MISSISSIPPI
DEPARTMENT OF ENVIRONMENTAL QUALITY

OFFICE OF POLLUTION CONTROL

STATE IMPLEMENTATION PLAN (SIP) REVISION
REGARDING FEDERAL REGIONAL HAZE PROGRAM REQUIREMENTS

INCLUDING THE SIP NARRATIVE

ADDRESSING VISIBILITY IMPROVEMENT

IN FEDERAL CLASS I AREAS

Adopted August 28, 2008Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 2

TABLE OF CONTENTS

1.44 Introduction: State Implementation Plan (SIP) Revision Regarding requirements of
Federal Clean Air Act Regiona l Haze Addressing Visibility in Federal Class I Areas.

1.45 Notification of Public Hearing for the Regional Haze SIP Revision.

3.21 Legal Authority for the Regional Haze SIP Revision.

5.19 Control Strategy for the Regional Haze SIP Revision.

6.23 Control Regulations for the Regional Haze SIP Revision.

14.1.18 Health Effects of the Regional Haze SIP Revision.

14.3.18 Economic Effects of the Regional Haze SIP Revision.

14.5.18 Social Effects of the Regional Haze SIP Revision.

14.6.18 Air Quality Effects of the Regional Haze SIP Revision.

Appendix R Regional Haze SIP Revision Narrative.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 3

1.44 Introduction: State Implementation Plan (SIP) Revision Regarding Regional Haze Requirements of the Federal Clean Air Act Addr essing Visibility in Federal Class I Areas.

Regional haze is pollution that impairs visi bility over a large region, including national parks, forests, and wilderness areas (many termed “Class I” areas). Regional haze is caused by sources and activities emitting fine particles and their precursors, often transported over large regions. Particles affect visibility th rough the scattering and absorption of light. Reducing fine particles in the atmosphere is an effective method of improving visibility. In the southeast, the most important sources of haze-forming emissions are coal-fired power plants, industrial boilers and other combusti on sources, but mobile source emissions, area sources, fires, and wind blown dust also contribute.

An easily understood measure of visibility to most people is visual range. Visual range is the greatest distance, in kilometers or miles, at which a dark object can be viewed against the sky. However, the most useful measure of vi sibility impairment is light extinction, which affects the clarity and color of objects being viewed. The measure used by the regional haze rule is the deciview (dv), calculated directly fr om light extinction using a logarithmic scale.

The regional haze rule requires states to dem onstrate reasonable progre ss toward meeting the national goal of a return to natural visibility conditions by 2064. The rule directs states with Class I areas to graphically show what would be a “uniform rate of progress”, also known as the “glide path”, toward natural conditions for each Class I area within the State.

Mississippi does not have any Class I areas, but the Class I areas: the Breton National Wildlife Refuge (Breton) in Louisiana, Sips ey Wilderness Area (Sipsey) in Alabama, and Caney Creek Wilderness Area (Caney Creek) in Arkansas, are the closest to its state boundaries and the impact of sources in Mississi ppi to those Class I ar eas has been assessed. The Area of Impact (AOI) analysis, devel oped by VISTAS, indicates that sources in Mississippi do not significantly c ontribute to visibility impairment for Sipsey, Caney Creek, or any other Class 1 area. Sources in Mississipp i appear to contribute to visibility impact for Breton. The AOI emission contribution spreadsh eets are further discu ssed in Section 7.5 and found in Appendix M. Since there are no Cla ss I areas in Mississippi, “uniform rate of progress” (or “glide path”) toward natural conditions will not be presented.

The Regional Haze SIP Narrative included in A ppendix R of this SI P Revision contains summaries of the technical analyses that will be used by Mississippi Department of Environmental Quality (MDEQ) to support th e regional haze state implementation plan pursuant to §§107(d)(3)(D) and (E) of the Clean Air Act, as amended.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 4

1.45 Notification of Public Hearing for Regional Haze SIP Revision.

Public participation on the Regional Haze SI P Revision was achieved by a public hearing held on Wednesday, July 16, 2008, at 1:30 p.m. in the Commission Hearing Room at the offices of the Mississippi Department of Environmental Quality, 515 E. Amite Street, Jackson, Mississippi in accordance with the in formation provided in the public notice and Mississippi Administrative Procedures Act. The notice for public hearing will be published consistent with procedures approved by EPA.

The notice of public hearing was published on June 16, June 23, and June 30, 2008, in daily newspapers in the cities of Gulfport, Jacks on, and Tupelo in the St ate of Mississippi. The notice of public hearing and the proposed SIP re vision was made available for public review in the main branches of the publ ic libraries in the above mentioned cities and at the offices of the Mississippi Department of Environmen tal Quality, 515 E. Amite Street, Jackson, Mississippi. This notice was also mailed to persons on the air pollution control regulation mailing list.

The notice of public hearing follows this page.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 5

MISSISSIPPI COMMISSION ON ENVIRONMENTAL QUALITY NOTICE OF PROPOSED PLAN REVISION NOTICE OF PUBLIC HEARING PUBLIC NOTICE START DATE: June 16, 2008

PLEASE TAKE NOTE that the Mississippi Commission on Environmental Quality (“Commission”) is considering a Revision to th e State Implementation Plan for Air Pollution Control (SIP Revision) and will conduct a public hearing to receive comments on the proposed SIP Revision. The proposed SIP Revision involves th e implementation of federal regional haze regulations as promulgated by the U.S. Environm ental Protection Agency (EPA). The proposed SIP Revision will be applicable statewide.

I. Subject of the Proposed Action.

The SIP Revision involves the State of Mississi ppi’s plan for implem enting federal regional haze regulations as promulgated by EPA. The SI P Revision addresses reasonable progress goals for visibility improvement in nearby Federal Class I areas and includes Best Available Retrofit Technology (BART) determinations for emission s ources located in the St ate of Mississippi. A summary of comments previously received from th e Federal Land Managers (FLMs) is included as an appendix to the proposed SIP Revision.

II. Manner By Which the Public May Comment.

Copies of the proposed SIP Revision may be obtained by calling Ms. Maya Rao at 601-961- 5242 or Mr. Elliott Bickerstaff at 601-961-5176 or writing to Mississippi Department of Environmental Quality, Air Division, P. O. B ox 2262, Jackson, Mississippi 39225. For those persons with internet access, a copy of the proposed SIP revision may be found on the Mississippi Department of Environmental Quality’s website at http://www.deq.state.ms.us . Also, copies of the proposed SIP Revision will be available for public review through Wednesday, July 16, 2008, in the main branch of public libraries in the cities of Gulfport, Jackson, and T upelo in the State of Mississippi. The proposed SIP Revision may also be reviewed in the offices of the Mississippi Department of Environmental Quality, 515 E. Amite St., Jackson, Mississippi. For an appointment to review the proposed SIP Revisi on at the offices of MDEQ, contact Mr. Elliott Bickerstaff at (601) 961-5176.

Members of the public may present verbal or written comments at the public hearing described below. Also, written statements regarding the proposed SIP Revision will be made part of the public hearing record if delivered by 5:00 p.m., Wednesday, July 16, 2008, to the attention of Ms. Maya Rao at the address shown above.

III. Notice of Public Hearing.

A public hearing regarding the proposed SIP Revision will be conducted. The hearing will be held on Wednesday, July 16, 2008, at 1:30 p.m . in the Commission Hear ing Room (Room 104A) of the Mississippi Department of Environmenta l Quality Office Building at 515 E. Amite St., Jackson, Mississippi.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 6

IV. Additional Information.

For additional information, please contact Ms. Maya Rao at 601-961-5242 or Mr. Elliott Bickerstaff at 601-961-5176.

Regional Haze SIP Public Notice June 16 2008Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 7

3.21 Legal Authority for the Regional Haze SIP Revision

No legislative actions are needed concerning this Regional Haze SIP revision. The State of Mississippi Air & Water Pollution Control La w, Section 49-17-1 to 49-17-43, Mississippi Code of 1972, gives the Commission on Environmental Quality the necessary legal authority to adopt and implement this Regional Haze SI P revision. State law (as of July 1, 2007) Mississippi Code Annotated, Section 49-17-13(1) designates the Commissi on as the State air pollution control agency for all purposes of the federal pollution control legislation and programs and to take all actions necessary thereto.

Public participation on this Regional Haze SIP revision was achieved by a public hearing held on Wednesday, July 16, 2008, at 1:30 p.m. in the Commission Hearing Room at the offices of the Mississippi Department of Environmental Quality, 515 E. Amite Street, Jackson, Mississippi.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 8

5.19 Control Strategy for the Regional Haze SIP Revision

The SIP narrative in Appendix R addresses control strategies for improveme nt of visibility in Federal Class I areas.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 9

6.23 Control Regulations for the Regional Haze SIP Revision

The regional haze SIP Revision does not include any changes to state regulations. The regional haze SIP Revision is a non-regulator y action. The SIP Narrative in Appendix R references Federal requirements addressing visibility in Federal Class I areas.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 10

14.1.18 Health Effects of the Regional Haze SIP Revision

No adverse health effects are expected to be caused by this Regional Haze SIP revision.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 11

14.3.18 Economics Effects of the Regional Haze SIP Revision

No adverse economic effects due to this Regional Haze SIP revision are foreseen.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 12

14.5.18 Social Effects of the Regional Haze SIP Revision

No adverse social effects are foreseen as a result of this Regional Haze SIP revision.Regional Haze Final SIP Re vision Master Document State of Mississippi C. Simmons September 9, 2008 13

14.6.18 Air Quality Effects of the Regional Haze SIP Revision

This Regional Haze SIP revision will not have any adverse air quality effects.Regional Haze Proposed SIP Revision Master Document State of Mississippi C. Simmons September 9, 2008 14

MISSISSIPPI DEPARTMENT OF ENVIRONMENTAL QUALITY OFFICE OF POLLUTION CONTROL

STATE IMPLEMENTATION PLAN REVISION REGARDING REGIONAL HAZE PROGRAM REQUIREMENTS

APPENDIX R

SIP NARRATIVE ADDRESSING VISIBILITY IMPROVEMENT IN FEDERAL CLASS I AREAS

Adopted August 28, 2008i Mississippi Regional Haze SIP Narrative, August 28, 2008 

### Preface: This document contains summaries of the technical analyses th at will be used by Mississippi Department of Envi ronmental Quality (MDEQ) to support the regional haze state implementation plan pursuant to §§107(d)(3)(D) and (E) of the Clean Air Act, as amended.ii Mississippi Regional Haze SIP Narrative, August 28, 2008 TABLE OF CONTENTS

1.0 INTRODUCTION ............................................................................................................... ..... 1

1.1 What is regional haze?..................................................................................................... ......... 1 1.2 What are the requirements under the Clean Air Act for addressing regional haze?............. 1 1.3 General overview of regiona l haze SIP requirements .......................................................... 2 1.4 Class I areas near Mississippi ............................................................................................. .. 4
1.5 State and Federal Land Mana ger (FLM) coordination ......................................................... 6

2.0 ASSESSMENT OF BASELINE AND CURR ENT CONDITIONS AND ESTIMATE OF NATURAL BACKGROUND CONDITI ONS IN CLASS I AREAS ................................... 9

3.0 GLIDEPATHS TO NATURAL CONDITIONS...................................................................... 9

4.0 EMISSION INVENTORY IMPROVEMENTS....................................................................... 9 4.1 Baseline Emissions Inventory............................................................................................... 9 4.1.1 Stationary Point Sources ............................................................................................ 10 4.1.2 Stationary Area Sources ............................................................................................. 11
4.1.3 Off-Road Mobile Sources .......................................................................................... 12 4.1.4 Highway Mobile Sources ........................................................................................... 12 4.1.5 Biogenic Emission Sources........................................................................................ 13 4.1.6 Summary of the Final 2002 (October 2007 ve rsion) Baseline Emissions Inventory. 13 4.1.7 Emissions Inventory Improvements........................................................................... 14
4.2 Assessment of Relative Contributions from Specific Pollutants and Sources Categories . 15

5.0 REGIONAL HAZE MODELING METHODS AND INPUTS ............................................. 16 5.1 Analysis Method............................................................................................................ ..... 16
5.2 Model Selection ............................................................................................................ ...... 17
5.2.1 Selection of Photochemical Grid Model .................................................................... 17 5.2.2 Selection of Meteorological Model............................................................................ 18 5.2.3 Selection of Emissions Processing System ................................................................ 20 5.3 Selection of the Modeling Year.......................................................................................... 21 5.4 Modeling Domains ........................................................................................................... .. 22 5.4.1 Horizontal Modeling Domain .................................................................................... 22 5.4.2 Vertical Modeling Domain......................................................................................... 24

6.0 MODEL PERFORMANCE EVALUATION......................................................................... 25 6.1 Modeling Performance Goals, and Criteria ........................................................................ 26
6.2 VISTAS Domain-Wide Performance ................................................................................. 27iii Mississippi Regional Haze SIP Narrative, August 28, 2008 6.3 Performance in Nearby Class 1 Areas ................................................................................ 31

7.0 LONG-TERM STRATEGY FOR CLASS I AREA S THAT ARE NEAR MISSISSIPPI..... 33 7.1 Overview of the Long-Term Strategy Development Process............................................. 33 7.2 Expected Visibility Results in 2018 for Class I Areas Neighboring Mississippi under existing and planned emissions co ntrols (Base G2 Inventory) ........................................ 34 7.2.1 Emission Controls Modeled and Requirements ......................................................... 34 7.2.2 Point Source Controls (EGU and non-EGU) ............................................................. 37
7.2.3 Area Source Controls ................................................................................................. 40
7.2.4 Mobile Sources........................................................................................................... 40
7.2.5 Non-Road ................................................................................................................. .. 41
7.2.6 Conclusion............................................................................................................... ... 41 7.3 What Control Determinations Represent Be st Available Retrofit Technology (BART) for Individual Sources? .......................................................................................................... 43 7.3.1 BART-Eligible Sources in Mississippi ...................................................................... 44 7.3.2 Determination of Sources Subj ect to BART in Mississippi....................................... 45 7.3.3 Determination of BART Requiremen ts for Subject-to-BART Sources..................... 48 7.4 Relative Contributions to Visibility Impa irment: Pollutants, Source Categories, and Geographic Areas ............................................................................................................. 49 7.5 Relative Contributions to Visibility Impa irment: Geographic Areas of Influence for Neighboring Class I Areas ............................................................................................... 52 7.5.1 Back Trajectory Analyses .......................................................................................... 53
7.5.2 Residence Time Plots ................................................................................................. 53
7.5.3 SO 2 Areas of Influence ............................................................................................... 54
7.5.4 Emissions Sources within SO 2 Areas of Influence .................................................... 55 7.5.5 Specific Sources in the Areas of Influence ................................................................ 59 7.6 Evaluating the Specific SO 2 Emissions Sources................................................................. 61
7.7 What Additional Emissions Controls Were C onsidered as part of the Long-Term Strategy for Visibility Improvement by 2018?............................................................................... 65 7.8 Long Term Strategy Summary ........................................................................................... 65

8.0 REASONABLE PR OGRESS GOALS................................................................................... 66

9.0 MONITORING STRATEGY................................................................................................. 66

10.0 INTERSTATE CONSULTATION ...................................................................................... 66

11.0 COMPREHENSIVE PERIODIC IMP LEMENTATION PLAN REVISIONS ................... 67

12.0 DETERMINATION OF ADEQUACY OF THE EXISTING PLAN .................................. 69iv Mississippi Regional Haze SIP Narrative, August 28, 2008 LIST OF APPENDICES

Appendix A: VISTAS Memorandum of Understanding and Bylaws

Appendix B: VISTAS Concep tual Description Document

Appendix C: Modeling Analysis Protocol and Quality Assurance Project Plan

Appendix D: Emissions Preparation and Results

Appendix E: Air Quality and Meteoro logical Preparations and Results

Appendix F: Meteorological Modeling Evaluation

Appendix G: VISTAS T echnical Support Document

Appendix H: Mississippi APC-S-1 Regulations

Appendix I: Data Access

Appendix J: Consultation Process

Appendix K: Recomm ended Improvements

Appendix L: BART information

Appendix M: Class 1 Area of Int erest (AOI) Contribution Spreadsheets

Appendix N: DuPont Reason able Progress Information

Appendix O: Regional Haze SI P Federal Land Managers Commentsv Mississippi Regional Haze SIP Narrative, August 28, 2008 

### EXECUTIVE SUMMARY

Introduction Regional haze is pollution that im pairs visibility over a large re gion, including national parks, forests, and wilderness areas (many termed “Cla ss I” areas). Regional haze is caused by sources and activities emitting fine particles and their pr ecursors, often transported over large regions. Particles affect visibili ty through the scattering an d absorption of light. Reducing fine particles in the atmosphere is an effective method of im proving visibility. In the southeast, the most important sources of haze-forming emissions are coal-fired power plants, industrial boilers and other combustion sources, but mobile source em issions, area sources, fires, and wind blown dust also contribute.

An easily understood measure of visibility to mo st people is visual range . Visual range is the greatest distance, in kilometers or miles, at wh ich a dark object can be viewed against the sky. However, the most useful measure of visibility impairment is light extinction, which affects the clarity and color of objects being viewed. The measure used by the regional haze rule is the deciview (dv), calcula ted directly from light extinction using a logarithmic scale.

The regional haze rule requires states to demonstrate reasonable progress toward meeting the national goal of a return to natural visibility c onditions by 2064. The rule directs states with Class I areas to graphically show what would be a “uniform rate of progress”, also known as the “glide path”, toward natural conditions for each Class I area within the State.

No Class I Areas within the State Boundaries of Mississippi Mississippi does not have any Cla ss I areas, but the Class I area s: the Breton National Wildlife Refuge (Breton) in Louisiana, Sipsey Wilderne ss Area (Sipsey) in Alabama, and Caney Creek Wilderness Area (Caney Creek) in Arkansas, are the closest to its state boundaries and the impact of sources in Mississipp i to those Class I areas has been assessed. The Area of Impact (AOI) analysis, developed by VISTAS, indicates th at sources in Mississippi do not significantly contribute to visibility impairment for Sipsey, Caney Creek, or any other Class 1 area. Sources in Mississippi appear to c ontribute to visibility impact for Breton. The AOI emission contribution spreadsheets are further discussed in Section 7.5 and found in Appendix M. Since there are no Class I areas in Mississippi, “uniform rate of progress” (or “glide path”) toward natural conditions will not be presented.

The Executive Summary Figure 1 below illustrates the location of these Class I areas that are nearest to Mississippi.vi Mississippi Regional Haze SIP Narrative, August 28, 2008 Executive Summary Figure 1. Class I Areas in States Surrounding Mississippi.

State Implementation Plan Requirements
States are required to submit state implement ation plans (SIPs) to the United States Environmental Protection Agency (USEPA) that set out each state’s plan for meeting the national goal of a retu rn to natural visibility conditions by 2064 for states with Class I areas. The plan includes the states’ reasonable progress goal s, expressed in decivi ews, for visibility improvement at each affected Class I area for each 10-year period until 2064. Since Mississippi does not have any Class I areas, Reasonable Pr ogress Goals are not presented. The reasonable progress goals for Class I areas near Mississippi are unde r the purview/scope of the states where the Class I areas reside. However, Mississi ppi has addressed the impact of sources in Mississippi on Class I areas in surrounding stat es and considered those impacts in the development of the long term strategy for Mississippi.

The long-term strategy includes enforceable emi ssions limitations, compliance schedules, and other measures as necessary to help achieve the reasonable progress goals. States must alsovii Mississippi Regional Haze SIP Narrative, August 28, 2008 consider ongoing control programs, measures to mitigate construction activities, source retirement and replacement sche dules, smoke management program s for agriculture and forestry, and enforceability of specific measures.

These plans will cover long-term strategies for visibility improvement between baseline conditions in 2000-2004 and 2018. Stat es are required to evaluate progress toward reasonable progress goals every 5 years to assure that installed emissions controls are on track with emissions reduction forecasts in each SIP.

Federal and State Control Requirements There are significant control programs being impl emented between the baseline period and 2018. These programs will all reduce the part iculate emissions that affect visibility in the Class I areas, and include: the Clean Air Interstate Rule (CAIR), the NO x SIP Call, consent agreement with Chevron, one-hour ozone SIPs submitted by Birmingham, Alabama and Baton Rouge, Louisiana, NO x RACT in 8-hour nonattainment area SI Ps, heavy duty diesel (2007) engine standard (for on-road trucks a nd buses), Tier 2 tailpipe standa rds for on-road vehicles, large spark ignition and recreational vehicle rule, non road diesel rule, and various Federal Maximum Achievable Control Technology regulations (MACT) . For more detailed explanation of these control programs see Section 7.2.1 – Emission Cont rol Modeled and Requirements. Of these, the CAIR rule has the largest effect. It requires significant reductions of SO 2 and NO x from Electric Generating Units (EGU) in a cap and tr ade program. Several large Electric Generating Units in South Mississippi are planning to install NO x and SO 2 controls to reduce emissions.

The regional haze rule also requires states to determine best available retrofit technology (BART) for certain facilities. There are fifteen (15) BART eligible Sources in Mississippi. Thirteen (13) of the BART-eligible sources were able to demonstrate that the facilities did not cause or contribute to visibility impairment, two are BART subject. BART analysis of one of the subject sources, Mississippi Phosphates in Pasc agoula, Mississippi, found that no additional controls may be necessary. This facility is cu rrently working on a construction application for planned modifications. As part of this process, they will address the BART requirements and submit their complete engineering analysis by th e end of the year. The planned modifications will result in reduced emissions for Mississipp i Phosphates. The other facility, Chevron Refinery in Pascagoula, Mississippi (Appendix L.10) is BART subject and there are significant emission reductions scheduled. Section 7.3.2 provi des detail on how the BART eligible sources were able to demonstrate they were not subject to BART.

Interstate Consultation

The Regional Haze Rule requires interstate consu ltation between states. As part of VISTAS, MDEQ has consulted with other VISTAS states re garding the impact of Mississippi’s sources on Class I areas in VISTAS states . In addition, Mississippi bo rders the CENtral Regional Air Planning (CENRAP) Organization wh ich contains Class I areas in Breton, Louisiana and Caney Creek, Arkansas. Mississippi ha s attended CENRAP meetings a nd, particularly, has consulted with Louisiana with regard to impact of Mississippi sources on Breton. Please refer to Section 10 and Appendix J for details on consultation.viii Mississippi Regional Haze SIP Narrative, August 28, 2008 Conclusion The modeling analysis performed by Visibility Improvement State and Tribal Association of the Southeast (VISTAS) finds that sulfur dioxide (SO 2 ) is the primary pollutant impacting visibility in the southeast. Executive Summar y Figure 2 shows that emissions of SO 2 from Mississippi sources are significantly less than those from su rrounding states. Further, MDEQ is expecting significant emissions reductions by 2018. Sectio n 7.2 addresses expected emission reductions from various sources resulting from existing federa l measures and Section 7.6 addresses facilities reviewed for Reasonable Progress Goals.

Executive Summary Figure 2. SO 2 Emission Totals for Mississippi and Surrounding States, 2002 and 2018 (2018 emission totals may no t reflect all emission reductions for each state).

Since Mississippi does not have any Class I areas within the state boundar ies, it is not in scope/purview of the state of Mississippi to set reasonable progress goals for any surrounding areas. However, there are significant emissions reductions expected fr om Mississippi sources that will help in attain ing the reasonable progress goals fo r Class I areas in surrounding states. 2002 2002

2002 2002

2002 2018

2002

2018

2018 2018 2018

2018

0 100,000 200,000 300,000 400,000 500,000 600,000 700,000



### AL FL MS TN AR LATons per Year, SO2 2002
20181 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 1.0 INTRODUCTION

1.1 What is regional haze?

Regional haze is pollution from disparate sources that impairs visibility over a large region, including national parks, forests, and wilderness areas (federal “Cla ss I” areas). Regional haze is caused by sources and activi ties emitting fine particles and thei r precursors. Those emissions are often transported ove r large regions.

Particles affect visibili ty through the scattering and absorption of light, and fine particles – particles similar in size to the wavelength of li ght – are most efficient, per unit of mass, at reducing visibility. Fine particles may either be emitted directly or formed from emissions of precursors, the most important of which are sulfur dioxides (SO 2 ) and nitrogen oxides (NO x ). Reducing fine particles in the atmosphere is gene rally considered to be an effective method of reducing regional haze, and thus improving visibil ity. Fine particles also adversely impact human health, especially respiratory and car diovascular systems. The United States Environmental Protection Agency (USEPA) has se t national ambient air quality standards for daily and annual levels of fine par ticles with diameter smaller than 2.5 μ m (PM2.5). The most important sources of PM2.5 and its precursors are coal-fired power plants , industrial boilers and other combustion sources. Other significant co ntributors to PM2.5 and visibility impairment include mobile source emissions, area s ources, fires, and wind blown dust.



### 1.2 What are the requirements under the Clean Air Act for addressing regional haze?

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 Class I Federal areas which impairment results from manmade ai r pollution.” Congress a dopted the visibility provisions to protect visibility in 156 nationa l parks and wilderness areas. On December 2, 1980, USEPA promulgated regulations to address visibility impairment (45 FR 80084). The 1980 regulations were developed to address vi sibility impairment that is “reasonably attributable” to a single source or small group of sources. These regulations represented the first phase in addressing visibility impairment a nd 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, Congre ss added section 169B and called on USEPA to issue regional haze rules. The Regional Haze ru le (RHR) that USEPA promulgated on July 1, 1999 (64 FR 35713), revised the existing visibility re gulations in order to integrate provisions addressing regional haze impairment and establish a comprehensive visibility protection program for Class I Federal areas. States are required to submit state implementation plans (SIPs) to USEPA that set out each states’ plan for comp lying with the regional haze rule, including2 Mississippi Regional Haze SIP Narrative, August 28, 2008 consultation and coordination with other states and with federal land managers. The timing of the SIP submittal is tied to USEPA’s promulgati on of designations for the National Ambient Air Quality Standard (NAAQS) for fine particulate ma tter (PM2.5) at 40 CFR Part 81. States must submit a regional haze implementation plan to US EPA within three years after the date of designation. Because USEPA promulgated PM2.5 designation dates on December 17, 2004, regional haze SIPs must be submitted by Decembe r 17, 2007, which is also specified at 40 CFR 51.308(b).

The regional haze rule addressed the combined visi bility effects of various pollution sources over a wide geographic region. This wide reaching po llution net meant that many states – even those without Class I Areas – would be required to participate in h aze reduction efforts. USEPA designated five Regional Planni ng Organizations (RPO) to assi st with the coordination and cooperation needed to addre ss the visibility issue. Those states that make up the southeastern portion of the contiguous United States are known as VISTAS (Visibility Improvement – State and Tribal Association of the Southeast), and include the following states: Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Virginia, and West Virginia.

Figure 1.2-1. Geographical Areas of Regional Planning Organizations.



### 1.3 General overview of regional haze SIP requirements

The regional haze rule (RHR) at 51.308(d) requires states to demonstrate reasonable progress toward meeting the national goal of a return to natural visibility conditions by 2064. As a guide for reasonable progress, the RHR directs states to graphically show what would be a “uniform3 Mississippi Regional Haze SIP Narrative, August 28, 2008 rate of progress” toward natura l conditions for each mandatory Class I Federal area within the State and/or for each mandatory Class I Federal area located outside the State, which may be affected by emissions from sources within the State. States are to estab lish baseline visibility conditions for 2000-2004, natural background visibi lity conditions in 2064, and the rate of uniform progress between baseline and background conditions. The uniform rate of progress is also known as the “glidepath.”

The RHR then requires States wi th Class 1 areas to establish reasonable progress goals (RPGs), expressed in deciviews, for visibility improveme nt at each affected Class I area covering each (approximately) 10-year period until 2064. The goa ls must provide for reasonable progress towards achieving natural visibil ity conditions, provide for improvement in visibility for the most impaired days over the period of the impl ementation plan, and ensure no degradation in visibility for the least impaired days over the same period (see §51.308(d)(1)).

In order to ensure that visibil ity goals are properly met and set, state implementation plans must include determinations, for each Class I area, of the baseline visibility conditions (expressed in deciviews) for the most impaired and least impair ed days. SIPs must also contain supporting documentation for all required analyses used to calculate the degree of visibility impairment under natural visibility conditions for the most impaired and least impaired days (see §51.308(d)(2)). In addition, states must in clude a monitoring strategy for measuring, characterizing, and reporting of regional haze visibil ity impairment that is representative of all mandatory Class I Federal areas within the state (see §51.308(d)(4)).

This first set of reasonable progress goals must be met through measures c ontained in the state’s long-term strategy covering the period from the present until 2018. The long-term strategy includes enforceable emissions limitations, co mpliance schedules, and other measures as necessary to achieve the reasonable progress goals, including all controls required or expected under all federal and state regulations by 2009 and by 2018. During development of the longterm strategy, states are also required to consider specific f actors such as the abovementioned ongoing control programs, measures to mitigate c onstruction activities, source retirement and replacement schedules, smoke management pr ograms for agriculture and forestry, and enforceability of specific measures (see §51.308(d)(3)).

In addition, a specific component of each state’ s first long-term strate gy is dictated by the specific best available retrof it technology (BART) requireme nts in 40 CFR 51.308(e) of the RHR. The RHR at §51.308(e) requi res states to include a dete rmination of BART for each BART-eligible source in the State that emits any air pollutant, wh ich may reasonably be anticipated to cause or contribu te to any impairment of visibi lity in any mandatory Class I Federal area. Clean Air Act s ection 169A(b) defines BART-eligib le sources as sources in 26 specific source categories, in operation within a 15-year period prior to enactment of the 1977 Clean Air Act Amendments, and has the potential to emit 250 tons a year of visibility-impairing pollution. States must determine BART according to five factors set out in section 169A(g)(7) of the Clean Air Act. Emission limitations repres enting BART and schedules for compliance with BART for each source subject to BART must be include d in the long-term strategy.4 Mississippi Regional Haze SIP Narrative, August 28, 2008 State Implementation Plans for the first revi ew period are due December 17, 2007. These plans will cover long-term strategies for visibility improvement between baseline conditions in 2000- 2004 and 2018. States are required to evaluate progress toward r easonable progress goals every 5 years to assure that installed emissions controls are on track w ith emissions reduction forecasts in each SIP. The first interim review would be due to USEPA in December 2012. If emissions controls are not on track to meet SIP forecasts, th en states may need to take action to assure emissions controls by 2018 will be consistent with the SIP or to revise the SIP to be consistent with the revised emissions forecast. The periodic review is addressed in more detail in section 11.



### 1.4 Class I areas near Mississippi

Mississippi has no Class I areas within its bord ers: The Class I Areas that are closest to Mississippi are Breton National Wildlife Refuge in Louisiana, Sipsey Wilderness Area in Alabama and Caney Creek Wilderness Area in Arka nsas. The Air Division of the Mississippi Department of Environment Quality (MDEQ) is responsible for developing the Regional Haze SIP. This SIP establishes a long-term strategy that will help achieve the reasonable progress goals set by the neighboring states within the first regional haze planning period.5 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 1.4-1. Class I Areas Near Mississippi.

In developing this SIP, MDEQ has also consider ed that emission sources within Mississippi may affect visibility at some of the Class I ar eas in neighboring states. Through VISTAS, the southeastern states have worked together to assess state-by-st ate contributions to visibility impairment in Class I areas within the VISTAS region and those in neighboring regions. This technical work is discussed furthe r in chapters 5, 6, and 7 below. Consultations to date between Mississippi and other states are summarized in chapter 10; cons ultations are ongoing.

Congress considered several legisl ative bills to reduce sulfur di oxide and nitrogen oxides from electric generating utilities. In 2004, USEPA promulgated the Clean Air Interstate Rule (CAIR) to require emissions reductions for sulfur dioxi de and nitrogen dioxide from electric generating utilities in 26 eastern states. The CAIR rule allo ws for interstate trading of emissions to find cost effective reductions. These reductions will im prove visibility in Class I areas closest to Mississippi.6 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 1.5 State and Federal Land Ma nager (FLM) coordination

As required by 40 CFR §51.308(i), the regional haze SIP must include procedures for continuing consultation between the States and Federal Land Managers on the implementation of the visibility protection program, including deve lopment and review of implementation plan revisions and 5-year progress reports, and on th e implementation of other programs having the potential to contribute to impa irment of visibility in any mandatory Class I Federal area.

Successful implementation of a regional h aze program will involve long-term regional coordination among States. VISTAS was formed in 2001 to address regional haze and visibility problems in the southeastern United States. Jurisdictions represented by VISTAS members include the Eastern Band of Ch erokee Indians; the States of Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolin a, South Carolina, Tennessee, Virginia, and West Virginia; and the local air pollution cont rol programs located in these St ates. A copy of the VISTAS Memorandum of Agreement and Bylaws, which Missi ssippi intends to reference as a guideline for consultation procedures, is enclosed as A ppendix A. Additional consultation procedures with FLMs are described in Sections 11 and 12.

The objectives of the VISTAS project are to es tablish natural background visibility conditions across the mandatory Class I Federal areas, identify current visibility impairment levels, analyze emission control levels that will achieve inte rim visibility goals, and provide adequate documentation to member agencies so that the states/tribes/local agen cies can develop the regional haze State/Tribal Impl ementation Plans (SIP/TIP). Figure 1.5-1 shows the eighteen (18) mandatory Class I Federal areas in the VIST AS Region, where visib ility is an important value. Table 1.5-1 lists these Class I areas. Mississippi is on the western Boundary of VISTAS. Two of the three closest Class I areas are in the Central Regional Air Planning Organization (CENRAP). In the technical analysis VISTAS co nsidered these areas. Mississippi has also attended CENRAP meetings and been in consultation with Louisiana.7 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 1.5-1. Class I Areas in the VIST AS Region and Neighboring States.8 Mississippi Regional Haze SIP Narrative, August 28, 2008 Mandatory Class I Federal Areas in the VISTAS Region and

Neighboring States where Visibility is an Important Value

Regulation Citation and State Area Name Acreage Federal Land Manager 40 CFR §81.401 Alabama Sipsey Wilderness 24,922 USDA-FSChassahowitzka Wilderness 23,360 USDIFWS Everglades National Park 1,397,42 9 USDI-NPS 40 CFR §81.407 Florida

St. Marks Wilderness 17,745 USDIFWS Cohotta Wilderness 36,977 USDA-FSOkefenokee Wilderness 343,850 USDIFWS 40 CFR §81.408 Georgia

Wolf Island Wilderness 5,126 USDIFWS 40 CFR §81.411 Kentucky Mammoth Cave National Park 51,303 USDI-NPS Great Smoky Mountains National Park 273,551 USDI-NPS Joyce Kilmer-Slickrock Wilderness 17,394 USDA-FS

Linville Gorge Wilderness 12,002 USDA-FS Shining Rock Wilderness 18,483 USDA-FS 40 CFR §81.422 North Carolina

Swanquarter Wilderness 9,000 USDIFWS 40 CFR §81.426 South Carolina Cape Romain Wilderness 28,000 USDIFWS Great Smoky Mountains National Park 241,207 USDI-NPS 40 CFR §81.428 Tennessee Joyce Kilmer-Slickrock Wilderness 17,394 USDA-FS

James River Face Wilderness 8,886 USDA-FS 40 CFR §81.433 Virginia Shenandoah National Park 190,535 USDI-NPS Dolly Sods Wilderness 10,215 USDA-FS 40 CFR §81.435 West Virginia Otter Creek Wilderness 20,000 USDA-FS 40 CFR §81.412 Louisiana Breton National Wildlife Refuge (CENRAP) 5,000 USDIFWS Caney Creek Wilderness (CENRAP) 14,460 USDA-FS 40 CFR §81.404 Arkansas Upper Buffalo Wilderness (CENRAP) 12,035 USDA-FS

Table 1.5-1. Mandatory Class I Federal Areas in the VISTAS Region and nearby where Visibility is an Im portant Value.9 Mississippi Regional Haze SIP Narrative, August 28, 2008 A technical support document for the regional haze state implementation plans (Appendix G) was prepared cooperatively by VISTAS staff and states to characteri ze regional haze in the southeastern United States. The report includes a review of the science and situa tion, calculation of initial baseline visibility, review of monitoring data/data gaps, and recommendations for additional monitoring, initial emission inve ntory characterization and projections, and compliance with existing contro l programs. Source contribu tions to VISTAS and nearby mandatory Class I Federal areas are also assessed.



### 2.0 ASSESSMENT OF BASELINE AND CURRENT CONDITIONS AND
ESTIMATE OF NATURAL BACKGROU ND CONDITIONS IN CLASS I
AREAS

The responsibility to assess the baseline and current conditions, dete rmine natural background and the glidepath falls to the states that the Clas s I areas are within. Si nce there are no Class I areas in Mississippi, these items will not addressed.



### 3.0 GLIDEPATHS TO NATURAL CONDITIONS

The responsibility to assess the baseline a nd current conditions and determine natural background falls to the states that the Class I areas are within. Since there are no Class I areas in Mississippi, these items will not addressed.



### 4.0 EMISSION INVENTORY IMPROVEMENTS

4.1 Baseline Emissions Inventory

The Regional Haze Rule at 51.308(d) (4) (v) re quires a statewide emissions inventory of pollutants that are reasonably anticipated to cause or contribute to visibility impairment in any mandatory Class I area. An inventory was de veloped for the baseline year 2002 and projected to 2009 and 2018. The pollutants inventoried include volatile organic compounds (VOC), nitrogen oxides (NO x ), fine particulate (PM2.5), coarse particulate (PM10), ammonia (NH4) and sulfur dioxide (SO 2 ). The baseline emissions inve ntory for 2002 was developed for MS following the methods described in Appendix D.

There are five different emission inventory source classifications: stationary point, stationary area, off-road mobile, on-road mobile, and biogeni c sources. Stationary point sources are those sources that emit greater than 100 tons per year of any criteria pollutant, with data provided at the facility level. Electric ge nerating utilities and industrial s ources are the major categories for stationary point sources. Stationary area sources are those sources whos e individual emissions are relatively small, but due to the large number of these sources, the collective emissions from10 Mississippi Regional Haze SIP Narrative, August 28, 2008 the source category could be signi ficant (i.e., dry cleaners, servi ce 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 locomotiv es, aircraft, etc. The emissions from these sources, like stationary area sources, are estimat ed on a countywide level. On-road mobile sources are automobiles, trucks, and motorcycle s 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 sour ces are the natural sources like tr ees, crops, grasses and natural decay of plants. The emissions from these sources are estimated on a countywide level.

In addition to the various source classificati ons, there are also various types of emission inventories. The first is the actua l base year inventory. This inve ntory 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 evaluati ng the air quality model performance.

The second type of inventory is th e typical base year inventory. Th is inventory is similar to the actual base year inventory, except that for sour ces 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 electric generating units (EGUs) and the wildland fire emissions. The air quality modeling runs using the t ypical base year inve ntory provide results which are then used to calculate relative reduction factors for future y ears. These relative reduction factors for future years are then used to dem onstrate reasonable progress to ward visibility goals.

Below is an overview of the inventories used fo r each source classification. More detailed discussion of the emissions inventory deve lopment is contained in Appendix D.

4.1.1 Stationary Point Sources

Point source emissions are emissions from indivi dual sources having a fixe d location. Generally, these sources must have permits to operate, and their emissions are inventoried on a regular schedule. Large sources emitting at least 100 tons per year (tpy) of a criteria pollutant, 10 tpy of a single hazardous air pollutant (HAP), or 25 tpy total HAP are inventoried annually. Smaller sources have been inventoried less frequently. The point source emissions data can be grouped as EGU sources and other industrial point sources, also called non-EGUs.

Electric Generating Units

The actual base year inventory for the EGU s ources used 2002 continuous emissions monitoring (CEM) data reported to the USEPA’s Acid Rain program or 2002 hourly emissions data provided by stakeholders. These data provide hourly emissions profiles for SO 2 and NO x that can be used in air quality modeling. Emissions pr ofiles are used to estimate emissions of other pollutants (volatile organic co mpounds, carbon monoxide, ammonia, fine particles, soil) based on measured emissions of SO 2 and NO x .
Emissions from EGU vary daily and seasonally as a function of variabil ity in energy demand and utilization and outage schedules. To avoid anomalies in future y ear emissions created by relying on 2002 operations to represent future operations, a typical base year em issions inventory was11 Mississippi Regional Haze SIP Narrative, August 28, 2008 developed for EGUs. This approach is consis tent with the USEPA’s modeling guidance. To develop a typical year 2002 emi ssions inventory for EGU sources, each unit’s average CEM heat input for 2000 through 2004 was divided by the 2002 act ual heat input to gene rate a unit specific normalizing factor. This normalizing factor was then multiplied by the 2002 actual emissions. The heat inputs for the period 2000 through 2004 we re used because the modeling current design values use monitored data from this same 5-year period. If a unit was shut down for an entire year during the 2000 through 2004 period, the averag e of the years the unit was operational was used. If a unit was shut down in 2002, but not permanently shutdown, the emissions and heat inputs from 2001 (or 2000) were used in the normalizing calculations.

As part of the VISTAS air quality modeling, VI STAS, in cooperation with the other eastern RPOs, contracted with ICF Resources, L.L.C., to generate future year emission inventories for the electric generating sector of the contiguous United States using the Integrated Planning Model (IPM), Version 2.1.9. IPM is a dynamic lin ear optimization model that can be used to examine air pollution control po licies for various pollutants th roughout the contiguous United States for the entire electric power system. Th e dynamic nature of IPM enables projection of the behavior of the power system over a specified future period. Optimization logic in IPM determines the least-cost means of meeting electric generation and capacity requirements while complying with specified constraints includi ng air pollution regulations, transmission bottlenecks, and plant-specific operational constraint s. The versatility of IPM allows users to specify which constraints to exercise, and to populate IPM with their own datasets.

The IPM modeling runs took into considerati on CAIR implementation, resulting in future reduction of NOx and SO2 air emissions for se veral EGUs in Mississi ppi. The IPM model predicted the shut down of several gas/oil-fi red EGU sources; however, those sources have no closure intentions. Therefore, these sources were re-integrated into the IPM model using 2002 emission inventory data.

Other Industrial Point Sources

For the non-EGU sources, the same inventory is us ed for both the actual and typical base year emissions inventories. The non-EGU category uses annual emissions as reported under the Consolidated Emissions Reporting Rule (CE RR) for the year 2002. These emissions are temporally allocated to month, day, and hour us ing source category code (SCC)-based allocation factors.

The general approach for assembling future year data was to use recently updated growth and control data consistent with USEPA’s CAIR anal yses. This data was supplemented with statespecific growth factors and stakeh older input on growth assumptions.

4.1.2 Stationary Area Sources

Stationary area sources are sources whose individua l emissions are relatively small, but due to the large number of these sources , the collective emissions could be significant (i.e., combustion of fuels for heating, structure fires, service stations, etc.). Emissions are estimated by multiplying an emission factor by some known i ndicator of collective activity, such as fuel12 Mississippi Regional Haze SIP Narrative, August 28, 2008 usage, number of households, or population. Stat ionary area source emissions are estimated at the countywide level.

The actual base year inventory will serve as the t ypical base year inventor y for all area source categories except for wildland fires. For wildland fires, a typical year inventory was used to avoid anomalies in wildfire activ ity in 2002 compared to longer te rm averages. Development of a typical year fire inventory provided the capabil ity of using a comparable data set for both the base year and future years. Thus, fire emissions remain the same for air quality modeling in both the base and any future years. The VISTAS Fire Special Interest Work Group used State records to ratio the number of acres burne d over a longer term period (thr ee or more years, as available from state records) to 2002. Based on these rati os, the 2002 acreage was then scaled up or down to develop a typical year inventory.

Future year emissions The VISTAS contractor generated future year emissions inventories for 2009 and 2018 for the regional haze modeling. Growth factors, supplie d either by states or taken from the CAIR emission projections, were applied to project the controlled emissions to 2018. If no growth factor was available from either a state or th e CAIR growth factor files, then the USEPA’s Economic Growth and Analysis System Version 5 growth factors were used.

4.1.3 Off-Road Mobile Sources

Off-road (or non-road) mobile s ources are equipment that can move but do not use the roadways, such as construction equipment, aircraft, railroad locomotives, lawn and garden equipment, etc. For the majority of the non-road mobile sources, the emissions for 2002 were estimated using the USEPA’s NONROAD2005c model. For the three source cate gories not included in the NONROAD model, i.e., aircraft engines, railroad locomotives and commercial marine, more traditional methods of estimating the emissions were used. The same inventory is used for both the actual and typical base year emissions inventories.

For the source categories estimated using the USEPA’s NONROAD model, the model growth assumptions were used to create the 2009 and 2018 future year inventories. The NONROAD model takes into consideration re gulations affecting emissions fr om these source categories. For the commercial marine, railroad locomotives a nd the remaining airport emissions, the VISTAS contractor calculated the future growth in emissions using deta iled inventory data (both before and after controls) for 1996 and 2010, obtained fr om the CAIR Technical Support Document. When available, state-specific growth factors were used.

4.1.4 Highway Mobile Sources

For onroad vehicles, the newest version of the MOBILE model, MOBILE6.2, was used. Key inputs for MOBILE include information on the age of vehicles on the roads, the average speeds on the roads, the mix of vehicles on the roads, any programs in place in an area to reduce emissions for motor vehicles (e.g., emissions inspection programs), and temperature.13 Mississippi Regional Haze SIP Narrative, August 28, 2008 The MOBILE model takes into consideration regulati ons that affect emissions from this source sector. The same MOBILE run is used to repres ent the actual and typical year emissions for onroad vehicles using input da ta reflective of 2002. The MOBI LE model then is run for 2018 inventory using input data refl ective of that year. The 2002 ve hicle miles traveled (VMT) and vehicle mix data were obtained from the Mississippi Department of Transportation ( M DOT).

4.1.5 Biogenic Emission Sources

Biogenic emissions were prepared with th e SMOKE-BEIS3 (Biogenic Emission Inventory System 3 version 0.9) preprocessor. SMOKE-BEIS3 is a modified version of the Urban Airshed Model (UAM)-BEIS3 model. Modifications incl ude use of MM5 data, gridded land use data, and improved emissions characterization. The em ission factors that are used in SMOKE-BEIS3 are the same as the emission factors as in UAM-B EIS3. The basis for the gridded land use data used by BEIS3 is the county land use data in the Biogenic Emissions Landcover Database version 3 (BELD3) provided by th e USEPA. A separate land classification scheme, based upon satellite (AVHRR, 1 km spatial re solution) and census information, aided in defining the forest, agriculture and urban portions of each county.

4.1.6 Summary of the Final 2002 (October 2007 version) Baseline Emissions Inventory

Below is a summary of the 2002 baseline emissi on inventory for Mississippi. The complete inventory and discussion of the methodology is contained in Appendix D. The emissions summaries for other VISTAS states can also be found in Appendix D.

VOC NO x PM2.5 PM10 NH 3 SO 2 Point 43,852 104,661 11,044 21,106 1,359 103,389 Area 131,808 4,200 50,401 343,377 58,721 771 On-Road Mobile 86,811 110,672 2,089 2,828 3,549 4,566 Non-Road Mobile 41,081 88,787 4,690 5,010 23 11,315 Biogenics 1,544,646 20,305 0 0 0 0 TOTAL 1,848,199 328,626 68,223 372,321 63,652 120,040

Table 4.1. 2002 Emissions Inventory Summary for MS in tons.14 Mississippi Regional Haze SIP Narrative, August 28, 2008 4.1.7 Emissions Inventory Improvements

Since the initial model performa nce evaluation, VISTAS has made several improvements to the emissions inventory which in turn improves mode l performance. These inventory improvements are detailed in the VISTAS emissions invent ory report and Appendix D, and are summarized here:

• For electric generating utilities, the Integrat ed Planning Model (IPM) was used to provide estimates of future year utility producti on and emissions. Continuous Emissions Monitoring data was used to define seasonal variability in production and emissions. For Base G2 emissions, states updated IPM mode l projections from 2005 with control data provided by utility companies in 2006 through winter 2007.

• For on-road vehicle emissions, states a nd local agencies provided updated MOBILE model input and vehicle-miles-traveled data.

• For ammonia emissions from agricultural sources, the Carnegie Mellon University ammonia model was used to impr ove annual and monthly estimates.

• For fires, the VISTAS states provided fire act ivity data for 2002 for wildfires, prescribed fire, land clearing and agricultural burn ing and MACTEC developed a 2002 fire inventory. Where data allowed, Alpine Geophysics modeled fire ev ents as point sources. In 2006,United States 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 USEPA 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 develope d for USEPA by Corbett at Univ ersity of Delaware. These emissions were incorporated in the Base G modeling.

• Updated inventories from the neighboring RP Os, Mexico, and Canada were incorporated as available.15 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 4.2 Assessment of Relative Contri butions from Specific Pollutants and Sources Categories

Ammonium sulfate is the largest contributor to visibility impairment for Class I in the southeastern United States, and reduction of SO 2 emissions would be the most effective means of reducing ammonium sulfate. As illustrated in Figure 4.2-1 , ninety-six (96) percent of SO 2 emissions in the VISTAS states are attributable to electric generating facilities and industrial point sources. As shown in Table 4.1 , eight-six (86) percent of SO 2 emissions in Mississippi are attributable to electric generating facilities and in dustrial point sources.

Figure 4.2-1. SO 2 emissions in 2002 in the VISTAS States. 

## VISTAS States SO2 Emissions - 2002

Utilities Industrial On road Non road Other Utilities: 76% Industrial: 20% 4.8 Million tons



## VISTAS States SO2 Emissions - 2002

Utilities Industrial On road Non road Other Utilities: 76% Industrial: 20% 4.8 Million tons16 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 5.0 REGIONAL HAZE MODELI NG METHODS AND INPUTS

Modeling for regional haze was performed by VISTAS for the ten southeastern states, including Mississippi. The sections below outline the methods and inputs used by VISTAS for the regional modeling. Additi onal details are provid ed in Appendices C.



### 5.1 Analysis Method

The modeling analysis is a complex technical eval uation that begins by se lection of the modeling system. VISTAS decided to use the following modeling system:

• Meteorological Model: The Pennsylvania St ate University/National Center for Atmospheric Research (PSU/NCAR) Meso scale Meteorological Model (MM5) is a nonhydrostatic, prognostic meteorological model r outinely used for urban- and regionalscale photochemical, fine particulate matte r, and regional haze regulatory modeling studies.

• Emissions Model: The Sparse Matrix Oper ator Kernel Emissions (SMOKE) modeling system is an emissions modeling system that generates hourly gridded speciated emission inputs of mobile, nonroad mobile, area, poi nt, fire and biogenic emission sources for photochemical grid models.

• Air Quality Model: USEPA’s Models-3/ Co mmunity Multiscale Air Quality (CMAQ), version 4.51 with SOAmods enhancement, modeling system is an ‘One-Atmosphere’ photochemical grid model capable of addressi ng ozone, particulate matter (PM), visibility and acid deposition at regional scal e for periods up to one year.

The USEPA 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 the meteorological model. Emission i nventories were also developed for 2002 and processed through the emissions model. These i nputs were used in the air quality model to predict fine particle mass a nd visibility. The model results for 2002 were compared with observed meteorological and air quality data to evaluate m odel performance. Several configurations of the meteor ological and air quality model were evaluated to select a configuration that gave the best overa ll performance for the VISTAS region.

Once model performance was deemed adequate, th e current and future year emissions were processed through the emissions model. The air qua lity 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 th is analysis can be found in Appendix C.17 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 5.2 Model Selection

To ensure that a modeling study is defensible, care must be taken in the selection of the models to be used. The models selected must be scient ifically appropriate for the intended application and be freely accessible to all stakeholders. Scie ntifically appropriate means that the models address important physical and chemical phenomen a in sufficient detail, using peer-reviewed methods. Freely accessible means that model form ulations and coding are freely available for review and that the models are available to stak eholders, and their consul tants, for execution and verification at no or low cost.

The following sections outline the criteria for select ing a modeling system that is both defensible and capable of meeting the study's goals. These criteria were used in selecting the modeling system used for this modeling demonstration.

5.2.1 Selection of Photochemical Grid Model

Criteria

For a photochemical grid model to qualify as a ca ndidate for use in a regional haze SIP, a State needs to show that it meets the same several general criteria as a model for an attainment demonstration for a national ambien t air quality standard (NAAQS):

• The model has received a scientific peer review

• The model can be demonstrated applicable to the problem on a theoretical basis

• Data bases needed to perform the analysis are available and adequate

• Available past appropriate performance evalua tions have shown the model is not biased toward underestimates or overestimates

• A protocol on methods and procedures to be followed has been established

• The developer of the model must be willing to make the source code available to users for free or for a reasonable cost, and th e model cannot otherwise be proprietary.

Overview of CMAQ

The photochemical model selected for this study was CMAQ version 4.5. For more than a decade, the USEPA has been developing the Models-3 CMAQ modeling system with the overarching aim of producing a ‘One-Atmosphere ’ air quality modeling system capable of addressing ozone, fine particul ate matter, visibility and ac id deposition within a common platform. The original justification for the M odels-3 development emerged from the challenges posed by the 1990 CAAA and the USEPA’s desire to develop an advanced modeling framework for ‘holistic’ environmental modeling utilizing st ate-of-science representations of atmospheric processes in a high performance computing envi ronment. The USEPA completed the initial stage of development with Models-3 and rel eased the CMAQ model in mid-1999 as the initial18 Mississippi Regional Haze SIP Narrative, August 28, 2008 operating science model under the Models-3 fr amework. The most recent rendition is CMAQ version 4.5, which was released in September 2005.

An advantage of choosing CMAQ as the atmosphe ric model is the ability to do one-atmospheric modeling. The same model configuration is being applied for the ozone and PM 2.5 attainment demonstrations SIPs, as well as the regional haze SIP. A number of features in CMAQ’s theoretical formulation and tec hnical implementation make the model well suited for annual PM modeling.

VISTAS used Version 4.51 of the Community Multi-scale Air Qual ity (CMAQ) modeling system with an enhanced secondary organic aerosol (SOA) module (SOAmods). Initial CMAQ 2002 simulations performed by VISTAS found that the model greatlyunderestimate Organic Mass Carbon (OMC) concentrations, especially in the summer (Morris et al., 2004b). A review of the CMAQ formulation found that it failed to treat Secondary Organic Aerosol (SOA) formation from sesquiterpenes and isoprene a nd also failed to account for polymerization of SOA so that it is no longer volatile and stays in the particle form. The standard versions of CMAQ V4.51 assume that SOA is volatile so that once an aerosol is formed it can evaporate from particle to gaseous form depending on atmospheric conditions (e.g., temperature and humidity). After a detailed literature review, VISTAS upda ted the CMAQ SOA module to include these missing processes and found th at the updated CMAQ V4.5 SOAmods produced much better OMC model performance in the summer (Morris et al., 2006c).

The configuration used for this modeling demonstra tion, as well as a more detailed description of the CMAQ model, can be found in Section 1.3.3.3 of the Technical Support Document (Appendix G).

5.2.2 Selection of Meteorological Model

Criteria

Meteorological models, either through objectiv e, diagnostic, or pr ognostic analysis, extend available information about the state of the atmosphere to the grid upon which photochemical grid modeling is to be carried out. The criteria for selecting a meteorological model are based on both the models ability to accura tely replicate important meteorological phenomena in the region of study, and the model's ability to interface with the rest of the modeling systems -- particularly the photochemical grid model. With these issues in mind, the following criteria were established for the meteorological model to be used in this study:

• Non-Hydrostatic Formulation

• Reasonably current, peer reviewed formulation

• Simulates Cloud Physics

• Publicly available on no or low cost

• Output available in I/O API format19 Mississippi Regional Haze SIP Narrative, August 28, 2008 • Supports Four Dimensional Data Assimilation (FDDA)

• Enhanced treatment of Planetary Bo undary Layer heights for AQ modeling

Overview of MM5

The non-hydrostatic MM5 model is a three-dime nsional, limited-area, primitive equation, prognostic model that has been used widely in regional air quality model applications. The basic model has been under continuous development, improvement, testing and open peer-review for more than 20 years and has been used worldw ide by hundreds of scientists for a variety of mesoscale studies.

MM5 uses a terrain-following non-dimensionalized pressure, or "sigma", vertical coordinate similar to that used in many ope rational and research models. In the non-hydrostatic MM5, the sigma levels are defined according to the initial hydrostatically-balanced reference state so that the sigma levels are also time-invariant. Th e gridded meteorological fields produced by MM5 are directly compatible with the input requirements of ‘one atmo sphere’ air-quality models using this coordinate. MM5 fields can be easily used in other regional air quality models with different coordinate systems by performing a vertical in terpolation, followed by a mass-conservation readjustment.

Distinct planetary boundary layer (PBL) para meterizations are available for air-quality applications, both of which repr esent sub-grid-scale turbulent fluxes of heat, moisture and momentum. One scheme uses a first-order eddy diffusivity formulation for stable and neutral environments and a modified first-order scheme for unstable regimes. The other scheme uses a prognostic equation for the second-order turbulent kinetic energy, while di agnosing the other key boundary layer terms.

Initial and lateral boundary conditions are specified for r eal-data cases from mesoscale threedimensional analyses performed at 12-hour interv als on the outermost grid mesh selected by the user. Surface fields are analyzed at three-hour in tervals. A Cressman-based technique is used to analyze standard surface and radiosonde observations, usi ng the National Meteorological Center's spectral analysis, as a first guess. The lateral boundary data are introduced using a relaxation technique applied in the outermost five rows and columns of the coarsest grid domain.

MM5 modeling system in regulatory air quality app lication studies have b een widely reported in the literature (e.g., Emery et al., 1999; Tesche et al., 2000, 20 03) and many have involved comparisons with other prognostic models such as the Regional Atmospheric Modeling System (RAMS) and the Systems Application Internati onal Mesoscale Model. The MM5 enjoys a far richer application history in re gulatory modeling studies compared with RAMS or other models. Furthermore, in evaluations of these models in over 60 recent regional scale air quality application studies since 1995, it has generally be en found that the MM5 model tends to produce somewhat better photochemical model i nputs than alternative models.

The configuration used for this modeling demonstra tion, as well as a more detailed description of the MM5 model, can be found in the mete orological modeling protocol (Appendix E).20 Mississippi Regional Haze SIP Narrative, August 28, 2008 5.2.3 Selection of Emissions Processing System

Criteria

The principal criterion for an emissions processi ng system is that it accurately prepares emissions files in a format suitable for the pho tochemical grid model being used. The following list includes clarification of this criterion and additional desirable criteria for effective use of the system.

• File System Compatibility with the I/O API

• File Portability

• Ability to grid emissions on a Lambert Conformal projection

• Report Capability

• Graphical Analysis Capability

• MOBILE6 Mobile Source Emissions

• Biogenic Emissions Inventory System version 3 (BEIS-3)

• Ability to process emissions for the proposed domain in a reasonable amount of time.

• Ability to process control strategies

• No or low cost for acquisition and maintenance

• Expandable to support other species and mechanisms

Overview of SMOKE

The SMOKE Emissions Processing System Protot ype was originally developed at the Microcomputing Center of North Carolina. As with most ‘emissions models’, SMOKE is principally

an emission processing system and not a true emissions modeling system in which emissions estimates are simulated from ‘first principles’. This means that, with the exception of mobile and biogenic sources, its purpose is to provide an efficient, modern tool for converting emissions inventory data into the formatted emission files required by an air quality simulation model. For mobile sources, SMOKE actually simulates em issions rates based on input mobile-source activity data, emission factors and outputs from transportatio n travel-demand models.

SMOKE was originally designed to allow emissions data processing methods to utilize emergent high-performance-computing as applied to sparse-matrix algor ithms. Indeed, SMOKE is the fastest emissions processing tool currently available to the air quality modeling community. The sparse matrix approach utilized throughout SM OKE permits both rapid a nd flexible processing of emissions data. The processing is rapid because SMOKE utilizes a series of matrix calculations instead of less effici ent algorithms used in previous systems. The processing is flexible because the processing steps of tem poral projection, controls, chemical speciation, temporal allocation, and spatial allocation have been separate d into independent operations21 Mississippi Regional Haze SIP Narrative, August 28, 2008 wherever possible. The results from these st eps are merged together at a final stage of processing.

SMOKE contains a number of ma jor features that make it an attractive component of the modeling system. The model s upports a variety of input fo rmats from other emissions processing systems and models. It supports bot h gridded and county total land use scheme for biogenic emissions modeling. SMOKE can acco mmodate emissions files from up to 10 countries and any pollutant can be processed by the system. For additional information about the SMOKE model please refer to Modeling Protocol (Appendix C).



### 5.3 Selection of the Modeling Year

A crucial step to SIP modeling is the selection of the period of time to model to represent current air quality conditions and to proj ect changes in air quality in res ponse to changes in emissions. The year 2002 was selected as the base year for several reasons.

The USEPA’s April 2007 Guidance on the use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goal s for Ozone, PM2.5, and Regional Haze identifies specific goals to consider when selecting one or more episodes for use in demonstrating reasonable progress in attaining the regional haze air quality goals. The USEPA recommends that episode selection derive from three principal criteria:

• Simulate a variety of me teorological conditions;

• Model time periods in which observed concentrat ions are close to the appropriate baseline design value or visibility impairment;

• Model periods for which extensive air qual ity/meteorological data bases exist; and

• Model a sufficient number of days so that th e modeled attainment te st applied at each monitor violating the NAAQS is based on multiple days.

For regional haze modeling, the guidance goes furthe r by suggesting that th e preferred approach is to model a full, representative year. Moreover, the required RRF values should be based on model results averaged over the 20% worst and 20 % best visibility days determined for each Class I are based on monito ring data from the 2000 – 2004 baseline period.

The USEPA also lists several ot her considerations to bear in mind when choosing potential regional haze episodes including: (a) choose pe riods which have already been modeled, (b) choose periods which are drawn from the years upon which the current design values are based, (c) include weekend days among those chosen, a nd (d) choose modeling periods that meet as many episode selection criteria as possible in the maximum number of nonattainment or Class I areas as possible. Finally, the USEPA explici tly recommended in its 2007 guidance to use 2002 as the baseline inventory year.22 Mississippi Regional Haze SIP Narrative, August 28, 2008 VISTAS adopted a logical, stepwise approach in implementing the USEPA guidance in order to identify the most preferable, representa tive year for regional haze modeling. These steps include the following:

Representativeness of Meteorological Conditions: The VISTAS meteorological contractor (BAMS) identified important meteor ological characteristics and data sets in the VISTAS region directly relevant to the evaluation of candidate annual modeling episodes.

Initial Episode Typing: At the time of selection in 2003, meteorological and air quality data were available for 2002 for model i nputs and model performance evaluation. VISTAS used Classification and Regression Tree Analyses to evaluate visibility conditions for 2000, 2001, and 2002, the candidate modeling years. The year 2002 was found to be representative of conditions in the other two years. Subsequently, these analyses were repeated with the meteorologi cal and air quality monitoring data for 2000 to 2004 to evaluate how well the 2002 m odeling year represented the full 2000-2004 baseline period. This analysis confirme d that visbility and PM2.5 mass in 2002 were representative of the five-y ear baseline period for the VI STAS Class I areas. This analysis is discussed in more detail in the project report in Appendix B.

Data Availability: In parallel with the CART analysis , episode characterization analyses, collaborative investigations by VISTAS stat es intensively studied the availability of PM2.5, meteorological, and emissions data and representativeness of alternative Baseline modeling periods from a regulatory standpoi nt. Additionally, 2002 was the year that USEPA was requiring states to provide emissions inventory data for the Comprehensive Emissions Reporting Rule, it made sense to use 2002 as the modeling year to take advantage of the 2002 inventory. Years to be used by other RPOs: VISTAS also considered what years other RPO would be modeling, and several had already chosen calendar year 2002 as the modeling year.

After a lengthy process of integrated studies, th e episode selection process culminated in the selection of calendar year 2002 (1 January through 31 December) as the most current, representative, and pragmatic choice for VIST AS regional haze modeling. All of the USEPA criteria for regional haze episode selection were di rectly considered in this process together with many other considerations (e.g., timing of new em issions or aerometric data deliveries by the USEPA or the states to the modeling teams).



### 5.4 Modeling Domains

5.4.1 Horizontal Modeling Domain

The USEPA’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 re solution was used for modeling th e entire United States and a finer 12-km grid was used to model the eastern United States.23 Mississippi Regional Haze SIP Narrative, August 28, 2008 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. One-wa y nesting is believed to be appropriate for the generally st agnant conditions experienced dur ing ozone episodes. Two-way nesting was not considered due to 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 loca tion of areas of interest, such as ozone and fine particulate matter nonattainment areas, as well as Class 1 and wilderness areas for regional haze. Processing time was also a factor in c hoosing a smaller 12-km grid, modeling domain.

The coarse 36-km horizontal grid domain covers th e continental United States. This domain was used as the outer grid domain for MM5 mode ling 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 5.4.1-1. The MM5 horizontal domain is the outer most, blue grid, with the CMAQ 36-km domain nested in the MM5 domain.24 Mississippi Regional Haze SIP Narrative, August 28, 2008 To achieve finer spatial resolution in the VI STAS states, a one-way nested high resolution (12-km grid resolution) was used. Figure 5.4.1-2 shows the 12-km grid, modeling domain for the VISTAS region. This is the modeling domai n for which the reasonable progress goals will be assessed.

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

5.4.2 Vertical Modeling Domain

The CMAQ vertical structure is primarily defined by the vert ical grid used in the MM5 modeling. The MM5 model employed a terrain following coordinate system defined by pressure, using 34 layers that extend from the surface to the 100 mb. A layer-averaging scheme was used to generate 19 verti cal layers for CMAQ to reduce th e computational cost of the CMAQ simulations. The effects of layer averag ing were evaluated in conjunction with the VISTAS modeling effort and was found to ha ve a relatively minor effect on the model performance metrics when both the 34 layer a nd a 19 layer CMAQ models were compared to ambient monitoring data.25 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 6.0 MODEL PERFORMA NCE EVALUATION

The initial modeling effort focused on evalua ting previous regional air quality modeling applications and testing candidate model conf igurations for the SMOKE emissions and CMAQ model for the VISTAS 36-km and 12-km modeling do mains. This effort resulted in a report recommending the model configuration for the an nual emissions and air quality modeling, which is included as part of the VISTAS Emissions a nd Air Quality Modeling Protocol. The evaluation of the meteorological modeling configuration can be found in Appendix F, with a summary of the final meteorological and air quality mode ling 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 one-atmosphere objective of the CMAQ modeling platform , model performance was evaluated based on measured ozone, fine particles, and acid deposition in the Ai r Quality System (AQS), IMPROVE, Speciated Trends Network (STN), Southeastern Aeroso l Research and Characterization (SEARCH), National Acid Deposition Program (NADP) a nd Clean Air Status and Trends Network (CASTNet) monitoring networks ( Figure 6.0-1 ). An examination of th e results is summarized in Appendix B.

Figure 6.0-1. Monitoring Networks used for VISTAS 2002 model performance evaluation and their location within the VISTAS 12km domain.26 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 6.1 Modeling Performance Goals, and Criteria

In 2004, VISTAS established model performance goals and criteria for components of fine particle mass ( Table 6.1-1 ) based on previous model performan ce for ozone and fine particles. The USEPA modeling guidance for fine particulat e matter at the time noted that PM models might not be able to achieve the same leve l of performance as ozone models. VISTAS’ evaluation considered several sta tistical performance measures a nd displays. Fractional bias and mean fractional error were selected as the most appropriate metrics to summarize model performance; other metrics were also calculated and are included for IMPROVE monitors in the full model performance evaluation (Appendix F).

Fractional Bias Mean Fractional Error Comment

< 15 percent < 35 percent Goal for PM model performance based on ozone model performance, considered excellent performance

< 30 percent < 50 percent Goal for PM model performance, considered good performance

< 60 percent < 75 percent Criteria for PM model performance, considered average performance. Exceeding this level of performance indicates fundamental concerns with the modeling system and trigge rs diagnostic evaluation.

Table 6.1-1. Established model performance goal s and criteria for the component species of fine particle mass.

Several graphic displays of model perf ormance were prepared including: 1. Scatter plots of predicted and observed c oncentrations and deposition by species, monitoring network, and month 2. Time series plots of predic ted and observed concentrati ons and deposition by species, monitoring site, and month 3. Spatially average time series plots 4. Time series plots of monthly fractional bias and error for a species, region, and network 5. Performance goal plots (“soccer plots”) that summarize model performance by species, region, season 6. Concentration performance plots (“bugle plots”) that display fractional bias or error as a function of concentration by species, region, monitoring network, and month

The “soccer plots” and “bugle pl ots” are relatively new tools in model performance evaluations, and have recently been included as model pe rformance evaluation displays in the USEPA’s modeling guidance for Ozone, PM2.5, and Regional Haze (2007). Both “soccer plots” and “bugle plots” allow for convenient way to examin e model performance with respect to set goals and criteria. The bugle plots ha ve the added benefit of adjus ting the goals and criteria to consider the concentration of th e species. Analysis of “bugle plots” generally suggests that greater emphasis should be placed on performa nce of those components with the greatest contribution to PM mass and visibility impair ment (e.g. sulfate and or ganic carbon) and that27 Mississippi Regional Haze SIP Narrative, August 28, 2008 greater bias and error could be accepted for comp onents with smaller contributions to total PM mass (e.g. elemental carbon, nitrate, and soil).



### 6.2 VISTAS Domain-Wide Performance

Further discussion of model performance in this document will focus on the comparison of observational data from the IMPROVE monitors and model output data from the 2002 VISTAS BaseG2-Actual annual air quality modeling. Fo cus is limited to the IMPROVE monitoring network as these sites are the locations used in projecting attainment visibility improvement goals in the Class I areas.

The evaluation will primarily focus on the air quality model’s performance with respect to individual components of fi ne particulate matter (PM 2.5 ), as good model performance of the component species will dictate good model performan ce of total or reconstituted fine particulate matter. Model performance of the total fine particulate matter and the resulting total light extinction will also be provided as a means to discuss the overall model performance for this Implementation Plan.

In our analyses, mean fractional bi as (error) is used in lieu of mean bias (error), to prevent low observations and model predictions from skewing the metrics. A full list of model performance statistics is found in Appendix G. The socce r and bugle plots for the all of the VISTAS IMPROVE monitors are included here for summary purposes. Plots have been developed for the average monthly concentrations and the performan ce 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.

The soccer plots of monthly concentrations ( Figures. 6.2-1 and 6.2-2 ) show that values for nitrate generally fall outside of criteria perf ormance thresholds. Sulf ates and organic carbon generally fall within goal thresholds, with a couple of months falling just outside the goal thresholds but well within the criteria thresholds. 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 provide d because performance is off sc ale with other constituents), when observed nitrate is quite lo w and predicted nitrate is even lower. When concentration is factored into performance criteria, nitrate pe rformance improves with respect to MFB and MFE ( 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 m onitoring 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.28 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 6.2-1. Soccer plot depicting both the mean fractional error and fractional bias for component concentration for a ll VISTAS sites based on Base G2 results. Each point represents a monthly value as compared to th e model performance criteria (red box) and modeling performance goals (green box).

Figure 6.2-2. A zoomed view of the soccer plot de picting both the mean fractional error and fractional bias for component concentration for all VISTAS sites based on Base G2 results. Each point represents a monthly value as compa red to the model performance criteria (red box) and modeling performance goals (green box).29 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 6.2-3. Seasonal soccer plots based on Base G1 results for all VISTAS IMPROVE monitors.30 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 6.2-4. Bugle plot of the mean fraction bias for particulate matter and its component concentrations for all VISTAS sites based on Base G2 results. Each point represents a monthly mean fraction bias value as compa red to the model performance criteria (red lines) and modeling performance goals (green lines).

Figure 6.2-5. Bugle plot of mean fraction er ror for particulate ma tter and its component species for all VISTAS sites based on Base G2 results. Each point represents a monthly mean fraction bias value as compared to th e model performance criteria (red lines) and modeling performance goals (green lines).31 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 6.3 Performance in Nearby Class 1 Areas

The following section provides stack bar charts (Figures 6.3.1 and 6.3.2) for closest Class 1 areas, Breton and Sipsey, comparing observed fi ne particulate matter composition and modeled fine particulate matter compositi on for the 20% worst days.

The stacked bar chart allows a side by side comparison of each day’s observed and modeled compositional and total light extinction. Within each bar the color codes are:

• Yellow = light extinction due to sulfates (bextSO4)

• Red = light extinction due to nitrates (bextNO3)

• Green = light extinction due to organic carbon (bextOC)

• Black = light extinction due to elemental (bextEC)

• Brown = light extinction due to soil (bextSoil)

• Grey = light extinction due to coarse mass (bextCM)

The components are presented in the same or der for both the observed (left hand bar) and modeled bar (right hand bar), so it easy to identify days when the predicted light extinction for the component differs from the observed. The total height of the bar provides the total reconstructed particulate matte r light extinction value.

Overall, model performance is good. Both the modeled and observed values demonstrate that sulfates are the largest contributor to visibi lity impairment. The model does significantly underestimate the observed values on a number of days. Since Breton is near the southern boundary of the modeling domain, there is signif icant uncertainty when the winds are from a southerly direction. This also indicates that Breton may experience si gnificant influence from international emissions that are di fficult to quantify or control. Section 3.5 of the Technical Support Document found in A ppendix G discusses the model performance in the various Class 1 areas more completely.32 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 6.3.1 Model Performance 20% Ha ziest Days in 2002 - Breton, LA Observations (left) vs Modeled Base G2a (right)

Figure 6.3.2 Model Performance 20% Haziest Days in 2002 - Sispey, AL Observations (left) vs Modeled Base G2a (right) 0 20 40 60 80 100 120 140 160 180

44 47 74 125 143 179 194 197 200 206 215 239 248 251 254 257 260 263 272 281 284 287 305 311 _ Avg Julian Day in Worst 20% groupbEXT (1/Mm) bCM
bSOIL
bEC
bOC
bNO3
bSO4

0 50 100 150 200 250 300 350

80 122 131 143 152 155 161 185 188 191 215 218 221 224 251 254 260 263 284 296 338 341 _ _ _ Avg Julian Day in Worst 20% groupbEXT (1/Mm) bCM
bSOIL
bEC
bOC
bNO3
bSO433 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 7.0 LONG-TERM STRATEGY FOR CL ASS I AREAS THAT ARE NEAR
MISSISSIPPI

As stated in section 1.3 above, the regional haze rule requires St ates to establish reasonable progress goals, expressed in deciviews, for visibi lity improvement at each affected Class I area covering each (approximately) 10-ye ar period until 2064. This first set of reasonable progress goals must be met through measures contained in the state’s long-term strategy covering the period from the baseline until 2018. This section discusses devel opment of Mississippi’s longterm strategy.



### 7.1 Overview of the Long-Term Strategy Development Process

The monitored data and modeling analyses cited in sections 2 and 5 above establish that for the VISTAS region, the key contributors to regiona l haze in the 2000-2004 baseline timeframe were large stationary sources of sulfur dioxide emissi ons. Keeping that key conclusion in mind, this section addresses the following questions:

a. Assuming implementation of existing federal and state air regulatory requirements in Mississippi and the VISTAS region, how much visibility improvement, compared to the glidepath, would MDEQ expect to see at Class I areas near Mississippi between now and 2018?

b. What additional emission controls represent BART in Mississippi?

c. What pollutants and source categories woul d the greatest visibility benefits be realized between th e baseline and 2018?

d. In what geographic locations are the emi ssions which have the greatest impact on visibility in speci fic Class I areas?

e. What types of emissions sources does MD EQ find in those geographic locations?

f. Which specific individual s ources in those geographic lo cations have the greatest visibility impacts at a given Class I area?

g. What additional emission controls repres ent reasonable progress for those specific sources?34 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### 7.2 Expected Visibility Results in 2018 for Class I Areas Neighboring Mississippi under existing and planned emissions controls (Base G2 Inventory)

There are significant emissions control programs being implemented between the baseline period and 2018. These programs are described in more detail below.

PURPOSE

The purpose of the section is to outline the St ate’s strategy for complying with the Long-term Strategy requirements of our Regional Haze SIP under 40 CFR 51.308(d)(3), and the requirements for establishing best available retrofit technology (BART) controls under 40 CFR 51.308(e).

The MDEQ long term strategy cont ains the following components:

I. Inventory of all controls required or exp ected under all federal and state regulations by 2009 and 2018. II. 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 Georgi a Institute of Technology). III. Examination of SO 2 Area of Influence (AOIs) proj ections for neighboring Class I areas to determine which specific sources are most likely to be im pairing visibility at specific Class I areas. IV. Using the results of the four factor analyses , identification of control determinations for specific sources. V. Identification of BART-eligible sources. VI. BART exemption modeling for BART-eligible sources. VII. BART determinations for sources subject to BART. VIII. Modeling demonstration of visibility im provement after inclusion of BART and reasonable progress control determinations.

7.2.1 Emission Controls Modeled and Requirements

CAIR

. Utility projections are based on the Integrated Planning Model ® (IPM ® ). CAIR will permanently cap emissions of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) in the eastern United States. CAIR achieves large reductions of SO 2 and/or NO x emissions across 28 eastern states and the District of Columbia. Wh en fully implemented, CAIR will reduce SO 2 emissions in these states by over se venty (70) percent and NO x emissions by over sixty (60) percent from 2003 levels.

NO x SIP Call . Phase I of the NO x SIP call applies to certain EGUs and large non-EGUs, including large industrial boilers and turbines, and cement kilns. Those states affected by the NO x SIP call in the VISTAS region have developed rules for the control of NO x emissions that35 Mississippi Regional Haze SIP Narrative, August 28, 2008 have been approved by the USEPA. The NO x SIP Call has resulted in a sixty-eight (68) percent reduction in NO x emissions from large stationary combus tion sources. For this analysis, the emissions for NO x SIP call-affected sources were capped at 2007 levels, and carried forward the capped levels for the 2009 and 2018 future year in ventories. Mississippi was not subject to the NO x SIP call; however, states north and east of Mi ssissippi are subject and the resulting emission reductions should improve conditions at Cl ass I areas throughout the Southeast.

Consent Agreements (Tampa Electric Company, Vi rginia Electric Power Company, Gulf Power Crist 7, Chevron Pascagoula Refinery).

• The settlement requires Tampa Elect ric Company (TECO) to pay a $3.5 million civil penalty. Under the agreement, TECO will install permanent emissionscontrol equipment to meet stringent pollu tion limits; implement a series of interim pollution-reduction measures to reduce em issions while the permanent controls are designed and installed; and retire pollution emission allowances that TECO or others could use, or sell to others , to emit additional pollution into the environment. The settlement also requi res the company to spend between $10 and $11 million on environmentally beneficial projects in the region designed to mitigate the impact of emissions from the company's plants.

• Virginia Electric and Power Co. (VEPCO ) agreed to spend $1.2 billion between now and 2013 to eliminate 237,000 tons of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) emissions each year from eight coal-fired electricity generating plants in Virginia and West Virginia.

• The 2002 agreement calls for Gulf Power to upgrade its operation to cut nitrogen oxide emission rates by sixty-one (61) pe rcent at its Crist generating plant by 2007 with major reductions beginning in early 2005. The Crist plant is a significant source of nitrogen oxide emissions in the Pensacola area.

• Under a 2005 settlement agreement, Chevron Refinery Pascagoula was required to significantly reduce emissions, particul arly of Sulfur Dioxide and Nitrogen Oxides. Emissions of other pollutants will be reduced to lesser extents. The major emissions points with reductions are two sulfur recovery units, the FCC regenerator, flares, and several boilers and heaters. The Chevron consent decree will result in emission reduc tions of 2900 lbs/hr of SO 2 , 960 lbs/hr of NOx, and 40 lbs/hr of PM10 with a modeled visibi lity improvement of 2.99dv at Breton. All of the reductions are to be in place by the end of 2011. Greater details of the consent decree and the emissions reductions can be found in the BART analysis, appendix L.10.

One-hour ozone SIP New SIPs have been submitted to the USEPA to demonstrate attainment of the one-hour ozone National Ambient Air Quality Standard (NAAQS) for areas in neighboring states. One-hour ozone SIPs Atlanta (Federal Regi ster: June 15, 2005 (Volume 70, Number 114)) / Birmingham (March 12, 2004 (Volume 69, Number 49))/ Northern Kentucky (Federal Register: September 16, 2004 (Volume 69, Nu mber 179)). The purpose of a state36 Mississippi Regional Haze SIP Narrative, August 28, 2008 implementation plan (SIP) is to demonstrate a ttainment or maintenance of the 1-hour ozone National Ambient Air Quality Standard (NAAQS). States must determine which Clean Air Act requirements are applicable to their area and submit plans to USEPA for public comment and approval.

Heavy Duty Diesel (2007) Engine St andard (for onroad trucks and buses). USEPA set a PM emissions standard for ne w heavy-duty engines of 0.01 grams per brakehorsepower-hour (g/bhp-hr), to take full effect for diesels in the 2007 model year. Also includes standards for NO x and non-methane hydrocarbons (NMHC) of 0.20 g/bhp-hr and 0.14 g/ bhp-hr, respectively. These NO x 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 e ffective on these trucks and buses. USEPA will require a ninety-seven (97) pe rcent reduction in the sulfur c ontent of highway diesel fuel from its current level of 500 parts per million (l ow sulfur diesel, or LSD) to 15 parts per million (ultra-low sulfur diesel, or ULSD).

Tier 2 Tailpipe (Onroad vehicles)

. USEPA mobile rules include the Tier 2 fleet averaging program, modeled after the California LEV II standards. Manufactur ers can produce vehicles w ith emissions ranging from relatively dirty to zero, but the mix of vehicles a manufacturer sells each year must have average NO x emissions below a specified value

. Tier 2 standards became effective in the 2005 model year.

Large Spark Ignition and Recreational Vehicle Rule

. USEPA has adopted new standards for em issions of oxides of nitrogen (NO x ), hydrocarbons (HC), and carbon monoxide (CO) from several groups of previously unregulated nonroad engines. Included in these are large industrial spark-igni tion engines and recreational vehicles. Nonroad spark-ignition engines are those powered by gasoline, liquid propane gas, or compressed natural gas rated over 19 kilowa tts (kW) (25 horsepower). These engines are used in commercial and industria l applications, including forklifts , electric generators, airport baggage transport vehicles, and a variety of farm and constr uction applications. Nonroad recreational vehicles include snowmobiles, off-highway motorcycles, and all-terrainvehicles. These rules were initi ally effective in 2004 and w ill be fully phased-in by 2012.

Nonroad Diesel Rule

. This rule sets standards that will reduce emi ssions by more than ninety (90) percent from nonroad diesel equipment, and reduce sulfur leve ls by ninety-nine (99) percent from current levels in nonroad diesel fuel starting in 2007. This step will apply to most nonroad diesel fuel in 2010 and to fuel used in loco motives and marine vessels in 2012. (http://www.epa.gov/nonroad-diesel/)

Industrial Boiler / Process Heat er / Reciprocating Internal Combustion Engines (RICE) Maximum Achievable Control Technology (MACT) standards. The USEPA issued final rules to substantially reduce emissions of toxic air pollutants from industrial, commercial and37 Mississippi Regional Haze SIP Narrative, August 28, 2008 institutional boilers, process h eaters and stationary RICE. Th ese rules reduce emissions of a number of toxic air pollutant s, including hydrogen chloride , manganese, lead, arsenic and mercury by 2009. This rule also reduces emission s of sulfur dioxide and particulate matter in conjunction with the toxic air pollutant reductions. The applie d MACT control efficiencies were four (4) percent for SO 2 and forty (40) percent for PM10 and PM2.5. The USEPA’s industrial boiler MACT rules were vacated on June 8, 2007. However, the USEPA is required under the Clean Air Ac t to issue revised boiler MA CT rules. These rules are scheduled to be proposed in 2009 and final in 2010. As such, it is likely that by 2018 MACT controls will be required for industrial boilers. Therefore, the VISTAS States decided to include control assumptions for industrial boilers due to MACT.

Combustion Turbine MACT

. The projection inventories do not include the NO x co-benefit effects of the MACT regulations for Gas Turbines or stationary Reciprocating Internal Combustion Engines (RICE), which USEPA estimates to be sm all compared to the overall inventory.

VOC 2-, 4-, 7-, and 10-year MACT Standards

. Volatile Organic Chemical (VOC) 2-, 4-, 7- , and 10-year MACT Standards. The point source MACTs and associated emission reducti ons were designed from Federal Register (FR) notices and discussions with USEPA’ s Emission Standards Division (ESD) staff. MDEQ did not apply reductions for MACT standards with an initial compliance date of 2001 or earlier, assuming that the effects of thes e controls are already accounted for in the 2002 inventories supplied by the States.

7.2.2 Point Source Controls (EGU and non-EGU)

Different approaches were used for the E GU and the non-EGU sectors of the point source inventory:

• For the EGUs, the State relied primarily on the Integrated Planning Model ® (IPM ® ) to project future generation as well as to calcula te the impact of the future emission control program CAIR. The IPM results were adju sted based on state and local agency knowledge of planned emission controls at specific EGUs.

• For non-EGUs, MDEQ used recently updated grow th and control data consistent with the data used in USEPA’s CAIR analyses, and s upplemented these data with available state and local agency input and updated fuel use fo recast data for the U.S. Department of Energy.

For both sectors, MDEQ generated 2009 and 2018 inventories for a control scenario which accounts for post-2002 emission reductions from promul gated and proposed federal, state, local, and site-specific control programs as of July 1, 2004.38 Mississippi Regional Haze SIP Narrative, August 28, 2008 7.2.2.1 Electric Generating Units (EGU)

State and local agencies specified a number of cha nges to the IPM results to better reflect current information on when and where future controls would occur. These changes to the IPM results primarily involved state and loca l agency addition or subtracti on of future emission controls based on the best available data from state ru les, enforcement agreements, compliance plans, permits, and discussions/commitments from individual companies.

Mississippi approved the us e of emissions projections from Mississippi Power fo r its facilities rather than the IPM outputs. These projections included the addition of NO x and SO 2 controls at Plant Watson in Gulfport and Plant Daniel in Escatapwa. The Emissions for South Mississippi Electric Power Association were al so revised to include greater SO 2 control. Several of Entergy’s units were proposed to be shut down by the IPM. There are no plans to remove the units in question from operation so the emissi ons were put back into the inventory at 2002 emission levels.

The following bar charts show expected decreases in emissions of SO 2 and NO x across the VISTAS states from 2002 through 2018. Note that for SO 2 emissions in particular, which are the largest contributors to haze, emissions from electri c generating facilities are expected to decrease dramatically (70 percent) be tween 2002 and 2018. However, even after implementation of CAIR, EGU emissions are projected to remain the largest contributor to haze, comprising more than half of remaining SO 2 emissions in most states.

7.2.2.2 Non-Electric Generating Units (Non-EGU)

The general approach for assembling future year data was to use recently updated growth and control data consistent with the data used in USEPA’s CAIR analyses, supplement these data with available stakeholder input, and provide the results for stakeholder review to ensure credibility.

MACTEC (MACTEC, 2006) used the same c ontrol programs for both the 2009 and 2018 nonEGU point inventory. Two control scenarios were developed: on-the-books (OTB) controls and on-the-way (OTW) controls. The OTB control scenario accounts for post-2002 emission reductions from recently promulgated federal, stat e, local, and site-specific control programs. The OTW control scenario accounts for proposed (but not final) control programs that are reasonably anticipated to result in post-2002 emission reductions.

Maximum achievable control technology (MACT) requirement s were also applied, as documented in the report entitled Control Packet Development and Data Sources, dated July 14, 2004. The point source MACTs and associated em ission reductions were designed from Federal Register (FR) notices and discussions with US EPA’s Emission Standards Division (ESD) staff. MDEQ did not apply reductions fo r MACT standards with an init ial compliance date of 2001 or earlier, assuming that the effects of these c ontrols are already accounted for in the 2002 inventories supplied by the States . Emission reductions were applied only for MACT standards with an initial compliance da te of 2002 or greater.39 Mississippi Regional Haze SIP Narrative, August 28, 2008 The final Phase II NO x SIP call rule was finalized on Ap ril 21, 2004. States had until April 21, 2005, to submit SIPs meeting the Phase II NO x budget requirements. The Phase II rule applies to large internal combustion (IC) engines, which are primarily used in pipeline transmission service at compressor stations. MDEQ id entified affected units using the same methodology as was used by USEPA in the proposed Phase II rule (i.e., a la rge IC engine is one that emitted, on average, more than 1 ton per day during 2002). The final ru le reflects a control level of eighty-two (82) percent for natural gas-fired IC engines and ninety (90) percent for diesel or dual fuel categories. Several state and local agencies provided more sp ecific information on the anticipated controls at the compressor stations. This information was us ed instead of the default approach used by USEPA in the proposed Phase II rule.

A summary of Non-EGU poi nt source control programs included in 2009/2018 projection invent ories include:

• Atlanta / Northern Kentucky / Birmingham 1-hr SIPs

• Industrial Boiler/Proces s Heater/RICE MACT. The applie d MACT control efficiencies were four (4) percent for SO 2 and forty (40) percent for PM 10 and PM2.5 to account for the co-benefit from installati on of acid gas scrubbers and other control equipment to reduce HAPs.

• NO x SIP Call (Phase I- except where States have adopted Phase II already) Phase I of the NO x SIP call applies to certain large non-EGUs , including large industrial boilers and turbines, and cement kilns. States in the VISTAS region affected by the NO x SIP call have developed rules for the control of NO x emissions that have been approved by USEPA.

• Petroleum Refinery Initiative (October 1, 2003 notice; Mississippi & West Virginia). This initiative addresses the most signi ficant Clean Air Act compliance concerns affecting the petroleum refinery industr y. Since December 2000, 17 global refinery settlements have been reached with refine rs representing nearly seventy-seven (77) percent of domestic refining capacity. Three re fineries in the VISTAS region are affected by two October 2003 Clean Air Act settleme nts under the USEPA Petroleum Refinery Initiative. The refineries are: (1) the Chevr on refinery in Pascagoul a, Mississippi; (2) the Ergon refinery in Vicksburg, Mississippi; a nd (3) the Ergon refinery in Newell, West Virginia. The emission reductions require d by the Consent decree for Chevron are significant and addressed to a gr eater degree in Appendix L.10.

• Reasonable Further Progress three (3) percen t plans where in place for one-hour ozone plans (Metropolitan Washington, DC, and Atlanta, Georgia).40 Mississippi Regional Haze SIP Narrative, August 28, 2008 • VOC 2-, 4-, 7-, and 10-year MACT Standard s. The point source MACTs and associated emission reductions were designed from Federa l Register (FR) notices and discussions with USEPA’s ESD staff. MDEQ did not appl y reductions for MACT standards with an initial compliance date of 2001 or earlier, assuming that the e ffects of these controls are already accounted for in the 2002 in ventories supplied by the States.

• Combustion Turbine MACT. The projecti on inventories do not include the NO x cobenefit effects of the MACT regulations for Gas Turbines or stationary Reciprocating Internal Combustion Engines, which USEPA estimates to be small compared to the overall inventory.

• NOx SIP Call (Phase II – remain ing states & IC engines).

For more information on the development of point source inventories, see Appendix D.

7.2.3 Area Source Controls

Controls (including control efficiency, rule eff ectiveness and rule penetration) provided by the States or originally developed for use in es timating projected emissions for USEPA’s Heavy Duty Diesel (HDD) rulemaking em ission projections and used in the CAIR projections were used to calculate cont rolled emissions.

The controls obtained by MA CTEC (MACTEC, 2006) for the HDD rulemaking were controls for the years 2007, 2020, and 2030. Since MACTEC was preparing 2009 and 2018 projections, control values for intermediate y ears were prepared using a straig ht-line interpolation of control level between 2007 and 2020. State submitted c ontrols had precedence over the U.S. EPA developed controls. For more information on th e development of area source inventories, see Appendix D.

7.2.4 Mobile Sources

The assumptions used for the 2002 initial base year inventory vary across the VISTAS region, but our presumption is that these data accurately reflected each State’s situ ation as it existed in 2002. If a State had no plans to change progr am requirements between 2002 and 2018, VISTAS proposed to maintain the 2002 program descriptions without change. However, if a State planned changes, information on those plans was request ed and used to develop the 2018 inventory. For more information on the development of mobile source inventories, see Appendix D.41 Mississippi Regional Haze SIP Narrative, August 28, 2008 7.2.5 Non-Road

Using the 2002 base year emissions inventory fo r aircraft, locomotives, and commercial marine vessels (CMV) prepared as de scribed earlier in this doc ument, corresponding emission projections for 2009 and 2018 were developed. Deta iled inventory data (both before and after controls) for these same emission sources for 1996, 2010, 2015, and 2020 were obtained from the USEPA's CAIR Technical Support Document . Using these data, combined growth and control factors for the period 2002-2009 and 2002-2018 were estimated using straight-line interpolation between 1996 and 2010 (for 2009) and 2015 and 2020 (for 2018). This is done at the State-county-SCC-pollutant level of detail. According to USEPA documentation, the CAIR baseline emissions include the impacts of the Tier 4 (T4) non-road diesel rulemaking, which implements a low sulfur fuel requirement th at affects both future CMV and locomotive emissions. For more information on the develo pment of non-road source inventories, see Appendix D.

7.2.6 Conclusion

In conclusion of this discu ssion on source sector controls, Figures 7.2.6-1 and 7.2.6-2 depict pollutant totals for NO x and SO 2 for the various sectors by state for 2002, 2009, and 2018 modeling. Due to emissions control requ irements already in place, both SO 2 and NO x emissions will be significantly lower in 2018 than in 2002. This will result in significant visibility improvement in 2018 over 2002.

Figure 7.2.6-1. Base G2 Annual SO 2 emissions for 2002, 2009, and 2018 in the VISTAS
states. W e s t V

i r g i n i a

A

l a b

a m

a F l o r i d

a

K e n t u cky
G

e o r g i a
M i s s i s s i p p i

S o u t h

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a r o l i n a

N

o r t h

C

a r o l i n a

T e n n e s s e e V i r g i n i a 100 200 300 400 500 600 700Annual SO2 (Thousand Tons) Miscellaneous
Nonroad Onroad
Industrial Other Fuel Combustion
EGU 2 0 0 2

2 0 0 9

2 0 1 8

W e s t V

i r g i n i a

A

l a b

a m

a F l o r i d

a

K e n t u cky
G

e o r g i a
M i s s i s s i p p i

S o u t h

C

a r o l i n a

N

o r t h

C

a r o l i n a

T e n n e s s e e V i r g i n i a 100 200 300 400 500 600 700Annual SO2 (Thousand Tons) Miscellaneous
Nonroad Onroad
Industrial Other Fuel Combustion
EGU 2 0 0 2

2 0 0 9

2 0 1 8

A

l a b

a m

a F l o r i d

a

K e n t u cky
G

e o r g i a
M i s s i s s i p p i

S o u t h

C

a r o l i n a

N

o r t h

C

a r o l i n a

T e n n e s s e e V i r g i n i a 100 200 300 400 500 600 700Annual SO2 (Thousand Tons) Miscellaneous
Nonroad Onroad
Industrial Other Fuel Combustion
EGU Miscellaneous
Nonroad Onroad
Industrial Other Fuel Combustion
EGU 2 0 0 2

2 0 0 9

2 0 1 842 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 7.2.6-2. Base G2 Annual NO x emissions in 2002, 2009, and 2018 in the VISTAS States

.

Summary of Final Emissions Inventories for 2009 and 2018

Table 7.2.6-1 is a summary of the 2009 final emission i nventory for Mississippi. The complete inventory and discussion of the me thodology is containe d in Appendix D.

VOC NO x PM2.5 PM10 NH 3 SO 2 Point 38,151 92,409 13,976 24,202 1,001 102,143 Area 124,997 4,249 51,661 356,324 63,708 753 On-Road Mobile 51,600 69,952 1,491 2,250 3,995 532 Non-Road Mobile 36,197 80,567 3,985 4,270 25 7,191 Biogenics 1,544,646 20,304 TOTAL 1,795,571 267,482 71,113 387,046 68,729 110,619

Table 7.2.6-1. Mississippi 2009 Emissions Inventory Summary in tons. 0 100 200 300 400 500 600 700 800 900 1,000

Alabama Flo r ida Georgia Kentucky

M i ssi

ssi

p p i

North Carolina

S

o ut

h C

a r o li n a

Te

nn

e ss

e e

V i r g i n ia

W est

Vir

g i n i aAnnual NOx (Thousand Tons) Miscellaneous Nonroad Onroad Industrial Other Fuel Combustion EGU 2 0 0 2

2 0 0 9

2 0

1 8

0 100 200 300 400 500 600 700 800 900 1,000

Alabama Flo r ida Georgia Kentucky

M i ssi

ssi

p p i

North Carolina

S

o ut

h C

a r o li n a

Te

nn

e ss

e e

V i r g i n ia

W est

Vir

g i n i aAnnual NOx (Thousand Tons) Miscellaneous Nonroad Onroad Industrial Other Fuel Combustion EGU Miscellaneous Nonroad Onroad Industrial Other Fuel Combustion EGU 2 0 0 2

2 0 0 9

2 0

1 843 Mississippi Regional Haze SIP Narrative, August 28, 2008 Table 7.2.6-2 is a summary of the 2018 final emission i nventory for Mississippi. The complete inventory and discussion of the me thodology is containe d in Appendix D.

VOC NO x PM2.5 PM10 NH 3 SO 2 Point 46,452 71,804 17,172 30,046 1,591 54,367 Area 140,134 4,483 53,222 375,495 69,910 746 On-Road Mobile 31,306 30,259 810 1,607 4,520 435 Non-Road Mobile 28,842 68,252 3,203 3,452 29 6,683 Biogenics 1,544,646 20,305 TOTAL 1,791,381 195,103 75,008 410,600 76,050 62,186

Table 7.2.6-2. Mississippi 2018 Emissions Inventory Summary in tons.



### 7.3 What Control Determinations Re present Best Available Retrofit Technology (BART) for Individual Sources?

Section 169A of the CAA directs States to asse ss certain large, olde r emission sources for additional controls in order to address visibility impacts. Stat es are directed to conduct BART determinations for such sources in specific source categories, and which c ontribute to visibility impairment in Class I areas. The 1999 regiona l haze rule includes the BART requirement, and directs States to include BART in their regi onal haze SIPs. On July 6, 2005, USEPA published a revised final rule, including A ppendix Y to 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 of these sources should be subject to BART, and how to determine BART for each source.

A BART-eligible source is one which has the poten tial to emit 250 tons or more of a visibilityimpairing air pollutant, was put in place be tween August 7, 1962 and August 7, 1977, and whose operations fall within one or more of 26 specifi cally 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 c ontribute 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 de terminations: (1) the costs of compliance, (2) the energy and non-air quality environmental imp acts of compliance, (3 ) any existing pollution control technology in use at the source, (4) the remaining usef ul life of the source, and (5) the degree of improvement in visibility which may r easonably be anticipated to result from the use of such technology.44 Mississippi Regional Haze SIP Narrative, August 28, 2008 7.3.1 BART-Eligible Sources in Mississippi

Table 7.3.1-1 is a list of facilities with BART-eligib le sources in Mississippi. See Appendix L for a detailed description of each BART-eligible emission unit.



### Facility Name City, County Chevron Products Company, Pascagoula Re finery Pascagoula, Jackson County Entergy Mississippi Inc, Baxter Wilson Plant Vicksburg, Warren County Entergy Mississippi Inc, Gerald Andrus Plant Greenville, Washington County Georgia Pacific Corp, Mo nticello Mill Monticel lo, Lawrence County
Greenwood Utilities, Hende rson Station Greenwo od, Leflore County

Holcim US Inc Artesi a, Lowndes County International Paper Company, Vicks burg Mill Vicksburg, Warren County Terra Mississippi Nitrogen Inc Yazoo City, Yazoo County Mississippi Phosphates Corporat ion Pascagoula, Jackson County Mississippi Power Compan y, Chevron Cogenerating Plant Pascagoula, Jackson County

Mississippi Power Company, Plant Jack Watson Gulfport. Harrison County Mississippi Power Company, Plant Victor J Daniel Ecatawpa, Jackson County Pursue Energy Corp, Thomasville Gas Plant Thomasville, Rankin County South Mississippi Electric Power Association, Moselle Plant Moselle, Jones County

South Mississippi Electric Power Association, R D Morrow Plant Purvis, Lamar County

Table 7.3.1-1. BART-eligible sources in Mississippi.

The BART-eligible sources were identified using the methodology in the BART Guidelines:

• One or more emissions 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 limited potential emissions from all emissi on units identified in the previous two bullets emission units were greater than 250 tons or more per year of any of these visibility-impairing pollutants: SO 2 , NO x , and PM10.45 Mississippi Regional Haze SIP Narrative, August 28, 2008 The BART Guidelines recommend addressing these visibility-impairing pollutants: SO 2 , NO x , and particulate matter, and suggest that States us e their best judgment in determining whether to address VOC or ammonia emissions. MDEQ addressed SO 2 and NO x , and used particulate matter less than 10 microns in diameter (PM 10 ) as an indicator for part iculate matter to identify BART-eligible units, as the BART Guidelines recommend. VISTAS modeling demonstrated that VOCs are not significant emissions for this planning period. Point-source impacts from VOC emissions are below a significance level that the emissions will not be evaluated. VISTAS modeled several large ammonia s ources whose potential emissions exceeded 250 tons per year and demonstrated an impact on vi sibility at Class I areas. Howe ver, Mississippi doesn’t have any large point sources of ammonia near Cla ss I areas. For these r easons, MDEQ did not evaluate emissions of VOCs and a mmonia in BART determinations.

7.3.2 Determination of Sources Subject to BART in Mississippi

Under the BART Guidelines, MDEQ may consid er exempting some sources from BART if MDEQ finds that the emissions do not cause or cont ribute to visibility impairment in a Class I area. In accordance with the BART guideline s, MDEQ chose to perform source-specific analyses to determine which sources cause or co ntribute to visibility impairment using the CALPUFF model. The CALPUFF m odeling protocol used for dete rmining which facilities are subject to BART is included in Appendix L. A contribution threshold of 0.5 deciviews was used for determining which sources were subject to BART. This is th e level suggested in the BART guidelines and the threshold used by the surrounding states with th e Class 1 areas that sources in Mississippi could impact. A complete discussion of the suitability of the 0.5 deciview threshold can be found in Appendix L.

Mississippi’s BART-eligible sources were screened to determine subjectivity in three different ways. Ten performed and submitted exemption modeling analysis. Two had the exemption analysis performed by TRC under VISTAS Contract . Three were exempted based on the model plant provision (Option 2 in the Guidelines).

For the facilities that performed modeli ng for exemption, the IMPROVE (Interagency Monitoring of Protected Visual Environments) eq uation was used to determine the impact of a facility’s emissions on visibility at Class 1 areas. This equati on determines light extinction (b ext ) in inverse megameters. Originally, the IMPR OVE equation was set forth in “Guidance for Estimating Natural Visibility Conditions U nder the Regional Haze Program”, EPA-454/B-03- 005, September 2003. 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.

. Among other improvements, the new equation allo ws for the use of site specific Raleigh Scattering factors and sea-salt va lues. Raleigh Scattering is the light scattering effect that the molecules exert and is greater at sea level. Se a-salt also has a light scattering effect and is important at coastal sites, such at Breton. There were no sea-salt values available for Breton, so the values for St. Marks, a gulf coas tal site in Florida, were used.46 Mississippi Regional Haze SIP Narrative, August 28, 2008 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. Mississippi allowed the use of the new IMPROVE equation in performing the scr eening analysis. The states of Alabama, Arkansas, and Louisiana whose Class 1 areas were potentially impacted also allowed the use of the new IMPROVE equation. However, since th e old IMPROVE equation was considered the default, gave more conservative results, and the new IMPROVE equation required additional processing to implement, only three facilities (Mississippi Power- Pl ant Watson, Mississippi Power-Plant Daniel, and Missi ssippi Power-Chevron Cogenerati on Station) used the new IMPROVE equation for the screening analys is. Appendix L.12 discusses the IMPROVE Equation in greater detail.

Three facilities used the Model Plant rule as gi ven in Part III, Option 2 of the BART Guidelines to be exempted. The model plant criteria for ex emption states that potential emissions of SO 2 or NO x or SO 2 + NO x should be less than 500 tons for facil ities greater than 50 kilometers (km) from the nearest class I area or potential emissi ons should be less than 1000 tons for facilities greater than 100 km from the near est class I area. The model plan t criteria proposed by the EPA does not consider the contribution from PM. L ogic to appropriately in clude PM in the model plant exemption process was developed by Jim Boylan of Georgia DNR. This rationale determines a “PM factor” to relate prim ary PM to secondary sulfate PM from SO 2 . The three facilities that were exempted based on the mode l plant rule are South Mississippi Electric Power Association (SMEPA)-Moselle Plant, SMEPA- R D Morrow Plant, and Terra Mississippi Nitrogen. Further detail on this exemption process is found in Appendices L.8 and L.9.

Thirteen of the fifteen sources were able to demonstrate exemption. Results of these demonstrations are summarized in Table 7.3.2-1 . Additional details are available in Appendix L. Facilities found to be subject to BART completed a BART analysis.

Seven (7) of the BART eligible sources are EGUs subject to CAIR. USEPA has determined that, as a whole, the CAIR cap-and-trade program impr oves 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 SO 2 or NO x emissions. Since Mississippi is participating in CAIR and accepts USEPA’s overall finding th at CAIR “substitutes” for BART for NO x and SO 2 , Mississippi’s EGUs were allowed to submit BART exemption modeling demonstrations for PM emissions only. All EGUs demonstrated that each facility’s emissions do not contribute to visibility impairment in any Class I area.47 Mississippi Regional Haze SIP Narrative, August 28, 2008 

### Facility Name Class I area Results/ Impact

Chevron Products Company, Pascagoula Refinery Breton National Wildlife Refuge Subject
3.89dv Mississippi Phosphates Corp oration Breton National Wildlife Refuge Subject

0.81dv Entergy Mississippi Inc, Baxter Wilson Plant Breton National Wild life Refuge Exempt

0.35dv Entergy Mississippi In c, Gerald Andrus Plant Caney Creek Wilderne ss Area Exempt

0.27dv Georgia Pacific Corp, Monti cello Mill Breton National WildlifeRefuge Exempt

0.33dv
Greenwood Utilities, Henders on Station Sipsey Wild erness Area Exempt

0.22dv Holcim US Inc Sipsey Wilderness Area Exempt

0.34dv International Paper Company, Vicksburg Mill Breton National Wild life Refuge Exempt

0.32 Mississippi Power Company, Chevron Cogenerating Plant Breton National Wild life Refuge Exempt

0.02dv Mississippi Power Co mpany, Plant Jack Watson Breton National Wild life Refuge Exempt

0.42dv Mississippi Power Company, Plant Victor J Daniel Breton National Wild life Refuge Exempt

0.23dv Pursue Energy Corp, Thomasville Gas Plant Breton National Wild life Refuge Exempt

0.17dv Terra Mississippi Nitrogen Inc Sipsey Wilderness Area Exempt (model plant) South Mississippi Electric Power Association, Moselle Plant Breton National Wild life Refuge Exempt (model plant) South Mississippi Electric Power Association, R D Morrow Plant Breton National Wild life Refuge Exempt (model plant)

Table 7.3.2-1. BART Exemption Modeling Results.48 Mississippi Regional Haze SIP Narrative, August 28, 2008 7.3.3 Determination of BART Requi rements for Subject-to-BART Sources

After the Screening analysis, tw o sources were determined to be “subject to BART” and were required to perform an engineering analysis containing their evaluation of potential BART options and proposed BART determinations. The two (2) “subject to BA RT” facilities are the Chevron Pascagoula Refinery in Pascagoula, Mississippi and Missi ssippi Phosphates in Pascagoula, Mississippi.

The modeled visibility impact resulting from Chevron Refinery’s emissions was 3.89dv, which exceeds the threshold of 0.5 dv. Chevron has sign ificant emissions reductions planned due to permitted projects that are currently or will soon be underway and an enforcement consent decree issued June 7, 2005. This will result in emission reductions of 2900 lbs/hr of SO 2 , 960 lbs/hr, of NOx and 40 lbs/hr of PM10 with a modeled visibility improvement of 2.99dv at Breton. See Table 7.3.3-1 below for a detailed acc ount of the units, involved in Chevron’s consent decree, that c ontribute to 96% of the SO 2 emissions for Chevron’s BART-eligible sources. Further reductions would be very costly without significant visibility improvement. Mississippi has determined that th e emissions controls and resulti ng reductions from the consent decree constitute BART

. The Complete BART analysis for Chevron can be found in appendix L.10.

Max Daily Averages (2001- 2003) Future Planned Emissions / Consent Decree NOx SO 2 VOC NOx SO 2 VOC

BART Eligible Unit lb/hr lb/hr lb/hr lb/hr lb/hr lb/hr Controls
F-1603/FCC Regenerator 374.000 841.000 111.000 80.000 60.000 99.000 NOx reducing catalyst

F-2101/Boiler No.1 86.000 4.300 1.800 0.000 0.000 0.000 F-2102/Boiler No.2 82.000 4.300 1.700 0.000 0.000 0.000 F-2103/Boiler No.3 84.000 4.600 1.800 0.000 0.000 0.000 Boilers being replaced by ULNB boilers

F-2745/SRU 2 w/Thermal Oxidizer 2.300 870.000 0.400 2.300 36.000 0.360
F-2765/SRU 3 w/Thermal Oxidizer 10.500 730.000 1.400 10.500 36.000 1.360 SCOT tail gas treatment systems

F-3801/Flare No. 1 8.700 110.800 3.900 0.690 0.003 0.007 F-3801/Flare No. 2 15.600 213.800 7.000 0.690 0.003 0.007 F-3801/Flare No. 3 7.300 174.200 3.300 0.690 0.003 0.007 F-3801/Flare No. 4 4.100 63.300 1.800 0.690 0.003 0.007 Flare gas recovery system

F-6101/6102 Crude Unit No.2 Heaters 282.000 16.400 5.300 28.160 16.410 5.350 ULNB will be installed

Total Reductions* NOx 832.78 SO 2 2884.28 VOC 33.30 *This table represents 96% of the SO2 emissions from BART-eligible units

Table 7.3.3-1. Major BART-eligible Units Involved in the Consent Decree49 Mississippi Regional Haze SIP Narrative, August 28, 2008 The modeled visibility impact resulting from Mississippi Phosphate’s emissions was 0.81dv, which exceeds the threshold of 0.5 dv. The prim ary emissions at Mississippi Phosphates are SO 2 from the facility’s two Sulfuric Acid Plants. The existing control equipment on the Acid Plants are a Dual Absorption System and Acid-Mist demist ers. This results in emissions of 4 lbs SO 2 per ton of Sulfuric Acid. The BART analysis find s that there may be ava ilable alternatives that are technically feasible at the facility and could further reduce emissions. However, Mississippi Phosphates is planning to modify the acid plants at the facility over the next several years. Mississippi Phosphates is currently in the desi gn phase for the new units which will include better emission controls for the acid plants. Th ey are planning to perform a combined BART and BACT analysis to determine the appropriate fu ture controls at the facility. This will take several months to complete and several more mo nths to evaluate and issue permits. Mississippi will submit a supplemental SIP with the control de termination one year af ter the initial Regional Haze SIP submittal. The complete BART Analys is and accompanying details for Mississippi Phosphates can be found in appendix L.11.



### 7.4 Relative Contributions to Visi bility Impairment: Pollutants, Source Categories, and Geographic Areas

An important step toward determining the long term strategy measures is to identify the key pollutants contributing to visibility impairment at each Class I area. To understand the relative benefit of further reducing emissions from diffe rent 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: Jan 2002, July 2001, and July 2002. These runs used the initial 2018 projections inventory and co nsidered thirty (30) percent reductions from specific pollutants, source categories, and ge ographic areas. A thirty (30) percent emission reduction was chosen for the sensitivity runs because it is large enough to obtain results and represents a reasonable expectation of reducti ons from various source categories. Emissions sensitivities were repeated using the 2009 Base D projection inventory and two month-long episodes from 2002: Jun 1-Jul 10 and Nov 19 – Dec 19. Emissions in 2009 were reduced by thirty (30) percent for each po llutant sensitivity run. The pollu tant contributions that were evaluated were:

• SO 2 from EGU sources in each VISTAS state, other RPOs in the VISTAS 12 km grid, and Boundary Conditions from outside the 12 km domain.

• SO 2 from non-EGU point sources in each VI STAS state, other RPOs, and Boundary Conditions

• NO x from ground level (on-road plus non-road pl us area) sources in each VISTAS state and other RPOs

• NO x from point (EGU plus non-EGU) sources in each VISTAS state and other RPOs

• NH 3 from all sources in VISTAS and other RPOs

• Volatile Organic Compounds from anthr opogenic and biogenic sources in the 12 km modeling domain

• Primary Carbon from all ground level source s in each VISTAS state and other RPOs50 Mississippi Regional Haze SIP Narrative, August 28, 2008 • Primary Carbon from all point sources in each VISTAS state and other RPOs

• Primary Carbon from all fires in ea ch VISTAS state and other RPOs

Results are shown in Figures 7.4-1 through 7.4-3 below for a thirty percent reduction in emissions for each of the three Class I areas near Mississippi. Responses for twenty (20) percent worst days were calculated by averaging the responses of the twenty (20) pe rcent worst days that were modeled in the two episodes for Sipsey and Caney Creek. Complete data was not available to determine the 20 percent worst days for Bret on so chart depicts th e response to the full summer episode.

Figure 7.4-1. CMAQ projections of visibility responses on to 30 percent reductions from the 2009 Base D inventory for visibility-reducin g pollutants in different source categories and geographic areas.51 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 7.4-2. CMAQ projections of visibility responses on 20 percent worst days at Sipsey, AL to 30 percent reductions from the 2009 Base D inventory for visibility-reducing pollutants in different source cate gories and geographic areas.

Figure 7.4-3. CMAQ projections of visibility responses on 20 percent worst days at Caney Creek, AR to 30 percent reductions from the 2009 Base D inventory for visibility-reducing pollutants in different source cate gories and geographic areas.52 Mississippi Regional Haze SIP Narrative, August 28, 2008 As Figures 7.4-1 through 7.4-3 illustrate, the greatest visibilit y benefits for these Class I areas are projected to result from reducing SO 2 from EGUs. Additionally, smaller benefits are projected from SO 2 emission reductions from non-utility, in dustrial point sources . The pattern of relative SO 2 contributions from non-EGUs among the va rious VISTAS states is similar to the pattern of relative SO 2 contributions from EGUs.

Figures 7.4-1 through 7.4-3 also indicate that Mississippi has minor impacts on all three (3) neighboring Class I sites. Missi ssippi has more significant imp acts on Breton than Sipsey or Caney Creek. The Area of Impacts analysis in Section 7.5.4 further illu strates Mississippi’s impact on the neighboring Class I areas.

Because ammonium nitrate is a small contributor to PM2.5 mass and visibility impairment on the twenty (20) percent worst days , the benefits of reducing NO x and NH 3 emissions in Mississippi are small.

VOCs do contribute to visibility impairment, but as shown in the Figures 7.4-1 through 7.4-3 above, this contribution is from biogenic sour ces such as vegetative emissions. Controlling anthropogenic sources of VOC emissions has little if any visibility benefit at the Class I areas. Reducing primary carbon from point sources, ground le vel sources or fires ar e projected to have small to no visibility benefit. Th is is consistent with the monitori ng data that shows that most of measured organic carbon is secondary in origin and primary carbon is only a small fraction of the total measured carbon (Appendix B). Reducing car bon from fires was not found to be effective because there was little fire activity at these sites on the days modele d in the sensitivity analyses.

The results indicate that sulfate is the dominant contributor to visi bility impairment on the twenty (20) percent worst days at all si tes, and that ammonium nitrate may be important for sites where the twenty (20) percent worst days occur in the winter. MDEQ concludes that reducing SO 2 emissions from EGU and non-EGU poi nt sources would have the gr eatest visibility benefits. Contributions from outside the VISTAS 12-km modeling domain are more important for the coastal Class I areas. These results are consis tent with the CMAQ model results indicating that contributions from international emissions to visi bility impairment at VISTAS Class I areas are greater closer to the boundari es of the modeling domain (s ee summary in section 7.3).



### 7.5 Relative Contributions to Visib ility Impairment: Geographic Areas of Influence for Neighboring Class I Areas

Once it was determined that SO 2 emission reductions from E GU and non-EGU point sources in the VISTAS states would be the most effective sources to control to improve visibility at neighboring Class I areas, the next step was to identify the specif ic geographic areas that most likely influence visibility in each Class I area, and then to identify the major SO 2 point sources located in those geographic areas . Mississippi, along with the ot her VISTAS states, developed an Area of Influence (AoI) for each Class I ar ea to represent the ge ographic area containing sources that would likely have the greatest impact on visibility at that Class I area. All SO 2 point sources within these Areas of Influence were identified and ranked by their 2018 emissions.53 Mississippi Regional Haze SIP Narrative, August 28, 2008 Mississippi used this AoI analysis to determine the sources that need to be evaluated to meet the reasonable progress goals for neighboring Cla ss 1 areas. The following sections contain an overview of the steps in the Area of Influence analyses.
7.5.1 Back Trajectory Analyses

The first step was to generate meteorological ba ck trajectories for IMPROVE monitoring sites in neighboring Class I areas for the 2000-2004 base line period. Back traj ectory analyses use interpolated measured or modele d meteorological fields to estimat e the most likely central path of air masses that arrive at a receptor at a given time. The method essentially follows a parcel of air backward in hourly steps for a specified length of time. Figure 7.5.1 is an example of a back trajectory analysis for Breton for the twen ty (20) percent worst days in 2002.

Figure 7.5.1. Example back trajectories for 20 percent worst visibility days in 2002 for Breton.

Trajectories were started at 100 meters and 500 meters above the surface and run backward from the site for 72-hours. These individual back traj ectories for twenty (20) percent worst days in 2002 were also useful in evaluati ng model performance for individual days at the Class I areas.

7.5.2 Residence Time Plots

The next step was to plot residence time for each Class I area using five year s of back trajectories for the twenty (20) percent worst visibility days in 2000-2004. Residence time is the frequency54 Mississippi Regional Haze SIP Narrative, August 28, 2008 that winds pass over a specific geographic area on th e path to a Class I area. Separate residence time plots were generated using trajectories with 100m start height. As illustrated in Figure 7.5.2 , winds influencing Breton on the twenty (20) percent worst days come from several directions with no single predominant wind direct ion influencing the twenty (20) percent worst visibility days.

Figure 7.5.2. Example residence time plot fo r 20 percent worst visibility days in 2000-2004 for Breton, Louisiana. Based on tr ajectories with 100m start height.

7.5.3 SO 2 Areas of Influence

The next step was to develop sulfate extinction weighted residence time plots to define the geographic area with highest proba bility of influencing the recep tor on the twenty (20) percent worst days in 2000-2004 that were dominated by sulf ate. Each back trajectory was weighted by sulfate extinction for that day. This allows us to focus on the twenty (20) percent worst days that are influenced by sulfate and place less importanc e on days influenced by organic carbon from55 Mississippi Regional Haze SIP Narrative, August 28, 2008 fires. Sulfate-weighted back tr ajectories for the twenty (20) pe rcent worst days were combined for 5 years of data. The resulting sulfate extin ction-weighted residence time plots were used to define the geographic Area of Influence for sources of SO 2 emissions. In Figure 7.5.3 the area representing ten (10) percent or greater residence time is outline d in red and the area representing five (5) percent or greater residence time is ou tlined in gray. The VISTAS states focused their analyses on the Area of Influence defined by fi ve (5) percent or greater sulfate extinctionweighted residence time.

Figure 7.5.3. Example SO 2 Area of Influence plot for sulf ate extinction weighted residence time for 20 percent worst visibility days in 2000-2004 for Breton, Louisiana. Based on trajectories with 100m start height.

7.5.4 Emissions Sources within SO 2 Areas of Influence

Residence time plots were then combined w ith geographically-gridded emission data based on the 2002 baseline and 2018 BaseG emissions inventorie s. Plots were generated for the Areas of Influence (AOI) defined by trajectories with 100m and 500 m start heights. As a way of incorporating the effects of transport, depositi on, and chemical transformation of point source56 Mississippi Regional Haze SIP Narrative, August 28, 2008 emissions along the path of the trajectories, these data were weighted by 1/d, where d was calculated as the distance, in kilometers, between the center of the grid cell in which a source is located and the center of the grid cell in which the IMPROVE mon itor is located. The distanceweighted point source SO 2 emissions are then combined with the gridded extinction-weighted back-trajectory residence times at a spatial resolution of 36-km.

The final step was to combine the residence times and gridded emissions data in plots and data sets. The distance weighted (1/d) gridded point source SO 2 emissions were multiplied by the total extinction-weighted back-tra jectory residence times on a grid cell by grid cell basis. These results were then normalized by the domain-wid e total and displayed as a percentage. The analysis was done using both the 2002 a nd 2018 base year inventories.

Figures 7.5.4-1 through 7.5.4-3 illustrate 2018 distance weight ed gridded emissions sulfate extinction weighted residence time plots for Breton, Sipsey and Caney Creek. For Breton, the Area of Influence only includes sources in south Mi ssissippi, primarily, in coastal counties. The AOI plots for Sipsey and Caney Creek do not indi cate any sources in Miss issippi. By examining these maps, the focus narrows to only working w ith sources in south Mi ssissippi with potential impacts on Breton.

These analyses are serving as the basis for consultation among the VISTAS states.57 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 7.5.4-1. Breton, Louisiana 2018 SO 2 distance weighted emissions * SO4 extinctionweighted residence time plots.58 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 7.5.4-2. 2018 SO 2 distance weighted emissions * SO 4 extinction-weighted residence time plot for Sipsey, Alabama.59 Mississippi Regional Haze SIP Narrative, August 28, 2008 Figure 7.5.4-3. 2018 SO 2 distance weighted emissions * SO 4 extinction-weighted residence time plot for Caney Creek, Arkansas.

7.5.5 Specific Sources in the Areas of Influence

The next step in the analysis was to review th e emissions inventories to determine the specific sources found to have the gr eatest impact on visibility at Breton. Lists of SO 2 point sources within the Areas of Influence for each Class I areas were developed using the most current (BaseG) VISTAS 2002 base year and 2018 future y ear emissions. For this purpose the Area of Influence was defined as the counties with maxi mum sulfate extinction we ighted residence time greater than 5. For SO 2 sources within each Area of Influence, the following attributes were defined for each individual unit:

• State, county, and source (plant), and industry iden tification codes

• SO 2 emissions for 2002 and 2018

• 2018 control efficiency

• Distance to Class I areas (defined by centroid of the Class I area)

• Emissions divided by distance (Q/d), a metr ic that accounts for the dispersion of emissions over distance

• Maximum sulfate extinction weighted residence time (RTmax)60 Mississippi Regional Haze SIP Narrative, August 28, 2008 Looking specifically at the Breton Class I area, MDEQ multiplied the RT Max by Q/d, added the RT Max * Q/d terms for all facilities, a nd then divided this term for each unit by that for all sources to get a percent (%) contribution. Table 7.5.5-1 shows this approach for Mississippi facilities and limited data. The complete spreadsheet can be found in Appendix M. The percent contribution is based on all facilities in all states in the 2018 inventory.

After developing the percent cont ribution values, MDEQ used a one percent (1%) per unit cut point to determine the facilities and units to further analyze. MDEQ 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 as follows:

• The BART rule specified that a maximum impact of 0.5 dv is an acceptable threshold for establishing significance. This threshold is repres entative of a 5 percent change in extinction.

• The NO x 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 3.75 percent 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/m 3 as significant. This threshold represents 1.3 percent of the Annual PM 2.5 standard of 15 μg/m 3

.

• The NAAQS assign significant impact levels for human health standards based on a sources’ contribution to air quality. These significance levels represent a percentage of the NAAQS. Those facilities able to demonstrate that a new or modified sources’ contribution is less than a particular significance level is relieved of further modeling. MDEQ examined all the averaging periods for the criteria pollutants and determined that the 1 percent threshold contribution chosen for reasonable further progress was as stringent as any significant impact level, the most restrictive being NO 2 at 1 μg/m 3 or 1 percent. (NO 2 NAAQS 100 μg/m 3 )

Based on the above, a 1% threshold is reasonable to determine emissions units to be further evaluated to help meet the Reasonable Progress Go als. It is also the threshold that surrounding VISTAS states have adopted.

Table 7.5.5-1 lists the significant fa cilities and units that may imp act Breton. The units that meet61 Mississippi Regional Haze SIP Narrative, August 28, 2008 a 1.0 % contribution test are highlighted in yellow in Table 7.5.5-1 . As can be seen in Table 7.5.5-1 , the 1.0 % contribution test yiel ds only a few sources that need to be examined further.

Facility Point ID SO 2 (tons) Dist Q/d RT Max** Qd* RTmax % cont

Mississippi Power Company, Plant Watson 004 7,640 148.07 51.60 28.09 1449.31 5.4% DuPont DeLisle Facility 024 1,645 137.98 11.92 28.09 334.80 1.2% DuPont DeLisle Facility 025 1,627 137.98 11.79 28.09 331.21 1.2% Mississippi Phosphates Corporation 006 918 140.83 6.52 28.09 183.02 0.7% Mississippi Phosphates Corporation 008 786 140.83 5.58 28.09 156.83 0.6% Mississippi Power Company, Plant Watson 005 759 148.07 5.13 28.09 144.03 0.5% Mississippi Power Company, Plant Daniel 002 847 169.42 5.00 28.09 140.45 0.5% Mississippi Power Company, Plant Daniel 001 799 169.42 4.71 28.09 132.42 0.5% Chevron Pascagoula Refinery 017 262.8 123.85 2.12 28.09 59.60 0.2% Chevron Pascagoula Refinery 052 157 123.85 1.27 28.09 35.61 0.1% Chevron Pascagoula Refinery 051 157 123.85 1.27 28.09 35.61 0.1% Holcim Inc, Artesia 002 3,991 475.57 8.39 8.93 74.93 0.3% Pursue Energy Corporation, Thomasville G 001 3,303 346.74 9.53 6.44 61.35 0.2% Choctaw Generation LLP, Red Hills Genera 001A 3,758 473.82 7.93 7.27 57.66 0.2% Georgia Pacific Corporation, Monticello 002 1,765 291.74 6.05 6.72 40.65 0.2% Georgia Pacific Corporation, Monticello 001 1,652 291.74 5.66 6.72 38.06 0.1% CII Carbon LLC 001 670 230.26 2.91 11.24 32.72 0.1% SMEPA , Plant Morrow 001 670 234.48 2.86 11.24 32.12 0.1% SMEPA, Plant Morrow 002 670 234.48 2.86 11.24 32.12 0.1%

Table 7.5.5-1. Percent Contributions to Breton



### 7.6 Evaluating the Specific SO 2 

### Emissions Sources

Mississippi used the Area of Im pact (AOI) analysis described in the preceding sections to determine sources that need further evaluati on to help meet reasonable progress goals. The sources identified by the Area of Impact analysis will be evaluated to determine if there are reasonable controls that can be applied to meet the reasonable progress goals for the impacted Class 1 area. The neighboring state of Alabama uses the same methodology. Louisiana is in a different planning organizati on and used different methods to for reasonable progress determinations; however, as noted in the Secti on 10, Mississippi and Louisiana have met several times and there were no issues with the AOI methodology.

The Regional Haze Rule states that the cost of controls, time necessary for compliance, energy and non-air environmental impacts, and the remain ing useful life of any potentially affected sources should be considered in setting the reasonable progress goals.

From Table 7.5.5-1 , there are only two facilities that meet the 1.0 % test and need to be evaluated for reasonable progress. Those facilities are:

• Mississippi Power Company, Plan t Watson, Harrison County, and62 Mississippi Regional Haze SIP Narrative, August 28, 2008 • DuPont Delisle Facility, Harrison County.

Mississippi Power Company, Plant Watson Mississippi Power Company, Plant Wa tson is a coal fired Electrici ty Generating Facility. Plant Watson is subject to the Clean Air Interstate Rule (CAIR) which requires significant reductions of NO x and SO 2 in the eastern United States. The CAIR results in reductions of over seventy (70) percent for SO 2 emissions and by over sixty (60) percent NO x emissions from 2003 levels. The CAIR is a cap and trade program that does not require specific emissions reductions from any specific facilities, but the utility companies wi ll have to reduce emissions from a significant number of EGU’s to meet the emissions cap. Plant Watson has two Coal fired units. Controls for NO x and SO 2 are proposed for unit 5 which is the larger unit with more emissions. This will result in significant emissions reductions from this facility. The facility be ing subject to CAIR is deemed sufficient for reasonable progress.

To further support EGUs subject to CAIR is suff icient for reasonable progress, a discussion in the CAIR rule highlighted below (70 FR 25197) a ddresses the reasonable pr ogress factors of cost and time necessary for compliance for these EGUs, and provide the necessary support for a State's four factor reasonable progress analys is that must accompany a State’s assertion that CAIR is sufficient for reasonable progress for subject EGU’s during the first planning period.

From past experience in examining multi-pollut ant emissions trading programs for SO2 and NOX, EPA recognized that the air pollution control retrofits that result from a program to achieve highly cost-effective reductions are qu ite significant and can not be immediately installed. Such retrofits require a large pool of specialized labor resources, in particular, boilermakers, the availability of which will be a major limiting factor in th e amount and timing of reductions

Also, EPA recognized that the regulated industry w ill need to secure large amounts of capital to meet the control requirements while managing an already large debt load, and is facing other large capital requirements to improve the trans mission system. Furthermore, allowing pollution control retrofits to be installed over time enabl es the industry to take advantage of planned outages at power plants (unplanned outages can lead to lost revenue) and to enable project management to learn from early installations how to deal with some of the engineering challenges that will exist, especially for the sm aller units that often present space limitations

Based on these and other considerations, EPA determin ed in the NPR that the earliest reasonable deadline for compliance with the final highly cost -effective control levels for reducing emissions was 2015 (taking into consideration the existing bank of title IV SO2 allowances). First, the Agency confirmed that the levels of SO2 and NOX emissions it believed were reasonable to set as annual emissions caps for 2015 lead to highly cost-effective controls for the CAIR region.

Once EPA determined the 2015 emissions reductions levels, the Agency determined a proposed first (interim) phase control level that would co mmence January 1, 2010, the earliest the Agency believed initial pollution controls could be fully op erational (in today's final action, the first NOX control phase commences in 2009 instead of in 2010, as explained in detail in section IV.C). The first phase would be the initial step on the slope of emissions reductions (the glide-path) leading to the final (second) control phase to commenc e in 2015. The EPA determined the first phase63 Mississippi Regional Haze SIP Narrative, August 28, 2008 based on the feasibility of installing the necessa ry emission control retrofits, as described in section IV.C.

Although EPA's primary cost-effectiveness determ ination is for the 2015 emissions reductions levels, the Agency also evaluated th e cost effectiveness of the first phase control levels to ensure that they were also highly cost effective. Thr oughout this preamble section, EPA reports both the 2015 and 2010 (and 2009 for NOX) cost-effectiv eness results, although the first phase levels were determined based on feasibility rather than cost effectiveness. The 2015 emissions reductions include the 2010 (and 2009 for NOX) emissions reductions as a subset of the more stringent requirements that EPA is imposing in the second phase.

Conclusion

It is Mississippi’s determinati on that Mississippi Power, Plant Wa tson being subject to CAIR and participating in the CAIR trading program meet s the reasonable progre ss requirements of the Regional Haze Rule.

DuPont DeLisle Facility DuPont DeLisle Facility is a Ti tanium Dioxide pigment plant locat ed in DeLisle, Mississippi. The facility has two 209 MM BTU/hr coal fired process boilers th at are of concern. The four factors listed in the Regional Haze Rule (40 CF R 51.308(d)(1)(i)(A)) will be applied to potential SO2 controls for these units. Dupont has submitte d a document (see appendix N) that addresses the potential controls and cost. Potential controls for SO2 reduc tion would include switching to a lower sulfur fuel, and post combustion scrubbers. The facility is currently permitted to burn 3% sulfur coal but uses 2.5% sulfur coal. D upont evaluated switching to 1.05%, 1.5% and 2.0% sulfur coal and using spray dry absorbers and sodium wet scrubbers in conjunction with lower sulfur fuel.

Cost of Controls

Compared to the current coal used, the SO 2 reduction would be 998 TP Y with an incremental cost effectiveness vs Baseline of $738/ton SO 2 removed for the 2.0% coal; and the SO 2 reduction would be 1996 TPY with an incremental cost effectiveness vs Baseline of $527/ton SO 2 removed for the 1.5% coal. The 1.05% sulfur coal would not be an option due to adverse impacts on the facilities recently upgraded elec trostatic precipitators. In ad dition, significant testing and evaluation would need to be conducted to determin e if any of the lower sulfur coal could be utilized and the boilers be able to me et the Subpart DDDDD Boiler MACT standards.

The additional SO2 reduction of using a scrubber in conjuncti on with a lower sulfur fuel compared to using the lower sulfur coal ( 1.5%) ranged from 2700 to 2900 TPY with a cost of $3000 to $4000/ton.

Time Necessary for Compliance

Options utilizing lower sulfur coal would require time for finding and eval uating alternative coal supplies that not only provide lowe r sulfur levels, but also that can provide required combustion performance and compliance with the Subpart DDDDD Boiler MACT regulations. In addition,64 Mississippi Regional Haze SIP Narrative, August 28, 2008 as noted above, the effects of lower sulfur coal use on the performance of the hot side ESP and resultant emissions and opacity impact need to be assessed. The evaluati on of the coal type and sources necessary to meet the lower sulfur sta ndards and securing necessary contracts will take several years. It is likely that conversion to a lternative coal would not be possible prior to 2013.

Options utilizing scrubbing woul d require extended time for compliance due to the need for detailed design and project implementation as well as capital planni ng. The high level of emissions control system installations in the fu ture planning period in response to CAIR and BART will put a significan t strain on resource availability and costs. Therefore, if scrubbing was required, it is likely that compliance woul d not be attainable until the 2013 time frame.

Energy and Non-Air Environmental Impacts

Use of lower sulfur alone coal would not entail any significant changes to energy use or non-air quality environmental impacts.

Use of a spray dry scrubber would require use of lime as the reagent. Solid waste disposal would increase over the current coal ash-only condition by the quantity of calcium sulfate formed in the scrubber. This can be estimated based on re moval percent and expected calcium/sulfur stoichiometric ratio. Costs for that disposal are included within the estimated O&M cost estimates. As indicated above, the additional wast e would be dry, so it would likely be disposed of in a landfill. Additional purchased electricit y would be required for op eration of the scrubber and baghouse, including, for example, lime transp ort, slurry preparati on and injection, baghouse pulse air, ash and spent sorbent handling, and in creased fan power to compensate for increased flue gas pressure drop. Water would also be consumed for slurry preparation.

Use of a sodium wet scrubber would require use of caustic as the reagent. Liquid waste disposal would increase for disposal of the scrubber blow down stream. The existing plant waste water treatment facility does not have adequate capacity for that waste stream directly, but some form of neutralization and oxidation woul d be required prior to transfer to the waste treatment system. Costs for that disposal are included within the estimated O&M cost estimates. Additional purchased electricity would be required for operation of the sc rubber, including, for example, liquid pumping power and increased fan power to compensate for increased flue gas pressure drop. Water would also be consum ed for the scrubber solution.

The use of scrubbers would also result in increased energy use. Increased purchased electricity would result in increased emissions of SO2, NOx , CO2, and other emissions from the electric utility generators providing that power, which coul d in fact, be units that themselves impact Breton with their SO2 and NOx emissions.

Remaining Useful Life

There is no indication that these units ar e near the end of their useful life.

Conclusion65 Mississippi Regional Haze SIP Narrative, August 28, 2008 Given the potential impact th at the DuPont DeLisle plan t has on Breton, Mississippi has determined that SO2 reductions are in order to help meet the Reasonable Progress Goals for Breton. DuPont is currently working with Mississi ppi to determine the level of reduction that is reasonable during this planning period. Mississippi will make the final determinations, issue a permit and submit a supplemental SIP within one year of the initial Regional Haze SIP submittal to EPA.



### 7.7 What Additional Emissions Control s Were Considered as part of the Long-Term Strategy for Visi bility Improvement by 2018?

Class 1 areas are sensitive visibility receptors and Section 308(d)(3)(v) of the regional haze rule lists several factors that could impact visibility to be addressed in each SIP. These factors include the role of fire at Class I areas and st atus 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 NH 3 and potential benefits if emissions from agricultural sources were mitigated.

Since there are no Class I areas in Mississippi and the Class I area that is closest and of greatest concern, Breton, is over 45 km offshore, these factor s will have little impact. As can be seen in Figures 7.4-1 through 7.4-3 , elemental carbon (sources include agriculture, prescribed wildland fires, and wildfires) is a relative ly minor contributor to visibility impairment at the Class I areas surrounding Mississippi. Mississipp i has drafted but not finalized a Smoke Management Plan. Under current smoke management practices , the Mississippi Fore stry Commission, in conjunction with the Mississippi Department of Environmental Quality, issues burning permits based on daily weather forecasts. A permit is required for any fire set for a recognized agricultural or forestry purpose.

Mississippi has no particular provisions to mitig ate dust emissions from construction activities. However, there are nuisance provisi ons in state regulations that would apply if construction or other activities were generating significant emissi ons. Given the distance of the closest Class 1 area to Mississippi, this w ould provide adequate contro l from these activities.



### 7.8 Long Term Strategy Summary

For this first planning period, the emissions contro ls from existing federal standards, such as CAIR and the Heavy Duty Diesel Rule, will be sign ificant and result in significant reductions of visibility impairing pollutants from sources in Mi ssissippi. There are two facilities in Mississippi that were identified by BART or the reasonable progress analysis that appear to need additional controls. Evaluations are still underway for these facilities. The appropriate determinations will be made for these sources over the next year and a supplemental SIP will be submitted within a year of the initial SIP submittal.

In the future, the impacts of new sources will need to be addressed. This will be done as part of the permitting process. The appropriate FLM for class 1 areas within 300km of a source66 Mississippi Regional Haze SIP Narrative, August 28, 2008 requiring new source review will be contacted and c oordinated with to address visibility impacts on the Class 1 area.



### 8.0 REASONABLE PROGRESS GOALS

Since there are no Class 1 areas in Mississipp i, there are no reasonable progress goals for Mississippi to set. The goals for the Class 1 areas in neighboring states will be set by those states. Mississippi has worked collaboratively with all of the VISTAS states by meetings, conference calls and sharing Regional Haze SIP Pre-hearing Drafts. Because the state of Mississippi has no Class I areas in Mississippi, MDEQ worked with neighboring states on emissions contributions to Class I areas in neighboring states. Mississippi is in agreement with the Reasonable Progress Goals for the Cl ass I areas in the neighboring states.



### 9.0 MONITORING STRATEGY

The State Implementation Plan is to be accomp anied by a strategy for monitoring regional haze visibility impairment. Specifically, the Regi onal Haze Rule states at 40 CFR 51.308(d)(4):

“(4) Monitoring strategy and other im plementation plan requirements. The State must submit with the implementation plan a monitoring stra tegy for measuring, char acterizing, and reporting of regional haze visibility impairment that is representative of all mandatory Class I Federal areas within the State. There are no Class 1 areas in Mississippi; th erefore, no monitoring strategy is necessary.



### 10.0 INTERSTATE CONSULTATION

The VISTAS states have jointly developed the technical analyses to define the visibility improvement by 2018 under existing federal and state regulations compared to the uniform rate of progress, SO 2 Areas of Influence for each Class I area , and methods to prioritize contributions from individual sources within the Areas of Influence. The states collectively accept the conclusions of these analyses.

In December 2006 the VISTAS State Air Directors he ld their first formal consultation meeting to review the Base G mode ling results and the SO 2 Areas of Influence analyses. The Air Directors agreed to look at reasonable control m easures for sources on the lists for the SO 2 Areas of Influence. Each state would c onsider sources within their state and would identify sources in neighboring states that each stat e would like to have that neig hboring state consider. States67 Mississippi Regional Haze SIP Narrative, August 28, 2008 acknowledged that the review pr ocess would differ among states since some Class I areas are projected to see visibility improvements near th e uniform rate of progress while most Class I areas are projected to have greater improve ments than uniform rate of progress.

In January 2007, the States of Alabama, Florid a, Louisiana, and Mississippi had a meeting to discuss the Breton Class 1 area. Since Louisian a is not part of VISTAS, this was the first meeting between all of the States surrounding Breton. The purpose was to better understand the conditions at Breton. Ther e were no formal decisions made at the meeting.

In May 2007 the VISTAS State Air Directors met for their second formal in terstate consultation. States shared their lists of sources in their stat e and neighboring states for each Class I area. The State Air Directors also shared their criteria for listing sour ces and their plans for further interstate consu ltation.

In June 2007, there was a VISTAS meeting between the VISTAS states, USEPA, and the Federal Land Managers to discuss the expectations the va rious states, USEPA, an d the FLMs with regard to the Class 1 areas and the Implementation Pl ans. Louisiana also attended this meeting.

In October 2007, there was a consultation conf erence call that was called by Louisiana to Discuss Breton. The surrounding states, USEPA, and FLMs were on the call.

The MDEQ has evaluated the imp act of Mississippi sources on Class I areas in neighboring states and determined that there are no additi onal reasonable control measures that should be implemented to mitigate impacts in Class I areas in neighboring states. The MDEQ has consulted with the responsible states rega rding its evaluation showing no co st-effective controls available for those units contributing at leas t one (1) percent to visibility impairment at Class I areas. Consultation documents may be found in Appendix J.



### 11.0 COMPREHENSIVE PERIOD IC IMPLEMENTATION PLAN
REVISIONS

40 CFR section 51.308(f) requires the regional haze implementation plan and submit a plan revision to USEPA by July 31, 2018 and every ten years thereafter. In accordance with the requirements listed in Section 51.308(f) of the federal rule fo r regional haze, Mississippi commits to revising and submitting this regiona l haze implementation plan by July 31, 2018 and every ten years thereafter.

In addition, Section 51.308(g) re quires periodic reports ev aluating progress towards the reasonable progress goals established for each mandatory Class I area. In accordance with the requirements listed in Section 51.308(g) of the federal rule for regi onal haze, the MDEQ commits to submitting a report on reasonable progre ss to USEPA 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 r easonable progress goal for each68 Mississippi Regional Haze SIP Narrative, August 28, 2008 mandatory Class I area located outside Mississi ppi which may be affected by emissions from within Mississippi

.
The requirements listed in 51.308( g) include the following: 1. Description of the stat us of implementation; 2. Summary of emission reductions achieved thus far, including especially the status of implementation of the CAIR compliance plans for EGUs compared to the control assumed in the modeling. [The MDEQ rec ognizes that the 2018 projections of EGU controls from the IPM runs represent one so lution to how the CAIR requirements will be met. By the time of the first periodic re port, the MDEQ anticip ates that the actual compliance strategy for the various utility co mpanies will be much more defined. An assessment of those actual compliance plans wi ll be done for the first periodic report.] 3. Assessment of changes in visibility conditions at each class I area (cur rent vs. baseline), expressed as 5-year averages of annual valu es for twenty (20) percent best and worst days; 4. Analysis of emission changes over the 5-year period, identified by source or activity; 5. Analysis of any siginificant changes in or out of the Stat e which have impeded progress; 6. Assessment of the sufficiency of the implementation plan to meet RPGs; 7. Review and any modifications to our visibility monitoring plan. All requirements listed in 51.308(g) shall be addressed in the progress report.

Since there are no Class 1 areas in Mississippi, also commits to ongoing consultation with the FLMs throughout the implemen tation process, including an nual discussion of the implementation process and the most recent IMPROVE monitoring data and VIEWS data.

There are several technical improvements that ar e recommended in the emissions inventory and air quality models that are used to support re gulatory decisions for regional haze. These improvements recommended, as funding is available, to support the next long term strategy. The following is an overall summary; Appendix K contai ns a fuller discussion of possible technical improvements.

First and foremost, continued improvements are n eeded in the integrated one-atmosphere air quality models that are used to project air qua lity responses to emissi ons reductions. As our understanding of partitioning between gaseous a nd aerosol phases improves, this understanding needs to be reflected in the models. Improvement s can also be made in how the models handle individual pollutants. Sulfate performance for the CMAQ regional air quality model is good overall. However sulfate deposition is frequently overestimated in the models, particularly in the summer months. At the coastal sites, when wi nds are blowing from the Gulf of Mexico or Atlantic Ocean, CMAQ underestimates measured sulfate at the monitors. CMAQ’s processes also should be reviewed for sulfate formation over water. Nitrate is over estimated by the model in the winter and underestimated in the summ er, although summer monitored values of nitrate are very low. Additional improvements in se asonal allocation of ammonia emissions would improve model estimates of ammonium nitrat e formation. Organic carbon is generally underestimated in the summer months. Improvement s are needed in the ch aracterization of both primary carbon emissions and formation of secondary organic carbon.69 Mississippi Regional Haze SIP Narrative, August 28, 2008 Other improvements needed include better tools for organic carbon source apportionment, and more consistent measurement techniques betwee n rural and urban monitoring networks. To improve our understanding of the contribution of fire from natural forest fires, prescribed burning, land clearing, and agricultural burning, states need improved record keeping. Additional improvements to international emission s inventory are also needed, to improve our understanding of boundary conditions for our modeling domain and of the contributions from international emissions to pollutant concen trations at the VISTAS Class I areas.



### 12.0 DETERMINATION OF ADEQU ACY OF THE EXISTING PLAN

Depending on the findings of the five-year progre ss report, Mississippi comm its to taking one of the actions listed in 40 CFR section 51.308(h). The findings of the five -year progress report will determine which action is appropriate and necessar y. There are four optio ns listed in the rule, but since there are no Class 1 areas in Mississi ppi, only the two listed below potentially apply.

List of Possible Actions fr om 40 CFR section 51.308(h)

1) MDEQ determines that the existing SIP requi res no further substantive revision in order to achieve established goals MDEQ provides to the Administrator a negative declaration that further revision of the SIP is not needed at this time.

2) MDEQ determines that the existing SIP is in adequate to ensure reasonable progress due to emissions within the state. MDEQ will revi se its SIP to address the plan’s deficiencies within one year.

Since there are no Class 1 areas in Mississippi, th e determination of adequacy will have to be done in consultation with the States that the Class 1 areas are in and the FLMs.