfires) is a relatively minor contributor to visibility impairment at 

the Sipsey Wilderness Area in Alabama. Section 51.308(d)(3)(iv)(E) of the Rule requires 

that each state must consider, at a minimum, the following factors in developing the LTS: 

Smoke Management techniques for agricultural and forestry management purposes 
38

include plans as they currently exist within the state for these purposes. The Alabama 

Forestry Commission (“AFC”) has developed The State of Alabama Smoke Management 

Program, which serves to regulate vegetative debris burning for forestry, agriculture, 

and wildlife purposes in the State of Alabama. ADEM‟s Air Division has developed a 

state air pollution control regulation (ADEM Admin. Code 335-3-3-.01, Open Burning) 

that lists the specific circumstances in which open burning is permissible. ADEM has an 

approved smoke management program that addresses the issues laid out in EPA‟s 1998 

draft guidance “Interim Air Quality Policy on Wildland and Prescribed Fires” for smoke 

management plans. The voluntary prescribed fire smoke management techniques 

practiced include Class I areas as a sensitive receptor, and ADEM contends that the 

current smoke management plan is sufficient to satisfy the directive in Section 

308(d)(3)(iv)(E). 

In regard to construction activities and fugitive dust emission sources, ADEM has issued 

regulations to address the control of fugitive dust from construction activities and to 

control particulates from fugitive dust emission sources generated within plant 

boundaries. ADEM Admin. Code 335-3-4-.02, reads as follows: 

(1) No person shall cause, suffer, allow, or permit any materials to be handled, 

transported, or stored; or a building, its appurtenances, or a road to be used, 

constructed, altered, repaired, or demolished without taking reasonable precautions to

prevent particulate matter from becoming airborne. Such reasonable precautions shall 

include, but not be limited to, the following: 

(a) Use, where possible, of water or chemicals for control of dust in the demolition of 

existing buildings or structures, construction operations, the grading of roads, or the 

clearing of land; 

(b) Application of asphalt, oil, water, or suitable chemicals on dirt roads, materials stock 

piles, and other surfaces which create airborne dust problems; 

(c) Installation and use of hoods, fans, and fabric filters (or other suitable control 

devices) to enclose and vent the handling of dusty materials. Adequate containment 

methods shall be employed during sandblasting or other similar operations. 

(2) Visible Emissions Restrictions Beyond Lot Line. No person shall cause or permit the 

discharge of visible fugitive dust emissions beyond the lot line of the property on which 

the emissions originate. 

(3) When dust, fumes, gases, mist, odorous matter, vapors, or any combination thereof 

escape from a building or equipment in such a manner and amount as to cause a 

nuisance or to violate any rule or regulation, the Director may order that the building or 

equipment in which processing, handling, and storage are done be tightly closed and 

ventilated in such a way that all air and gases and air or gas-borne material leaving the 

building or equipment are treated by removal or destruction of air contaminants before 

discharge to the open air. 

In regards to agricultural ammonia, ADEM currently has no regulations. EPA‟s Safe 

Harbor Agreement, called the Air Compliance Agreement, is intended to produce air 

quality monitoring data on Animal Feeding Operations (AFOs) emissions during a twoyear study, while at the same time protecting participants through a “safe harbor” from 

liability under certain provisions of federal environmental laws. The purpose of the 
39

monitoring is to allow development of valid emission factors for equivalent (but 

unmonitored) farms. At this time, the study is ongoing to develop the emissions factors, 

and as such, there are currently no federal regulations related to the control of ammonia 

from AFOs. Once EPA has proposed regulations for these sources, ADEM will commit to 

evaluating potential controls on applicable sources in Alabama. 

A final CMAQ modeling run was performed in early 2008 to account for the cumulative 

benefits of the Base G2a emissions controls, BART controls, and additional measures to 

achieve reasonable progress by 2018. This SIP contains the revised RPGs for the Sipsey 

Wilderness Area reflecting these final decisions. 

EPA Findings: EPA proposes to find that ADEM has adequately identified the 29 nonEGU sources to be evaluated for reasonable progress. The analysis for Cargill is 

addressed in EPA’s TSD - III.C.3.

ADEM has concluded that, at this time, the application of BART constitutes reasonable 

progress for five units at Solutia and International Paper-Courtland and thus, is not 

requiring any additional controls for reasonable progress. As discussed in EPA’s 

Reasonable Progress Guidance document, since the BART analysis is based, in part, on 

an assessment of many of the same factors that must be addressed in establishing the 

RPG, EPA believes it is reasonable to conclude that any control requirements imposed in 

the BART determination also satisfy the RPG-related requirements for source review in 

the first RPG planning period.2 Thus, EPA proposes to agree with the State’s conclusions 

that the BART control evaluations satisfy reasonable progress for the first planning 

period for these five units. 

For the three units at Sanders Lead and Escambia impacting Class I areas in other states 

who are using different methodologies, EPA proposes to agree with ADEM that it is the 

responsibility of the state in which the Class I area resides to establish procedures for 

evaluating reasonable progress for that Class I area. EPA proposes that the elimination of 

Akzo Nobel because of updated data is also appropriate.

Prior to the CAIR remand by the court, EPA believed the State’s demonstration that no 

additional controls for SO2 beyond CAIR are reasonable for the 19 affected EGUs for the 

first implementation period was acceptable. As explained in Section III.C.1–EPA 

Findings, the State’s demonstration regarding CAIR and reasonable progress for EGUs, 

and other provisions in this SIP revision, are based on CAIR.

In a separate action proposing limited disapproval of the regional haze SIPs of a number 

of states, EPA noted that these states relied on the trading programs of CAIR to satisfy 

the BART requirement and the requirement for a LTS sufficient to achieve the stateadopted reasonable progress goals. See 76 FR 82219 (December 30, 2011). In that action, 

EPA proposed a limited disapproval of Alabama’s regional haze SIP submittal insofar as 

 

2

Pages 4.2-4.3, July 1, 2007 memorandum from William L. Wehrum, Acting Assistant 

Administrator for Air and Radiation, to EPA Regional Administrators, EPA Regions 1-

10, Guidance for Setting Reasonable Progress Goals under the Regional Haze Program,
40

the SIP relied on CAIR. For that reason, EPA is not taking action on that aspect of 

Alabama’s regional haze SIP in this action. 
41

III. Evaluation of Regional Haze Submittal

C. Long-Term Strategy 

C.3. Source or Source Category Specific Analyses for Reasonable Progress: (40 

CFR 51.308(d)(1)(i)(A)

For the significant sources and source categories located within the State and determined 

to be significantly impacting a mandatory Class I Federal area, the State must document 

that it considered the costs of compliance, the time necessary for compliance, the energy 

and non-air quality environmental impacts of compliance, the remaining useful life of 

any potentially affected sources, and how these factors were taken into consideration in 

establishing the reasonable progress goal.

State Regional Haze Submittal

AL SIP Narrative, Page 81:

The emission unit identified in Step 4 above [EPA Note: Cargill, Inc, facility, the Keeler 

Stoker Boiler (Unit S-407] was evaluated using the statutory and regulatory factors of 1) 

cost of compliance, 2) time necessary for compliance, 3) the energy and non-air quality 

environmental impacts of compliance, and 4) the remaining useful life of the emissions 

unit. For the limited purpose of evaluating the cost for the reasonable progress 

assessment in this first Regional Haze SIP, ADEM believes it is not equitable to require 

non-EGUs to bear a greater economic burden than EGUs for a given control strategy. 

ADEM used the capital and operating costs provided in the CAIR rule to establish a 

$2,000 cost/ton of SO2 removed threshold. This limit acts as an inherent barrier to nonEGUs considering additional controls. The cost of controls is significant--not just in 

terms of capital cost, but also the cost of labor needed to efficiently and effectively 

maintain the equipment. “The availability of skilled labor--specifically, boilermakers--is 

an important constraint for the installation of significant amounts of emission controls. 

Boilermakers are skilled steel workers who are specially trained to install both NOX 

controls, such as SCR, and SO2 controls, such as scrubbers” (69 FR 4617). During the 

current reasonable progress assessment, no units in Alabama were identified for 

additional control since no measures were found to be below the $2,000 cost threshold. 

The analysis of Cargill Unit S-407 is included in Appendix O and a summary of the 

Cargill facility is provided below. 

Cargill, Inc. Four Factor Analysis 

Cargill Unit S-407 showed an impact of 1% or greater; therefore, a four factor analysis 

was necessary. The unit is permitted to burn coal, natural gas, or No. 2 fuel oil. Coal is 

the primary fuel source. The unit is equipped with a Lear Sigler Continuous Opacity 

Monitor and Nitrogen Oxide/Oxygen Emissions Monitor. The boiler exhaust is controlled 

by a Carborundum baghouse. The coal handling system is controlled by a Griffin 

baghouse. The pneumatic flyash conveying system is controlled by an Ultra Industries

Baghouse, while air displaced by the flyash to the ash silo is controlled by a National 

Conveyor Baghouse. A summary of control options considered is listed below: 

Cargill evaluated 3 options: lower sulfur content coal, wet scrubbers and dry scrubbers. 
42

Lower sulfur content coal could not be used because of its availability. Also, lower sulfur 

content coal would require significant modification to the boiler to burn it and would 

challenge the combustion integrity due to the higher dust content nature of lower sulfur 

coal. Therefore, lower sulfur coal is technically infeasible. As for the add-on controls 

(wet and dry scrubbers), Cargill estimated that it would cost $2,946/ton to control SO2 

with these technologies. As such, no control was deemed feasible for this unit.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. ADEM concluded, based on the State’s evaluation of the four CAA factors, 

that no further controls were warranted for Cargill unit S-407. After reviewing ADEM’s 

methodology and analyses, EPA proposes to find Alabama’s conclusions acceptable. 

EPA also proposes to find that all currently available control technologies at the time of 

analysis and applicable to this facility were evaluated fully in terms of the four reasonable 

progress factors, and the State consistently applied its criteria for reasonable compliance 

costs. Although the use of a specific threshold for assessing costs means that Alabama 

may not have fully considered other available emissions reduction measures above its 

threshold, EPA believes that the Alabama SIP still ensures reasonable progress. In 

considering Alabama’s approach, EPA is also proposing to place great weight on the fact 

that there is no indication in the SIP submittal that Alabama, as a result of using a specific 

cost effectiveness threshold, rejected potential reasonable progress measures that would 

have had a meaningful impact on visibility in its Class I area. EPA notes that given the 

emissions reductions resulting from CAIR, Alabama’s BART determinations, and the 

measures in nearby states, the visibility improvements projected for the affected Class I 

area are in excess of that needed to be on the uniform rate of progress. 
43

III. Evaluation of Regional Haze Submittal

C. Long-Term Strategy 

C.4. Enforceability of Reasonable Progress Measures: The SIP needs to provide 

enforceable emissions limitations and schedules for compliance for each newly adopted 

measure needed to achieve the reasonable progress goals. 

State Regional Haze Submittal

EPA Note: No newly adopted source specific measures were required by the State of 

Alabama to achieve the reasonable progress goals for Sipsey Wilderness Area.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. 
44

III. Evaluation of Regional Haze Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.1. Identification of all BART Eligible Sources: The SIP should include a list of all 

BART-eligible sources within the State.

State Regional Haze Submittal

AL SIP Narrative, Pages 81-82:

Section 169A of the CAA directs states to assess certain emission sources which meet 

specific criteria for additional controls in order to address visibility impacts. States are 

directed to conduct BART determinations for such sources in specific source categories, 

whose emissions contribute to visibility impairment in Class I areas. The 1999 Regional 

Haze rule includes the BART requirement, and directs states to include BART in their 

Regional Haze SIPs. On July 6, 2005, EPA published a revised final rule, including 

Appendix Y of 40 CFR Part 51, the Guidelines for BART Determinations Under the 

Regional Haze Rule (hereinafter referred to as the “BART Guidelines”) that provides 

direction to states on determining which sources should be subject to BART, and how to 

determine BART for these sources. 

A BART-eligible source is one which has the potential to emit 250 tons or more of 

a visibility-impairing air pollutant, was put in place between August 7, 1962 and August 

7, 1977, and whose operations fall within one or more of 26 specifically listed source 

categories. Under the CAA, BART is required for any BART-eligible source that a State 

determines „„emits any air pollutant which may reasonably be anticipated to cause or 

contribute to any impairment of visibility in any such area.‟‟ 

For those sources subject to BART, Section 169A(g)(7) of the CAA requires that 

States must consider the following factors in making BART determinations: (1) the costs 

of compliance, (2) the energy and non-air quality environmental impacts of compliance, 

(3) any existing pollution control technology in use at the source, (4) the remaining 

useful life of the source, and (5) the degree of improvement in visibility which may 

reasonably be anticipated to result from the use of such technology. 

AL SIP Narrative, Page 83:

The following is a list of facilities with BART-eligible sources in Alabama. Please see 

Attachment H3 to Appendix H for a description of each BART-eligible emission unit: 

Alabama BART Eligible Facility List: 

3M Company, Decatur Plant Hunt Refining Co, Tuscaloosa 

Alabama Electric Coop Lowman International Paper Co Prattville 

Alabama Power Co Barry International Paper Co Riverdale 

Alabama Power Co EC Gaston International Paper Co Courtland 

Alabama Power Co Gorgas JSC Brewton (Smurfit Stone) 

Alabama Power Co Greene Co Lehigh Cement – JCDH 

Alabama Power Co Miller- JCDH MeadWestvaco Mahrt Mill 

American Cast Iron Pipe- JCDH National Cement Co of Alabama 

Boise White Paper Oak Grove Resources- JCDH 
45

Bowater Inc.- Alabama Sanders Lead Co 

BP Amoco Chemicals Shell Chemical Co Saraland 

Carmeuse Lime & Stone Solutia- Decatur 

CEMEX, Inc. Sloss Industries- JCDH 

Chemical Lime Co Alabaster TVA, Colbert 

Chemical Lime Co Montevallo TVA, Widows Creek 

Ciba Specialty Chemicals Corp US Pipe & Co- Bessemer- JCDH 

ConocoPhillips Co Chatom US Steel- Fairfield- JCDH 

Degussa Corporation Weyerhaeuser 

Escambia Operating Co Big Escambia Creek Wise Alloys LLC, Alloys Plant 

Ft Jms-Pennington, Naheola Vintage Petroleum, Inc, Flomaton 

These BART-eligible sources were identified using the following methodology in the 

BART Guidelines3;

• One or more emission units at the facility fit within one of the 26 categories listed 

in the BART Guidelines;

• The emission unit(s) were in existence on August 7, 1977, and began operation at 

some point on or after August 7, 1962; and

• The potential emissions, considering federally enforceable permit limits, from all 

emission units identified in the previous two bullets were greater than 250 tons or 

more per year of any of these visibility-impairing pollutants: SO2, NOX, and PM10.

The BART Guidelines recommend addressing these visibility-impairing pollutants: SO2, NOx, 

and PM, and suggest that states use their best judgment in determining whether to address 

VOC or ammonia (NH3) emissions. ADEM addressed SO2 and NOx, and used PM10 as an 

indicator for particulate matter to identify BART-eligible units, as the BART Guidelines 

recommend. As discussed in detail in subsequent sections as well as in Appendix H, VISTAS 

modeling demonstrated that VOCs and NH3 from point sources do not contribute to visibility 

impairment at Class I areas within the VISTAS region. As such, ADEM did not evaluate 

emissions of VOCs and NH3 in BART determinations. VISTAS did evaluate a few large 

ammonia sources, none of which were located in Alabama.

 

3 List of BART Source Categories. The BART requirement only applies to sources in specific categories 

listed in the Clean Air Act. These categories are: (1) Fossil-fuel fired steam electric plants of more than 250 

million British thermal units (BTU) per hour heat input, (2) Coal cleaning plants (thermal dryers), (3) Kraft 

pulp mills, (4) Portland cement plants, (5) Primary zinc smelters, (6) Iron and steel mill plants, (7) Primary 

aluminum ore reduction plants, (8) Primary copper smelters, (9) Municipal incinerators capable of charging 

more than 250 tons of refuse per day, (10) Hydrofluoric, sulfuric, and nitric acid plants, (11) Petroleum 

refineries, (12) Lime plants, (13) Phosphate rock processing plants, (14) Coke oven batteries, (15) Sulfur 

recovery plants, (16) Carbon black plants (furnace process), (17) Primary lead smelters, (18) Fuel 

conversion plants, (19) Sintering plants, (20) Secondary metal production facilities, (21) Chemical process 

plants, (22) Fossil-fuel boilers of more than 250 million BTUs per hour heat input, (23) Petroleum storage 

and transfer facilities with a capacity exceeding 300,000 barrels, (24) Taconite ore processing facilities, 

(25) Glass fiber processing plants, and (26) Charcoal production facilities.
46

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision.
47

III. Evaluation of Regional Haze Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.2. Modeling or Other Demonstrations for BART Exempt Sources: For each 

BART-eligible source in the State exempted from BART a demonstration, using an 

acceptable approach, that the source or group of sources does not violate the established 

threshold. The established exemption threshold for determining if a BART-eligible 

source contributes to regional haze cannot exceed 0.5 deciviews.

State Regional Haze Submittal

AL SIP Narrative, Pages 83-88:

Of the original 40 sources considered by ADEM as part of its BART source list, 3 

sources were given exemption status solely for this reason. [EPA Note: VOC emissions 

from BART sources do not cause or contribute to visibility impairment and do not need to be 

included in BART analyses.] After estimating the potential emissions across all BART 

eligible sources at these facilities, ADEM determined that the following facilities‟ 

visibility impairing pollutant (VIP) emissions no longer exceed 250 tons per year (Table 

7.8.2-1). Therefore, these sources are no longer considered “BART-eligible” for 

evaluation of visibility impairment at Federal Class I areas.

The BART Guidelines list specific criteria that must be met in order for sources to be 

considered BART-eligible. One of the criteria for a source to be considered BARTeligible was the potential emissions from all affected emission units considering all 

federally enforceable permit limits, were greater than 250 tons or more per year of any of 

these visibility-impairing pollutants: SO2, NOx, and PM10. Alabama had three sources 

which chose to take emissions limits in order to be exempt from the entire BART process. 

By taking an emissions limit, Gulf States Paper Corporation, Kerr-McGee Chemical 

LLC, and Mobile Energy Services Company no longer have BART-eligible sources. 

Additionally, the Escambia Operating Company‟s Big Escambia Creek facility also took 

an enforceable limit that resulted in an insignificant impact, (i.e. less than 0.5 dv) thereby 

relieving the source from completing a BART determination. These limits have been 

written into and are enforced through the permits for each applicable source at the 

facility. Table 7.8.3-1 provides information on these sources. 
48

EPA‟s documents strive to set these thresholds in the context of the human perception of 

visibility change. As noted above, EPA considers a 1.0 dv change in visibility to be 

humanly perceptible “in virtually all situations.” Also, the preamble to the BART 

Guidance cites an analysis in an Appendix of a NAPAP (National Acid Precipitation 

Assessment Program) report, which asserts that “changes in light extinction of 5% will 

evoke just noticeable changes in most landscapes.” (A 5% change is approximately 0.5 

dv.) But, as noted above, the preamble also states that perceptibility is not a prerequisite 

for choosing a contribution threshold. Putting all this together, it appears that “causing” 

visibility impairment means having a humanly perceptible impact (for which EPA 

considers the practical threshold to be 1.0 dv) while “contributing” to visibility 

impairment means having a smaller impact (for which EPA considers the threshold to be 

0.5 dv or some smaller value) that may or may not be perceptible. 

ADEM retained the threshold of 0.5 dv for evaluating significance for several reasons. 

First, there is a clear spatial variability of sources across the state. Additionally, ADEM 

is electing to use half of the threshold established by EPA for causing visibility 

impairment. Lastly, the BART rule is a source specific rule and ADEM does not have a 

technical justification for lowering the threshold based on concerns of multiple plume 

interaction. As such, ADEM concluded that EPA‟s suggested contribution threshold of 

0.5 dv was appropriate for evaluating facility contributions at Class I areas that Alabama 

sources impact. 
49

Of Alabama‟s 37 final BART-eligible sources that submitted exemption modeling 

demonstrations, 35 of the 37 sources were able to exempt using the 0.5 dv threshold. 

Results of these demonstrations are summarized in Tables 7.8.4-1 and 7.8.4-2 below. 

Additional details are available in Appendix H. Facilities found to be subject to BART 

must complete a BART determination analysis and these analyses can be found in the 

Attachments to Appendix H as well. 

ADEM requested that its sources follow the VISTAS modeling protocol in development of 

their site specific protocols and explain any deviations that they proposed to use. In the 

site-specific modeling demonstrations submitted by Alabama‟s BART-eligible sources, 

the CALPUFF model incorporating three years of pre-processed MM5 meteorological 

data was used to evaluate the deciview change compared to natural background 

conditions at each of the Class I areas within 300 km of the source. Both the 4 km and 12 

km MM5 datasets prepared by VISTAS were used. Facilities submitted site-specific 

modeling protocols and subsequent modeling demonstrations based upon the VISTAS 

modeling protocol. The site-specific protocols are found in Attachment H-5 and the 

demonstrations are found in Attachment H-6. The protocols and demonstrations were 

reviewed by ADEM‟s Industrial Chemicals and Industrial Minerals Sections as well as 

the Meteorological Section. The individual facility modeling demonstrations were shared 

with both EPA and FLMs for their review and comment. The resulting comments were in 

turn shared with the facilities. ADEM worked throughout the process to resolve many of 

the issues and concerns reflected in their comments. ADEM staff reviewed the 

demonstrations to determine whether sources demonstrated impacts of 0.5 deciview (dv) 

or less on any Class I area within 300 km of the source. Sources demonstrating less than 

a 0.5 dv impact are considered exempt. Sources contributing 0.5 dv impact or greater 

were considered subject to BART and were required to proceed to an analysis of what 

control measures, if any, constitute BART for the source.

Table 7.8.4-1 lists the facilities that were able to demonstrate exemption from BART 

based on CALPUFF modeling conducted using the VISTAS modeling protocol and the 

old IMPROVE equation. [EPA Note: This table shows all modeling results. International 

Paper – Courtland and Solutia were not “exempted” out of BART.]
50

Table 7.8.4-2 lists the facilities that were able to demonstrate exemption from BART based on 

the VISTAS modeling protocol and the new IMPROVE equation.
51

In total, 35 of Alabama‟s 37 BART-eligible sources were able to demonstrate that they 

did not cause or contribute to visibility impairment in any Class I area within 300 km of 

the source. Two sources used the new IMPROVE equation in efforts to demonstrate 

exemption. 

Eight of Alabama‟s BART-eligible sources are EGUs. EPA has determined that, as a 

whole, the CAIR cap-and-trade program improves visibility more than implementing 

BART for individual sources in states affected by CAIR. A state that opts to participate in 

the CAIR program under part 96 AAA-EEE need not require affected BART-eligible 

EGUs to install, operate, and maintain BART for SO2 or NOx emissions. Given that 

many of the BART-eligible units are installing scrubbers and NOx controls, and since 

Alabama is participating in CAIR and accepts EPA‟s overall finding that CAIR 

“substitutes” for BART for NOx and SO2, Alabama‟s EGUs were allowed to submit 

BART exemption modeling demonstrations for PM emissions only. All eight EGUs 

demonstrated visibility impacts below the exemption threshold for all Class I areas.

AL SIP Narrative, Appendix H12 - 15:

Determination of pollutants to address in BART

7.5 Exemption of Point Source Volatile Organic Compounds (VOCs) for BART 

Purposes

The State of Alabama has determined through modeling that VOCs from point sources 

are notanticipated to cause or contribute significantly to the impairment of visibility in 

any Class I area and should be exempt for BART purposes.

7.5.1 Method

It was determined through modeling that VOCs from point sources are not anticipated to 

cause or contribute significantly to the impairment of visibility in any Class I area.

Modeling was conducted through the Visibility Improvement State and Tribal Association 

of the Southeast (VISTAS). VISTAS is a collaborative effort of state governments, tribal 

governments, and various federal agencies established to initiate and coordinate 

activities associated with the management of regional haze, visibility and other air 

quality issues in the Southeastern U.S. VISTAS contracted with Georgia Institute of 

Technology (GA Tech) to perform model sensitivity runs to determine the impact of point 

source VOCs on visibility in Class I areas.

GA Tech performed emission sensitivities to examine the impact of emission reductions 

on Regional Haze, annual PM2.5, and 8-hour Ozone concentrations using 

CMAQv4.4_SOAmods on the VISTAS 12 km modeling domain, using the 2009 OTW (on 

the way) Base D emissions. One such sensitivity run reduced anthropogenic, point source 

VOCs by 100%. The purpose was to quantify the impact of VOC emissions from VISTAS 
52

BART sources on Class I areas. Two episodes were examined: June 1-July 10, 2002 and 

November 19 – December 19, 2002. The approach included calculating the extinction 

coefficient in deciviews (dv), then determining the maximum impact of point source 

VOCs. 

....

7.5.2 Conclusions

The results show that the maximum impact from eliminating all point source VOC 

emissions in the VISTAS 12 km domain is less than a 0.5 dv for all Class I areas in the 

VISTAS domain.

Given that the fraction of the total point source VOC emissions would be less than the 

emissions from BART-eligible sources in Alabama, the expected impact of controlling 

VOCs from a BART source would be much less than the 0.5 dv threshold. Therefore, 

VISTAS and the State of Alabama concluded that VOCs from point sources are not a 

visibility impairing pollutant for BART purposes and that BART-eligible sources do not 

need to consider VOC emissions.

7.6 Treatment of Ammonia (NH3) Emissions for BART Purposes

Similar to its treatment of VOCs, EPA guidance allows States the discretion to decide 

whether or not NH3 emissions are to be considered for BART purposes based on 

evaluations of the contributions of the emissions to haze at Class I areas. One approach a 

State can use to determine whether applying BART will be needed is to evaluate the haze 

impacts of all BART-eligible emissions of NH3. If the impact at the Class I area is less 

than the contribution threshold established by the State, 0.5 dv for Alabama, then source 

by source analysis for BART is not needed.

The State of Alabama has determined through modeling that NH3 emissions from point 

sources are not anticipated to cause or contribute significantly to any impairment of 

visibility in Class I areas and should be exempt for BART purposes.

7.6.1 Method

It was determined through modeling that NH3 emissions from point sources are not 

anticipated to cause or contribute significantly to any impairment of visibility in any 

Class I area affected by Alabama sources.

VISTAS contracted with GA Tech to perform model sensitivity runs to determine the 

impact of point source NH3 on visibility in Class I areas. 

GA Tech performed emission sensitivities to examine the impact of emission reductions 

on Regional Haze using CMAQv4.5 with SOA mods on the VISTAS 12 km modeling 

domain, using the VISTAS 2009 OTW (on the way) Base F4 emissions. One such 

sensitivity run reduced BART-eligible source ammonia by 100%. The purpose was to 

quantify the impact of NH3 emissions from VISTAS BART sources on Class I areas. Two 

episodes were examined:

June 1-July 10, 2002 and November 19 – December 19, 2002. The approach included
53

calculating the extinction coefficient in deciviews (dv), then determining the maximum 

impact of BART-eligible source NH3. 

....

The majority of ammonia emissions in VISTAS region come from four BART-eligible 

sources, None of the above sources are significant contributors to the Sipsey Wilderness 

area.

7.6.2 Conclusions

The BART requirements of the RHR allow states to determine whether or not ammonia is 

to be considered a visibility impairing pollutant to be addressed for BART purposes. NH3 

emissions from BART sources may impair visibility; however the majority of NH3 

emissions in the VISTAS region are from a few BART sources. Removal of the large NH3 

emission sources results in minimal impact on visibility at Class I areas in the VISTAS 

region. At their discretion states may ask those few large sources to evaluate NH3 impacts 

and potential controls for NH3.

Based on the CMAQ sensitivity analyses of the impact of ammonia emissions, Alabama

identified no large sources of ammonia emissions affecting the Sipsey Wilderness or 

neighboring Class I areas. As a result, Alabama has concluded that NH3 emissions from 

point sources are not a visibility impairing pollutant for BART purposes and that BARTeligible sources need not consider NH3 emissions.

CALPUFF MODELING

AL SIP Appendix H page7:

Alabama used a multifaceted approach to implement the RHR BART requirements. The 

approach consists of source identification efforts, use of a permitting process to establish 

any resulting BART limits for inclusion in the SIP submittal as well as participation in 

VISTAS BART subgroup to resolve technical issues spanning states in the VISTAS region, 

and ongoing consultation with affected sources, and EPA and FLMs throughout the 

BART process.

....

Alabama‟s BART-eligible sources were presumed to be subject to BART but were 

provided the opportunity to submit modeling demonstrations showing that they did not 

contribute to visibility impairment, i.e., had less than 0.5 deciview (dv) impact, on any 

Class I area within 300 km. 
54

AL SIP Narrative, Pages 85-86; 

Justification of 0.5 dv contribution threshold for CALPUFF BART modeling

Under the BART Guidelines, ADEM may consider exempting some sources from BART if it 

can be shown that they do not cause or contribute to visibility impairment in a Class I area. 

In accordance with the BART Guidelines, ADEM chose to require source-specific analyses to 

determine which sources cause or contribute to visibility impairment using the CALPUFF 

model. The CALPUFF modeling protocol used for determining which facilities are subject to 

BART is included in Attachment H4 to Appendix H. 

Determining whether a source causes or contributes to visibility impairment is one step in the 

BART review process. The BART Guidelinesstate that “A single source that is responsible 

for a 1.0 deciview (dv) change or more should be considered to „cause‟ visibility 

impairment.” The guideline document also states that “the appropriate threshold for 

determining whether a source „contributes to visibility impairment‟ may reasonably differ 

across states,” but, “As a general matter, any threshold that you use for determining whether 

a source „contributes‟ to visibility impairment should not be higher than 0.5 dv.” The 
55

rationale for these instructions is provided in the preamble to the BART Guidance, in the 

statement, “If „causing‟ visibility impairment means causing a humanly perceptible change 

in visibility in virtually all situations (i.e. a 1.0 dv change), then „contributing‟ to visibility 

impairment must mean having some lesser impact on the conditions affecting visibility that 

need not rise to the level of human perception.” The Guidance itself also states that, “States 

remain free to use a threshold lower than 0.5 dv if they conclude that the location of a large 

number of BART-eligible sources within the state and in proximity to a Class I area justify 

this approach.” 

EPA‟s documents strive to set these thresholds in the context of the human perception of 

visibility change. As noted above, EPA considers a 1.0 dv change in visibility to be humanly 

perceptible “in virtually all situations.” Also, the preamble to the BART Guidance3 cites an 

analysis in an Appendix of a NAPAP (National Acid Precipitation Assessment Program) 

report, which asserts that “changes in light extinction of 5% will evoke just noticeable 

changes in most landscapes.” 4 (A 5% change is approximately 0.5 dv.) But, as noted above, 

the preamble also states that perceptibility is not a prerequisite for choosing a contribution 

threshold. Putting all this together, it appears that “causing” visibility impairment means 

having a humanly perceptible impact (for which EPA considers the practical threshold to be 

1.0 dv) while “contributing” to visibility impairment means having a smaller impact (for 

which EPA considers the threshold to be 0.5 dv or some smaller value) that may or may not 

be perceptible. 

ADEM retained the threshold of 0.5 dv for evaluating significance for several reasons. First, 

there is a clear spatial variability of sources across the state. Additionally, ADEM is electing 

to use half of the threshold established by EPA for causing visibility impairment. Lastly, the 

BART rule is a source specific rule and ADEM does not have a technical justification for 

lowering the threshold based on concerns of multiple plume interaction. As such, ADEM 

concluded that EPA‟s suggested contribution threshold of 0.5 dv was appropriate for 

evaluating facility contributions at Class I areas that Alabama sources impact.

 

AL SIP Appendix H, Pages 21 to 22:

Use of the New IMPROVE Algorithm 

During the Regional Haze SIP development process, the IMPROVE Steering Committee 

made recommendations for a new IMPROVE equation. Among other things, the new 

equation includes components that take into account the effects of sea salt and site 

specific Rayleigh scattering. Additional discussion of the new IMPROVE equation can be 

found in Appendix C.

VISTAS contracted Dr. Ivar Tombach to develop a post processor to allow CALPOST 

outputs to be used with the new IMPROVE equation. A discussion of the rationale for use 

of the new IMPROVE equation follows. The new IMPROVE postprocessor and 

instructions are included in the request to EPA for approval of its use in Attachment H11.

Rationale for Need for Use of New IMPROVE Equation
56

The new IMPROVE equation is a much better representation of the effects of particulate 

matter on light extinction than the old equation and takes into account the latest scientific 

understanding of several parameters.

1. The new algorithm overcomes biases of the old algorithm on the haziest days and the

clearest days as demonstrated by comparing the measured light extinction from

nephelometers at Class I areas to light extinction calculated using each of the equations.

2. The new algorithm recognizes spatial and temporal variation in light extinction as size

distribution of the aerosol changes by increasing extinction efficiency as sulfate, nitrate

and organics concentrations increase.

3. The new algorithm incorporates a term to reflect the contribution of fine sea salt and

its hygroscopic growth with increasing relative humidity recognizing research findings

showing that fine sea salt can be an important contributor to light extinction in coastal

areas.

4. The new algorithm reflects research finding that the mass concentration of particulate

organic matter in rural areas is greater than represented by the old equation.

5. The new algorithm includes a NO2 term to represent times when light absorption by

NO2 is a meaningful contributor to light extinction.

6. The new algorithm incorporates site-specific Rayleigh scattering values to better

represent sites close to sea level or with very hot or cold climates.

With this combination of revisions to the IMPROVE equation, the resulting 

apportionment of extinction to various components is more accurate on the haziest and 

clearest days. This is important for development of emission control strategies since the 

benefits of control of concentrations of each species will be represented more correctly 

with the new algorithm. 

Two of Alabama‟s BART eligible sources elected to use the new IMPROVE equation The

spreadsheet developed by Dr. Tombach to implement the entire new IMPROVE equation 

for use with CALPUFF contains a modification of CALPOST that calculates the light 

extinction from the CALPUFF output. In their review of the spreadsheet and supporting 

documentation, EPA Region 4 staff commented that the VISTAS methodology contained 

in the spreadsheet developed by Dr. Tombach appropriately implements the features of 

the new IMPROVE equation, with the exception of the nitrogen dioxide term. EPA 

Region 4 further stated that with the addition of their recommendation for addressing the 

NO2 term, the VISTAS methodology to incorporate the new IMPROVE equation is 

acceptable. In addition to its impact for the two non-EGU sources in Alabama, use of the 

full new IMPROVE equation was used in Base G modeling.

Data Access

EPA Note: Due to the excessive size of data and modeling files that constitute the BART 

modeling developed by the sources, the archival and access of this data is made available 

to the public upon request and is discussed in Appendix I.

EPA Findings: EPA proposes that the State has adequately identified the BART-eligible 

sources and those sources subject to BART controls and that the State successfully 

developed and provided the technical analyses to support the BART assessment provision 

for the non-CAIR sources. However, Alabama opted to have CAIR satisfy BART for 

SO2 and NOx for affected CAIR EGUs, as allowed under the Regional Haze regulations. 
57

As explained in Section III.C.1–EPA Findings, the State’s demonstration regarding CAIR 

and reasonable progress for EGUs, and other provisions in this SIP revision, are based on 

CAIR. 

In a separate action proposing limited disapproval of the regional haze SIPs of a number 

of states, EPA noted that these states relied on the trading programs of CAIR to satisfy 

the BART requirement and the requirement for a LTS sufficient to achieve the stateadopted reasonable progress goals. See 76 FR 82219 (December 30, 2011). In that action, 

EPA proposed a limited disapproval of Alabama’s regional haze SIP submittal insofar as 

the SIP relied on CAIR. For that reason, EPA is not taking action on that aspect of 

Alabama’s regional haze SIP in this action. 

CALPUFF MODELING

EPA proposes to find that the CALPUFF4 modeling system was appropriately applied by 

ADEM in the assessment of visibility impairment in Class I areas for specific sources 

subject to the BART regulations. The BART regulations indicate that CALPUFF or 

other appropriate models can be used to determine if an individual source is anticipated to 

cause or contribute to impairment of visibility in Class I areas. The current regulatory 

niche for the CALPUFF modeling system in 40 CFR part 51, Appendix W: Guideline on 

Air Quality Models (Appendix W) is for compliance with non-attainment New Source 

Review (NNSR) and Prevention of Significant Deterioration (PSD) permitting 

requirements for long range transport (i.e., greater than 50 km) applications at Class I 

areas. There is no preferred model for assessing visibility impact under BART. 

However, EPA believes that it is appropriate for the State of Alabama to use the 

CALPUFF modeling system for its BART exemption and control determination 

modeling.

VISTAS developed a “Protocol for the Application of CALPUFF for BART Analyses.” 

The final VISTAS BART Modeling Protocol (Revision 3.2, dated Aug. 6, 2006) states 

that VISTAS will use CALPUFF ver. 5.754 and CALMET ver. 5.7 (i.e., the VISTAS 

version of CALPUFF). No formal approval of the CALPUFF VISTAS version (either 

ver. 5.754 or 5.756) has been made by EPA Region 4. However, there has been an 

implied acceptance of the VISTAS CALPUFF version as EPA Region 4 has reviewed 

and commented on the VISTAS BART Modeling Protocol and the source-specific 

modeling protocols and reports that were developed by the Alabama specific sources 

performing BART modeling. The VISTAS BART modeling protocol underwent an 

extensive stakeholder development and review process, that involved EPA, FLMs, 

industrial sources, trade groups, lawyers and other interested parties, before the State 

decided to require CALPUFF modeling to evaluate the BART requirements. 

 

4 Note that EPA’s reference to CALPUFF encompasses the whole CALPUFF modeling system, including 

CALMET/CALPUFF/CALPOST and other pre and post processors. The different versions of CALPUFF 

have corresponding versions of CALMET, CALPOST, etc. which may not be compatible with previous 

versions (e.g., the output from a newer version of CALMET may not be compatible with an older version 

of CALPUFF). The different versions of the CALPUFF modeling system are available from the model 

developer on the following website: http://www.src.com/verio/download/download.htm
58

The State required all BART-eligible sources to perform BART exemption modeling and 

to develop source-specific protocols that complied with the VISTAS protocol. EPA 

Region 4 provided reviews and comments on the source-specific protocols and their 

subsequent exemption modeling reports. The exemption protocols and modeling reports 

are presented in Appendix H of the Alabama regional haze SIP. 

New IMPROVE Equation

The CALPUFF model was simulated with the default inputs as recommended in the 

March 16, 2006 EPA memorandum, “Dispersion Coefficients for Regulatory Air Quality 

Modeling in CALPUFF.” A new methodology was used by the VISTAS states to 

process the mass concentrations from CALPOST (post-CALPUFF processor) using the 

new IMPROVE equation so that the BART analyses could consider both the old and new 

IMPROVE equations. EPA Headquarters and other EPA regional offices and the Federal 

Land Managers (FLMs) from the National Park Service and the U.S. Fish and Wildlife 

Service consulted on the VISTAS approach that was developed to utilize the new 

IMPROVE equation in the BART assessment and to determine the change in visibility 

impacts. While these other parties were consulted in preparation of EPA Region 4’s 

response, the response represented the EPA Region 4 position on the new methodology. 

The new methodology uses a spreadsheet developed by VISTAS to post-process the 

visibility modeling output from the CALPUFF and CALPOST models. The spreadsheet 

implements the new IMPROVE equation for calculating visibility impacts that was 

adopted by the IMPROVE Steering Committee in December 2005. EPA Region 4 has 

previously provided comments indicating that new methodology is an alternative 

modeling approach and should meet the requirements in Section 3.2 of Appendix W, 

Guideline on Air Quality Models contained in 40 CFR part 51. The State’s

demonstration included a rationale for the need to use the new IMPROVE equation, a 

discussion of the performance of the equation versus measured values, a submittal of the 

modified post-processing methodology and documentation to support the development of 

concentrations for the different terms in the equation.

Contribution Threshold

With respect to the contribution threshold used in the CALPUFF modeling, the State was 

also required to justify its choice of the 0.5 dv contribution threshold for exempting 

sources from BART eligibility. EPA proposes to agree with the State’s rationale for 

choosing this threshold value since there are a limited number of in and out of state 

sources that impact the various Class I areas in the State. In addition, there are a limited 

number of sources in close proximity to each of the Class I areas. Considering results of 

the visibility impacts modeling conducted (see Appendix H.6), a 0.5 dv threshold was 

appropriate and a lower threshold was not warranted since the majority of the visibility 

impacts were well below 0.5 deciview. Also, even though several sources impacted each 

Class I area, the overall impacts were low from the BART sources, and EPA has not 

made any adverse comments on the use of the CALPUFF VISTAS versions.

References used in the EPA review: 
59

1. 40 CFR Part 51, Appendix W: Guideline on Air Quality Models

2. Appendix Y to 40 CFR Part 51, the Guidelines for BART Determinations Under 

the Regional Haze Rule.

3. IWAQM. 1998. Interagency Workgroup on Air Quality Modeling (IWAQM) 

Phase 2 Summary Report and Recommendations for Modeling Long-Range 

Transport and Impacts on Regional Visibility. EPA-454/R-98-019. U.S. 

Environmental Protection Agency, Office of Air Quality Planning and Standards, 

Research Triangle Park, NC. 

4. VISTAS, 2006. Tombach, I., P. Brewer, T. Rogers, and C. Arrington, Protocol 

for the Application of the CALPUFF Model for Analysis of Best Available Retrofit 

Technology (BART) Revision 2 – 3/9/06 developed through consultation with 

EPA, the FLMs, VISTAS state and local Agencies and industry stakeholders 

VISTAS, 2006. Tombach, I., P. Brewer, T. Rogers, and C. Arrington, Located at 

http://www.vistassesarm.org/documents/BARTModelingProtocol_rev3.2_31Aug06.pdf.

5. March 16, 2006, EPA memorandum from Dennis Atkinson to Kay T. Prince on 

Dispersion Coefficients for Regulatory Air Quality Modeling in CALPUFF.

6. Additional Regional Haze Questions, EPA, September 27, 2006 Revision. 

Answers to questions that PA received from various States and Regional Planning 

Organizations (RPOs) related to the submission of regional haze SIPs under the 

program described by 40 CFR 51.308. This document provides guidance to the 

State air pollution control agencies and the general public on meeting the regional 

haze SIP requirements. 

7. "QAPP for VISTAS Emissions and Air Quality Modeling", Revision 0, dated 

November 17, 2004, approved 8-29-05 by EPA Region 4.
60

III. Evaluation of Regional Haze Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.3. Identification of Sources Addressed by CAIR: States which adopt the CAIR cap 

and trade program for SO2 and NOx are allowed to apply CAIR controls as a substitute 

for controls required under BART. The SIP should include a list of all BART-eligible 

sources within the State for which the CAIR rule is being applied.

State Regional Haze Submittal

AL SIP Narrative, Page 88:

Eight of Alabama‟s BART-eligible sources are EGUs. EPA has determined that, as a 

whole, the CAIR cap-and-trade program improves visibility more than implementing 

BART for individual sources in states affected by CAIR. A state that opts to participate in 

the CAIR program under part 96 AAA-EEE need not require affected BART-eligible 

EGUs to install, operate, and maintain BART for SO2 or NOx emissions. Given that 

many of the BART-eligible units are installing scrubbers and NOx controls, and since 

Alabama is participating in CAIR and accepts EPA‟s overall finding that CAIR 

“substitutes” for BART for NOx and SO2, Alabama‟s EGUs were allowed to submit 

BART exemption modeling demonstrations for PM emissions only. All eight EGUs 

demonstrated visibility impacts below the exemption threshold for all Class I areas.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision except for its reliance on CAIR. EPA believes that the State has appropriately 

identified the BART-eligible sources and those sources subject to BART controls. 

However, Alabama opted to have CAIR satisfy BART for SO2 and NOx for affected 

CAIR EGUs, as allowed under the Regional Haze regulations. As explained in Section 

III.C.1–EPA Findings, the State’s demonstration regarding CAIR and reasonable 

progress for EGUs, and other provisions in this SIP revision, are based on CAIR. 

In a separate action, EPA has proposed a limited disapproval of the Alabama regional 

haze SIP because of deficiencies in the State’s regional haze SIP submittal arising from 

the State’s reliance on CAIR to meet certain regional haze requirements. See 76 FR 

82219 (December 30, 2011). EPA is not proposing to take action in this rulemaking on 

issues associated with Alabama’s reliance on CAIR in its regional haze SIP. 
61

III. Evaluation of Regional Haze Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.4. Source Specific BART Determinations: For each BART-eligible source in the 

State subject to BART, a determination of BART based on an analysis of the best system 

of continuous emission control technology available and associated emission reductions 

achievable (unless the State demonstrates that an emissions trading program or other 

alternative will achieve greater reasonable progress toward natural visibility conditions). 

To address the requirements for BART, the State must take into consideration of “Five 

Factors” from 51.308(e)(1)(ii)(A): (1) the technology available, (2) the costs of 

compliance, (3) the energy and non-air quality environmental impacts of compliance, any 

pollution control equipment in use at the source, (4) the remaining useful life of the 

source, and (5) the degree of improvement in visibility that may reasonably be anticipated 

to result from the use of such technology.

State Regional Haze Submittal

AL SIP Narrative, Pages 88-91:

Two sources, Solutia Inc. in Decatur, Alabama, and International Paper in Courtland, 

Alabama, were unable to demonstrate a contribution of less than 0.5 dv at all Class I 

areas within 300 km from their BART-eligible sources. These two sources are considered 

to be “subject to BART” and were required to submit permit applications containing 

their evaluation of potential BART options and proposed BART determinations. These 

facilities submitted permit applications including their proposed BART determinations in 

the spring and summer of 2007. The proposed BART determinations have been concluded 

and the requirements have been incorporated into Air Permits. The Air Permits were 

issued on February 5, 2008. A public comment period was held on the Regional Haze 

SIP. Summaries of the Solutia and International Paper Courtland BART determinations 

are listed below. 

SOLUTIA

The Department has concluded that no additional particulate controls would be cost 

effective for the BART units at Solutia. Each BART unit is currently equipped with an 

electrostatic precipitator, which range in efficiency from 96% to 99%. The addition of 

NOx controls would not be cost effective for the Solutia BART units. However, Boiler 7 

would be required to install a ROFA (rotating opposed fired-air) system or comparable 

technology for NOx since Solutia assume the control system as an existing control for the 

unit. For the control of SO2, Solutia has proposed to utilize low sulfur coal for Boiler 5 

and Boiler 6, and the installation of a flue solvent injection (FSI) system for Boiler 7. It 

was concluded that the addition of any controls for the coking units would negate the 

viability of the coking units; therefore, no additional controls were proposed for these 

units. The BART limits for each unit are listed below. 

NOx 

• Solutia has proposed no add on controls for Boiler 5, Boiler 6, and the Cokers for the 

control of NOx emissions. 
62

• Boiler 7 would be required to meet an emission limit of 0.36 lb NOx/MMBTU with the 

installation of a ROFA system or a comparable technology. 

SO2 

• Solutia has proposed to limit Boilers 5 and 6 to burning coal with a sulfur content 

resulting in SO2 emissions less than 1.40 lbs/MMBTU. 

• Boiler 7 would be required to meet a limitation of 0.47 lb SO2/MMBTU with the 

installation of the FSI system or a comparable technology. 

• Solutia has proposed no add on controls for the Cokers. 

PM10 

• The existing electrostatic precipitators will be utilized to control PM emissions for each 

BART unit (Boiler 5-7, Cokers 1-2). 

INTERNATIONAL PAPER, COURTLAND MILL

The Department has concluded that additional controls for SO2 would not be cost 

effective at the Courtland Mill and that the control of NOx is only cost effective for the 

No. 2 Combination Boiler and that no other add-on controls would be cost effective for 

all other sources. The current add-on controls which control particles at the Courtland 

mill have efficiencies of greater than 90% therefore no additional controls would be cost 

effective. The BART limits for each unit are listed below. 

NOx 

• Install low NOx Burners or only operate the No. 1 Combination Boiler when one of the 

following emissions units is either not operating or in periods of start-up of shutdown: 

the No. 2 Combination Boiler the No. 2 Recovery Furnace, the No. 3 Combination Boiler, 

or the No. 3 Recovery Furnace. 

• Install low NOx Burners, which will give a 30% baseline reduction in emissions, on the 

No. 2 Combination Boiler. 

• IP has proposed using existing combustion control techniques for the control of NOx on 

the Package Boiler. 

• The No. 2 Recovery Furnace will utilize existing combustion control techniques for the 

control of NOx. 

• IP proposed the existing Low NOx burners for the No. 1 and No. 2 Lime Kilns for 

control of NOx emissions for these units. 
63

SO2 

• IP has proposed no add on controls for the No. 1 Combination Boiler, No. 2 Recovery 

Furnace, No. 2 Smelt Tank, No. 1 Lime Kiln, and No. 2 Lime Kiln for the control of SO2 

emissions. 

• The existing Wet Scrubber will be utilized to control SO2 emissions from the No. 2 

Combination Boiler. 

• Since the Package Boiler only fires natural gas, no add-on controls are warranted. The 

firing of only natural gas will be a federally enforceable limit 

PM10

• IP has proposed utilizing the existing Venturi Scrubber for the control of PM emissions 

from the No. 1 Combination Boiler. 

• The No. 2 Combination Boiler will utilize the existing multi tube dust collectors with 

electrostatic precipitator for the control of PM emissions. 

• IP had proposed no controls for the Package Boiler due to the low particulate 

emissions associated with the firing of natural gas. 

• The existing electrostatic precipitator will be utilized to control PM emissions for the 

No. 2 Recovery Furnace. 

• IP has proposed to utilize the existing wet scrubber which is required by 40, CFR Part 

63, Subpart MM, as the BART control device for the control of PM emissions from the 

No. 2 Smelt Tank 

• The existing Venturi Scrubbers will be utilized to control PM emissions from both Lime 

Kilns No. 1 and No. 2. 

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. EPA believes that the State appropriately documented the technical analysis to 

assess the need and implementation of BART controls as applicable for those non-CAIR 

EGU emission units of PM, SO2 and NOx precursor emissions. This involved 

identification of existing controls on applicable emission units, potential control options 

for applicable emission precursors, and the successful application of the five factors to 
64

determine the feasibility of controls that constituted BART. In particular, the limited 

expected impact of the projected controls was influential for these sources.

EPA proposes to agree with Alabama’s analyses and conclusions for BART for Solutia 

and International Paper-Courtland because the analyses were conducted consistent with 

EPA’s BART Guidelines and EPA’s Air Pollution Control Cost Manual, and the 

conclusions reflect a reasonable application of EPA’s guidance to these sources.
65

 

III. Evaluation of Regional Haze Submittal

D. Best Available Retrofit Technology (BART) Requirements

D.5. Enforceability of BART: For each BART-eligible source in the State subject to 

BART, the SIP should include emission limitations representing BART and schedules for 

compliance with BART. For each BART-eligible source in the State subject to BART, 

the SIP must include a requirement that each source subject to BART be required to 

install and operate BART as expeditiously as practicable, but in no event later than five

years after approval of the implementation plan revision and a requirement that each 

source subject to BART maintains the control equipment required by this subpart and 

establishes procedures to ensure such equipment is properly operated and maintained. 

State Regional Haze Submittal

AL SIP Narrative, Page 88:

These facilities submitted permit applications including their proposed BART 

determinations in the spring and summer of 2007. The proposed BART determinations 

have been concluded and the requirements have been incorporated into Air Permits. The 

Air Permits were issued on February 5, 2008. A public comment period was held on the 

Regional Haze SIP. 

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision. Alabama directly adopted BART emissions limits in its SIP. The proposed 

BART determinations have been concluded and the requirements have been incorporated 

into state air permits issued on February 5, 2008. Existing emissions limits are 

immediately effective, and newly added emission limits will become effective January 1, 

2013. These limits will be added to the appropriate title V (i.e., Part 70) permits. 
66

III. Evaluation of Regional Haze Submittal

E. Coordination of Regional Haze and RAVI Requirements

The State must revise its plan to provide for review and revision of a coordinated longterm strategy for addressing reasonably attributable and regional haze visibility 

impairment.

State Regional Haze Submittal

EPA Note: Alabama did not explicitly address this provision regarding a coordinated 

RAVI and regional haze long-term strategy. However, ADEM has included provisions 

that updated the elements subject to the RAVI long-term strategy requirements (including 

monitoring and new source review (NSR)):

AL SIP Narrative, Page 99:

Monitoring Strategy 

Because the current IMPROVE monitor in Alabama represents a unique airshed and a 

significant component of the contributions are regional, reduction of the IMPROVE 

network by shutting down these monitoring sites impedes tracking progress or planning 

improvements at the affected Class I areas. If this occurs, Alabama, in consultation with 

EPA and the relevant Federal Land Managers, will develop an alternative approach for 

meeting the tracking goal, perhaps by seeking contingency funding to carry out limited 

monitoring, or by relying on data from nearby urban monitoring sites to demonstrate 

trends in speciated PM2.5 mass. 

Data produced by the IMPROVE monitoring network will be used nearly continuously 

for preparing the 5-year progress reports and the 10-year SIP revisions, each of which 

relies on analysis of the preceding five years of data. Consequently, the monitoring data 

from the IMPROVE sites needs to be readily available and up to date. Presumably, 

IMPROVE will continue to process information from its own measurements at about the 

same pace and with the same attention to quality as it has shown to date. The Visibility 

Information Exchange Web System (VIEWS) website has been maintained by VISTAS and 

the other Regional Planning Organizations (RPOs) to provide ready access to the 

IMPROVE data and data analysis tools. Alabama is encouraging VISTAS and the other 

RPOs to maintain VIEWS or a similar data management system to facilitate analysis of 

the IMPROVE data.

AL SIP Narrative, Pages 100-101:

Five-year and Ten-year reviews

Section 51.308(f) requires ADEM to revise its Regional Haze State Implementation Plan 

(SIP) and submit a plan revision to EPA by July 31, 2018 and every ten years thereafter. In 

accordance with the requirements listed in Section 51.308(f) of the Rule, Alabama commits to 

revising and submitting this Regional Haze SIP by July 31, 2018 and every ten years 

thereafter. 
67

In addition, Section 51.308(g) requires periodic reports evaluating progress towards the 

reasonable progress goals (RPGs) established for each mandatory Class I area. In 

accordance with the requirements listed in Section 51.308(g) of the Rule, ADEM commits to 

submitting a report on reasonable progress to EPA every five years following the initial 

submittal of the SIP. The report will be in the form of a SIP revision. The reasonable 

progress report will evaluate the progress made towards the RPG for the Sipsey Wilderness 

Area located within Alabama and in each mandatory Federal Class I area located outside 

Alabama which may be affected by emissions from within Alabama. 

....

All requirements listed in 51.308(g) shall be addressed in the SIP revision for reasonable 

progress. 

ADEM also commits to ongoing consultation with the FLMs throughout the implementation 

process, including discussions on the implementation process and the most recent IMPROVE 

monitoring data and VIEWS data. 

AL SIP Narrative, Page101

Review of New Sources

Relating to the New Source Review/Prevention of Significant Deterioration Programs, 

ADEM believes that its New Source Review regulations will address emissions from new 

sources that may locate near a Class I area, or increased emissions from major 

modifications to existing sources. In addition to the regulations that would govern these 

sources, consultation with the FLMs is also required for sources that are subject to the Class 

I provisions of the regulations.

EPA Findings: EPA proposes to find that this regional haze submittal adequately 

supplements and augments Alabama’s RAVI visibility provisions to address regional 

haze by updating the monitoring and LTS provisions as summarized below in this 

section. 

EPA’s visibility regulations direct states to coordinate their RAVI LTS and monitoring 

provisions with those for regional haze. Under EPA’s RAVI regulations, the RAVI 

portion of a state SIP must address any integral vistas identified by the FLMs pursuant to 

40 CFR 51.304. An integral vista is defined in 40 CFR 51.301 as a “view perceived from 

within the mandatory Class I area of a specific landmark or panorama located outside the 

boundary of the mandatory Class I area.” Visibility in any mandatory Class I area

includes any integral vista associated with that area. The FLMs did not identify any 

integral vistas in Alabama. In addition, the Class I area in Alabama is neither 

experiencing RAVI, nor are any of its sources affected by the RAVI provisions. Thus, 

the Alabama regional haze SIP submittal does not explicitly address the two requirements 

regarding coordination of the regional haze with the RAVI LTS and monitoring 

provisions. However, Alabama previously made a commitment to address RAVI should 

the FLM certify visibility impairment from an individual source.5 EPA proposes to find 

that this regional haze submittal appropriately supplements and augments Alabama’s 

 

5Alabama submitted its visibility SIP revisions addressing RAVI on November 20, 1985, which EPA 

approved on February 10, 1986 (51 FR 4908). 
68

RAVI visibility provisions to address regional haze by updating the monitoring and LTS 

provisions as summarized below in this section.

In its July 15, 2008, submittal, ADEM updated its visibility monitoring program and 

developed a LTS to address regional haze. Also in this submittal, ADEM affirmed its 

commitment to complete items required in the future under EPA’s RHR. Specifically, 

ADEM made a commitment to review and revise its regional haze implementation plan 

and submit a plan revision to EPA by July 31, 2018, and every 10 years thereafter. See 

40 CFR 51.308(f). In accordance with the requirements listed in 40 CFR 51.308(g) of 

EPA’s regional haze regulations and 40 CFR 51.306(c) of the RAVI LTS regulations, 

ADEM made a commitment to submit a report to EPA on progress towards the RPGs for 

each mandatory Class I area located within Alabama and in each mandatory Class I area 

located outside Alabama which may be affected by emissions from within Alabama. The 

progress report is required to be in the form of a SIP revision and is due every five years 

following the initial submittal of the regional haze SIP. Consistent with EPA’s 

monitoring regulations for RAVI and regional haze, Alabama will rely on the IMPROVE 

network for compliance purposes, in addition to any RAVI monitoring that may be 

needed in the future. See 40 CFR 51.305, 40 CFR 51.308(d)(4). Also, the Alabama new 

source review (NSR) rules, previously approved in the State’s SIP, continue to provide a 

framework for review and coordination with the FLMs on new sources which may have 

an adverse impact on visibility in either form (i.e., RAVI and/or regional haze) in any 

federal Class I area. 

The original Alabama visibility SIP submitted to EPA November 20, 1985, addressing 

the NSR and monitoring strategy requirements in 40 CFR 51.307 and 40 CFR 51.305, 

respectively, was supplemented by an EPA regulation (40 CFR 52.61) on November 24, 

1987 (52 FR 45138), which incorporates 40 CFR 52.29 into the Alabama SIP and 

continues to be in effect. Because the July 15, 2008, submittal appropriately addresses 

the LTS requirements and supersedes these previous requirements, EPA is proposing to 

rescind the federal regulations in 40 CFR 52.61 and rely on the provisions in Alabama’s 

regional haze SIP submittal to meet these requirements.
69

III. Evaluation of Regional Haze Submittal

F. Monitoring Strategy and Other Implementation Requirements

Monitoring Strategy: The SIP must include a monitoring strategy for measuring, 

characterizing, and reporting of regional haze visibility impairment that is representative 

of all mandatory Class I Federal areas within the State and/or summarize monitoring 

strategy of States with affected mandatory Class I Federal areas. Compliance with this 

requirement may be met through participation in the Interagency Monitoring of Protected 

Visual Environments (IMPROVE) network. 

Other Requirements: The implementation plan must also provide for the following:

A. The establishment of any additional monitoring sites or equipment needed to 

assess whether reasonable progress goals to address regional haze for all 

mandatory Class I Federal areas within the State are being achieved.

B. Procedures by which monitoring data and other information are used in 

determining the contribution of emissions from within the State to regional haze 

visibility impairment at mandatory Class I Federal areas both within and outside 

the State.

C. The reporting of all visibility monitoring data at least annually for each mandatory 

Class I Federal area in the State. To the extent possible, the State should report 

monitoring data for visibility electronically and use of the Visibility Information 

Exchange Web System (VIEWS) is encouraged.

D. Other elements, including reporting, recordkeeping, and other measures, 

necessary to assess and report on visibility.

State Regional Haze Submittal

AL SIP Narrative, Pages 96-99:

The primary monitoring network for regional haze, both nationwide and in Alabama, is 

the IMPROVE network. Given that IMPROVE monitoring data from 2000-2004 serve as 

the baseline for the Regional Haze program, the future Regional Haze monitoring 

strategy must necessarily be based on, or directly comparable to, IMPROVE. The 

IMPROVE measurements provide the only long-term record available for tracking 

visibility improvement or degradation. Therefore, Alabama intends to rely on the 

IMPROVE network for complying with the Regional Haze monitoring requirement in the 

Rule. 

There is currently one IMPROVE site in the State, at the Sipsey Wilderness area within 

the Bankhead National Forest. The State supplements the IMPROVE sampling by 

operating additional collocated monitoring at the Sipsey, including: 

A PM2.5 FRM monitor 
70

The IMPROVE measurements are central to Alabama‟s Regional Haze Monitoring 

Strategy, and it is difficult to visualize how the objectives listed above could be met 

without the monitoring data provided by IMPROVE. Any reduction in the scope of the 

IMPROVE network in Alabama and neighboring Class I areas would jeopardize the 

state‟s ability to demonstrate reasonable progress toward visibility improvement in its 
71

Class I areas and plan for appropriate future programs. In particular, Alabama‟s 

Regional Haze strategy relies on emission reductions that will result from CAIR and 

reductions in neighboring states, which occur on different time scales and will most likely 

not be spatially uniform. Monitoring at Class I areas is important to document the 

different air quality responses to the emissions reductions. 

Because the current IMPROVE monitor in Alabama represents a unique airshed and a 

significant component of the contributions are regional, reduction of the IMPROVE 

network by shutting down these monitoring sites impedes tracking progress or planning 

improvements at the affected Class I areas. If this occurs, Alabama, in consultation with 

EPA and the relevant Federal Land Managers, will develop an alternative approach for 

meeting the tracking goal, perhaps by seeking contingency funding to carry out limited 

monitoring, or by relying on data from nearby urban monitoring sites to demonstrate 

trends in speciated PM2.5 mass. 

Data produced by the IMPROVE monitoring network will be used nearly continuously 

for preparing the 5-year progress reports and the 10-year SIP revisions, each of which 

relies on analysis of the preceding five years of data. Consequently, the monitoring data 

from the IMPROVE sites needs to be readily available and up to date. Presumably, 

IMPROVE will continue to process information from its own measurements at about the 

same pace and with the same attention to quality as it has shown to date. The Visibility 

Information Exchange Web System (VIEWS) website has been maintained by VISTAS and 

the other Regional Planning Organizations (RPOs) to provide ready access to the 

IMPROVE data and data analysis tools. Alabama is encouraging VISTAS and the other 

RPOs to maintain VIEWS or a similar data management system to facilitate analysis of 

the IMPROVE data.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision.
72

III. Evaluation of Regional Haze Submittal

G. Emission Inventory (40 CFR 51.308(d)(4)(v) (See also TSD Section III.C.))

The SIP must include a statewide inventory of emissions of pollutants that are reasonably 

anticipated to cause or contribute to visibility impairment in any mandatory Class I 

Federal area within the State. The inventory must include emissions for a baseline year, 

emissions for the most recent year for which data are available, and estimates of future 

projected emissions, and a commitment to update the inventory periodically.

State Regional Haze Submittal

AL SIP Narrative, Pages 17, 20, 51-52 (additional details are located in Appendix D and 

K):

There are five different emission inventory source classifications: stationary point and 

area sources, off-road and on-road mobile sources, and biogenic sources. Stationary 

point sources are those sources that emit greater than a specified tonnage per year, with 

data provided at the facility level. Electric generating utilities (EGUs) and industrial 

sources are the major categories for stationary point sources. Stationary area sources 

are those sources whose individual emissions are relatively small, but due to the large 

number of these sources, the collective emissions from the source category could be 

significant (i.e., dry cleaners, service stations, agricultural sources, fire emissions, etc.). 

These types of emissions are estimated on a countywide level. Non-road (or off-road) 

mobile sources are equipment that can move but do not use the roadways, (i.e., lawn 

mowers, construction equipment, railroad locomotives, aircraft, etc.) The emissions from 

these sources, like stationary area sources, are estimated on a countywide level. On-road 

mobile sources are automobiles, trucks, and motorcycles that use the roadway system. 

The emissions from these sources are estimated by vehicle type and road type and are 

summed to the countywide level. Biogenic sources are natural sources like trees, crops, 

grasses and the natural decay of plants. The emissions from these sources are also 

estimated on a countywide level. 

In addition to the various source classifications, there are also various types of emission 

inventories. The first is the actual base year inventory. This inventory is the base year 

emissions that correspond to the meteorological data used, which for this modeling effort 

is data from 2002. These emissions are used for evaluating air quality model 

performance. 

The second type of inventory is the typical base year inventory. This inventory is similar 

to the actual base year inventory, except that for sources whose emissions change 

significantly from year to year, a more typical emission value is used. In this modeling 

effort, typical emissions were developed for the EGUs and the wildland fire emissions. 

The air quality modeling runs using the typical base year inventory provide results which 

are then used to calculate Relative Response Factors (RRFs) for future years. These 

RRFs for future years are then used to demonstrate reasonable progress toward visibility 

goals. 
73

Below is an overview of the inventories used for each source classification. A more 

detailed discussion of the emissions inventory development is contained in Appendix D.
74

AL SIP Narrative, Page 101:

The requirements listed in 51.308(g) include the following:

...

Summary of emission reductions achieved thus far, including the status of implementation 

of the CAIR compliance plans for EGUs compared to the control assumed in the 
75

modeling. [ADEM recognizes that the 2018 projections of EGU controls from the IPM 

runs represent one solution to how the CAIR requirements will be met. By the time of the 

first periodic report, ADEM anticipates that the actual compliance strategy for the 

various utility companies will be much more defined. An assessment of those actual 

compliance plans will be completed for the first periodic report.] 

...

All requirements listed in 51.308(g) shall be addressed in the SIP revision for reasonable 

progress.

EPA Findings: EPA proposes to find that Alabama has adequately addressed this 

provision of the RHR. The Alabama SIP submittal includes a statewide inventory of 

emissions of pollutants that are reasonably anticipated to cause or contribute to visibility 

impairment in any mandatory Class I Federal area within the State. The inventory 

includes emissions for a 2002 baseline year and estimates of future projected emissions 

(i.e., 2018) and a commitment to update the inventory periodically (see also Appendix 

K). The VISTAS states collaborated with the other RPOs to utilize the regional 

emissions inventories that were developed by those organizations for their air quality 

modeling. This ensured that the most current and RPO-specific data that was being used 

across the nation was incorporated into the VISTAS analyses. The VISTAS emissions 

inventories were developed consistently with EPA guidance. The VISTAS emissions 

data underwent several iterations before the technical analyses were completed and 

submitted in the SIP. The VISTAS emissions data were also developed consistent with 

EPA quality assurance guidance. An emissions inventory quality assurance project plan 

for VISTAS was developed and approved by EPA on August 29, 2005. See the Alabama 

SIP and associated EPA TSD for additional documentation on the tools and assumptions 

used to develop the emissions inventory to support the RH LTS technical analyses. 

References used in the EPA review: 

"QAPP for VISTAS Emissions and Air Quality Modeling", Revision 0, dated November 

17, 2004, approved 8-29-05 by EPA Region 4.
76

IV. Conclusion

EPA is proposing a limited approval of a revision to the Alabama SIP submitted by the 

State of Alabama on July 15, 2008, as meeting some of the applicable regional haze 

requirements as set forth in sections 169A and 169B of the CAA and in 40 CFR 51.300-

308, as described previously in this action. Also in this action, EPA is proposing to 

rescind the federal regulations in 40 CFR 52.61 that were approved into the Alabama SIP 

on November 24, 1987, and to rely on the provisions in Alabama’s July 15, 2008, SIP 

submittal to meet the LTS requirements for RAVI at 40 CFR 51.306. 

 
77