## South Carolina
8-Hour Ozone Attainment Demonstration

For the Portion of York Count y, South Carolina Within the

Rock Hill-Fort Mill Area Tr ansportation Study (RFATS) Metropolitan Planning Organization (MPO)

Part of the
Charlotte-Gastonia -Rock Hill, NC-SC

8-Hour Ozone Nonattainment Area

Prepared by the South Carolina Department of He alth and Environmental Control

Bureau of Air Quality

April 29, 2010TABLE OF CONTENTS

RFATS MPO 8-HOUR OZONE ATTAINMENT DEMONSTRATION EXECUTIVE SUMMARY.......1

I. 8-hour Ozone National Ambi ent Air Quality Standards ........................................................................ ...1

II. Modeling Protocol......................................................................................................... ..........................1

III. Conceptual Descrip tion of Ozone Formation ................................................................................ ........1

IV. Attainment Demonstr ation Methods and Inputs............................................................................... .....2

V. Model Performance Evaluation............................................................................................... ................3

VI. Attainment Demonstration.................................................................................................. ...................3

VII. Attainment of the 8-hour Ozone N AAQS by 2009............................................................................. ..3

SECTION I. SOUTH CAROLINA AIR QUALITY IMPLEMENTATION PLAN .........................................5

A. Introduction to 8-Hour Ozone NAAQS ......................................................................................... .........5

1. Ground-Level (Tropospheric) Ozone......................................................................................... ......5

2. Health Concerns........................................................................................................... ....................5

3. National Ambient Air Quality Standards (NAAQS) .......................................................................6

4. 8-Hour Ozone NAAQS........................................................................................................ ............6

B. Nonattainment Area D esignations and Classifications ........................................................................ ...6

1. Area Designations......................................................................................................... ...................6

2. Nonattainment Area Boundaries............................................................................................. .........7

3. Nonattainment Area Classifications........................................................................................ .........7

C. 8-hour Ozone Designations for South Carolina ................................................................................ .......8

D. Charlotte-Gastonia-Rock Hill, NC -SC Metropolitan Statistical Area ....................................................9

1. Charlotte-Gastonia-Rock Hill, NC-SC Metropolitan Statistical Area .............................................9

2. Monitors in the Charlotte-Gastonia-Rock Hill, NC-SC MSA .........................................................9

3. 2001-2003 Design Values for Monitors Located in the MSA .......................................................10E. Charlotte-Gastonia-Ro ck Hill, NC-SC Area ................................................................................... ......11

1. Metrolina Area ............................................................................................................ ...................11

2. Metrolina Nonattainment Area Boundaries ................................................................................... 11

3. Metrolina Nonattainment Area Classification ............................................................................... 11

F. Conceptual Description of Ozone Formation in the Metrolina Area.....................................................11

G. Clean Air Act Requirements ................................................................................................. ................14

1. Section 172(c) - Nonattainment Plan Provisions ...........................................................................1 4

2. Section 182(a) - Plan Submissions and Requirements for Marginal Areas ...................................14

3. Section 182(b) - Additional Plan Subm issions and Requirements for Moderate Areas ................14

SECTION II. ATTAINMENT DEMONSTRATION METHODS AND INPUTS...................................15

A. Analysis Method ............................................................................................................ .......................15

B. Model Selection............................................................................................................ .........................16

1. Selection of Photochemical Grid Model..................................................................................... ...16

a. Criteria ................................................................................................................. ......................16

b. Overview of CMAQ ......................................................................................................... .........16

2. Selection of Meteorological Model......................................................................................... .......17

a. Criteria ................................................................................................................. ......................17

b. Overview of MM5.......................................................................................................... ...........17

3. Selection of Emissions Processing System.................................................................................. ..18

a. Criteria ................................................................................................................. ......................18

b. Overview of SMOKE ........................................................................................................ ........18

C. Episode Selection .......................................................................................................... ........................19

1. Overview of EPA Guidance on Ozone ......................................................................................... .19

2. Episode Selection......................................................................................................... ..................19

D. Modeling Domains........................................................................................................... .....................201. Horizontal Modeling Domain ................................................................................................ ........20

2. Vertical Modeling Domain .................................................................................................. ..........22

E. Emission Inventory......................................................................................................... .......................23

1. Stationary Point Sources .................................................................................................. ..............24

a. Electric Generating Units................................................................................................ ...........24

b. Other Point Sources...................................................................................................... .............25

2. Stationary Area Sources................................................................................................... ..............25

3. Nonroad Mobile Sources .................................................................................................... ...........26

4. Highway Mobile Sources.................................................................................................... ...........26

5. Biogenic Emission Sources................................................................................................. ...........27

SECTION III. MODEL PERFORMANCE EVALUATION ....................................................................28

A. Domain-Wide Performance .................................................................................................... ..............29

1. Spatial Plots ............................................................................................................. ......................30

2. Scatter Plots ............................................................................................................. ......................38

a. North Carolina Scatter Plots ............................................................................................. .........38

b. South Carolina Scatter Plots............................................................................................. .........40

3. Time Series Plots ......................................................................................................... ..................42

4. Domain-Wide Summary ....................................................................................................... .........43

B. Area and Monitor Statistics................................................................................................ ...................44

SECTION IV. CONTROLS APPLIED.................................................................................................. ...45

A. Federal Control Measures ................................................................................................... ..................45

1. Tier 2 Vehicle Standards.................................................................................................. ..............45

2. Heavy-Duty Gasoline and Di esel Highway Vehicl es Standards ...................................................45

3. Large Nonroad Diesel Engines Rule......................................................................................... .....454. Nonroad Spark-Ignition Engines and Recreational Engines Standard...........................................45

5. NOx SIP Call in Surrounding States........................................................................................ ......46

6. Clean Air Interstate Rule................................................................................................. ...............46

B. State Cont rol Measures ..................................................................................................... ....................47

1. New Source Review Regulations............................................................................................. ......47

a. South Carolina Air Pollution Control Regulation R. 61-62, Definitions and General .................

Requirements , Section II - Permit Requirements .....................................................................47

b. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 7, Prevention of .....

Significant Deterioration ..........................................................................................................47

c. South Carolina Air Pollution Control Regulation R. 61-62.5, No. 7.1 - Nonattainment New ......

Source Review ..........................................................................................................................47

2. NO

x Regulations ................................................................................................................... .........47

a. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 2 - Ambient Air ......

Quality Standards .....................................................................................................................47

b. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 5.2 - Control of ......

Oxides of Nitrogen (NO

x ) .........................................................................................................48

c. South Carolina Air Pollution Control Regulation R. 61-62.96 - Nitrogen Oxides (NO

x ) Budget .

Trading Program ......................................................................................................................48

d. South Carolina Air Pollution Control Regulation R. 61-62.99 - Nitrogen Oxides Budget ...........

Program Requirements for Stationa ry Sources Not in the Trading Program ..........................48

e. South Carolina Air Pollution Control Regulation R. 61-62.2 - Prohibition of Open Burning ..48

3. VOC Regulations: South Carolina Air Polluti on Control Regulation R. 61-62.5, Standard No. 5 -

Volatile Organic Compounds .........................................................................................................48

4. Other State Control Measures.............................................................................................. ..........48

a. Clean Air Inte rstate Rule (CAIR) ......................................................................................... .....48

b. Permitting Requirements Involving Emi ssion Offsets - Conditions for Approval....................495. Emissions Inventory: S outh Carolina Regulation R. 61-62.1, Definitions and General

Requirements , Section III - Emissions Inventory........................................................................51

6. Reasonably Available Control Measures (RACM)........................................................................51

a. Reasonably Available Control Technology (RACT).................................................................52

b. Early Action Compacts.................................................................................................... ..........52

c. Take a Break from the Exhaust............................................................................................ ......53

d. Overall RACM Conclusions................................................................................................. .....53

SECTION V. ATTAINMENT DEMONSTRATION ...............................................................................54

A. Attainment Test Introduction ............................................................................................... .................54

B. Attainment Test Results .................................................................................................... ....................55

C. Supporting Weight of Evidence .............................................................................................. ..............55

1. Alternative DVF Calculation ............................................................................................... ..........56

2. Additional Air Quality Modeling Metrics ................................................................................... ..57

3. Air Quality Modeling Results From Other Studies........................................................................57

4. Positive Trends in Observed Air Qu ality and Additional Emissions Reductions..........................58

5. Local Measures Not Modeled................................................................................................ ........61

D. Unmonitored Area Attainment Analysis....................................................................................... ........61

E. Data Access ................................................................................................................ ...........................62

SECTION VI. MODERATE NONATTAINMENT AREA REQUIREMENTS......................................63

A. Clean Air Act (CAA), as amended (42 U.S.C. 7401, et seq .)...............................................................63

1. CAA Section 172(c) - N onattainment Plan Provisions..................................................................63

2. CAA Section 182 - Plan Submissions and Requirements..............................................................64

a. CAA Section 182(a) - Marginal Areas ...................................................................................... 64

b. CAA Section 182(b) - Moderate Areas .....................................................................................6 4c. CAA Section 182(f) - NO

x Requirements..................................................................................65

B. South Carolina Air Quality Implementation Plan (SIP) Provisions......................................................65

1. RACM/RACT Requirements.................................................................................................... .....65

a. RACM..................................................................................................................... ...................65

b. RACT ..................................................................................................................... ...................67

2. Reasonable Further Progress............................................................................................... ...........68

3. Actual Emissions Inventory................................................................................................ ...........71

4. Emissions Inventory Statement............................................................................................. .........71

5. Periodic Emissions Inventory .............................................................................................. ..........71

6. Permit Program Requirements............................................................................................... ........71

7. Gasoline Vapor Recovery ................................................................................................... ...........72

8. Inspection and Maintenance Program........................................................................................ ....72

9. Other Measures ............................................................................................................ ..................73

a. NO

x SIP Call...................................................................................................................... ........73

b. 8-hour Ozone Early Action Compact Regulations ....................................................................73

c. Clean Air Interstate Rule ................................................................................................ ...........74

d. Regulation R. 61.62.2, Prohibition of Open Burning ................................................................75

e. Regulation R. 61-62.5, Standard 5.2, Control of Oxides of Nitrogen ........................................76

10. Compliance with Section 110(a)(2) ........................................................................................ .....76

11. Equivalent Techniques.................................................................................................... .............76

12. Contingency Measures..................................................................................................... ............76

SECTION VII. MOTOR VEHI CLE EMISSION BUDGET.....................................................................78

A. Transportation Conformity .................................................................................................. .................78

1. Memorandum of Agreement................................................................................................... .......78

2. Conformity Interagency Cons ultation - York County/RFATS MPO ............................................793. RFATS - CMAQ Projects..................................................................................................... .........79

B. Highway Mobile Source VOC Insignificance................................................................................... ....80

C. Motor Vehicle Emission Budgets............................................................................................. .............81LIST OF FIGURES

Figure I-1: 8-hour ozone nonattainme nt boundaries for South Carolina .....................................................9

Figure I-2: Monitors in the Charlotte-Gastonia-Rock Hill, NC-SC MSA .................................................10

Figure I-3: Location of electric generating facilities in and near the Metrolina nonattainment area.........12

Figure I-4: 2002 NOx emissions for the Metrolina nonattainment area and ne ighboring counties...........13

Figure II-1: The MM5 horizontal domain is the outer most, blue grid,......................................................21

Figure II-2: A more detailed view of th e 12-km grid over the VISTAS region. ........................................22

Figure III-1: Spatial plots for modeled predicted a nd observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for May 25, 2002.......................................................................................... ............31

Figure III-2: Spatial plots for modeled predicted a nd observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for June 3, 2002.......................................................................................... ..............32

Figure III-3: Spatial plots for modeled predicted a nd observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for June 12, 2002......................................................................................... .............33

Figure III-4: Spatial plots for modeled predicted an d observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for July 3, 2002 .......................................................................................... ..............34

Figure III-5: Spatial plots for modeled predicted an d observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for July 17, 2002. ........................................................................................ .............35

Figure III-6: Spatial plots for modeled predicted an d observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for August 2, 2002........................................................................................ ............36

Figure III-7: Spatial plots for modeled predicted an d observed peak 1-hour (top) and 8-hour (bottom)

ozone concentrations for August 10, 2002....................................................................................... ...........37

Figure III-8: 8-hour ozone scatter plot for No rth Carolina 12-km grid for June 2002...............................38

Figure III-9: 8-hour ozone scatter plots for North Carolina 12-km grid for July 2002..............................39

Figure III-10: 8-hour ozone scatter plots for North Carolina 12-km grid for August 2002.......................39

Figure III-11: 8-hour ozone scatter plots for South Carolina 12-km grid for June 2002...........................40Figure III-12: 8-hour ozone scatter plots for South Carolina 12-km grid for July 2002............................41

Figure III-13: 8-hour ozone scatter plots for South Carolina 12-km grid for August 2002.......................41

Figure III-14: Time series plot of model predic ted versus mean 8-hour observed for North Carolina

monitors for June 2002. ........................................................................................................ ......................42

Figure III-15: Time series plot of model predic ted versus mean 8-hour observed for North Carolina

monitors for July 2002......................................................................................................... .......................43

Figure III-16: Times series plot of model predicte d versus mean 8-hour observed for North Carolina

monitors for August 2002 ....................................................................................................... ....................43

Figure V-1: Location and size of the Duke Energy facilities located in the vicinity of the Metrolina

nonattainment area............................................................................................................. .........................60LIST OF TABLES

Executive Summary Table 1: Attainment Test Results ............................................................................ ...3

Table I-1: Subpart 2 Classifica tions and Attainment Dates ..................................................................... ....8

Table I-2: 2001-2003 Design Values............................................................................................ .............10

Table II-1: Vertical Layer Definition for MM5 and CMAQ .....................................................................23

Table III-1: 12-km Domain Model Statistics for 8-Hour Ozone ...............................................................30

Table III-2: Metrolina Nonattainme nt Area Monitor Statistics .................................................................4 4

Table V-1: Attainment Test Results............................................................................................ ...............55

Table V-2: 5-Year Average Alternativ e Attainment Test Results for 2009 ..............................................56

Table V-3: Metrolina DVF s Based on EAC Modeling..............................................................................5 8

Table V-4: Metrolina DVFs Based on USEPA’s CAIR Modeling............................................................58

Table V-5: Design Values (ppm) for the North Carolina Monitors in the Metrolina Area .......................59

Table V-6: Utility NO

x Emission Reductions since 2006 Ozone Season ..................................................60

Table VI-1: York County Nonattainment Ar ea 2002 Baseline VOC Emissions (tons/day)......................70

Table VI-2: York County Nonattainment Ar ea 2008 Projected VOC Emissions (tons/day) ....................70

Table VI-3: York County Nonattainment Area 15% RFP Analysis ..........................................................70

Table VII-1: 2009 Highway Mobile Source NO

x Emissions York County Nonattainment Area.............81

Table VII-2: York County South Carolina NO

x MVEB for 2009 ............................................................811 LIST OF APPENDICES

Appendix A: Correspondence and Guidance Documents

Appendix B: Inspection and Maintenance Program

Appendix C: Historic Air Quality Data

Appendix D: Modeling Protocol

Appendix E: Emissions Inventory Summary

Appendix F1: Point Source Emissions Inventory Documentation

Appendix F2: Area and Nonroad Emissions Inventory Documentation

Appendix F3: On-road Mobile Source Emissions Inventory

Appendix G: Quality Assurance of the Emissions Inventories

Appendix H: Emissions Modeling Deviation from Defaults

Appendix I: Meteorological Model Performance

Appendix J: Model Performance Evaluation

Appendix K: Modeling Results

Appendix L: Attainment Test

Appendix M: Adopted State Measures

Appendix N: Grid Resolution Journal Article

Appendix O: Reasonable Further Progress

Appendix P: Contingency Measures Documentation

Appendix Q: Supporting Documentation from VISTAS

Appendix R: Reasonably Available Control Technology

Appendix S: RFATS Transportation Conformity1 SOUTH CAROLINA AIR QUALITY IMPLEMENTATION PLAN

RFATS MPO 8-HOUR OZONE ATTAINMENT DEMONSTRATION EXECUTIVE SUMMARY

I. 8-hour Ozone National Ambient Air Quality Standards

On April 30, 2004, the United States Environmental Protection Agency (EPA) designated and classified that portion of York County, South Carolina within the Rock Hill Fort Mill Area Transportation Study (RFATS) Metropolitan Planning Organization (MPO) as a moderate nonattainment area for the 8- hour ozone National Ambient Air Quality Standards (NAAQ S) as part of the Char lotte-Gastonia-Rock Hill, NC-SC (Metrolina) nonattainment area. As a result of this designation, the Sout h Carolina Department of
Health and Environmental Cont rol (SCDHEC or Department) is required to amend the South Carolina Air Quality Implementation Plan , also known as the State Implementation Plan, or SIP, in accordance with the requirements of the Clean Air Act (CAA), as amended (42 U.S.C. 7401, et seq .). States involved in a multi-State ozone nonattainment area must work together to perform the appropriate modeling analyses to identify control measures that will en able the area to achieve attainme nt as expeditiously as practicable. Each State is responsible for its portion of the cont rol program and will be held accountable for controls identified for implementation within its State boundaries.

II. Modeling Protocol

The modeling protocol contains an overview of the models and model configurations that were chosen for use in future year attainment demonstr ations. Because the Charlotte-Gastonia-Rock Hill area
has been classified moderate nonatta inment with a required attainment date set for June 15, 2010, the future year emission inventory for 2009 is used fo r attainment demonstrations . Using EPA’s guidance on ozone episode selection, 2002 is meteorologically well- suited for demonstrating future year attainment because 2002 exhibited the most number of days ( 38) exceeding the 0.08 ppm ozone standard and because 2002 had numerous (13) and a wide variety (sev eral different types of scenarios) of high ozone episodes.

The models that were chosen include the M esoscale Meteorological Model (MM5), the Sparse Matrix Operator Kernel Emissions (SMOKE) mo deling system, and the Community Multiscale Air Quality (CMAQ) model. MM5 and SMOKE outputs w ill provide the meteorological and emissions data that will be input into the CMAQ model. After completion of all CMAQ model runs, the final output undergoes operational and diagnostic evaluations to determine mode l performance. While there are limitations in each of the three chosen models, each m odel is considered the best available for its intended

use.

The modeling protocol also provides in-depth discu ssion on inventories of point source, area source, on-road, non-road and biogenic source emission rate s. The development and implementation of quality assurance (QA) and quality control (QC) strategies is the most important step in developing these inventories. QA and QC strategies are described in addition to the process of developing emission control strategies that may be applied to demonstrate compliance.

III. Conceptual Description of Ozone Formation

To fully understand the complexity of the ozone formation across North and South Carolina, one
must first examine the interactions between the biogenic and anthropogenic emissions sources within North and South Carolina and throughout the surroundi ng region, as well as the geographical orientation,2 topography, and the meteorological patterns that develop over each of the Carolinas on a typical summertime day. All of these interacting components play a pivotal role in the day-to-day air quality response across the state. On a few select days each summer and often occurring together in episodes, these components work together to produce 8-hour ozone concentrations in excess of the NAAQS. The frequency and duration of these high ozone episodes in an individual summer season are significantly impacted by global scale meteorological patterns and climate deviations (see Appendix D for details).

IV. Attainment Demonstration Methods and Inputs

The attainment modeling for the Metrolina nonatta inment area was performed in conjunction with the regional haze modeling being do ne by the Southeast Regional Planning Organization, Visibility Improvement State and Tribal Association of the S outheast (VISTAS) and the fine particulate matter (PM 2.5 ) and ozone modeling being done by the Association of Southeastern Integrated Planning (ASIP).

Attainment for the Metrolina nonattainment area was demonstrated through the use of a modeling system consisting of the EPA’s Models-3/Community Multiscale Air Quality (CMAQ) modeling system, the Pennsylvania State University/National Center for Atmospheric Research (PSU/NCAR) Mesoscale Meteorological Model (MM5), and the Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system. The CMAQ modeling system is a "one-atm osphere" photochemical air quality modeling system capable of addressing ozone, fine particulate matter, visibility, and acid deposition. The MM5 modeling system is a three-dimensional, limited-area, primiti ve equation, prognostic meteorological model that accurately replicates important meteorological phenom ena that are used as inputs for the CMAQ air quality model. The SMOKE model is principally an emission processing system that converts emissions inventory data into formatted emission files that are used as inputs for the CMAQ air quality model.

Base year 2002 was chosen to process the typical emissions through the SMOKE emissions model, which corresponds to the same year as the historic meteorology used in the air quality model. Since the mandatory attainment date for the Charlotte-Gastonia-Rock Hill, NC-SC area is June 15, 2010, a future year of 2009 was chosen as the modeled attainme nt year. A comparison of the air quality modeling results between these two years is used to determine a relative reduction in future ozone, which is used in the attainment demonstration. A key step in a ttainment demonstration mo deling is the selection of episodes to model. For this attainment de monstration, criteria set out in the EPA’s Guidance on the Use of Models and Other Analyses for Demonstrating Attainment of Air Quality Goals for Ozone, PM 2.5 , and Regional Haze ("Attainment Guidance") were used to select th e episodes that were used in the attainment modeling for the Charlotte-Gastonia-Rock Hill, NC-SC area. The 2002 peak ozone season was chosen to model as this episode covers several criteria liste d in the EPA Attainment Guidance, including the modeling of weekends and a sufficient number of days to ensure a robust modeled attainment test. Modeling the 2002 peak ozone season will also accomplish the goal of encompassing a myriad of meteorological conditions that influence tropospheri c ozone formation. A detailed discussion of the configuration and description of CMAQ, MM5, and SMOKE, as well as a discussion of the episode selection process can be found in the M odeling Protocol (Appendix D).

Another consideration for the attainment modeling was an appropriate domain for which to model. The CMAQ model was run in one-way nested grid mode , which allowed the larger outer domains to feed
concentration data to the inner nested domain. A high resolution 12-km grid covering the entire VISTAS region was chosen as the horizontal domain modeling dom ain for this attainment modeling. The vertical structure of the modeling is primarily defined by th e MM5 34 layer terrain foll owing coordinate system that extends from the surface to the 100 mb layer. The vertical domain in the CMAQ air quality modeling was reduced to 19 layers using a layer-averaging scheme, reducing the computational cost of the simulations with only a minor effect on model performance.3 V. Model Performance Evaluation

Overall, the SCDHEC believes that the model perfo rmance is well within the limits of acceptable performance established in the EPA’s. Attainment Guid ance For the most part, mean normalized bias and mean normalized gross error fall w ithin the recommended limits for good model performance. The model appears to do a good job of capturing ozone concentr ations through various episode ramp-up and cleanout cycles. There are some instances of under and over predictions. However, in most instances, the model does well in simulating the afternoon ozone peak throughout the Carolinas and produces results reliable enough for use as meteorological inputs in th e Metrolina Area attainment demonstration CMAQ modeling.

VI. Attainment Demonstration

The attainment demonstration is based on relative reductions of ozone rather than absolute modeling results and is only applied at grid cells near the monitors. Reviewing the modeling results of how the predicted ozone decreases in the future years and ho w widespread the reductions are play an important role for the State in determining if ad ditional controls should be considered.

The air quality modeling is used in a relative sense by determining what re lative reduction in ozone occurred between the baseline year (2002) and the atta inment year (2009). Table 1 lists the attainment test results for the Charlotte-Gastonia-Rock Hill, NC -SC area. The first two columns are the monitoring site and the county in which the site is located. The next three columns are the modeling base year design value (DVB), the relative response factor (RRF) and the future design value (DVF). According to the EPA’s Attainment Guidance, areas with future design values between 0.082 and 0.087 ppm need to provide additional weight of evidence that the area will attain the 8-hour ozone NAAQS. Weight of
evidence to demonstrate attainment is not required for the monitor in York County.

Executive Summary Table 1: Attainment Test Results

2009 Monitoring Site County DVB (ppm) 5-year weighted
2000-2004 RRF DVF (ppm) Arrowood Mecklenburg 0.0847 0.892 0.075 County Line Mecklenburg 0.0973 0.874 0.085
Crouse Lincoln 0.0907 0.868 0.078
Enochville Rowan 0.0970 0.870 0.084 Garinger (Plaza) Mecklenburg 0.0953 0.883 0.084
Monroe Union 0.0870 0.884 0.076
Rockwell Rowan 0.0973 0.862 0.083 York York, SC* 0.0830 0.861 0.071 *Represents only that portion of the county that is located in the Metrolina nonattainment area

VII. Attainment of the 8-hour Ozone NAAQS by 2009

The SCDHEC believes that the modeling attainment demonstration, in conjunction with the weight of evidence analyses, provides the necessary evidence that the Metrolina nonattainment area will attain the NAAQS by the prescribed attainment date.

The North Carolina Division of Air Quality (NCDAQ) and South Carolina Department of Health and Environmental Control (SCDHEC) provided strong wei ght of evidence that the Metrolina nonattainment4 area will attain the 8-hour ozone NAAQS by 2009. This weight of evidence included looking at alternative methods to calculate the future design values, additional metrics of air quality modeling results, air quality modeling results from other stud ies, positive trends in observed air quality and additional emissions reductions, and additional me asures that were not included in the air quality modeling.5 SECTION I. SOUTH CAROLINA AIR QUALITY IMPLEMENTATION PLAN

On April 30, 2004, the United States Environmental Protection Agency (EPA) designated and classified that portion of York County, South Carolina within the Rock Hill Fort Mill Area Transportation Study (RFATS) Metropolitan Planning Organization (MPO) as a moderate nonattainment area for the 8-
hour ozone National Ambient Air Quality Standards (NAAQS) as part of the Metrolina nonattainment area. As a result of this designation, the South Caroli na Department of Health and Environmental Control (SCDHEC or Department) is required to amend the South Carolina Air Quality Implementation Plan , also known as the State Implementa tion Plan, or SIP, in accordance with the requirements of Title I, Part D - Plan Requirements for Nonattainmen t Areas, Subpart 1, Section 172, and Subpart 2, Section 182 of the
Clean Air Act (CAA), as amended (42 U.S.C. 7401, et seq .). States involved in a multi-State ozone nonattainment area must work together to perform th e appropriate modeling analyses to identify control
measures that will enable the area to achieve attainme nt as expeditiously as practicable. Each State is responsible for its portion of the control program and will be held accountable for controls identified for implementation within its State boundaries.

A. Introduction to 8-Hour Ozone NAAQS

1. Ground-Level (Tropospheric) Ozone

Ozone is a colorless gas that occurs naturally in the atmosphere and can be found in the air we breathe. Ozone is composed of three atoms of oxygen (O 3 ), one more than the common oxygen molecule (O 2 ) we need to breathe to sustain life. The add itional oxygen atom makes ozone extremely reactive. Ozone in the Earth's upper atmosphere, known as strato spheric ozone, shields the Earth from the harmful effects of the sun's ultraviolet rays. Ozone found in the atmosphere closer to the Earth's surface (tropospheric ozone) is considered a harmful air polluta nt due to its adverse impacts on human health and
welfare.

Tropospheric ozone is commonly referred to as ground-level ozone and so metimes called smog. Ozone is not emitted directly by the combustion of fu els. Ozone is formed in the atmosphere by the reaction of volatile organic compounds (VOC) and oxides of nitrogen (NO

x ) in the presence of sunlight. These air pollutants, often referred to as ozone precurs ors, are emitted by many types of pollution sources, including on-road and off-road motor vehicles and e ngines, power plants and industrial facilities, and smaller sources, collectively referred to as area sources. Ozone is predominately a summertime air pollutant. Changing weather patterns contribute to year ly differences in ozone concentrations from region to region. Ozone and the pollutants that form ozone also can be transported into an area from pollution sources found hundreds of miles upwind.

2. Health Concerns

During the hot summer months, ground-level ozone reaches unhealthy levels in several parts of the country. Ozone has been associated with increased hospitalizations a nd emergency room visits, school absences, and reduced activity and productivity. Even at relatively low levels, breathing ozone can trigger a variety of health problems. Ozone can irritate the respiratory system, causing coughing, throat irritation, an uncomfortable sensation in the chest, and/ or pain when breathing deeply. Ozone can worsen asthma and possibly other respiratory diseases, such as bronchitis and emphysema. When ozone levels are high, more people with asthma have attacks that re quire a doctor's attention or the use of additional medication. Ozone can reduce lung function and make it more difficult to breathe deeply, and breathing may become more rapid and shallow than normal, thereby limiting a person's normal activity. In addition, breathing ozone can inflame and damage th e lining of the lungs, which may lead to permanent changes in lung tissue, irreversible reductions in lung function, and a lower quality of life if the6 inflammation occurs repeatedly over a long time peri od (months, years, a lifetime). People who are particularly susceptible to the effects of ozone incl ude children and adults wh o are active outdoors, people with respiratory disease, such as asthma, a nd people with unusual sensitivity to ozone.

3. National Ambient Air Quality Standards (NAAQS)

The CAA requires the EPA to set NAAQS for polluta nts considered harmful to public health and the environment. National primary and secondary ambi ent air quality standards under Section 109 of the
CAA are set forth in Title 40 of the Code of Federal Regulations, part 50. NAAQS are subject to revision, and additional primary and secondary standards may be promulgated as the EPA deems necessary to protect the public health and welfare. The EPA has promulgated primary and secondary NAAQS for carbon monoxide, lead, nitrogen dioxide, particulate matte r, sulfur oxides, and ground level ozone. The EPA calls these pollutants "criteria" air pollutants because it regulates them by developing human healthbased and/or environmentally-based criteria (science-b ased guidelines) for setting permissible levels. For each pollutant, a health-based or "prima ry" standard has been set to protect public health in general, and a welfare-based or "secondary" standa rd has been set to protect quality of life and the environment. Primary standards set limits to protect public health, including the health of "sensitive" populations such as asthmatics, children, and the elderly. Secondary standards set limits to protect public welfare, including protection against decreased visibility, da mage to animals, crops, vegetation, and buildings.

4. 8-Hour Ozone NAAQS

In 1997, the EPA revised the NAAQS for ground-leve l ozone, setting the standard at 0.08 parts per million (ppm) averaged over an 8-hour period. At each ozone monitoring site, hourly average concentrations are recorded in parts per million (p pm). Running 8-hour averages are computed from the hourly ozone concentration data for each hour of the year. The daily maximum 8-hour concentration for a given calendar day is the highest of the 24 possible 8-hour average concentrations computed for that day. The standard-related summary statistic is the three- year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations. The thr ee-year average is computed using the three most recent, consecutive calendar years of monitoring data . This three-year average annual fourth-highest daily maximum 8-hour average ozone concentration is also the air quality design value for the monitoring site. A violation of the 8-hour ozone NAAQS occurs when the computed design value is greater than or equal to 0.085 ppm.

B. Nonattainment Area Desi gnations and Classifications

1. Area Designations

On February 8, 1979, the EPA promulgated the 0. 12 parts per million (ppm) 1-hour ozone standards, (44 Federal Register 8202). On July 18, 1997, the EPA promul gated a revised ozone standard of 0.08 ppm, measured over an 8-hour period [i.e., the 8-hour standard (62 FR 38856)]. Upon promulgation of a new or revised NAAQS, the CAA requires the EPA to designate areas as attaining or not attaining that NAAQS. On April 30, 2004, the EPA announced a nd promulgated designations, classifications, and boundaries for every area in the United States with respect to the 8-hour ozone NAAQS (69 FR 23857).

The 8-hour ground-level ozone NAAQS design values we re calculated for each ozone monitor in the United States. The EPA area designations were gene rally based on air quality monitoring data collected from 2001 to 2003. The highest monitor design value in an area was used to de termine its designation. The CAA then specifies requirements for areas based on whether such areas are or are not attaining the NAAQS.7 2. Nonattainment Area Boundaries

The CAA defines a nonattainment ar ea as an area that is violating an ambient standard or is contributing to a nearby area that is violating the standard. Once it is determined that a monitor is recording a violation, the next step is to determine if there are any nearby areas that are contributing to the violation and include them in the designated nonattain ment area. When evaluating the air quality factors for individual areas, the EPA took into account its view that, in most cases, data recorded by an ozone air quality monitor represents air quality throughout the area in which the monitor is located. The EPA used the county as the basic jurisdictional unit in determin ing the extent of the area reflected by the ozone monitor data. As a result, if an ozone monitor wa s violating the standard based on the 2001–2003 data, the EPA designated the entire county as nonattainment. The actual size of the nonattainment area may be larger or smaller, depending on air quality-related t echnical factors contained in the EPA guidance on determining nonattainment area boundari es for the 8-hour ozone standard.

Section 107(d)(4) of the CAA established the Consol idated Metropolitan Statistical Area (CMSA) or Metropolitan Statistical Area (MSA) as the presumptive boundary for areas designated nonattainment in 1991 for violating the ozone NAAQS. Once a CMSA, MSA, or single county area was determined to contain a monitor that was violating the standard, the EPA and the State considered several factors, including emissions, population density, traffic c ongestion, commercial de velopment, industrial development, meteorological conditions, and polluti on transport in establishing the nonattainment area boundaries. It is necessary to evaluate all counti es in and around an area containing a monitor that is violating the standard to justify including counti es outside the CMSA or MSA or excluding counties in the CMSA or MSA. In some cases, in considering these factors as well as information and recommendations provided by the State, the EPA determ ined that only part of a county was contributing to the nearby nonattainment area.

3. Nonattainment Area Classifications

Title I, part D of the CAA contains two sets of provisions that address planning and control requirements for nonattainment areas. Subpart 1 (which is referred to as "basi c" nonattainment) contains general, less prescriptive, requirements for nonattain ment areas for any pollutant governed by a NAAQS, including ozone. Subpart 2 (which is referred to as "classified" nonattainment) provides more specific requirements for ozone nonattainment areas.

An area designated nonattainment for the 8-hour oz one NAAQS with a 1-hour design value less than 0.121 ppm at the time of designation is subject to the requirements of Subpart 1 and is covered under Section 172(a)(1) of the CAA. These "basic" nonatta inment areas have five years from designation to
attain the standard. The EPA has provided flexibility for areas that have entered into a compact and take early action to achieve emissions reductions necessary to attain the 8-hour ozone standard. This action
defers the effective date of the nonattainment d esignation for these areas and establishes regulations governing future actions with respect to these areas. The EPA has also promulgated deferral of the
effective date of the nonattainment d esignation for Early Action Compact areas.

8-hour ozone nonattainment areas with 1-hour design values of 0.121 ppm or greater at the time of designation are subject to the provisions of Subpart 2 and are classified in accordance with Section 181 of the CAA as marginal, moderate, seri ous, severe, or extreme depending on the area's 8-hour design value. Nonattainment areas with more serious ozone polluti on, as differentiated by these area classifications, are subject to more control requirements as prescribed in Section 182 of the CAA. These prescribed requirements are designed to bring areas into attainment by their specified attainment dates, which are also based upon the area's classification. (See Ta ble I-1: "Subpart 2 Classifications and Attainment Dates.")8 Table I-1: Subpart 2 Classifications and Attainment Dates

Classification Design Value Range (ppm) Attainment Date Marginal 0.085 up to 0.092 June 15, 2007 Moderate 0.092 up to 0.107 June 15, 2010 Serious 0.107 up to 0.120 June 15, 2013 Severe 15 0.120 up to 0.127 June 15, 2019 Severe 17 0.127 up to 0.187 June 15, 2021 Extreme 0.187 and above June 15, 2024

C. 8-hour Ozone Designations for South Carolina

On April 15, 2004, the EPA promulgated 8-hour ozon e designations and classifications for all of the counties in South Carolina based on the design values calculated from air quality monitoring data collected during the 2001, 2002, and 2003 ozone seasons . Almost all of South Carolina was designated
unclassifiable/attainment for the 8-hour ozone st andard; however, the following three areas of South Carolina were designated nonattainment:

1. Greenville-Spartanburg-Anderson Area: This nonattainment area includes the entirety of Greenville, Spartanburg, and Anderson Counties. The Greenville-Spartanburg-Anderson Area was designated a Subpart 1 nonattainment area. The Greenville-Spartanburg-Anderson Area has opted to enter into an Early Action Compact and take early action to achieve emissions reductions necessary to attain the 8-hour ozone standard. The EPA has pr omulgated deferral of the effective date of the nonattainment designation for the Gree nville-Spartanburg-Anderson Area.

2. Columbia Area: This nonattainment area includes the portions of Richland and Lexington
counties within the borders of the Columbia Area Transportation Study (COA TS) Metropolitan Planning Organization (MPO). The Columbia Area was designa ted a Subpart 1 nonattainment area. The Columbia Area has opted to enter into an Early Action Comp act and take early action to achieve emissions reductions necessary to attain the 8-hour ozone standard. The EPA has promulgated deferral of the
effective date of the nonattainmen t designation for the Columbia Area.

3. Charlotte-Gastonia-Rock Hill, NC-SC Ar ea: The Charlotte-Gastonia-Rock Hill, NC-SC nonattainment area includes that portion of York County , South Carolina within the Rock Hill Fort MillArea Transportation Study (RFATS) Metropolitan Planning Organization (MPO). The CharlotteGastonia-Rock Hill, NC-SC Area (also referred to as the Metrolina area) is classified as a Subpart 2
moderate nonattainment area.

Figure I-1, 8-hour ozone nonattainment boundaries for South Carolina , outlines the majority of the State that was designated attainment/unclassifiable and highlights the corresponding boundaries of the three areas designated nonattainment.9 Figure I-1: 8-hour ozone nonattainment boundaries for South Carolina

D. Charlotte-Gastonia-Rock Hill, NC-SC Metropolitan Statistical Area

1. Charlotte-Gastonia-Rock Hill, NC-SC Metropolitan Statistical Area

The Charlotte-Gastonia-Rock Hill, NC-SC Metropolita n Statistical Area (MSA), as defined by the Federal Office of Management and Budget (OMB) on June 30, 1999, consists of Cabarrus, Gaston, Lincoln, Mecklenburg, Rowan, and Union Counties in NC; and York County in SC. MSA boundaries are based on city and county populations in urbanized areas, with "outlying counties" being included in the MSA contingent upon their commuting patterns into th e central counties. Under OMB standards, the county (or counties) that contains the largest city becomes the "central county" (counties), along with any adjacent counties that have at least 50 percent of th eir populations in the urba nized area surrounding the largest city. The MSA are named according to the popul ations of the largest central cities. As noted previously, the CMSA or MSA is the EPA presump tive boundary for areas designated nonattainment for violating the ozone NAAQS.

2. Monitors in the Charlotte-Gastonia-Rock Hill, NC-SC MSA

Figure I-2: "Monitors in the Charlotte-Gastonia-Ro ck Hill, NC-SC MSA" displays where monitors
are located in the Charlotte-Gastoni a-Rock Hill, NC-SC MSA. There are no ozone monitors located in either Cabarrus County or Gaston County in NC. The historic air quality data for the monitors in the Charlotte-Gastonia-Rock Hill, NC-S C MSA is listed in Appendix C.10 Figure I-2: Monitors in the Charlotte-Gastonia-Rock Hill, NC-SC MSA

3. 2001-2003 Design Values for Monitors Located in the MSA

Table I-2: "2001-2003 Design Values" lists th e annual fourth-highest daily maximum 8-hour average ozone concentration and calculated design valu es for all of the monitors within the CharlotteGastonia-Rock Hill, NC-SC MSA.

Table I-2: 2001-2003 Design Values

4 th Highest 8-hour Ozone Value Monitor County 2001 2002 2003 2001-2003 Design Value

Crouse Lincoln 0.094 0.095 0.089 0.092 County Line Mecklenburg 0.099 0.107 0.088 0.098 Garinger (Plaza) Mecklenburg 0.099 0.103 0.086 0.096 Arrowood Mecklenburg 0.086 0.094 0.073 0.084
Enochville Rowan 0. 103 0.108 0.087 0.099
Rockwell Rowan 0.097 0.106 0.098 0.100
Monroe Union 0.081 0.100 0.083 0.088 York York, SC* 0.080 0.096 0.076 0.084

Values shown in bold represent violations of the 8-hour ozone NAAQS *Represents only that portion of the county that is located in the Metrolina nonattainment area11 E. Charlotte-Gastonia-Rock Hill, NC-SC Area

1. Metrolina Area

The EPA designated and classified ozone nonattainme nt areas according to the calculated 2001-2003 design values listed in Table I-2: "2001-2003 Desi gn Values." An area referred to as the CharlotteGastonia-Rock Hill, North Carolina-South Carolin a (Metrolina) Area was designated a nonattainment
area for the 8-hour ozone standard.

2. Metrolina Nonattainment Area Boundaries

The EPA considered several factors, including emissions, population density, traffic congestion, commercial development, industrial development, me teorological conditions, and pollution transport, in evaluating all counties in and around the MSA to esta blish the nonattainment area boundaries. The entire North Carolina portion of the MSA, which includes Ca barrus, Gaston, Lincoln, Mecklenburg, Rowan and Union Counties, was designated to be part of the Me trolina nonattainment area. Two North Carolina areas outside of the MSA, Coddle Creek Township and Davi dson Township in Iredell C ounty, were determined to be contributing to violating monitors and are in cluded in the Metrolina nonattainment area. Although the monitor in York County, South Carolina during th at time was below the 8-hour ozone standard of 0.085 parts per million (ppm), the EPA determined that a portion of York County contributed to violating monitors in nearby North Carolina. That portion of York County, South Carolina, which is situated within the Rock Hill Fort Mill Area Transportation Stud y (RFATS) Metropolitan Planning Organization (MPO) (the York County nonattainment area) was designated as a partial county nonattainment area and included in the Metrolina nonattainment area. (It s hould be noted that the York County ozone monitor is located outside of the designated nonattainment area boundary.)

3. Metrolina Nonattainment Area Classification

The EPA resolved that the Metrolina nonattain ment area classification should be based on the highest 8-hour ozone design value calculated for any of the monitors located within the boundaries of the designated nonattainment area. In reviewing the data analysis reflected in Table I-2: "2001-2003 Design Values," the highest regional design value was 0.100 ppm.

In accordance with the classification criteria su mmarized in Table I-1: "Subpart 2 Classifications and Attainment Dates," the EPA classified the Metrolin a area as a Subpart 2, moderate nonattainment area.

The Metrolina nonattainment area must demonstrat e attainment of the 8-hour ozone NAAQS by no later than June 15, 2010.

F. Conceptual Description of Ozone Formation in the Metrolina Area

The full conceptual description of ozone fo rmation in North Carolina and the Metrolina nonattainment area is discussed in Appendix D. This section will focus on the conceptual description of
ozone formation in the Metrolina area.

As stated earlier, ozone forms through the reaction of NO

x and VOC emissions. Due to generally
warm and moist climate of the Caro linas, vegetation abounds in many fo rms. The emissions from natural sources, such as vegetation, are referred to as bioge nic emissions and account for approximately 90% of
the total VOC emissions in the Carolinas. This results in the Carolinas being a NO

x -limited environment,
which means that reductions in NO

x emissions will have the greatest im pact on reducing ozone formation in the Carolinas, including the Metrolina area.12 North Carolina’s most populous metropolitan regi ons are located in the central portions or the Piedmont of the state. The three largest cities (C harlotte, Greensboro, and Raleigh) form a partial crescent extending from the southwest to the northeast. This combination of metropolitan regions is often
referred to as the Piedmont Crescent. A network of interstate and intrastate highways interconnects these three largest cities and further extends into adjo ining states (such as South Carolina) in a general southwest to northeast pattern. The mobile-based NO

x emissions follow these highway networks with the highest emissions occurring in or near the city centers. The industrial point sources with both anthropogenic NO

x and VOC emissions are also generally located in close proximity to the cities and the major road networks. Finall y, North Carolina’s largest NO

x point sources are electric generating facilities, which are spatially scattered around state but are most heavily concentrated near the Piedmont Crescent. Figure I-3 displays the location of the el ectric generating facilities in and near the Metrolina
nonattainment area.



### Figure I-3: Location of electric genera ting facilities in a nd near the Metrolina
nonattainment area

By combining each of the major emission source categories (biogenic source VOC emissions and mobile sources (highway and non-ro ad) and electric generating facilities NO

x emissions), the highest concentrations of precursor pollutants for ozone fo rmation are focused throughout the Piedmont Crescent, which includes the Metrolina area. Therefore, the gr eatest potential for ozone formation, with the right weather conditions, is also in this central portion of North Carolina.

Figure I-4 displays the breakdown of man-made NO

x emissions in and near the Metrolina nonattainment area. This figure shows that in the Metrolina area, including the counties that neighbor the nonattainment area, point source and highway mobile source NO

x emissions account for over three quarters on the NOx emissions. The majority of the point source NO

x emissions come from the electric13 generating facilities. Therefore, these sources that most impact ozone formation in the Metrolina region are highway mobile sources and electric generating facilities.

Figure I-4: 2002 NOx emissions for the Metrolin a nonattainment area and neighboring counties

In addition to the emissions, meteorology plays an important role in ozone formation as well. Almost all high ozone episodes occurring in the Southeastern United States will have some common meteorological characteristics, including warm te mperatures, lower relative humidity, little or no precipitation, and relatively light winds. These cond itions are nearly universally indicative of regional high-pressure patterns causing large-scale sinking (subsiding) air at various levels of the atmosphere. The differences in the position, strength, and movement of these high pressure areas, along with differences in various mid-to-upper level wind patterns, allow sta ff to discern five meteorological scenarios, or “regimes”, in which high ozone episodes are likel y to occur in the Carolinas. These meteorological regimes are discussed in detail in Appendix D.

The regional transport of ozone into the Metro lina area also contributes to the high ozone values
observed in the Metrolina area. Just outside the borders of the Carolinas is a collection of large metropolitan regions. These metropolitan regions have similar emissions profiles and frequencies of high ozone concentrations leading to exceedances of the 8-hour ozone NAAQS. It is reasonable to conclude that precursor pollutants, as well as formed oz one, can be transported from any of these larger metropolitan regions into the Carolinas with an appropr iate wind flow orientati on from one or more of these regions. In recognition of the effects of regi onal transport of ozone, the EPA has promulgated two rules to help reduce the effects of transported pollutants; the NO

x SIP Call Rule and the Clean Air
Interstate Rule.

In additional to regional transport, recirculated pollution around the Metrolina area affects high ozone events. Winds in the lower and middle atmosphe re can shift around in a variety of directions. In the most frequent scenarios, winds transition from one di rection to another in a clockwise fashion during the extent of the complete synoptic cycle or scenar io. This clockwise shifting of the winds is a key characteristic of eastward-moving high pressure syst ems in the Northern Hemisphere. In a large recirculation pattern, plume(s) of precursor pollutants and formed ozone may leave the Metrolina area one day, travel across multiple regions, then return to the very air shed from where it started within a matter of days. Throughout the journey of air parcels in th is type pattern, precursor pollutants and ozone are constantly being exchanged and added to the air pa rcels from each source sector and metropolitan region along the way, irrespective of any geo-political boundari es. In such smaller scal e recirculation patterns, precursor pollutants and ozone from two neighboring metropolitan regions can exchange back and forth over a series of days, especially as a strong area of high-pressure moves from west to east across the region. Point
25% Area
4% Nonroad Mobile
17%

Highway Mobile
54%14 To summarize the conceptual description of oz one formation in the Metrolina area, various meteorological regimes in conjunction with biogenic VOC emissions and man-made NO

x emissions can result in high ozone values in the Metrolina area. Reductions in highway mobile source and electric generating facility NO

x emissions in and near the Metrolina area will have the greatest impact on reducing
ozone formation.

G. Clean Air Act Requirements

Sections 172(c), 182(a), and 182(b) of the Clean Air Act (CAA), as amended (42 U.S.C. 7401, et

seq. ), prescribe the requirements for ozone nonattainment areas. All designated nonattainment areas must comply with the general requirements mandated by Sec tion 172(c) of the CAA. As a Subpart 2, moderate ozone nonattainment area, the Metrolina area must also meet the additional requirements prescribed by
Section 182 of the CAA. Each State in which all or part of a moderate nonattainment area is located shall
make the submissions described unde r Section 182(a) (relating to margin al nonattainment areas) and shall also submit the revisions to the applicable implem entation plan described under Section 182(b) with respect to moderate nonattainment areas. These require ments are listed below a nd are discussed in more
details in Section VI of this attainment SIP.

1. Section 172(c) - Nonattainment Plan Provisions

a. Reasonably available control measures (RACM) b. Reasonable further progress (RFP)
c. Actual emissions inventor y and periodic emissions inventory d. New source review (NSR) / Attainment Demonstration e. Permit requirements for new and modified sources f. Other measures as may be necessary to provide attainment by specified attainment date g. Compliance with Section 110(a)(2) h. Equivalent techniques i. Contingency measures

2. Section 182(a) - Plan Submissions and Requirements for Marginal Areas

a. Actual emissions inventory in accordance with 172(c)(3)
b. Corrections to SIP i. Reasonably available control technology (RACT) ii. Motor vehicle inspection and maintenance (I/M) iii. Permit programs c. Periodic emissions inventory i. General emission inventory every thr ee years until area is redesignated to attainment
ii. Annual emissions statement for sources emitting 25 tons per year or greater of VOC or
NO

x

3. Section 182(b) - Additional Plan Submissions and Requirements for Moderate Areas

a. Reasonable further progress b. Reasonable available control technology c. Gasoline vapor recovery
d. Motor vehicle I/M e. Offset requirements of at least 1.15 to 1.15 SECTION II. ATTAINMENT DEMONSTRATION METHODS AND INPUTS

The attainment modeling for the Metrolina nonattain ment area was performed in conjunction with the regional haze modeling being do ne by the Southeast Regional Planning Organization, Visibility Improvement State and Tribal Association of the S outheast (VISTAS) and the fine particulate matter (PM 2.5 ) and ozone modeling being done by the Associati on of Southeastern Integrated Planning (ASIP). VISTAS and ASIP are run by the ten Southeast states (Alabama, Florida, Georgia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Virginia and West Virginia). Since the regional haze modeling uses annual simulati ons and includes an intermediate year that is the attainment year required for the Metrolina nonattainment area, the NCDAQ and the SCDHEC decided to use the this modeling for
our ozone attainment demonstration. The sections below outline the methods and inputs used by VISTAS/ASIP for this regional modeling.

A. Analysis Method

The modeling analysis is a complex technical ev aluation that begins by selection of the modeling system. VISTAS decided to use the following modeling system:

1. Air Quality Model: the EPA’s Mode ls-3/Community Multiscale Air Quality (CMAQ) modeling system is a ‘One-Atmosphere’ photoche mical grid model capable of addressing ozone, particulate matter (PM), visibility and acid depos ition at regional scale for periods up to one year.

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

3. Emissions Model: The Sparse Matrix Operator Kernel Emissions (SMOKE) modeling system is an emissions modeling system that ge nerates hourly gridded speciated emission inputs of mobile, nonroad mobile, area, point, fire and bioge nic emission sources for photochemical grid models.

Additionally, a historical year is selected to m odel that represent typical meteorological conditions in the Southeast when high ozone, PM 2.5 and poor visibility are observed throughout the Region. Once the historical year is selected, meteorological inputs ar e developed using the meteor ological model. Emission inventories are also developed for the historical year and processed through the emissions model. These inputs are used in the air quality model to predict ozone, PM 2.5 and visibility, with the results compared to the historic data. The model performance is evaluate d by comparing the modeled predicted data to the historic air quality data.

Once model performance is deemed adequate, typical baseline and future year emissions are processed through the emissions model. For this demonstration, the baseline year was 2002, which corresponds with the same year as the historic meteorol ogy used in the modeling. The attainment future year the NCDAQ and the SCDHEC are using for this demonstration is 2009, since the mandatory attainment date for the Metrolina area is June 15, 2010. Since this attainment date is set prior to the completion of the 2010 ozone season, the attainment of the NAAQS would have to be met by the end of
the 2009 ozone season. These 2002 baseline and 2009 future typical emissions are processed through the air quality model with the meteorological inputs. The air quality modeling results are used to determine a relative reduction in future ozone, which is used in the attainment demonstration.

The complete modeling protocol used for th is analysis can be found in Appendix D.16 B. 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 scientifically ap propriate for the intended application and be freely accessible to all stakeholders. Scientifically a ppropriate means that the models address important physical and chemical phenomena in sufficient de tail using peer-reviewed methods. Freely accessible means that model formulations and coding are freel y available for review and that the models are
available to stakeholders and their consultants for execution and verification at no or low cost.

The following sections outline the criteria for selectin g a modeling system that is both defensible and capable of meeting the study's goals. These criteria we re used in selecting the modeling system used for this modeling attainment demonstration.

1. Selection of Photochemical Grid Model

a. Criteria

For a photochemical grid model to qualify as a candi date for use in an attainment demonstration of the 8-hour ozone NAAQS, a State needs to show that it meets several general criteria:

• The model has received a scientific peer review; • The model can be demonstrated applicab le to the problem on a theoretical basis; • Databases needed to perform the analysis are available and adequate; • Appropriate performance evaluations have shown the model is not biased toward underestimates or overestimates; • A protocol on methods and procedures to be followed has been established; and • The developer of the model must be willing to make the source code available to users for free or for a reasonable cost, and the model cannot otherwise be proprietary.

b. Overview of CMAQ

The photochemical model selected for this study w as CMAQ version 4.4. For more than a decade, the EPA has been developing the Models-3 CMAQ modeling system with the overarching aim of producing a ‘One-Atmosphere’ air quality modeling sy stem capable of addressing ozone, fine particulate matter, visibility, and acid deposition within a comm on platform. The original justification for the Models-3 development emerged from the challenges posed by the 1990 CAAA and the EPA’s desire to develop an advanced modeling framework for ‘holisti c’ environmental modeling utilizing state-of-science representations of atmospheric processes in a high performance computing environment. The EPA completed the initial stage of development with M odels-3 and released the CMAQ model in mid 1999 as the initial operating science model under the Models -3 framework. The most recent rendition is CMAQ version 4.4, which was released in October 2004.

Another reason for choosing CMAQ as the atmos pheric model is the ability to do one-atmospheric modeling. Since the SCDHEC will be using the sa me modeling exercise for the ozone attainment demonstration SIP as well as the regional haze SIP, having a model that can handle both ozone and particulate matter is essential. A number of features in CMAQ’s theoretical formulation and technical implementation make the model well suited for annual particulate matter modeling.

The configuration used for this modeling demonstr ation, as well as a more detailed description of the CMAQ model, can be found in the Modeling Protocol (Appendix D).17 2. Selection of Meteorological Model

a. Criteria

Meteorological models, either through objective, diagnostic, or prognostic an alysis, 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 meteorolog ical model are based on the model’s ability to both accurately replicate important meteorological phenomena in the region of study and 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 meteor ological model to be used in this study:

• Non-Hydrostatic Formulation • Reasonably current, peer reviewed formulation • Simulates Cloud Physics • Public availability at no or low cost • Output available in I/O API format • Supports Four Dimensional Data Assimilation (FDDA) • Enhanced treatment of Planetary Boundary Layer heights for air quality modeling

b. Overview of MM5

The non-hydrostatic MM5 model is a three-dimensional, limited-ar ea, primitive equation, prognostic model that has been used widely in regional air qual ity modeling applications. The basic model has been under continuous development, impr ovement, testing and open peer-revi ew for more than 20 years and has been used worldwide by hundreds of scientists for a variety of mesoscale studies.

MM5 uses a terrain-following non-dimensionalized pressu re, or "sigma," vertical coordinate similar to that used in many operational 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. The gridded meteorological fields produced by MM5 are directly compatible with the input requirements of ‘one atmosphe re’ air quality models using the same coordinate system. MM5 fields can be easily used in other regional air quality mode ls with different coordinate systems by performing a vertical interpolation, followed by a mass-conservation adjustment.

Distinct planetary boundary layer (PBL) paramete rizations are available for air quality applications, both of which represent sub-grid-scale turbulent flux es of heat, moisture, and momentum. One scheme uses a first-order eddy diffusivity formulation for st able and neutral environmen ts and a modified firstorder scheme for unstable regimes. The other sch eme uses a prognostic equation for the second-order turbulent kinetic energy, while diagnosi ng the other key boundary layer terms.

Initial and lateral boundary conditions are speci fied for real-data cas es from mesoscale threedimensional analyses performed at 12-hour intervals on the outermost grid mesh selected by the user. Surface fields are analyzed at three-hour intervals. A Cressman-based technique is used to analyze standard surface and radiosonde observations using the National Meteorological Center's spectral analysis as a first guess. The lateral boundary data are intr oduced using a relaxation technique applied in the outermost five rows and columns of the coarsest grid domain.

Results of detailed performance evaluations of the MM5 modeling system in regulatory air quality application studies have been widely reported in th e literature (e.g., Emery et al., 1999; Tesche et al., 2000, 2003), and many have involved comparisons w ith other prognostic models such as the Regional Atmospheric Modeling System (RAMS) and the Syst ems Application International Mesoscale Model.18 The MM5 enjoys a far richer application history in regulatory modeling studies compared with RAMS or other models. Furthermore, in evaluations of these models in ove r 60 recent regional scale air quality application studies since 1995, it has generally been found that the MM5 model tends to produce somewhat better photochemical model inputs than alternative models.

The configuration used for this modeling demonstr ation, as well as a more detailed description of the MM5 model, can be found in the Modeling Protocol (Appendix D).

3. Selection of Emissions Processing System

a. Criteria

The principal criterion for an emissions processing system is that it accurately prepares emissions files in a format suitable for the photochemical gr id model being used. The following list includes
clarification of this criterion and additional d esirable 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 2 (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

b. Overview of SMOKE

The SMOKE Emissions Processing System Prototype was originally developed at the Microcomputing Center of North Carolina. As with mo st ‘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, w ith the exception of mobile and biogenic sources, its purpose is to provide an efficient, modern tool for converting emissions inventor y data into the formatted emission files required by an air quality simulation model. For mobile sources, SMOKE actually simulates emissions rates based on input mobile-sour ce activity data, emission factors and outputs from transportation travel-demand models.

SMOKE was originally designed to allow emissi ons data processing methods to utilize emergent high-performance-computing as applied to sparse-matr ix algorithms. Indeed, SMOKE is the fastest emissions processing tool currently available to th e air quality modeling community. The sparse matrix approach utilized throughout SMOKE permits both rapi d and flexible processing of emissions data. The processing is rapid because SMOKE utilizes a series of matrix calculations instead of less efficient algorithms used in previous systems. The processing is flexible because the processing steps of temporal projection, controls, chemical speciation, temporal al location, and spatial allocation have been separated into independent operations wherever possible. The r esults from these steps are merged together at a final stage of processing.

SMOKE contains a number of major features that make it an attractive component of the modeling system. The model supports a variety of input formats from other emissions processing systems and19 models. It supports both gridded and county total land use schemes for biogenic emissions modeling. SMOKE can accommodate 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 the Modeling Protocol (Appendix D).

C. Episode Selection

A crucial step to SIP modeling is the selection of episodes to model. Several considerations need to be weighed before settling on not only which days to model, but how many days are modeled for each episode. This section details the guidance and proc ess by which episodes were selected for the 8-hour Ozone SIP modeling package.

1. Overview of EPA Guidance on Ozone

The EPA’s Attainment Guidance on 8-hour ozone modeling sets out specific criteria for the selection of episodes to model for attainment of the 8-hour ozone NAAQS. First, episodes should include days encompassing a variety of meteorological conditions, including varying wind directions, for days exceeding 0.084 ppm. Additionally, episodes should be selected that contain days close to (within ± 0.010 ppm) the current design value (DVC). Episodes should also be chosen around days for which there are extensive air quality and meteorology measurements, including measurements aloft, measurements of indicator species and/or precursor measurements. Fina lly, a sufficient number of days should be selected to ensure robust attainment tests at violating monitoring sites.

The EPA also suggests a set of secondary criteria, in addition to the primary criteria, that may be used in the selection of episodes. This set of crite ria allows states to give preference to previously modeled episodes. This is a very valuable c onsideration, as the EPA points out, since it can save modeling resources and effort. A dditional considerations include selecting episodes maximizing the number of days and sites observing a violation, sel ecting episodes that include weekends, and, when considering regional scale modeling, selecting episodes th at meet primary and secondary criteria in other nonattainment areas. Using these criteria laid out by the EPA, the data ava ilable was systematically examined to determine the best episodes for modeling.

2. Episode Selection

With the advances in computing and storage technologies, and with the aid provided by regional modeling efforts, the NCDAQ and the SCDHEC intend to move toward the modeling of the peak ozone
season for the 8-hour ozone attainment demonstration SI P. By modeling the peak season, several criteria are covered, including the modeling of weekends a nd a sufficient number of days to ensure a robust modeled attainment test. Modeling the peak ozone season will also accomplish the goal of encompassing a myriad of meteorological conditions that influence tropospheric ozone formation.

Efforts were made to determine an appropriate period to model. The selection process started with
an examination of the 8-hour ozone maxima fo r the 1997 through 2004 seasons to determine which season may yield the most days to be included for study. Following the second primary criteria, the number of days each monitoring site observed a value within 0.010 ppm of the design value was tabulated using the recently suggested 5-year weighted average (the average of the three 3-year design values in the five year period centered on the base year).

It was found that, overall, 2002 had the most da ys within 0.010 ppm of the design values, and20 generally had the most exceedance days for the indi vidual monitoring sites. When 2002 was not the highest year, it was generally either the second or thir d highest for either design value convention. Since 2002 was the base year for the VISTAS modeling as well, choosing the 2002 ozone season for the episode allowed the use of the VISTAS ASIP mode ling for the attainment demonstration for ozone.

The months of May through Sept ember 2002 were typical of the me teorology one would expect for an active ozone season, namely warmer and drier than av erage. Temperatures were 1 to 2 oF warmer than average across the state and throughout the Mid-Atla ntic States, and the precipitation values were 4-6
inches below normal for most of the Carolinas. The dry conditions were also present for much of the
coastal Mid-Atlantic States. The warmer and drier conditions led to lower soil moisture throughout much of the East coast, which reduced the evaporation of moisture into the air and decreased dew point temperatures. With less available moisture in the atmosphere, cloud cover w as decreased, which led to more sunlight, increased photochemistry, and higher levels of ozone across the region.

Additionally, the episode classification further ve rifies that the 2002 ozone season is a representative year for use in attainment demonstration modeli ng. The 2002 ozone season encompasses six of the region’s typical meteorological scenarios: eastern st acked highs, frontal approaches, Canadian highs, modified Canadian highs, progressive continental highs and the subcategory of tropical influence. Thus, the 2002 season provides an excellent case to evaluate various control strategies for maintaining the NAAQS for ozone.

For these reasons, the 2002 ozone season was selecte d as the episode to model for the attainment demonstration. Further details of the episode sel ection process, episode classification procedures, and episode classifications for the 2002 ozone season can be found in the Modeling Protocol (Appendix D).

D. Modeling Domains

1. Horizontal Modeling Domain

The CMAQ model was run in one-way nested grid m ode. This allowed the larger outer domains to
feed concentration data to the inner nested domain. One-way nesting is believed to be appropriate for the generally stagnant conditions experienced during Me trolina ozone episodes. Two-way nesting was not considered due to numerical and computationa l 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. Sin ce this national modeling domain was used in the VISTAS regional haze modeling, it was used for the a ttainment demonstration as well. A smaller 12-km grid modeling domain was selected in an attempt to balance location of areas of interest, such as ozone and fine particulate matter nonattainment areas, as we ll as Class 1 and wilderness areas for regional haze. Processing time was also a factor in choosing a smaller 12-km grid modeling domain.

The coarse 36-km horizontal grid domain covers the continental United States. This domain was used as the outer grid domain for MM5 modeling with the CMAQ domain nested within the MM5 domain. Figure II-1 shows the MM5 horizontal dom ain as the outer most, blue grid with the CMAQ 36-
km domain nested in the MM5 domain.21 Figure II-1: The MM5 horizontal domain is the outer most, blue grid, with the CMAQ 36-km
domain nested in the MM5 domain.

To achieve finer spatial resolution in the VISTAS states, a one-way nested high resolution (12 km grid resolution) was used. Figure II-2 shows the 12- km grid modeling domain for the VISTAS region. This is the modeling domain on which the attainment test results are based. A study was performed to determine if using a finer grid resolution provided di fferent modeling results. Since the EPA’s attainment test uses the modeling results to determine the relativ e reductions in ozone between the base year and the future year, it was determined that essentially the same attainment test results are obtained from either 12- km grid modeling or 4-km grid modeling. Since 4-km grid modeling takes significantly more time and resources to run, it was decided that the VISTAS 12-km grid modeling results for this attainment demonstration would be used. A copy of a journal article describing the results of the grid resolution study can be found in Appendix N.22 Figure II-2: A more detailed view of the 12-km grid over the VISTAS region.

2. Vertical Modeling Domain

The CMAQ vertical structure is primarily defined by the vertical grid used in the MM5 modeling. The MM5 model employed a terrain following coordi nate system defined by pressure, using 34 layers that extend from the surface to the 100 mb layer. Table II-1 lists the layer definitions for both MM5 and for CMAQ. A layer-averaging scheme is adopted fo r CMAQ to reduce the computational cost of the CMAQ simulations. The effect of layer averagin g was evaluated in conjunction with the VISTAS modeling effort. It was found that layer averaging ha d a relatively minor effect on the model performance metrics when both the 34 layer and a 19 layer CMAQ m odels were compared to ambient monitoring data. A discussion of the modeling sensitivity for this laye r averaging can be found in Section 9.1 of the
VISTAS Model Performance Evaluation and Model Se nsitivity Tests for Three Phase I Episodes report dated September 7, 2004.23 Table II-1: Vertical Layer Definition for MM5 and CMAQ

MM5 Simulation CMAQ 19 Layers

Layer Sigma Pressure (mb) Height (m) Depth (m) Layer Sigma Pressure (mb) Height (m) Depth (m)

34 0.000 100 14662 1841 19 0.000 100 14662 6536
33 0.050 145 12822 1466 0.050 145
32 0.100 190 11356 1228 0.100 190
31 0.150 235 10127 1062 0.150 235
30 0.200 280 9066 939 0.200 280
29 0.250 325 8127 843 18 0.250 325 8127 2966
28 0.300 370 7284 767 0.300 370
27 0.350 415 6517 704 0.350 415
26 0.400 460 5812 652 0.400 460
25 0.450 505 5160 607 17 0.450 505 5160 1712
24 0.500 550 4553 569 0.500 550
23 0.550 595 3984 536 0.550 595
22 0.600 640 3448 506 16 0.600 640 3448 986
21 0.650 685 2942 480 0.650 685
20 0.700 730 2462 367 15 0.700 730 2462 633
19 0.740 766 2095 266 0.740 766
18 0.770 793 1828 259 14 0.770 793 1828 428
17 0.800 820 1569 169 0.800 820
16 0.820 838 1400 166 13 0.820 838 1400 329
15 0.840 856 1235 163 0.840 856
14 0.860 874 1071 160 12 0.860 874 1071 160
13 0.880 892 911 158 11 0.880 892 911 158
12 0.900 910 753 78 10 0.900 910 753 155
11 0.910 919 675 77 0.910 919
10 0.920 928 598 77 9 0.920 928 598 153
9 0.930 937 521 76 0.930 937
8 0.940 946 445 76 8 0.940 946 445 76
7 0.950 955 369 75 7 0.950 955 369 75
6 0.960 964 294 74 6 0.960 964 294 74
5 0.970 973 220 74 5 0.970 973 220 74
4 0.980 982 146 37 4 0.980 982 146 37
3 0.985 986.5 109 37 3 0.985 986.5 109 37
2 0.990 991 73 36 2 0.990 991 73 36
1 0.995 995.5 36 36 1 0.995 995.5 36 36
0 1.000 1000 0 0 0 1.000 1000 0 0

E. Emission Inventory

There are five different emission inventory source classifications: stationary point and area sources, off-road and on-road mobile sources, and biogenic s ources. Stationary point sources are those sources that emit greater than a specified tonnage per year and th e data is provided at the f acility level. Stationary24 area sources are those sources whose emissions are relatively small but due to the large number of these sources, the collective emissions could be significant (e.g., dry cleaners, service stations, etc.). These types of emissions are estimated on the county level. Off-road mobile sources include equipment (e.g., lawn mowers, construction equipment, railroad locomotiv es, aircraft, etc.) that can move, but do not use the roadways. The emissions from these sources, like st ationary area sources, are estimated on the county level. On-road mobile sources are automobiles, truc ks, and motorcycles that use the roadway system. The emissions from these sources are estimated by vehicle type and road type and are summed to the county level. Biogenic sources are the natural sour ces like trees, crops, grasses, and natural decay of plants. The emissions from these sour ces are estimated on a county level.

In addition to the various source classifications, ther e are also various types of emission inventories. The first is the actual base year inventory. This in ventory is the base year emissions that correspond to the meteorological data. For this modeling effort, th e base year is 2002. These emissions are used for evaluating the air quality model performance.

The second type of inventory is the typical base y ear inventory. This inve ntory is similar to the actual base year. However, for sources that may ha ve significant changes from year-to-year, a more typical emission value is used. In this modeling ef fort, typical emissions were developed for electric generating units (EGUs) and wildla nd fire emissions. The air quality modeling results using these emissions are used in calculating the relative response factors used in the attainment demonstration test. The future year base inventory is an inventory develope d for some future year for which attainment of the ozone standard is needed. For this modeling project , the future year inventory will be 2009, the last complete year for which the standard must be attained . It is the future base year inventory to which control strategies and sensitivities are applied to dete rmine what controls beyond those measures already included in the future year base inve ntory, to which source classifications must be made in order to attain
and maintain the ozone standard.

In the sections that follow, a synopsis of the inventories used for each source classifications are
discussed. Detailed discussions of the emissions inve ntory development can be found in Appendix F, and emission summaries by county for the Metrolina nonatta inment area and for the State are in Appendix E.

1. Stationary Point Sources

Point source emissions are those emissions from larger individual sources having a fixed location. Generally, these sources must have permits to operate , and their emissions are inventoried on a regular schedule. Large sources having emissions of 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 regularly. Smaller sources have
not been inventoried and are included in the area s ource inventory. The point source emissions data can be grouped into the EGU sources and th e other point sources (e.g., non-EGUs).

a. Electric Generating Units

The actual base year inventory for the EGU sources used 2002 continuous emissions monitoring (CEM) data reported to the EPA’s Acid Rain pr ogram or 2002 hourly emissions data provided by stakeholders. This data provides hour ly emissions profiles that can be used in the modeling of these large
sources of NO

x and helps to provide more accurate modeling of these sources.

Since the NO

x emissions from EGU sources are a significant part of the emissions inventory, a typical base year emissions inventory was developed for these sources to avoid anomalies in emissions due to variability in meteorology a nd economic and outage factors in 2002. This approach is consistent with the EPA’s modeling guidance. To develop a typical year 2002 emissions inventory for EGU25 sources, the average CEM heat input for 2000 through 2004 was divided by the 2002 actual heat input for each unit to generate 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 were used since the modeling current design values use monitoring data from this same five-year period. If a unit was shutdown for an entire year during the 2000 through 2004 period, the average of the years the unit was operational was used. If a unit was shutdown temporarily in 2002, the emissions and heat inputs for 2001 (or 2000) were used in the normalizing calculations.

As part of the VISTAS modeling, VISTAS a nd the Midwest Regional Planning Organization contracted with ICF Resources, L.L.C., to generate the future year emission inventory for the electric generating sector of the contiguous United States us ing the Integrated Planning Model (IPM). IPM is a dynamic linear optimization model that can be used to examine air pollution control policies for various pollutants throughout the contiguous United States for the entire electric power system. The dynamic nature of IPM enables the projection of the behavior of the power system over a specified future period. The optimization logic determines the least-cost m eans of meeting electric generation and capacity requirements while complying with specified constr aints including air pollution regulations, transmission bottlenecks, and plant-specific operational constraints. The versatility of IPM allows users to specify which constraints to exercise and populate IPM with their own datasets.

The IPM modeling runs took into consideration the EPA’s Clean Air Interstate Rule (CAIR) implementation and North Carolina’s Clean Smokest acks Act compliance plans for Duke Power and Progress Energy.

b. Other Point Sources

For the non-EGU sources, the same inventory will be used for both the actual and typical base year emissions inventories. The non-EGU category will u se annual emissions as reported for the Consolidated Emissions Reporting Rule (CERR) for the year 2002. These emissions were temporally allocated to month, day, and hour using sour ce category code (SCC) based allocation factors using the SMOKE
emissions model.

The general approach for assembling future year data was to use recently updated growth and control data consistent with the EPA’s analyses. This da ta was supplemented with st ate specific growth factors and stakeholder input on growth assumptions.

2. Stationary Area Sources

Stationary area sources include sources whose emissi ons are relatively small but, due to their large numbers, whose collective emissions could be significan t (e.g., combustion of fuels for heating, structure fires, service stations, etc.). Emissions are estimat ed by multiplying an emission factor by some known indicator of collective activity, such as fuel usage, number of households, or population. Stationary area source emissions are estimated on the county level.

The area source 2002 base year inventory for Sout h Carolina was developed by the VISTAS/ASIP
contractor. The VISTAS/ASIP contractor used the 2002 CERR as the basis for the area source inventory. The sources estimated by the contractor include emi ssions from animal husbandr y, wildland fires, and particulate matter from paved and unpaved roads. Fo r the other states within the modeling domain, the state supplied data or the CERR data for 2002 was used.

The actual base year inventory will serve as th e typical base year inventory for all area source categories except for wildland fires. For this source category, development of a typical year fire26 inventory provided the capab ility of using a comparable data set for both the base year and future years. Thus, fire emissions would remain the same for ai r quality modeling in both the base and any future years. The VISTAS Fire Special Interest Work Gr oup was consulted and decided that State-level ratios of acres over a longer term record (three or more year s) developed for each fire type relative to 2002 would be used. The 2002 acreage was then scaled up or down based on these ratios to develop a typical year inventory.

For categories other than wildland fires, the VISTA S/ASIP contractor generated the future base year emissions inventory used in the attainment demons tration modeling. Growth factors supplied from the states or the EPA’s emission projections were app lied to project the controlled emissions to the appropriate year. In some cases, EPA’s Economic Grow th and Analysis System Version 5 growth factors were used if no growth factor was available from either the states or the growth factor files.

3. Nonroad Mobile Sources

Nonroad mobile sources include equipment that can move but do not use the roadways, such as construction equipment, aircraft, railroad locomotives, la wn and garden equipment, etc. For the majority of the nonroad mobile sources, the emissions were estimated using the EPA’s NONROAD2005c model. For the three source categories not included in the NONROAD model (aircraft engines, railroad locomotives, and commercial marine engines), more tr aditional methods of estimating the emissions were used. The same inventory will be used for both the act ual and typical base year emissions inventories for
the nonroad mobile sources.

For the source categories estimated using the EPA’s NONROAD model, the model was used to create a future base year inventory. The NONROAD m odel takes into consideration rules that are in effect that could impact the emissions from these source categories. For the commercial marine, railroad, and airport emissions, the VISTAS/ASIP contractor calculated the future base year emissions using detailed inventory data (both be fore and after controls) for 1996 and 2010 obtained from the EPA’s Clean Air Interstate Rule Technical Support Document . When available, state specific growth factors were
used.

4. Highway Mobile Sources

The attainment modeling for the Metrolina area w as performed in conjunction with the regional haze modeling being done by the Southeast Regional Plan ning Organization, Visibility Improvement State and Tribal Association of the Southeast (VISTAS) and the fine particulate matter (PM 2.5 ) and ozone modeling being done by the Association of Southeastern Integr ated Planning (ASIP). VISTAS and ASIP are run by the ten Southeast states (Alabama, Florida, Geor gia, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee, Virginia and West Virginia).

The South Carolina transportation partners i nvolved in attainment demonstration State Implementation Plan (SIP) and motor vehicle emis sion budget development included: EPA Region 4, South Carolina Department of Transportation (S CDOT), Federal Highway Administration (FHWA), Federal Transit Administration (FTA), South Carolina Department of Health and Environmental Control (SCDHEC), and the Rock Hill-Fort Mill Area Tran sportation Study (RFATS) Metropolitan Planning Organization (MPO). The Charlotte Department of Transportation (CDOT) was consulted for speeds and
VMT data derived from the Metrolina travel demand model (TDM). Refer to Appendix F.3 for more
detailed information.

In order to accurately model the mobile source em issions in the Metrolina nonattainment area, the newest version of the MOBILE model, MOBILE6.2, was used. Key inputs for the MOBILE model27 include information on the age of vehicles on the ro ads, the average speed on the roads, the mix of vehicles on the roads, any control technologies in pl ace in an area to reduce emissions for motor vehicles (e.g., emissions inspection programs), and temperature.

The MOBILE model takes into consideration rules th at are in effect that impact the emissions from this source sector. For highway mobile sources, the actual and typical year emissions were the same and the MOBILE model was run using input data reflectiv e of 2002. The same model then is run for the future year emissions inventory using input data reflective of 2009. The 2002 and 2009 vehicle miles traveled (VMT) are based on data provided by th e South Carolina Department of Transportation (SCDOT).

5. Biogenic Emission Sources

Biogenic emissions were prepared with the SMOKE-BEIS3 (Biogenic Emission Inventory System 3 version 0.9) preprocessor. SMOKE-BEIS3 is basically the Urban Airshed Model (UAM)-BEIS3 model, but also includes modifications to use MM5 data, gridded land use data, and science updates. The
emission factors that are used in SMOKE-BEIS3 ar e the same as the emission factors in UAM-BEIS3.

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) provi ded by the EPA. A separate land classification scheme, based upon satellite (AVHRR, 1 km spatial reso lution) and census information, aided in defining the forest, agriculture, and urban portions of each county.28 SECTION III. MODEL PERFORMANCE EVALUATION

There are many accepted methodologies for evaluati ng the performance of any air quality model. This section, however, will focus primarily on the methods and techniques recommended by the EPA for evaluating the performance of air quality models. Befo re the air quality model can be fully evaluated, a comprehensive understanding of the performance of the meteorological model being used for its inputs is essential. This evaluation should be specifically desi gned to identify potential biases and errors that may be passed directly from the meteorological model into the air quality model. The meteorological modeling evaluation is fully documented in Appendi x I and is briefly summarized in the next few paragraphs.

Generally speaking, the meteorological modeling performance was quite good at both the 36-km and 12-km grid resolutions. Synoptic features were acc urately predicted and the meteorological model showed considerable skill in replicating all important atmospheric variables (e.g., temperature, mixing ratio, relative humidity, wind speed and direction, cl oud cover, and precipitation) necessary to drive the CMAQ air quality model. Performance statistics s how that the meteorological modeling results fell within expected and acceptable ranges of error during the majority of the 2002 modeled year.

The meteorological modeling performance for Nort h and South Carolina was very similar to the performance for the VISTAS/ASIP region for the 12- km modeling domain. As before, large-scale meteorological patterns were accurately predicted. The meteorological model demonstrated substantial skill throughout the entire 2002 modeling year, and w as especially skillful during the summertime (core ozone) season from May through September.

For the North Carolina portion of the 12km modeling domain (which includes York County, SC), the temperature bias was near zero in May, June, and Augus t. July had a slight negative temperature bias near –0.25 Kelvin (K), and September had a negative temperature bias of –0.1 K. The mixing ratio bias was near 0 gram/kilogram (g/kg) in May through July and then fell to –0.2 g/kg in August and to -0.6 in September. The relative humidity bias generally hovered around ± 3% throughout the summer. Cloud coverage bias peaked near 10% in July and was biase d less than 5% during the other summertime months.
Wind direction was the most erratic of the measurem ents. The direction bias throughout North Carolina was more pronounced than for the full 12-km domain , being more negative May through July, and more positive in August and September. When considering all wind measurements, the wind speed was 0.8 to 1.0 meters per second (m/s) too strong. When omitting cal m observations, the bias falls to 0.2 to 0.5 m/s. Additionally, the meteorological model noticeably overestimated the amount of summertime precipitation across both Carolinas. However, it was reasonably accu rate in reproducing the spatial coverage of measurable precipitation.

Overall, excess wind speeds, increased rela tive humidity, more daytime cloud cover, and precipitation overestimations will likely contribute to slight under predictions of the daily maximum peak ozone concentration in the CMAQ air quality model. Based on the comprehensive VISTAS & NCDAQ evaluation of the 2002 VISTAS MM5 results, the SCDHEC believes that the meteorological model performance is adequate for this modeling exercise for the York County nonattainment area, and should produce credible inputs for CMAQ air quality modeling fo r the Metrolina Area attainment demonstration.

Following the meteorological modeling performance evaluation, the next step in the modeling process was to verify the actual air quality model’s perfo rmance in terms of its ability to predict the ozone in the right locations and at the right levels. To do this, the actual base year model predictions were compared to the ambient data observed in the histor ical season (2002). The methodology in this type of
verification involved a combination of statistical and graphical evaluations, with the goal of determining if the air quality model appears to be reproducing ozone trends in the right locations for the right reasons.29 If this goal is met, then the model can reasonably be u sed as a predictive tool in evaluating various control strategies and their effects on ozone.

The key statistical measures used to evalua te CMAQ air quality model performance for the
Metrolina Area attainment demonstration are as follows:

1. Comparison of modeled mean of ozone to the observed mean of ozone. This metric is an evaluation of how, on average across the modeling pe riod, the model compares to the observed values.

2. Bias in the model, calculated by taking the difference between the modeled mean and the
observed mean.

3. Normalized bias, calculated by taking th e bias for each observation/prediction pair, and then dividing by the number of pairs that are used in th e calculations. The EPA recommends that normalized bias fall between ± 5 – 15 percent.

4. Gross error. For the entire modeling domain, gross error for all pairs above 60 parts per billion (ppb) of ozone was calculated. For the Me trolina nonattainment area, the gross error was calculated on the daily 8-hour ozone maximums. Th e EPA’s Attainment Guidance suggests that gross error can be interpreted as precision of the model. This metric is typically used to compare various modeling applications. EPA recommends that the gro ss error of all pairs >60 ppb be less than 30-35 percent.

These statistics will be presented in the sections that follow for the entire 12-km VISTAS/ASIP modeling domain, then, specifically, for the Metrolina nonattainment area.

In addition to statistical methods, model performan ce was evaluated by reviewing spatial and time series plots of the modeled versus observed data. These graphical plots aided in gaining a better understanding of how the model performed across the entire modeling domain.

Only the model performance evaluation for th e 12-km grid domain will be discussed in the subsections to follow. For the full model perform ance evaluation for both the 36-km and 12-km grid domains, please refer to Appendix J.

A. Domain-Wide Performance

As a first-line screening of overall CMAQ model pe rformance, 8-hour ozone statistical metrics were calculated for the 12-km domain for the VISTAS/ASIP states, North Carolina, and South Carolina (presented in Table III-1). The mean normalized bi as was well within the recommended ± 5 - 15 percent for the entire "core ozone" season (May through Se ptember). The individual monthly statistics for August and September in North and South Carolina, however, showed a mean normalized bias slightly outside the suggested range. This suggests an under prediction of ozone by the model toward the end of the summer. However, the SCDHE C does not believe this slight under prediction for August and September impacts the overall modeling results. The mean normalized gross error was significantly below the 30-35 percent range at the 60 ppb threshold for all regions across the domain.30 Table III-1: 12-km Domain Model Statistics for 8-Hour Ozone

Region/Month Modeled Mean (ppb) Observed Mean (ppb) Mean Bias (ppb) Mean
Normalized

Bias (%) Mean
Normalized
Gross Error (%)
ASIP States combined May 61.26 67.69 -6.44 -8.96 12.47

June 62.62 70.99 -8.37 -11.37 14.02 July 62.73 70.85 -8.12 -10.90 14.74 August 61.33 72.57 -11.24 -14.92 16.98 September 60.81 71.98 -11.17 -14.98 17.07 Mean (May-September) 61.75 70.82 -9.07 -12.23 15.06
North Carolina May 64.06 69.05 -5 -6.86 10.76

June 62.21 71.82 -9.62 -13.03 14.47 July 62.94 72.10 -9.16 -12.09 14.63 August 60.60 73.92 -13.33 -17.40 18.34 September 57.90 69.37 -11.46 -16.11 17.68 Mean (May-September) 61.54 71.25 -9.71 -13.10 15.18

South Carolina May 63.87 67.71 -3.85 -5.31 9.66

June 61.95 70.92 -8.97 -12.10 13.52 July 60.89 70.24 -9.35 -12.73 14.75 August 59.77 71.39 -11.62 -16.03 16.64

September 61.18 72.62 -11.44 -15.22 16.32

Mean (May-September) 61.53 70.58 -9.05 -12.28 14.18

1. Spatial Plots

Overall, the model performed well with the spatial extent of higher ozone concentrations. There is, however, a slight under-prediction of the ozone in the model, most notably in the 1-hour ozone plots. As expected, higher ozone concentrations are seen in the urban areas. In general, the SCDHEC believes the model does an acceptable job capturing the spatial di stribution and concentrations of ozone in the Metrolina area. Appendix J shows all of the domain- wide spatial plots of m odeled 1-hour and 8-hour maximum ozone with the observations, overlaid for the days used in the relative response factor (RRF) calculations. Only representative days are disp layed below in Figure III-1 through Figure III-7.31 Figure III-1: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for May 25, 2002.32 Figure III-2: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for June 3, 2002.33 Figure III-3: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for June 12, 2002.34 Figure III-4: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for July 3, 2002.35 Figure III-5: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for July 17, 2002.36 Figure III-6: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for August 2, 2002.37 Figure III-7: Spatial plots for modeled predicte d and observed peak 1-hour (top) and 8-hour (bottom) ozone concentrations for August 10, 2002.38 2. Scatter Plots

The SCDHEC and the NCDAQ are most concerned about how the model performed for North and South Carolina, primary to the entire 12-km VISTAS /ASIP domain. For this reason, the scatter plots below are for the Carolinas only, with the domain- wide scatter plots found in Appendix J. The model performance scatter plots of "model-pr edicted" versus "observed" for 1-hour and 8-hour oz one have been compiled for each month used in the attainment test (May through September of 2002). Only the 8-hour ozone scatter plots for the three months (June through August), in which the majority of the modeled days used in the relative response factor, are shown. Although there are some outliers, the overall model performance was good for the 2002 ozone season, with the majority of the points falling within acceptable limits.

a. North Carolina Scatter Plots

Since the majority of the Metro lina Area is in North Carolina, s catter plots for the North Carolina domain are shown first, in Figure III-8 through Fi gure III-10 below. These scatter plots show 8-hour ozone for June, July, and August for all of the m onitoring sites in North Carolina only (York, SC omitted). The 1-hour ozone scatter plots and the rema ining 8-hour ozone scatter plots for North Carolina can be found in Appendix J. Overall, for the No rth Carolina monitoring sites the model performance is good. Although there are some days where over-predi ctions and under-predictions are observed, in general most days fall within acceptable ranges of the 1:1 line.

Figure III-8: 8-hour ozone scatter plot for North Carolina 12-km grid for June 2002.39 Figure III-9: 8-hour ozone scatter plots for North Carolina 12-km grid for July 2002.

Figure III-10: 8-hour ozone scatter plots for North Carolina 12-km grid for August 2002.40 b. South Carolina Scatter Plots

Figure III-11 through Figure III-13 display the scatte r plots for 8-hour ozone for June, July and August for all of the monitoring sites in South Caroli na (even though the York County, SC portion of the Metrolina Area is evaluated in most cases as a part of North Carolina proper). The 1-hour ozone scatter plots and the remaining 8-hour ozone scatter plots can be found in Appendix J. Overall, the model performance is good for the South Carolina monitoring sites, including York. Again, although there are some days where over-predictions and under-predictions are observed, in general most days fall within acceptable ranges of the 1:1 line.

Figure III-11: 8-hour ozone scatter plots fo r South Carolina 12-km grid for June 2002.41 Figure III-12: 8-hour ozone scatter plots for South Carolina 12-km grid for July 2002.

Figure III-13: 8-hour ozone scatter plots for South Carolina 12-km grid for August 2002.42 3. Time Series Plots

Following are 8-hour time series plots from the 12-km domain for the North Carolina monitors for June through August. The time series presents the obser ved values [displayed as black asterisks (*)] and the predicted values (displayed as green lines) by month. The 1-hour and 8-hour ozone time series plots for the ASIP region, North Carolina, and South Caro lina (including York) can be found in Appendix J.

The model predicts the overall diurnal pattern we ll; however, it tends to under-predict peak values and over-predict minimum values. In particular th e last few days of August shows the model not handling the prediction of the absolute value of oz one well. Overall, the model is within acceptable tolerances for model performance.

Figure III-14: Time series plot of model pred icted versus mean 8-hour observed for North
Carolina monitors for June 2002.43 Figure III-15: Time series plot of model pred icted versus mean 8-hour observed for North Carolina monitors for July 2002.

Figure III-16: Times series plot of model pred icted versus mean 8-hour observed for North Carolina monitors for August 2002

4. Domain-Wide Summary

Overall, the SCDHEC believes that the VISTA S/ASIP CMAQ model performance across the44 domain and throughout the ozone seas on is good. For the most part, mean normalized bias and mean normalized gross error fall within the recommende d limits for good model performance. The model seems to do a good job capturing ozone concentrations through various episode ramp-up and clean-out cycles. There are some instances of under- and over-p redictions, but, as the scatter plots show, most of the time, the model does well simulating the afte rnoon ozone peak throughout the Carolinas. The SCDHEC believes that the model performance is we ll within the limits of acceptable performance
established in the EPA’s Attainment Guidance an d produces results reliable enough for use in the
Metrolina Area attainment demonstration.

B. Area and Monitor Statistics

Table III-2 displays the model performance statis tics comparing the modeled 8-hour ozone mean and
the observed 8-hour ozone mean at each monitor in th e Metrolina area, as well as the combined statistics
for all of the monitors in the Metrolina area. The statistics represent the May through September ("core ozone season") time period.

Table III-2: Metrolina Nonattainment Area Monitor Statistics

Monitor Modeled Mean (ppb) Observed Mean (ppb) Mean Bias (ppb) Mean
Normalized

Bias (%) Mean
Normalized
Gross Error (%)

Metrolina Area 65.25 73.00 -7.875 -10.152 13.289

Crouse 69.0 73.0 -4.0 -5.330 9.868 County Line 67.0 74.0 -7.0 -8.807 11.885 Garinger (Plaza) 63.0 73.0 -11.0 -14.470 16.125

Arrowood 67.0 72.0 -5.0 -5.837 12.249

Enochville 65.0 75.0 -9.0 -11.790 13.710

Rockwell 65.0 73.0 -9.0 -10.989 13.322

Monroe 62.0 72.0 -10.0 -13.097 14.958 York County, SC* 64.0 72.0 -8.0 -10.898 14.197 *Represents only that portion of the county that is located in the Metrolina nonattainment area

The EPA recommends that the combined mean nor malized bias fall within ± 5-15 percent and the combined mean normalized gross error not exceed the 30-35 percent range. For a specific monitor, it is
recommended that the mean normalized bias fall with in ± 20 percent. The table above shows the VISTAS/ASIP CMAQ modeling demonstrated that the mean bias, mean normalized bias, and mean normalized gross error were all within recommended and accepted ranges.

A slight under-prediction of 8-hour ozone was also observed at this more refined level of analysis and was similar to what was seen at the larger state and VISTAS/ASIP region levels. Individual monthly statistics are not presented here due to the very limite d number of modeled and ob served data pairs at only the eight Metrolina Area ozone monitoring sites. Whole season statistics are more representative of how this air quality modeling will be app lied in the modeled attainment test discussed in Appendix L. Across the whole season, the Metrolina Area as a whole, as well as the individual ozone monitoring sites, showed a mean normalized bias within the suggested ± 5-15 percent range. Additionally, mean normalized gross error fell within the suggested 30-35 percent range given a 60 ppb threshold.45 SECTION IV. CONTROLS APPLIED

Several control measures already in place or be ing implemented over the next few years will reduce stationary point, highway mobile, and nonroad mobile sources emissions . The Federal and State control measures were modeled for all of the future y ears and are discussed in the sections below.

A. Federal Control Measures

1. Tier 2 Vehicle Standards

Federal Tier 2 vehicle standards will require all passenger vehicles in a manufacturer’s fleet, including light-duty trucks and Sport Utility Vehicles (S UVs), to meet an average standard of 0.07 grams
of NO

x per mile. Implementation began in 2004, and should be completely phased in by 2007. The Tier 2 standards will also cover passenger vehicles over 8,50 0 pounds gross vehicle weight rating (the larger pickup trucks and SUVs), which are not covered by the current Tier 1 re gulations. For these vehicles, the standards will be phased in beginning in 2008, with full compliance in 2009. The new standards require
vehicles to be 77% to 95% cleaner than those on the road today. The Tier 2 rule also reduced the sulfur content of gasoline to 30 ppm starting in January of 2006. Most gasoline sold in South Carolina prior to January 2006 had a sulfur content of about 300 ppm. Sulfur occurs naturally in gasoline but interferes with the operation of catalytic converters on vehicles, resulting in higher NO

x emissions. Lower-sulfur gasoline is necessary to achieve the Tier 2 vehicle emission standards.

2. Heavy-Duty Gasoline and Diesel Highway Vehicles Standards

New EPA standards designed to reduce NO

x and VOC emissions from heavy-duty gasoline and diesel highway vehicles commenced implementation in 2004. A second phase of standards and testing procedures, which begins in 2007, is reducing particulate matter fro m heavy-duty highway engines and has reduced highway diesel fuel sulfur content to 15 ppm. The total program for these new engines using low sulfur diesel is expected to achieve a 90% reduction in particulate matter (PM) emissions and a 95%
reduction in NO

x emissions (as compared to existing engines using higher-content sulfur diesel).

3. Large Nonroad Diesel Engines Rule

In May 2004, the EPA promulgated new rules for large nonroad diesel engines (such as those used in construction, agricultural, and industrial equipm ent) to be phased in between 2008 and 2014. The nonroad diesel rules also reduce the allowable sulfur in nonroad diesel fuel by over 99%. Nonroad diesel fuel currently averages about 3,400 ppm sulfur. The rule limits nonroad diesel sulfur content to 500 ppm in 2006 and 15 ppm in 2010. The combined engine and fuel rules would reduce NO

x and PM emissions from large nonroad diesel engines by over 90% (as co mpared to current nonroad engines using highercontent sulfur diesel).

4. Nonroad Spark-Ignition Engines and Recreational Engines Standard

The new standard, effective in July 2003, regulates NO

x , HC, and CO for groups of previously unregulated nonroad engines. The new standard will apply to all new engines imported into or sold within the United States after these standards begi n and will apply to large spark-ignition engines (forklifts and airport ground service equipment), recr eational vehicles (off-highway motorcycles and allterrain-vehicles), and recreational marine diesel engi nes. The regulation varies based upon the type of engine or vehicle.

The large spark-ignition engines contribute to oz one formation and ambient CO and PM levels in46 urban areas. Tier 1 of this standard was implemented in 2004, and Tier 2 is sche duled to start in 2007. Like the large spark-ignition, recreational vehicles co ntribute to ozone formation and ambient CO and PM levels. For all model-year 2006 off-highway motorc ycles and all-terrain-vehicles, the new exhaust emissions standard was phased-in at 50%; for model years 2007 and later, the standard will be phased-in at 100%. Recreational marine diesel engines over 37 k ilowatts (used in yachts, cruisers, and other types of pleasure craft) contribute to ozone formation a nd PM levels, especially in marinas. For certain recreational marine diesel engine sizes, the standard began to be phased-in in 2006.

When all of the nonroad spark-ignition engin es and recreational engines standards are fully implemented, overall reductions of 72% in HC, 80% in NO

x , and 56% in CO emissions are expected by 2020. These controls will help reduce ambient concentrations of ozone, CO, and fine PM.

5. NOx SIP Call in Surrounding States

In October 1998, the EPA made a finding of significant contribution of NO

x emissions from certain states and published a rule that set ozone season NO

x budgets for the purpose of reducing regional transport of ozone (63 FR 57356). This rule, referred to as the NO

x SIP Call, called for ozone season controls to be put on utility and industrial boilers, as well as internal combustion engines in 22 states in
the Eastern United States. A NO

x emissions budget was set for each stat e, and the states were required to develop rules that would allow their respective states to meet their budgets. A NO

x trading program was established, allowing sources to buy credits to meet their NO

x budgets as opposed to actually installing controls. The emission budgets were to be met by the beginning of 2004. Even with the trading program,
the amount of ozone season NO

x emissions has decreased significantly in and around North and South
Carolina.

6. Clean Air Interstate Rule

On May 12, 2005, the EPA promulgated the “Rule to Reduce Interstate Transport of Fine Particulate Matter and Ozone (Clean Air Inters tate Rule); Revisions to Acid Rain Program; Revisions to the NO

x SIP Call,” referred to as CAIR. This rule established th e requirement for states to adopt rules limiting the
emissions of NO

x and sulfur dioxide (SO 2 ) and established a model rule for the states to use in developing their rules. The purpose of the CAIR is to reduce inte rstate transport of precursors to fine particulate and ozone. The CAIR applies to: (1) any stationary, fo ssil-fuel-fired boiler or stationary, fossil-fuel-fired combustion turbine serving at any time, since the st art-up of a unit’s combustion chamber, a generator with nameplate capacity of more than 25 MWe producing electricity for sale; and (2) for a unit that qualifies as a cogeneration unit during the 12-month peri od starting on the date that the unit first produces electricity and continues to qualify as a cogenera tion unit, a cogeneration unit serving at any time a generator with nameplate capacity of more than 25 MWe and supplying in any calendar year more than one-third of the unit’s potential electric output capacity or 219,000 MWh, whichever is greater, to any utility power distribution system for sale. Th is rule provide annual state caps for NO

x and SO 2 in two phases, with the Phase I caps for NO

x and SO 2 starting in 2009 and 2010, respectively. Phase II caps become effective in 2015. The EPA is allowing the caps to be met through a cap and trade program if a state so chooses to participate in the program.47 B. State Control Measures

1. New Source Review Regulations

On December 31, 2002, the EPA finalized revisions governing the New Source Review (NSR) program. The major NSR program is a preconstructi on review and permitting program applicable to new or modified major stationary sources of air polluta nts. In areas not meeting health-based NAAWS, the program is referred to as the Prevention of Significant Deterioration (PSD) program. Collectively, these programs are commonly referred to as the major NSR program.

In accordance with EPA’s final rule revisions , state agency programs must adopt and submit revisions to their SIPs to include the minimum program elements outline in the final rules. States may choose to adopt provisions that differ from the fina l rules; however, to be approvable under the SIP, the state must show that the regulations is at least as stringent as EPA’s amendments.

After a lengthy stakeholder process, SCDHEC submi tted revisions to the Legislature in January 2005 to comply with the EPA requirements. The re visions adopted by SCDHEC differ from the federal revisions in several key respects and have the effect of being more stringent than the federal rules. These revisions were approved by the General Assembly and became state-effective upon publication in the State Register on June 24, 2005. The final regulations pr omulgated amendments to regulations R. 61- 62.1, Definitions and General Requirements , and R. 61-62.5, Standard No. 7, Prevention of Significant
Deterioration , and also promulgated a new regulati on, R. 61-62.5, Standard No. 7.1, Nonattainment New
Source Review

.

a. South Carolina Air Pollution Control Regulation R. 61-62, Definitions and General Requirements , Section II - Permit Requirements

This regulation implements a program for the minor new source review permitting program, which enhances the State’s prevention of significant deterioration of air quality initiatives.

b. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 7, Prevention of Significant Deterioration

This regulation implements a program for the preven tion of significant deterioration of air quality for sources located in or whose construction is proposed in an unclassifiable/attainment area of the State.

c. South Carolina Air Pollution Control Regulation R. 61-62.5, No. 7.1 - Nonattainment
New Source Review

This regulation implements a program whereby s ources located in or whose construction is proposed in nonattainment areas are subject to the re quirements of R. 61-62.5, Standard No. 7.1

2. NO

x Regulations

These regulations specify the requirements for controlling NO

x and for demonstrating compliance
with NO

x limitations and the NO

x SIP Call.

a. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 2 - Ambient Air Quality Standards48 This regulation contains the State of South Ca rolina ambient air quality standards, which have recently been amended to include the 8-hour ozone standards.

b. South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 5.2 - Control of Oxides of Nitrogen (NO
x )

This regulation contains the NO

x control standards applicable to a ffected stationary sources that emit or have the potential to emit NO

x generated from fuel combustion.

c. South Carolina Air Pollution Control Regulation R. 61-62.96 - Nitrogen Oxides (NO
x ) Budget Trading Program

On October 27, 1998, the EPA finalized a Nitrogen Oxides (NO

x ) State Implementation Plan (SIP)
Call Rule. The NO

x SIP Call was designed to reduce the regiona l transport of ground-level ozone through
reductions in NO

x from electric-generating unit (EGU) sources and from some non-EGU sources. The rule requires that, beginning in 2004, NO

x reductions must occur during ground-level ozone season in
states whose NO

x emissions have been identified as contribut ing to 1-hour ozone standard nonattainment in “downwind” states. The rule also requires stat es to identify pollution-re duction measures and develop a plan to achieve these reductions.

Each state subject to the NO

x SIP Call regulation has a NO

x budget that the state allocates to applicable sources. The budget is based on cost-effec tive reductions in emissions that can be achieved by the affected sources. South Carolina’s state trading program budget, as specified in R. 61-62.96, Nitrogen Oxides (NO

x ) Budget Trading Program, is 19,678 tons. The NO

x SIP Call regulation will be repealed after 2009 upon implementation of the Clean Air Interstate Rule.

d. South Carolina Air Pollution Control Regulation R. 61-62.99 - Nitrogen Oxides Budget Program Requirements for Stationary Sources Not in the Trading Program

This regulation details requirements for controlling NO

x emissions from cement manufacturing.

e. South Carolina Air Pollution Control Regulation R. 61-62.2 - Prohibition of Open Burning

The revision of R. 61-62.2, Prohibition of Open Burning , includes a ban of certain open burning during the ozone season for additional control of NO

x emissions.

3. VOC Regulations: South Carolina Air Pollu tion Control Regulation R. 61-62.5, Standard
No. 5 - Volatile Organic Compounds

This regulation contains re quirements for controlling VOCs.

4. Other State Control Measures

a. Clean Air Interstate Rule (CAIR)

On March 10, 2005, the EPA finalized the Clean Ai r Interstate Rule, also referred to as CAIR. On May 12, 2005, CAIR was published in the Federal Register . CAIR affects 28 states and the District of Columbia, whose emissions of sulfur dioxide (SO 2 ) and/or NO

x produced by EGU sources and some nonEGU sources contribute significantly to the nonattain ment of the National Ambient Air Quality Standards (NAAQS) for fine particles (PM 2.5 ) and/or 8-hour ozone in downwind states. (SO 2 and NO

x are both49 precursors to ground-level ozone formation, and NO

x is also a precursor to PM 2.5 formation.) The EPA
has determined that EGU sources in South Carolin a are affecting the nonattainment of ozone and PM 2.5 standards in downwind states. CAIR is a cap-and-trade program for NO

x and SO 2 emissions from affected facilities and has two phases of implem entation. The caps for the phases are as follows:

Phase I, which begins in 2009 for NO

x (annual and ozone season) and 2010 for SO 2 CAIR NO

x annual cap = 32,662 tons (T)
CAIR EGU SO 2 annual cap = 57,271 T
CAIR NO

x ozone season cap = 15,249 T

Phase II, which begins in 2015 for both pollutants
CAIR NO

x annual cap = 27,219 T
CAIR EGU SO 2 annual cap = 40,089 T
CAIR NO

x ozone season cap = 12,707 T

CAIR was due for submission to the EPA for a pproval on September 11, 2006. South Carolina is one of many states that did not meet this deadline because of a lengthy regulatory process. SCDHEC is working closely with EPA Region IV toward implem entation of the state’s rule. SCDHEC has adopted
the federal CAIR with modifications in areas where the state has flexibility. A Notice of Drafting was published in the State Register on July 22, 2005; a second Notice of Drafting was published in the State Register on February 24, 2006. The initial approval to proceed with the proposed regulation was given by the SCDHEC Board on September 14, 2006. The Noti ce of Proposed Rule was first published in the State Register on October 27, 2006. A public hearing befo re the SCDHEC Board was held on January 11, 2007. On January 22, 2007, th e proposed regulation was submitted to the South Carolina Legislature for approval. On March 8, 2007, SCDHEC submitted a request to EPA Region 4 for parallel processing. South Carolina’s CAIR was state-effective upon publi cation in the State Register on June 22, 2007. A
final state-version of CAIR was su bmitted to the EPA on August 16, 2007.

b. Permitting Requirements Involving Emission Offsets - Conditions for Approval

If SCDHEC finds that the major stationary source or major modification would be constructed in an area designated in 40 CFR 81.341 as nonattainment for a pollutant for which the stationary source or modification is major, approval may be gran ted only if the following conditions are met:

(A) The major stationary source or major modifi cation is required to meet an emission limitation which specifies the lowest achievable em ission rate (LAER) for such source.

(B) The applicant must certify that all existing ma jor sources owned or operated by the applicant (or any entity controlling, controlled by, or under common c ontrol with the applicant) in the same State as the proposed source are in compliance wi th all applicable emission limitati ons and standards under the Clean Air Act (or are in compliance with an expeditious sch edule which is Federally-enf orceable or contained in a court decree).

(C) The owner or operator of the proposed new major stationary source or major modification will obtain sufficient emission reductions of the nonattainment pollutant from other sources. Emission reductions shall be in effect and enforceable prior to the date the new source or modification commences operation. The emission reductions shall be obtai ned in accordance with the following provisions:

(1) Where the permitted emissions limit allows greater emissions than the potential to emit of the source, emissions offset credit will be a llowed only for control below this potential;50 (2) For an existing fuel combustion source, cred it shall be based on the allowable emissions for the type of fuel being burned at the time the appli cation to construct is filed. If the existing source
commits to switch to a cleaner fuel at some future date, emissions off set credit based on the allowable (or actual) emissions for the fuels involved is not accep table, unless the permit is conditioned to require the use of a specified alternative control measure which would achieve the same degree of emissions
reduction should the source switch back to a dirtier fuel at some later date.

(3) (a) Emissions reductions achieved by s hutting down an existing source or curtailing production or operating hours below b aseline levels may be generally credited if such reductions are permanent, quantifiable, federally enforceable, occurred on or after the date of the most recent emissions inventory, and if the area has an EPA-approved attainment plan.

(b) Such reductions may be credited if the shutdown or curtailment occurred on or after the date the new source permit applicati on is filed, or, if the applicant can establish that the proposed new source is a replacement for the shutdown or curtaile d source, and the cutoff date provision of paragraph (d)(C)(iii)(a) of Standard 7.1 are observed.

(4) No emissions credit may be allowed for replacing one hydrocarbon compound with another of lesser reactivity, except for those compounds lis ted in Table 1 of EPA's "Recommended Policy on Control of Volatile Organic Compounds " (42 FR 35314, July 8, 1977);

(5) All emission reductions claimed as o ffset credit shall be federally enforceable;

(6) Location of offsetting emissions. Emission offsets shall be obtained from sources currently operating within the same designated nonattainment ar ea as the new or modified stationary source. Emission offsets may be obtained from another nonatta inment area with the Department's approval only
if: (a) The other area has an equal or highe r nonattainment classification than the area in which the proposed source is located; and,

(b) Emissions from the other area contri bute to a violation of the NAAQS in the
nonattainment area in which the source is located.

(7) Emission offsetting ratios. Emission offsets shall be required in nonattainment areas in accordance with the following provisions:

(a) Emissions for carbon monoxi de (CO), nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), lead (Pb), particulate matter (PM 10 and PM 2.5 ) nonattainment areas shall be offset at a ratio greater than

one to one.

(b) Emissions for ozone nonattainment areas shall be offset for volatile organic compounds (VOCs) and nitrogen oxides (NO

x ) in accordance with the following table:51 (8) Credit for an emissions reduction can be clai med to the extent that the Department has not relied on it in issuing any permit unde r regulations approved pursuant to 40 CFR part 51 subpart I or the Department has not relied on it in demonstrati ng attainment or reasonable further progress.

(9) Decreases in actual emissions resulting from the installation of add-on control technology or application of pollution prevention measures that we re relied upon in designating an emissions unit as a Clean Unit or a project as a PCP cannot be used as offsets.

(10) Decreases in actual emissions occurring at a Clean Unit cannot be used as offsets, except as provided in paragraphs (f)(8) and (g)(10) of Regulatio n 61-62.5, St. No. 7.1. Si milarly, decreases in actual emissions occurring at a PCP cannot be used as off sets, except as provided in paragraph (h)(6)(iv) of Regulation 61-62.5, St. No. 7.1.

(11) The total tonnage of increased emis sions, in tons per year, resulting from a major
modification that must be offset in accordance with section 173 of the Clean Air Act shall be determined by summing the difference between the allowable emissions after the modification (as defined by paragraph (b)(3) of Regulation 61-62.5, St. No. 7.1) and the actual emissions before the modification (as defined in paragraph (c)(1) of Regulation 61- 62.5, St. No. 7.1) for each emissions unit.

(D) The emission offsets must provide a positive net air quality benefit in the affected area as determined by 40 CFR 51, Appendix S, Em ission Offset Interpretative Ruling.

(E) Alternative Sites Analysis. An analysis of alternative sites, sizes, production processes, and environmental control techniques for such proposed source demonstrates that benefits of the proposed source significantly outweigh the environmental and so cial costs imposed as a result of its location, construction, or modificat ion shall be required.

5. Emissions Inventory: South Carolina Regulation R. 61-62.1, Definitions and General Requirements , Section III - Emissions Inventory

This regulation requires the submittal of emissi ons inventory information by affected sources.

6. Reasonably Available Control Measures (RACM)

Reasonably Available Control Measures is a broadl y defined term referring to technologies and other measures that can be used to control pollution; includes Reasonably Available Control Technology (see Appendix R - RACT SIP) and other measures.

EPA's final 8-hour ozone implementation rule in 40 CFR 51.912(d), pursuant to section 172(c)(1) of the CAA, requires the attainment demonstration SIP submittal to include "a SI P revision demonstrating that it has adopted all RACM necessary to demonstrat e attainment as expeditiously as practicable and to meet any RFP requirements." In addition, EPA's RA CM policy indicates that areas should consider all candidate measures that are potentially available, including any that have been suggested for the particular nonattainment area. Although areas should c onsider all available measu res, areas need only to adopt measures if they are both economically and t echnologically feasible and will contribute to timely attainment or are necessary for RFP. Measures that might be available but would not advance attainment
or contribute to RFP need not be considered RACM.52 a. Reasonably Available Control Technology (RACT) The case-by-case RACT analysis for existing sources located in the ozone nonattainment area with the potential to emit greater than 100 tons per year of NO

x and/or VOC is found in Appendix R - RACT SIP. In the York County nonattainment ar ea, there are no VOC sources subject to CTGs.

b. Early Action Compacts

On August 22, 2002, DHEC published a Notice of Drafting in the State Register announcing its intent to pursue Early Action Compacts (EAC) for th e 8-hour ozone standard. Through the EAC process, local, state, and EPA officials commit to working t ogether to develop and implement plans that will reduce ozone pollution so that areas are attaining the 8- hour ozone standard earlier than would be required by the Clean Air Act. Only areas that are attaining the 1-hour ozone standard are eligible to participate in the EAC process. The compact require s these areas to attain the 8-hour ozone standard by December 31, 2007, a date that is sooner than would otherwise be required through the traditional nonattainment designation process.

At the end of 2002, 45 of South Carolina's 46 counties, SCDHEC, and EPA Region 4 had signed compacts to implement ozone reduction strategies earlie r than federally required. Statewide stakeholder groups involving local and federal governments, industry, environmen tal groups, and other interested parties have worked together to plan and implemen t strategies for ozone pollution prevention throughout the state. Plans involve mobile source pollution reduc tion, outreach actions, and point source prevention, which provide flexibility and foster "homegrown" solutions.

The most important reasons for moving forward in this proactive manner are the public health benefits realized by meeting the new standard sooner than required and also the deferral of the effective date of a nonattainment designation.

As part of this process, the EAC stakeholders developed statewide regulations aimed at achieving additional reductions in ozone precu rsors. One new regulation that w as developed as part of this process was South Carolina Air Pollution Control Regulation R. 61-62.5, Standard 5.2, Control of Oxides of Nitrogen (NO

x ) . This is a broad-based regulation that app lies statewide to new and existing stationary
sources that emit NO

x from fuel combustion and have not under gone a best available control technology (BACT) analysis for NO

x . For new sources, the regulation requires the installation of control technology
that is based on BACT standards found in the RACT/BACT/LAER clearinghouse. For existing sources, the regulation only applies when an applicable unit replaces their burner. At this point, they will be required to replace their burner with a low NO

x burner or equivalent technology capable of achieving a 30 percent reduction from uncontrolled levels.

Also, as part of the EAC process, South Caro lina Air Pollution Control Regulation R. 61-62.2, Prohibition of Open Burning , was revised by deleting the exception for the burning of household trash, revising the exception for the burning of construction waste, and revising the exception for fires set for the purpose of firefighter training. The burning of household trash presents health and environmental concerns for many communities. The smoke generate d from these activities is a nuisance to some and a health threat to others with asthma or other respir atory problems. With respect to the exception for the burning of construction waste, the regulation was revi sed to allow only residential construction waste to be burned outside the ozone season, and this will onl y be allowed if it meets the provisions of the regulation. Finally, the exception for the purpose of firefighter training was revised to ensure that minimum health, environmental, and safety concerns are addressed.

These regulations were approved by the SCDHEC Board in January 2004, and, in accordance with South Carolina law, they were subsequently subm itted to the Legislature for approval. The South53 Carolina General Assembly approved the regulations, and the rules were published and became effective upon publication in the State Register on June 25, 2004. In accordance with the EAC process, SCDHEC incorporated the statewide regulations and the local early action plans into the agency's Early Action SIP
revision and submitted it to the EPA in D ecember 2004, for review and approval.

c. Take a Break from the Exhaust

Take a break from the exhaust (TABFTE) is an a lternative commute initiative that uses a competitive model in which points are assigned/ awarded for each action that is done to minimize air pollution. A computer program is used by participants to report th eir actions and to record their daily points. The webbased program is available to state and local govern ment, industry, and the public. The program tracks and calculates vehicle miles, determines emissi on reductions, is free and requires no additional equipment.

TABFTE was started by the SCDHEC Bureau of Air Quality in 2001 and is still being used by the bureau staff. In 2003, it was awarded the Governor 's Pollution Prevention Award and became Internet accessible. The program was expanded to other state agencies in 2004. The primary benefits of TABFTE are reduced emissions from mobile sources and increased awareness of the impact of mobile sources on air quality; it also encourages participants to take voluntary actions to help improve air quality.

d. Overall RACM Conclusions

A number of emissions controls programs have been implemented in South Carolina since the Clean Air Act Amendments of 1990, and s ubstantial further emissions reductions will occur in the State as well
as the Metrolina area in 2007. SCDHEC intends to con tinue to investigate and, where appropriate, adopt
additional measures that would reduce emissions of oz one precursors even further. Such measures may help the State in the future as it moves towards attainment of the eight-hour ozone NAAQS. The source categories emitting the vast preponderance of ozone precu rsor emissions in the State are already subject to control requirements. South Carolina has adopted all of the above RACM and have since determined that there are no additional technologically and econo mically feasible control measures that would result in South Carolina attaining the one -hour ozone NAAQS earlier than 2007.54 SECTION V. ATTAINMENT DEMONSTRATION

A. Attainment Test Introduction

The modeled attainment test is the practice of using air quality modeling results for baseline and future years to determine if an ar ea is expected to attain the NAAQS. For the 8-hour ozone NAAQS, the
baseline and future model estimates are used in a "rela tive" rather than an "absolute" sense. Specifically, the ratio of the air quality model’s future to current predictions is calculated at each ozone monitoring site. These monitoring site-specific ratios are calle d relative response factors (RRFs). Future ozone design values (DVFs) are then estimated at each monitor by multiplying the monitor-specific baseline ozone design value (DVB) by the modeled RRF for each monitor. If all of the predicted monitor-specific DVFs in a given area are less than or equal to 0.084 ppm, the attainment test is passed and the area is said to demonstrate attainment. Equation V-1 presents the m odeled attainment test, applied at monitoring site
"x" as described in Section 4.0 of the EPA’s Attainment Guidance

.

Equation V-1 (Future Design Values):

(DVF) = (RRF) x (DVB)

Where:

(DVB) = the baseline design value monitored at site "x" in ppm = the average of the three desi gn value periods which include the baseline inventory year (i.e., the average of the 2000-2002, 2001-2003, and 2002-2004 design value periods for the 2002 baseline inventory year).

(RRF) = the ratio of the future 8-hr da ily maximum concentration predicted "nearby" a monitor (averaged over each day of the episode) to the current 8-hr daily maximum concentration predicted "nearby" the monitor (avera ged over each day of the episode).

(DVF) = the estimated future design value in ppm.

It is important to consider an array of cells "n earby" a monitor rather than focusing on the individual cell containing the monitor. This allows for varia tions in the model performance where the peak ozone concentration occurs in a nearby grid cell rather than in the grid cell that contains the monitor.

The RRF is calculated by taking the ratio of the mean future year modeling 8-hour ozone daily maximum (averaged over all of the episode days) to the mean current year modeling 8-hour ozone daily maximum "near" the monitor (averaged over all of the episode days) (Equation V-2).

Equation V-2 (Relative Response Factors):

RRF = (mean future yr. 8-hr daily max "near" monitor "x") (mean current yr. 8-hr daily max "near" monitor "x")

The DVB, for purposes of the modeled attainment test, is defined in the EPA’s Attainment Guidance as the average of the three design value periods that straddle the baseline inventory year (i.e., the average55 of the 2000-2002, 2001-2003, and 2002-2004 design va lue periods for a 2002 baseline inventory year).

B. Attainment Test Results

As stated above, the attainment test is not based on absolute modeling results but, rather, relative reductions of ozone and is only applied at the monito rs. However, reviewing the modeling results of how the predicted ozone decreases in the future years a nd how widespread the reductions are plays an import role for the State in determining if additional cont rols should be considered. The modeling results for each day used in the RRF calculations are available in Appendix K. Additionally, discussions about how this modeling demonstration meets the screening test for areas away from the monitoring sites and additional matrices performed to support the a ttainment test results are in Appendix L.

The EPA states that future design values (DVFs) that fall below 0.082 ppm demonstrate attainment whereby little weight of evidence is needed. For monitors with DVFs between 0.082 ppm and 0.087 ppm, weight of evidence must be submitted that suppor ts a demonstration of attainment. DVFs greater than 0.085 ppm fail the attainment test.

Table V-1 lists the attainment test results for th e Metrolina nonattainment area. The first column is the monitoring site, followed by the base year design va lue discussed in Section V.A. The next series of columns are the calculated RRF and the resulting DVF for the 2009 attainment year. Monitors with DVFs that fall in the additional weight of evidence requirement appear in bold.

Table V-1: Attainment Test Results

2009 Monitoring Site County DVB (ppm) 5-year weighted
2000-2004 RRF DVF (ppm) Arrowood Mecklenburg 0.0847 0.892 0.075 County Line Mecklenburg 0.0973 0.874 0.085
Crouse Lincoln 0.0907 0.868 0.078
Enochville Rowan 0.0970 0.870 0.084 Garinger (Plaza) Mecklenburg 0.0953 0.883 0.084
Monroe Union 0.0870 0.884 0.076
Rockwell Rowan 0.0973 0.862 0.083 York York, SC* 0.0830 0.861 0.071 *Represents only that portion of the county that is located in the Metrolina nonattainment area.

C. Supporting Weight of Evidence

As part of the weight of evidence determina tion, the following analyses will be evaluated: alternative DVF calculations, additional metrics of air quality modeling results, air quality modeling results from other studies, positive trends in observe d air quality and additional emissions reductions, and local measures that were not modeled. The weight of evidence determination is a supplement to the modeled attainment test and further supports that the area will attain the NAAQS for 8-hour ozone by June 15, 2010.

The SCDHEC believes that the weight of evidence pr ovided in the sections below is strong evidence
that the Metrolina nonattainment area will attain the 8-hour ozone NAAQS by 2009.56 1. Alternative DVF Calculation

The EPA recommends calculating the DVB by averag ing the three design value periods that straddle the baseline inventory year. This methodology result s in a center weighting of annual 4th highest ozone concentrations around the baseline inventory year b ecause the three design value periods averaged contain overlapping data. A weighted DVB can be si gnificantly affected by an abnormally hot/dry or cool/wet year, if the year happens to be the center weighted year.

To minimize potential impacts of any abnormal meteorological conditions while still considering ozone conditions across a 5-year span, the NCD AQ and the SCDHEC prefer an alternative DVB calculation that does not weigh any of the years more than another but is the straight average of annual 4th highest ozone concentrations for the 5-year span centered on the baseline inventory year.

This preferred DVB calculation is applied to the re mainder of the modeled attainment test equations and the resulting DVFs are shown in Table V-2 at each monitoring site in the Metrolina region.

Table V-2: 5-Year Average Alternat ive Attainment Test Results for 2009

Monitoring Site County DVB 5-Year Straight Average
2000-2004 (ppm) RRF DVF (ppm)

Arrowood Mecklenburg 0.0834 0.892 0.074 County Line Mecklenburg 0.0956 0.874 0.083

Crouse Lincoln 0.0892 0.868 0.077

Enochville Rowan 0. 0944 0.870 0.082 Garinger (Plaza) Mecklenburg 0.0938 0.883 0.082

Monroe Union 0.0846 0.884 0.074

Rockwell Rowan 0.0946 0.862 0.081
York York, SC* 0.0798 0.861 0.068 *Represents only that portion of the county that is located in the Metrolina nonattainment area.

The alternative DVFs are slightly lower at each m onitoring site compared to the attainment test
DVFs. These differences were expected as 2002 was an abnormally hot and dry year throughout the Southeast, resulting in ozone concentra tions that were higher than normal and that were much higher than in the surrounding years of 2000, 2001, 2003, and 2004. Thus, the EPA recommended DVB calculation weighted these abnormally-high air quality conditions sev eral times more than in the straight average alternative DVB calculations. The NCDAQ and the SC DHEC firmly believe that the straight five-year average approach to the DVB calculation is more a ppropriate and minimizes dr amatic fluctuations in meteorological and air quality conditions from year to year.

While none of the monitoring sites in the Metro lina region had DVF values at or above 0.085 ppm using the straight average alternative DVB calculation, there are still three monitors that have DVFs that fall between 0.082 and 0.087 ppm. This continues to indicate that some additional weight of evidence
should be included to de monstrate attainment.57 2. Additional Air Quality Modeling Metrics

A series of five additional air quality modeli ng outputs or metrics is recommended to provide
assurance the modeled attainment demonstration indi cates attainment. These metrics look at the relative change between the baseline and future years mode ling and help to demonstrate how widespread the improvement in air quality is expected in the future. These metrics include:

• The relative change in surface grid-hours greater th an 0.084ppm. This is the number of grid cells in a Metrolina region with predicted hourly 8-hour ozone concentrations greater than 0.084 ppm. The relative change is the percent reduction fro m the baseline year to the future year.

• The relative change in the number of grid cells with predicted 8-hour daily maximums greater than 0.084 ppm. This metric uses the modeled daily maxi mum 8-hour ozone concentrations greater than 0.084 ppm. The relative change is the percent reducti on from the baseline year to the future year.

• The relative change in the sum of hourly predic tions greater than 0.084 ppm. This metric is the sum of all grid cells with predicted hourly 8-hour ozone concentrations greater than 0.084 ppm. The relative change is the percent reduction fro m the baseline year to the future year.

• The relative change in the sum of the predic ted 8-hour daily maximums greater than 0.084 ppm. This metric uses the modeled daily maximum 8-hour oz one concentrations greater than 0.084 ppm. The relative change is the percent reduction fro m the baseline year to the future year.

• The change in the Air Quality Index (AQI) c ounts. The AQI counts metric is a count of the number of grid cells with predicted maximum 8-hour oz one concentrations sorted within each of the color codes as defined by the EPA’s AQI.

The EPA recommended that these metrics should indi cate a reduction in ozone of 80% or more in order to provide weight of evidence that an area would attain the ozone NAAQS. The additional air quality modeling metric analyses demonstrated reductions of greater than 85% for all metrics in the 2009 attainment year for modeled days above the NAAQS in the Metrolina nonattainment area. A full discussion of the metrics and the results can be found in Appendix L.

3. Air Quality Modeling Results From Other Studies

Another recommended weight of evidence analysis is to review other air quality modeling results
that included the Metrolina nonattainment area to de termine how other modeling results compare to the attainment demonstration. There are two air quality modeling studies for which results are available for
the Metrolina area.

The first is the Early Action Compact (EAC) modeling that the NCDAQ and the SCDHEC performed for the EAC areas within North and Sout h Carolina. Since the modeling domain for this analysis covered the majority of North and South Carolina, including the Metrolina nonattainment area, the modeling results can be easily compared to the attainment demonstration. Although there are some differences between the two modeling exercises, the m odeling results for 2012 show all of the monitors well below the 8-hour ozone NAAQS, with the highest monitor having a DVF of 0.081 ppm.58 Table V-3: Metrolina DVFs Based on EAC Modeling

2012 Monitoring Site County DVB (ppm) RRF DVF (ppm) Arrowood Mecklenburg 0.092 0.848 0.078 County Line Mecklenburg 0.101 0.802 0.081
Crouse Lincoln 0.092 0.826 0.076
Enochville Rowan 0.099 0.818 0.081 Garinger (Plaza) Mecklenburg 0.098 0.816 0.080
Monroe Union 0.088 0.795 0.070
Rockwell Rowan 0.100 0.800 0.080 York York, SC* 0.086 0.844 0.073

*Represents only that portion of the county that is located in the Metrolina nonattainment area.

Another air quality modeling exercise that containe d results for the Metrolina nonattainment area is the EPA’s modeling for the Clean Ai r Interstate Rule (CAIR). The Technical Support Document for the final , dated March 2005, provided mo deling results with and without the implementation for the . These modeling results are listed in the table below.

Table V-4: Metrolina DVFs Based on EPA’s Modeling

DVF (ppb) County DVB (ppb) 2010 Base 2010

Lincoln 92.3 76.1 74.5 Mecklenburg 100.3 82.5 81.4

Rowan 99.7 81.3 80.1
Union 87.7 71.9 71.1 York, SC* 83.3 70.0 68.5 *Represents only that portion of the county that is located in the Metrolina nonattainment area.

The EPA’s modeling results predicts that the Me trolina nonattainment area should be below the 8- hour ozone standard by 2010. Althoug h this is one year later than the attainment year for the Metrolina area, the EPA’s 2010 DVFs are 2 to 4 ppb lower than th e DVFs predicted in the attainment demonstration and support weight of evidence that the Metrolina ar ea will attain the 8-hour ozone standard by its attainment year of 2009.

4. Positive Trends in Observed Air Quality and Additional Emissions Reductions

Since the 8-hour ozone designation for the Metr olina area, the 8-hour ozone design values have improved significantly. The 2001-2003 design value period had values as high as 0.100 ppm, and six out
of the seven North Carolina monitors in the area were violating the NAAQS. Each year since, the design values have decreased and/or the number of violating monitors in the region has decreased. For the latest design value period, 2004-2006, the highest violating monitor has a value of 88 ppb, with only three monitors exceeding the NAAQS (See Table V-5).59 Table V-5: Design Values (ppm) for the No rth Carolina Monitors in the Metrolina Area

Monitoring Site County 2001-2003 2002-2004 2003-2005 2004-2006 Arrowood Mecklenburg 0.084 0.081 0.078 0.080 County Line Mecklenburg 0.098 0.092 0.087 0.088
Crouse Lincoln 0.092 0.086 0.081 0.079
Enochville Rowan 0.099 0.091 0.085 0.085 Garinger (Plaza) Mecklenburg 0.096 0.091 0.086 0.088
Monroe Union 0.088 0.085 0.079 0.078
Rockwell Rowan 0.100 0.094 0.088 0.083 York York, SC* 0.084 0.081 0.075 0.076 *Represents only that portion of the county that is located in the Metrolina nonattainment area.

The current ozone design values are very close to the predicted attainment year design values, however, there are still significant nitrogen oxides (NO

x ) emission reductions that are expected between now and the attainment year. Although most of these expected NO

x emission reductions have been included in the attainment demonstration modeling, it does not appear the model is responsive enough to expected emission reductions.

As mentioned in earlier in the na rrative, the Metrolina area is a NO

x -limited area, and the major
sources of NO

x emissions in the region comes from mobile sources and electric generating facilities.
Reduction of emissions from these two source sectors can significantly influence the ozone formation in this region. The NCDAQ and the SC DHEC have estimated that there will be approximately 7.6 tons per day of NO

x emissions reduced each year from the mobile sector. These reductions are the result of Federal motor vehicle and equipment standards for both highway vehicles and off-road equipment.

Another source of NO

x emission reductions that are expected to occur between now and the attainment year are from the electric generating facilit ies located in and near the Metrolina nonattainment area. Several of the Duke Energy units are still exp ected to have controls installed over the next two years. Figure V-1 displays the location and size of the Duke Energy facilities located in the vicinity of the
Metrolina nonattainment area. Table 5.3.4-2 lists the units that are in and aro und the Metrolina area and shows the year the controls are expected to come on line and the estimated amount of NO

x emissions
reductions for the ozone season.60 

### Figure V-1: Location and size of the Duke En ergy facilities located in the vicinity of the
Metrolina nonattainment area

Table V-6: Utility NO

x Emission Reductions since 2006 Ozone Season

Facility County Technology Operational Date Ozone Season Reductions (tons/season)

Allen Steam Station
Unit 2
Unit 3 Gaston SNCR
SNCR Spring 2007
Fall 2007 ~300

Buck Steam Station
Units 3 & 4
Units 5 & 6 Rowan Low NO

x Burners
SNCR Spring 2007
Fall 2006 ~350

Riverbend
Unit 4
Unit 5
Unit 6
Unit 7 Gaston SNCR
SNCR & Burners
SNCR & Burners
SNCR Spring 2007 Spring 2007
Fall 2006
Fall 2006 ~325

Marshall Steam Station
Unit 2
Unit 3
Unit 4 Catawba SNCR
SCR
SNCR Spring 2007
Fall 2008
Fall 2006 ~2,300

Total expected reduction = 3,275 tons/ozone season SNCR = Selective Non-Catalytic Reduction SCR = Selective Catalytic Reduction61 The combination of the mobile source and utility NO

x emission reductions that are expected in the
Metrolina area after the end of the 2006 ozone seas on and before the beginning of the attainment year 2009 is significant. Since the 2004-2006 design valu es are just above the standard, the additional NO

x emission reductions in the area should ensure that the Metrolina area will attain the NAAQS by the prescribed attainment year.

5. Local Measures Not Modeled

A significant source of NO

x emission reductions that has not been included in the modeling is the
addition of a SCR unit at Marshall Unit 3. This SCR unit should be installed the fall of 2008 and will be operational before the beginning of 2009.

In addition to the Marshall NO

x emission reductions, the Metrolina area has a number of groups that are working towards decreasing emissions. These are voluntary measures that, although not accounting for large emission reductions, are reductions nonethel ess. A few of the known measures that are under way in the Metrolina area include: I-77 High Occ upancy Vehicle (HOV) lanes in Mecklenburg County, truckstop electrification in Rowan County, express bus routes, pedestrian walkway and bikeway projects, idle reduction policies, and biodiesel use and diesel retrofit projects. Discussions of these measures can be found in Appendix L.

D. Unmonitored Area Attainment Analysis

The modeled attainment test does not address future air quality at locations where there is not an ozone monitor nearby. To guard against the possibility that air quality levels could exceed the standard in areas with limited monitoring, Section 3.4 of the Attainment Guidance suggest that additional review is “necessary, particularly in nonattainment areas where the ozone or PM 2.5 monitoring network just meets or minimally exceeds the size of the network required to report data to Air Quality System (AQS).” This review is intended to ensure that a control strategy leads to reductions in ozone at other locations that could have baseline (and future) design values exceed ing the NAAQS were a monitor deployed there. The test is called an “unmonitored area analysis”. Th e purpose of the analysis is to use a combination of model output and ambient data to identify areas that might exceed the NAAQS if monitors were located
there.

NCDAQ and SCDHEC believe that the density of th eir monitoring network relieves the necessity of applying this additional analysis. With an average of one monitor per 3,077 km 2 , this is one of the densest statewide ozone monitoring networks in the na tion. Additionally, the monitor density across the
Metrolina nonattainment area is more than twice th at of the statewide monitor density (on average a monitor every 1,278 km 2 ).

The Modeled Attainment Test Software (MATS) t ool has been developed by the EPA to spatially interpolate data, adjust the spatial fields based on model output gradients, and multiply the fields by model calculated RRFs for analysis of unmonitored ar eas. However, this tool has just recently been released with documentation (June 2007), and neither the NCDAQ nor the SCDHEC has had sufficient
time to review documentation and fu lly understand the output from this tool, nor has the tool been peer reviewed. The NCDAQ and the SCDHEC are committed to evaluate the MATS tool output and any peer
review comments that are submitted to dete rmine if additional monitoring or further NO

x controls may be
needed to ensure attainment of the NAAQS throughout the Metrolina region.

Refer to Appendix L for a complete discussion of this topic.62 E. Data Access

The modeling input and output files are very larg e and it would not be reasonable to submit all of
these files with the SIP attainment demonstration. These include all files used to process the emissions, meteorology, and air quality models and any other files used to develop the modeling. To request access to these files, please contact the Bureau of Air Quality at 803-898-4123.63 SECTION VI. MODERATE NONATTAINMENT AREA REQUIREMENTS

A. Clean Air Act (CAA), as amended (42 U.S.C. 7401, et seq .)

Sections 172(c), 182(a), and 182(b) of the CAA pr escribe the requirements for ozone nonattainment areas. Any State with a designated nonattainment area must promulgate amendments to their SIP to address the requirements mandated by Section 172(c) of the CAA. As a Subpart 2, moderate ozone nonattainment area, the Metrolina area must meet th e additional requirements prescribed by Section 182 of the CAA. Each State in which all or part of a Moderate Nonattainment Area is located shall make the submissions prescribed under Section 182(a) relating to Marginal Nonattainment Areas and shall also submit the revisions to the applicable implementation pl an described under Section 182(b) with respect to Moderate Nonattainment Areas. The requirements are listed below, and the SCDHEC's activities in promulgating amendments to the South Carolina Air Quality Implementation Plan (SIP) to comply with these mandates are discussed in more detail in the various parts of this section.

1. CAA Section 172(c) - Nonattainment Plan Provisions

Any State with a designated nonattainment area must promulgate amendments to its SIP to address the requirements mandated by Section 172(c) of the CAA. The SIP provisions (including plan items) required to be submitted under this part sh all comply with each of the following:

(1) RACM - Implementation of all reasonably available control measures (RACM) as expeditiously as practicable [including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a mini mum, of reasonably available control technology (RACT)] and provide for attainment of the na tional primary ambient air quality standards.

(2) RFP - Require reasonable further progress (RFP).

(3) Inventory - Include a comprehensive, accu rate, current inventory of actual emissions from all sources of the relevant pollutant or pollutant s in the nonattainment area, including such periodic revisions as the EPA may determine necessary to assure that the requirements are met.

(4) New Source Review (NSR): Identification and quantification - Identify and quantify the emissions, if any, of any such pollutant or pollu tants that will be allowed from the construction and operation of major new or modified stationary sour ces in the nonattainment area. Demonstrate to the satisfaction of the EPA that the emissions quantif ied for this purpose will be consistent with the achievement of reasonable further progress and will not interfere with attainment of the applicable NAAQS by the applicable attainment date.

(5) Permits for new and modified major stationary sources - Require permits for the construction and operation of new or modified majo r stationary sources anywhere in the nonattainment

area.

(6) Other measures - Include enforceable emission limitations, and other such control measures, means, techniques (including economic incentives such as fees, marketable permits, and auctions of emission rights), and schedules and timetables for compliance determined necessary or appropriate to provide for attainment of such st andard in the nonattainment area by the applicable
attainment date.

(7) Compliance with Section 110(a)(2) of the CAA.64 (8) Equivalent techniques - Upon application by any State, the EPA may allow the use of equivalent modeling, emission inve ntory, and planning pr ocedures unless the EPA determines that the proposed techniques are, in the aggregate, less ef fective than the methods specified by the EPA.

(9) Contingency measures - Provide for th e implementation of specific measures to be
undertaken if the area fails to make reasonable furthe r progress or to attain the NAAQS by the applicable
attainment date. Such measures shall be included in the plan revision as contingency measures to take effect in any such case without further action by the State or the EPA.

2. CAA Section 182 - Plan Submissions and Requirements

Each State in which all or part of a Moderate Nonattainment Area is located shall make the submissions prescribed under Section 182(a) relating to Marginal Nonattainment Areas and shall also
submit the revisions to the SIP described under Secti on 182(b) with respect to Moderate Nonattainment
Areas.

a. CAA Section 182(a) - Marginal Areas

Each State in which a nonattainment area is lo cated shall submit to the EPA the SIP revisions (including the plan items) described under Section 182(a) of the CAA.

(1) Inventory - Submit a comprehensive, accurate, current inventory of actual emissions
from all sources.

(2) Corrections to the SIP - Submit a revision to the SIP that meets the following requirements:

(A) Reasonably available control tec hnology (RACT) corrections - Submit, within 6 months of the date of classification, a revision that includes such provisions to correct requirements in (or add requirements to) the SIP concerning RACT.

(B) Motor vehicle inspection and maintenance (I/M) program.

(C) Permit programs - Provisions to require permits for the construction and operation of each new or modified major stationary source (with respect to ozone) to be located in the

area.

(3) Periodic inventory

(A) General requirement - Submit a revised inventory every three years until the area is redesignated to attainment.

(B) Emissions statements - Require that the owner or operator of each stationary source of oxides of nitrogen or volatile organic com pounds provide the State with an annual statement showing the actual emissions of oxides of nitrogen and volatile organic compounds from that source. The
statement shall contain a certification that the inform ation contained in the statement is accurate to the best knowledge of the individual certifying the statement. The State may waive the annual emissions inventory submittal requirement for any class or categor y of stationary sources that emit less than 25 tons per year of VOCs or NO

x .

b. CAA Section 182(b) - Moderate Areas65 As a Subpart 2, modera te ozone nonattainment area , the Metrolina area must also meet the additional requirements prescribed by Section 182(b) of the CAA.

(1) RFP - Provide for volatile organic co mpound emission reductions, within 6 years, of at least 15 percent from baseline emissions, accounting fo r any growth in emissions. Provide for such specific annual reductions in emissions of VOCs and NO

x as necessary to attain the NAAQS for ozone.

(2) RACT - Require the implementation of reasonably available control technology with respect to all VOC sources in the area covered by any CTG issued by the EPA and all other major stationary sources of VOCs that are located in the area. There are no VOC sources subject to CTGs located in York County portion of the nonattainment area.

(3) Gasoline vapor recovery - Section 1 82(b)(3) of the CAA requires moderate and above ozone nonattainment areas to implement Stage II vapo r recovery programs. However, Section 202(a)(6) of the CAA states that the Section 182(b)(3) Stage II re quirement shall not apply in moderate areas after onboard refueling vapor recovery (ORVR) rules ar e promulgated. The EPA promulgated the ORVR regulations on April 16, 1994. Because of the EP A’s promulgation of ORVR and York County not already having Stage II vapor recovery in place, that portion of York County that is located in the Metrolina nonattainment area is not required to im plement Stage II vapor recovery requirements.

(4) Motor vehicle inspection and mainte nance - Provide for a vehicle inspection and maintenance program.

(5) General offset requirement - The ratio of total emission reductions of VOCs to total increased emissions of such air pollutant shall be at least 1.15 to 1.

c. CAA Section 182(f) - NO

x Requirements

(1) The plan provisions required under this Subpart for major stationary sources of volatile organic compounds shall also apply to major st ationary sources [as defined in Section 302 and Subsections (c), (d), and (e) of this Section] of oxides of nitrogen.

B. South Carolina Air Quality Implementation Plan (SIP) Provisions

1. RACM/RACT Requirements

Section 172(c)(1) of the CAA requires an amendment to the SIP to provide for the implementation of all reasonably available control measures (RACM) to demonstrate attainment as expeditiously as practicable [including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technolog y (RACT)] and provide for attainment of the national primary ambient air quality standards. Sensitivity analysis has demonstrated that VOC reductions have very little impact on ozone in South Carolina. The SCDHEC has determined
that the entire state is NO

x -limited and that the control program for reducing ozone should be focused on
NO

x emission reductions. The overwhelming abundance of biogenic VOC emissions makes the majority of North and South Carolina, including the Metrolina area, a NO

x -limited environment for the formation
of ozone.

a. RACM

In August of 2006, stakeholders involved in supporting South Carolina' s "Cleaner Air Sooner" effort66 convened in Columbia to share and exchange ideas and information about their local strategies. It was appropriate that this "first of its kind" meeting was he ld in the state, since Sout h Carolina, with forty-five of its forty-six counties participating, leads the natio n in the number of local areas that are committed to implementing emission reduction measures. The EAC Summit was coordinated by SCDHEC staff with input from stakeholders for the purpose of offering the lo cal leadership a stage to highlight their activities. This sharing of ideas and local strategies served as an opportunity to connect EAC contacts and develop a network of peers for sharing information on positive st rategies. To re-emphasize the importance of this work in South Carolina, EPA Assistant Administ rator Bill Wehrum addressed the attendees as the keynote speaker. Items on the agenda for the EAC Summit included: Energy Conservation; Diesel Retrofits; Land Use Planning; Alternative Fuel s; Commuting Options; Innovative Education and Outreach; Health Impacts/Lifestyle; Finding th e Funding; and Commuting Options (to Multi-Modal Transportation).

SEQL (Sustainable Environment for Quality of Li fe) is a special EPA Region 4 bi-state project involving the Charlotte-Mecklenburg area of North Carolina and the Catawba region of South Carolina, which includes Chester, Union, Lancaster, and York counties. The Centralina and Catawba Regional Councils of Government (COGs) have been inst rumental in involving other local government organizations, state agencies and the public in SE QL. Due to these areas experiencing strong and sustained population growth, they f ace many challenges in maintaining good air quality and in contending with nonattainment for the eight-h our ozone NAAQS in some areas.

As part of the SCDHEC's involvement in SEQL, the Bureau of Air Quality partnered with the Catawba Regional COG to develop model ordinances, examples of best management practices, and program guidance documents to assist local government s in implementing programs such as tree planting, bike trails, and parking with green spaces to addr ess environmental concerns. The Model Ordinances are posted on the SCDHEC's Web site as well as a link to the SEQL Web site. The Centralina and Catawba Regional COGs continue to work together to address air quality and other envir onmental concerns and are now developing a regional vision that will represent what residents, local jurisdictions, and private sector leaders want the region to be.

The following emission reduction measures impacting mobile sources are planned or have been implemented in York County:

• York County gas can exchange in 2004. Catawba Regional Council of Government (COG), Rock Hill Clean and Green, York County Govern ment, City of Rock Hill, Palmetto State Clean Fuels Coalition, and Sustainable Environment for Qua lity of Life (SEQL) collaborated with the SCDHEC
on the event. A total of 110 old cans were turned in.

• South Carolina has two current school bus retrofit projects, a Santee Cooper Supplemental Environmental Project (SEP) project that involves installation of diesel particulate filters, and a Clean School Bus USA grant involving installations of diesel oxidation catalysts, crankcase ventilation systems, and anti-idling hardware. The nonattainment portion of York County is a priority area for both projects.

• Breathe Better anti-idling program is bei ng implemented at Rosewood Elementary School in Rock Hill. Additionally, the Catawba Regional Council of Governments, the South Carolina Energy Office, and the Museum of York County have provide d matching funds for a two-year implementation of this Idle Reduction Program in York County School s through Congestion Mitigation and Air Quality (CMAQ) funding.

• Additional emission reducing projects to receive CMAQ funds include signal controller upgrades, intersection improvements, and bike/pedestrian projects.67 • York Technical College has received a gr ant to retrofit nonroad equipment with diesel oxidation catalysts. The catalysts will be installed on 50 vehicles, including backhoes, bulldozers, motor graders, and others from the fleets of the City of Rock Hill, the South Carolina Department of Transportation, and Chester County.

• Where no transit has been available, Dial-a-R ide service will start in the City of Rock Hill (expanded from York County.)

• RFATS is participating in the Charlotte Region HOV lane study for I-77.

• A lawn mower exchange was held in York County in April 2007.

• RFATS is studying transit alternatives to connect downtown Rock Hill and Uptown Charlotte (Rock Hill-York County-Charlotte Transit Study.)

• Duke Energy launched a pilot program to subsidize public transportation costs for Charlotte area employees as part of the company's co mmitment to the environment and its ongoing efforts to help reduce ozone related em issions. Beginning September 1 a nd running through December 31 of 2006, the pilot program provided subsidies and ince ntives around bus transit, carpools and vanpools for full time and part time employees who work at the fo llowing Duke Energy locations: Catawba Nuclear Station (York, S.C.), Customer Contact Center (U niversity Research Park), McGuire Nuclear Station (Huntersville, N.C.), and uptown Charlotte.

• EnviroFlash has been configured and activ ated for South Carolina's Catawba region. The Catawba region will include York, Chester, and Lancast er counties. By including York County in the Catawba region, the SCDHEC will take over duties from North Carolina with regard to ground-level ozone forecasting for the county. The SCDHEC be lieves that the resource s in South Carolina are available to provide York County with an accurate and reliable forecast during the ground-level ozone

season.

The SCDHEC has initiated a program to continue the statewide focus on air quality that began with the Early Action Compact process. Staff are assigned to all counties of the st ate to work with local governments, businesses, and citizens to continue wo rking to maintain and improve air quality. The SCDHEC, with its York County partners, will con tinue to seek opportunities that offer emission reductions that may be needed to show ma intenance of the 8-hour ozone standard.

b. RACT

In accordance with 40 CFR Part 51, Subpart X - §5 1.912 pertaining to moderate nonattainment areas under the 8-hour ozone NAAQS, the State is required to submit to the EPA an amendment to the SIP that includes the identification and implementation of r easonably available control technology (RACT). The
SIP amendment must meet the NO

x and VOC RACT requirements in S ections 172(c)(1), 182 (a)(2)(A), 182(b)(2), and 182(f) of the CAA. The State must im plement all reductions in emissions from existing sources in the nonattainment area as may be obtained th rough the adoption of RACT that will provide for attainment of the NAAQS as expeditiously as practicab le. The CAA requires that RACT be applied to major stationary sources of NO

x and VOCs located in ozone nonattainment areas. A major source is considered any source with the potential to emit 100 tons per year or more of NO

x or VOCs.

As defined by the EPA in 40 CFR Section 51.100 - Definitions: Reasonably Available Control Technology (RACT) means devices, systems, process m odifications, or other apparatus or techniques that are reasonably available taking into account (1) the neces sity of imposing such controls in order to attain68 and maintain a national ambient air quality standard; (2) the social, environmental, and economic impact of such controls; and (3) alternative means of provid ing for attainment and maintenance of such standard.

RACT requirements are typically prescribed by State and local rules and regulations but may also be made on a case-by-case basis. In performing a RACT an alysis, the State must look at available controls to conclude whether they are reasonably availabl e for a specific source or source category. RACT requires that sources adopt controls that are reasonably available, thus they may not be the most stringent controls that have been adopted for other similar so urces. The fact that another similar source has such controls in place does not mean that such a control is reasonably available for all other similar sources.

The SCDHEC has determined that there are no CTG (Control Technology Guidance) sources located within the nonattainment portion of York County. The SCDHEC has identified three affected major nonCTG sources within the ozone nonattainment portion of York County subject to RACT requirements and has approached these facilities to conduct a RACT analysis:

(1) Bowater, Inc. (Title V permit # 2440-0005); (2) Cytec Carbon Fibers, LLC (Title V permit # 2440-0097); and (3) Georgia Pacific Wood Produc ts, LLC (Title V permit # 2440-0026).

The above facilities determined their RACT applicability based on "top down" procedures established for prevention of significant deterior ation (PSD) and nonattainment new source review (NSR). A report of each facility's applicability dete rmination that was prepared and submitted to the SCDHEC for review is contained in Appendix Q. The SCDHEC concurred with the reports' conclusions
that installation of additional emission control de vices would not be economically feasible, thus only work practice revisions will be utilized for RACT at these facilities. Georgia Pacific Wood Products, LLC, however, will comply with maximum achievabl e control technology (MACT) requirements in accordance with 40 CFR 63, Subpart DDDD, whereby MA CT is at least as stringent as RACT.

Any new sources with the potential to emit 100 tons per year or more of NO

x or VOCs will be covered under the requirements of South Carolina Air Pollution Control Regulation R. 61-62.5, Standard No. 7.1, Nonattainment New Source Review (NSR).

On June 8, 2007, the EPA published a final notice of reconsideration (72 FR 31727), Phase 2 of the Final Rule To Implement the 8-Hour Ozone National Ambient Air Quality Standard—Notice of
Reconsideration . In this notice, the EPA states that it h as determined that EGU sources complying with rules implementing the Clean Air Interstate Rule (CAIR) requirements meet ozone NO

x RACT requirements in states where all required emissions reductions are achieved from EGUs only. The EPA does not believe that requiring source-specific RACT controls on EGUs in nonattainment areas will
reduce total NO X emissions from EGU sources covered by the below the levels that would be achieved
under the alone.

The SCDHEC amended South Carolina Air Pollution Control Regulation 61-62.72, Acid Rain ; South Carolina Air Pollution Control Regulation 61-62.96, Nitrogen Oxides (NO

x ) Budget Trading Program General Provisions, and the SIP to ensure compliance with th e provisions of the , which was published in
the Federal Register on May 12, 2005. On June 22, 2007, the South Carolina State Register (State Register) promulgated the full text of the noted revi sions, which became effective upon the date of publication. The South Carolina Legislature approved the amendments on May 27, 2007.

2. Reasonable Further Progress

Section 182(b)(1) of the CAA mandates a 15 percent VOC emission reduction, accounting for69 growth, in the first 6 years after the baseline year (2002) for moderate and above ozone nonattainment areas. Thus, for the York County nonattainment area, a reasonable further progress (RFP) analysis between 2002 and 2008 is required.

The methodology the SCDHEC used to calculate th e RFP target levels of VOC emissions is based on the method developed in the CAA while taking into account the restrictions on creditable emissions and the need to use the 2002 inventory as a baseline. The CAA specifies four types of measures that are not creditable toward the 15 percent RFP requirement:

1. Any measure relating to motor vehicle exha ust or evaporative emissions promulgated by the EPA by January 1, 1990.

2. Regulations concerning Reid Vapor Pr essure (RVP) promulgated after 1990 or required under Section 211(h) of the CAA.

3. Measures required under Section 182(a)(2)(A) of the CAA to correct deficiencies in the SIP regarding VOC RACT regulations required prior to enactment of the CAA Amendments of 1990.

4. State regulations submitted to correct deficiencies in existing or required I/M programs.

These four types of measures were all expected to result in a decrease in emissions between 1990 and 1996. Of these four types of measures, RACT and I/M program corrections did not apply to South
Carolina because the State was in attainment for all standards at that time, and the 1990 RVP requirements were completely in place by 1996 and therefore are already accounted for in the 2002 baseline. As a result, they would produce no additional reductions betw een 2002 and 2008 or later milestone years.

However, the pre-1990 Federal Motor Vehicle Cont rol Program (FMVCP) will continue to provide additional benefits during the first two decades of the 21st century as remaining vehicles meeting pre1990 standards are removed from the vehicle fleet. Because these benefits are not creditable for RFP purposes, in order to calculate the target level of em issions for future RFP milestone years, the SCDHEC
first calculated the reductions that would occur ov er these future years as a result of the pre-1990 FMVCP. Consistent with the requirements of Sec tions 182(b)(1)(C) and (D) and 182(c)(2)(B) of the CAA, the SCDHEC used the pro cess described in Method 1 below to account for non-creditable reductions in calculating RFP targets for the 2008 milestone year. The SCDHEC did not have VOC RACT regulations in the York County nonattainment area prior to the enactment of the 1990 CAA, thus only the on-road mobile source sector required an estimation of non-creditable emissions.

Method 1: For areas that must meet a 15 percent VOC reduction requirement by 2008:

(A) Estimate the actual anthropogenic base year VOC inventory in 2002 with all 2002 control programs in place for all sources.

(B) Using the same highway vehicle ac tivity inputs used to calculate the actual 2002 inventory, run the appropriate motor vehicle em issions model for 2002 and for 2008 with all post-1990 CAA measures turned off. Any other local inputs fo r vehicle I/M programs should be set according to the program that was required to be in place in 1990. Fuel RVP should be set at 9.0 or 7.8 depending on the RVP required in the local area as a result of fu el RVP regulations prom ulgated in June, 1990.

(C) Calculate the difference between the 2002 and 2008 VOC emission factors calculated in Step B and multiply by 2002 vehicle miles tr aveled (VMT). The result is the VOC emissions70 reductions that will occur between 2002 and 2008 without the benefits of any post-1990 CAA measures. These are the non-creditable reductions that occur over this period.

(D) Subtract the non-creditable reductions calculated in Step C from the actual anthropogenic 2002 inventory estimated in Step A. This adjusted VOC inventory is the basis for calculating the target level of emissions in 2008.

(E) Reduce the adjusted VOC inventory calcula ted in Step D by 15 percent. The result is the target level of VOC emissions in 2008 in orde r to meet the 2008 RFP requirement. The actual projected 2008 inventory for all sources with all control measures in place, including projected 2008 growth in activity, must be at or lowe r than this target level of emissions.

The 2002 baseline VOC emissions for the York C ounty nonattainment area are presented in Table
VI-1.

Table VI-1: York County Nonattainment Area 2002 Baseline VOC Emissions (tons/day)

Point Area Nonroad Highway
Mobile Total

York* 7.29 7.48 3.19 6.84 24.80 *Represents only that portion of the county that is located in the Charlotte-Gastonia-Rock Hill, NC-SC
nonattainment area.

The 2008 VOC emission estimates are included in Table VI-2.

Table VI-2: York County Nonattainment A rea 2008 Projected VOC Emissions (tons/day)

Point Area Nonroad Highway
Mobile Total

York* 3.60 7.90 2.40 3.94 17.84 *Represents only that portion of the county that is located in the Metrolina nonattainment area.

Table VI-3 provides the summary 15% RFP analysis showing the projected 2008 VOC emissions for the area, 17.84 tons/day, are well below the target le vel of emissions, 20.23 tons/day, as calculated using Method 1. See Appendix O fo r detailed modeling data.

Table VI-3: York County* Nonattainment Area 15% RFP Analysis

York County 15% RFP Analysis VOC (tons/day) Step from Method 1

Total 2002 Base year anthropogenic VOC
emissions 24.80 Step A

Non-creditable VOC reductions 1.00 Step C 2002 base year minus the non-creditable emissions 23.80 Step D 2008 target level of VOC emissions 20.23 Step E 2008 projected VOC emissions 17.84 Projection < Target RFP goal met *Represents only that portion of the county that is located in the Metrolina nonattainment area.71 The SCDHEC must show continued progress from 2008 through the attainment date (June 15, 2010). To do so, the SCDHEC calculated the expected benefits from the fleet turnover for the on-road and offroad mobile sectors. In 2009 and 2010, the SCDH EC expects approximately 0.73 tons per day of NO

x emissions reductions from this fleet turnover. Th e SCDHEC did not calculate future expected VOC
emissions reductions in 2009 and 2010 since the area is NO

x -limited, but additional VOC emission reductions are expected from the fleet turnover of the on-road mobile sector. The SCDHEC believes
these additional reductions demonstrate continued reas onable further progress toward attainment beyond
2008.

3. Actual Emissions Inventory

Section 182(a)(1) and Section 172(c)(3) of the CA A require the development of a comprehensive, accurate current inventory of actual emissions from all sources of VOC and NO

x in the nonattainment area. Such inventory was due two years after desi gnation of the 8-hour ozone nonattainment areas, or by June 15, 2006. The SCDHEC met this requireme nt through the submission of the 2002 emission inventories under the Consolidated Emission Reporti ng Rule (CERR) for that portion of York County
within the nonattainment area. The SCDHEC submitte d statewide emissions inventories for point, area, nonroad mobile, and highway mobile sources.

The final 2002 emission inventories used in the a ttainment demonstration (found in "Appendix E - Emission Inventory Summary") will go through the public hearing process as part of the full attainment demonstration, which will include any updates or re visions that are necessary since the CERR submittal.

4. Emissions Inventory Statement

Section 182(a)(3)(B) requires the SIP to contain a requirement for all owners or operators of stationary sources located in the nonattainment area and emit either VOC or NO

x to submit a statement of actual emissions annually. The State may waive the requirement for sources that emit less than 25 tons per year of NO

x or VOC emissions.

5. Periodic Emissions Inventory

Section 172(c)(3) and 182(a)(3)(A) of the C AA require periodic inventory submissions. Specifically, Section 182(a)(3)(A) requires the inventor y be submitted every three years until the area is redesignated to attainment. The SCDHEC plans to meet this requirement through the CERR submittal. As such, the SCDHEC will submit the 2005 emission s inventory on or before June 1, 2007.

6. Permit Program Requirements

It is required per Sections 172(c)(5) and 182(a)(2 )(C) of the CAA that there be a permit program consistent with the requirements of Section 173. In addition, an offset requirement of 1.15 to 1 is required per Section 182(b)(5). The SCDHEC subm itted the regulations fo r the nonattainment new source review (NSR) contained in Regula tion R. 61-62.5, Standard No. 7.1, Nonattainment New Source
Review on July 1, 2005, to the EPA for review and appr oval. These regulations adopted the new offset requirement. Furthermore, the SCDHEC submitted amen dments to Regulation R. 61-62.5, Standard No. 7, Prevention of Significant Deterioration (PSD) permitting regulations to the EPA for approval on July 1, 2005. The SCDHEC believes that the "prevention of significant deterioration" requirement of Section 110(a)(2)(D)(i) is met by the adopti on and submittal of the NSR and PSD regulations since PSD and NSR are applicable to major sources in South Carolina. The SCDHEC believes it has satisfied the permit program requirements for a moderate nonattainment area.72 7. Gasoline Vapor Recovery

Section 182(b)(3) of the CAA requires moderate and above ozone nonattainment areas to implement Stage II vapor recovery programs. However, Sec tion 202(a)(6) of the CAA states that the Section 182(b)(3) Stage II requirement shall not apply in mode rate areas after onboard refueling vapor recovery (ORVR) rules are promulgated. The EPA promulga ted the ORVR regulations on April 16, 1994. Therefore, 8-hour ozone moderate ar eas designated in 2004 are not subject to the Stage II vapor recovery program requirements. The attainment plan and c ontingency plan contained in this submittal addresses the necessary controls to attain the 8-h our standard in the Metrolina region.

8. Inspection and Maintenance (I/M) Program

The EPA initially recommended the development of an On-Board Diagnos tics (OBD) program for the Rock Hill-Fort Mill Area Transportation Stud y (RFATS) Metropolitan Planning Organization (MPO) portion of the Charlotte-Gastonia-Rock Hill, NC -SC moderate nonattainment area. The SCDHEC examined the feasibility and impact of implementi ng an I/M program for the nonattainment portion of York County that would have affected only 55,700 vehi cles. Emissions modeling indicated that an OBDII program, if implemented in the nonattainment area, would only reduce NO

x emissions by about 87 tons annually and volatile organic compounds emissions by a bout 63 tons annually, or approximately 49 tons and 37 tons, respectively, during the ozone season. The SCDHEC approached several contractors to develop and implement an OBDII I/M program in the area but was unable to find a contractor who would undertake the expenses involved in running an I/M progr am of this size. The SCDHEC found that it was not economically feasible to proceed with implementation of an I/M program in South Carolina, and proceeded to petition the EPA for a waiver of this moderate nonattainment area requirement.

Based upon correspondence between the SCDHEC a nd the EPA Region 4 after their consultation with the EPA's Office of Transportation and Air Quality and the Office of General Counsel, the EPA concurred that the I/M requirement for moderate ar eas is not applicable to York County, SC. On November 23, 2005, the EPA Region 4 notified the SC DHEC that the CAA requirement to implement an Inspection and Maintenance (I/M) program was not applicable to the York County, South Carolina
RFATS MPO moderate nonattainment area. The correspondence from EPA Region 4 stated:

"Even though a portion of York County was designated as part of the Charlotte moderate 8-hour ozone nonattainment area, applicability of the I/M re gulations to areas outside the Ozone Transport Region is based on the population of the urbanized area as defined by the 1990 census. As defined by the 1990 census (see enclosed map), the Rock Hill and Char lotte urbanized areas are distinct and are not contiguous. Although the Charlotte urbanized por tion of the MSA is contiguous to the North Carolina/South Carolina border, it does not extend into South Carolina. The Rock Hill urbanized area is totally contained within South Carolina and does no t touch the State line. Therefore, the applicability level of a 1990 census population of 200,000 or more in an urbanized area (40 CFR 51.350(a)(1)) applies to each of the two urbanized areas separately. Si nce the Rock Hill urbanized area has a population less than 200,000, the I/M requirement in Section 182(b)(4) of the CAA is not applicable to York County."

See "Appendix R - I/M Supporting Documents" for copies of the following correspondence between the SCDHEC and the EPA Region 4 relating to the I/M requirement for the nonattainment portion of York County.

October 26, 2004 (SCDHEC BAQ to EPA Region 4)

December 27, 2004 (EPA Region 4 to SCDHEC BAQ)73 August 26, 2005 (SCDHEC to EPA Region 4)

October 3, 2005 (EPA Region 4 to SCDHEC)

November 23, 2005 (EPA Region 4 to SCDHEC)

"Appendix R - I/M Supporting Documents" also includes a copy of the SCDHEC comments on the proposed rulemaking amendments to the vehicle I/M programs requirements to address the 8-hour NAAQS for Ozone dated February 7, 2005.

9. Other Measures

The SCDHEC evaluated the expected emission re ductions through the impl ementation of Federal and State programs and regulations. Many of the NO

x stationary point sources have already been or will be controlled upon implementation of the NO

x SIP call and SIP initiatives. In addition, the South Carolina Air Pollution Control Regulations and Standa rds has been amended with the addition of a new Regulation 61-62.5, Standard No. 5.2 - Control of Oxides of Nitrogen, and a revision of Regulation 61- 62.2 - Prohibition of Open Burning, for additional control of NO

x emissions.

a. NO

x SIP Call

On October 27, 1998, the EPA finalized a Nitrogen Oxides (NO

x ) State Implementation Plan (SIP)
Call Rule. The NO

x SIP Call was designed to reduce the regiona l transport of ground-level ozone through
reductions in NO

x from electric generating unit (EGU) sour ces and from some non-EGU sources. The rule requires that, beginning in 2004, NO

x reductions must occur during ground-level ozone season in
states whose NO

x emissions have been identified as contribut ing to 1-hour ozone standard nonattainment in "downwind" states. The rule also requires stat es to identify pollution-re duction measures and develop a plan to achieve these reductions.

A draft SIP revision was submitted to the EPA on October 30, 2000. The SCDHEC Board (Board) granted initial approval on December 14, 2000. A pub lic hearing was conducted before the Board on April 12, 2001, at which time the Bo ard instructed staff to provide an additional 30-day comment period. A second notice of proposed regulations was published in the State Register on April 27, 2001. Final Board approval was granted on June 14, 2001. Legi slative review was required and the final regulation was published in the State Register on May 24, 2002, as document number 2593. The draft SIP revision was submitted to the EPA on July 30, 2001 for pa rallel processing. On April 10, 2002, the EPA published the proposed approval of the plan in the Federal Register (67 FR 17317). Final EPA approval was published in the Federal Register on June 28, 2002.

Each state subject to the NO

x SIP Call regulation has a NO

x budget that the state allocates to applicable sources. The budget is NO

x -based on cost-effective reductions in emissions that can be achieved by the affected sources. South Carolina' s state trading program budget, as specified in Regulation 61-62.92, Nitrogen Oxides (NO

x ) Budget Trading Program, is 19,678 tons. The NO

x SIP Call regulation will be repealed after 2009 upon impl ementation of the Clean Air Interstate Rule.

b. 8-hour Ozone Early Action Compact Regulations

On August 22, 2002, the SCDHEC published a Notice of Drafting in the State Register announcing its intent to pursue Early Action Compacts (EAC) for the 8-hour ozone standard. Through the EAC process, local, state, and EPA officials committed to wo rk together to develop and implement plans that will reduce ozone pollution so that ar eas are attaining the 8-hour ozone standard earlier than would be74 required by the Clean Air Act. Only areas that are attaining the 1-hour ozone standard are eligible to participate in the EAC process. The compact requires these areas to attain the 8-hour ozone standard by December 31, 2007, a date that is sooner than would otherwise be required through the traditional nonattainment designation process.

At the end of 2002, 45 of South Carolina's 46 counties, the SCDHEC, and the EPA Region 4 had signed compacts to implement ozone reduction strategi es earlier than federally required. Statewide stakeholder groups involving local and federal govern ments, industry, environmental groups, and other interested parties have worked together to plan and implement strategies for ozone pollution prevention throughout the state. Plans involve mobile source pollution reduction, outreach actions, and point source prevention, which provide flexibility and foster local solutions to local problems. In 2002, York County elected to participate in the 8-hour Ozone EAC pr ocess. However, due to an area of York County (RFATS MPO) being included in the Metrolina nonattain ment area, that portion of the county designated as nonattainment was no longer eligible to par ticipate even though York County was designated
attainment for the 1-hour ozone standard. York County officials have continued working with stakeholders to implement emission reduction measures and submit EAC progress reports every 6
months.

As part of this process, the EAC stakeholders developed statewide regulations aimed at achieving additional reductions in ozone precu rsors. One new regulation that w as developed as part of this process was Regulation 61-62.5, Standard 5.2, Control of Oxides of Nitrogen (NO

x ). This is a broad-based regulation that applies statewide to new and existing stationary sources that emit NO

x from fuel combustion and have not undergone a best availa ble control technology (BACT) analysis for NO

x . For new sources, the regulation requires the installati on of control technology that is based on BACT standards found in the RACT/BACT/LAER clearingho use. For existing sources, the regulation only applies when an applicable unit replaces its burner. At this point, they will be required to replace their
burner with a low NO

x burner or equivalent technology capable of achieving a 30 percent reduction from
uncontrolled levels.

Also, as part of the EAC process, Regulation 61-62. 2, Prohibition of Open Bu rning, was revised by deleting the exception for the burning of household trash, revising the exception for the burning of construction waste, and revising the exception for fires set for the purpose of firefighter training. The burning of household trash presents health and en vironmental concerns for many communities. The smoke generated from these activities is a nuisance to some and a health threat to others with asthma or other respiratory problems. With respect to the exception for the burning of construction waste, the regulation was revised to allow only residential construction waste to be burned outside the ozone season, and this will only be allowed if it meets the provisions of the regulation. Finally, the exception for the purpose of firefighter training was revised to ensure that minimum health, environmental, and safety
concerns are addressed.

These regulations were approved by the Board in January 2004, and, in accordance with South Carolina law, they were subsequently submitted to the Legislature for approval. The South Carolina General Assembly approved the regulations, and th e rules were published and became effective upon publication in the State Register on June 25, 2004. Statewide NO

x reductions from the Control of NO

x regulation are estimated at 3,357 tons a year. Stat ewide reductions resulting from the revisions to the Prohibition of Open Burning regulation are estimated at 147 tons of NO

x and 698 tons of VOC per ozone

season.

c. Clean Air Interstate Rule

On March 10, 2005 the EPA finalized the Clean Air Interstate Rule, also referred to as CAIR. On75 May 12, 2005, CAIR was published in the Federal Register

.

CAIR affects 28 states and the District of Columbia, whose emissions of sulfur dioxide (SO 2 ) and/or
NO

x produced by EGU sources and some non-EGU sources contribute significantly to the nonattainment of the National Ambient Air Quality Standards (NAAQS) for fine particles (PM 2.5 ) and/or 8-hour ozone in downwind states. (SO 2 and NO

x are both precursors to ground-level ozone formation, and NO

x is also a precursor to PM 2.5 formation.) The EPA has determined that EGU sources in South Carolina are affecting
the nonattainment of ozone and PM 2.5 standards in downwind states. CAIR is a cap-and-trade program
for NO

x and SO 2 emissions from affected facilities and has two phases of implementation. The caps for the phases are as follows:

Phase I, which begins in 2009 for NO

x (annual and ozone season) and 2010 for SO 2 CAIR NO

x annual cap = 32,662 tons (T)
CAIR EGU SO 2 annual cap = 57,271 T
CAIR NO

x ozone season cap = 15,249 T

Phase II, which begins in 2015 for both pollutants
CAIR NO

x annual cap = 27,219 T
CAIR EGU SO 2 annual cap = 40,089 T
CAIR NO

x ozone season cap = 12,707 T

was due for submission to the EPA for approval on September 11, 2006. South Carolina is one of many states that did not meet this deadline because of a lengthy regulatory process. The SCDHEC is working closely with EPA Region 4 toward implementation of the State's rule. The SCDHEC has adopted the federal with modifications in areas wher e the state has flexibility. A Notice of Drafting was published in the State Register on July 22, 2005; a second Notice of Drafting was published in the State Register on February 24, 2006. The initial approval to pr oceed with the proposed regulation was given by the SCDHEC Board on September 14, 2006. The Noti ce of Proposed Rule was first published in the State Register on October 27, 2006. A public hearing befo re the SCDHEC Board was held on January 11, 2007. On January 22, 2007, th e proposed regulation was submitted to the South Carolina Legislature for approval. In March of 2007, the SCDHEC su bmitted a request to the EPA Region 4 for parallel processing. The SCDHEC anticipates the proposed regulation to become state-efffective upon publication in the State Register in mid-Summer 2007. South Carolina is working with the EPA to complete the parallel processing at this time.

d. Regulation R. 61.62.2, Prohibition of Open Burning

On June 24, 2004, the Department revised its ex isting regulation regarding open burning activities to reduce emissions of ozone precursor pollutants. Am ong the revisions were elimination of the exception for burning household trash, modification of the exception of burning of construction waste, and modification to the exception for fires set for firefighter training. Based on the Department’s 1999 emissions inventory, residential burning of household waste generates 2,379 tons of NO

x and 11,896 tons of VOCs in the state annually. As for the ban on the burning of construction waste, the data indicates that
the ban on residential construction waste alone w ill result in annual reductions of 147 tons of NO

x and
625 tons of PM. Information on the amount of reducti ons to be expected from the ban on the burning of commercial construction waste is not available, but it is clear that substantial reductions in NO

x and VOCs will occur statewide starting in 2004 as a direct r esult of the elimination of this activity as well.

Regarding the burning of construction waste, the Department revised this provision to allow only
residential construction waste to be burned and only unde r the following conditions: the burning must take place outside of ozone season (not during April 1 through October 30 in South Carolina), the burning76 must be conducted at least 500 feet from any occupied structure, and the burning must be only of “clean” waste. Further, the exception for the purpose of fi refighter training has been revised to ensure that minimum health, environmental and safety concerns are addressed. The Department intends to do a review of permanent firefighter training faciliti es and will evaluate nonpermanent sites and require Department approval prior to a burn. Finally, in accordance with South Carolina Air Pollution Control Regulation 61-62.2, Section II.C., the Department reserves the right to restrict open burning on forecasted code orange and higher air quality ozon e action days for York County.



### e. Regulation R. 61-62.5, Standard 5.2, Control of Oxides of Nitrogen

On June 24, 2004, South Carolina adopted Air Pollu tion Control Regulation R.61-62.5, Standard No. 5.2, Control of Oxides of Nitrogen to ensure areas attain and maintain the 8-hour ozone standard. This regulation requires Best Available Control Technolog y (BACT)-level controls on all stationary sources that emits or have the potential to emit NO

x . Many of these sources would not otherwise be required to
control their NO

x emissions. For example, under the Clean Air Act requirements, the preconstruction review program referred to as New Source Review (NSR) only applies to larger sources (generally those with potential emissions greater than 100 tons per year or more). For sources with emissions below these levels, there are generally no controls for NO

x required.

This newly-developed regulation applies state-wi de to new and existing stationary sources of NO

x emissions. Larger sources that ha ve undergone a BACT review for NO

x are exempt from the regulation; however, larger sources that have taken limits to opt out of a Prevention for Significant Deterioration (PSD) review will still be required to comply with this regulation which covers sources ranging from
boilers and turbines to fluidized be d combustors and lime kilns. For existing sources, the regulation only applies when an applicable unit repl aces their burner. At this point, th ey will be required to replace their burner with a low burner or equivalent technol ogy capable of achieving a 30% reduction from
uncontrolled levels.

10. Compliance with Section 110(a)(2)

Section 172(c)(7) requires nonattainment SIPs to meet the applicable provisions of Section 110(a)(2). The NCDAQ and the SCDHEC - BAQ have reviewed the requirements of Section 110(a)(2) and have concluded that the prior rule submittals, along with this a ttainment demonstration plan, address the relevant requirements.

11. Equivalent Techniques

The SCDHEC believes that the procedures for mode ling, emissions inventory and planning follow EPA guidance and is not requesti ng approval for equivalent tec hniques, as allowed under Section 172(c)(8) of the CAA.

12. Contingency Measures

Section 172(c)(9) requires that the nonattainment SIPs contain specific measures that would take effect upon a State's failure to attain the ozone standard in a given area, without further action by the State
or the EPA. Guidance from the EPA indicates that the measures should be approximately three percent of the baseline emissions, so that reasonable progress level of reduction could be expected to occur in the year following the failure to attain. The SCDHEC elected to adopt NO

x -only contingency measures since
the area is NO

x -limited. The contingency plan consists of Federal and State measures. The Federal measures result from the fleet turnover of the light and heavy-duty engine standards from the on-road mobile sector and the nonroad engine standards. These measures are already adopted and the fleet77 turnover will occur without further action by either th e State or the EPA. The fleet turnover will result in approximately 0.11 tons/day NO

x emission reductions, or about 2.2% of the base emissions. The analysis
of these emission reductions is included in Appendix P.

The State anticipates additional reductions from lo cal measures implemented by the Rock Hill-Fort Mill Area Transportation Study (RFATS) Metropo litan Planning Organization (MPO). SC has been
determined to be NO

x limited, the SCDHEC will encourage th e RFATS Interagency Partners to fund future CMAQ projects that will result in the most reduced NO

x emissions. There is no easy way to
estimate the amount of reductions that would be ach ieved through Congestion Mitigation and Air Quality (CMAQ) projects.78 SECTION VII. MOTOR VEHICLE EMISSION BUDGET

A. Transportation Conformity

The purpose of transportation conformity is to ensu re that Federal transportation actions occurring in
nonattainment and maintenance areas do not hinder the area from attaining and maintaining the 8-hour
ozone standard. The level of emissions estimated by RFATS for the Transportation Implementation Plan (TIP) and Long Range Transportati on Plan (LRTP) must not exceed the motor vehicle emission budget (MVEB) as defined in this attainment demonstration.

1. Memorandum of Agreement

On September 27, 1996, a Memorandum of Ag reement (MOA), negotiated between the South Carolina Department of Health and Environmen tal Control (SCDHEC) and the South Carolina Department of Transportation (SCDOT), was published in the South Carolina State Register . The purpose of the MOA was to formal ly incorporate the applicable provisions of the transportation conformity review process in accordance with the re quirements of the CAA as promulgated by the EPA on November 24, 1993 (58 FR 62188) in 40 CFR Part 51 Subpart T, as amended August 7, 1995 (60 FR 40098), and November 14, 1995 (60 FR 57179). Under those authorities, no department, agency, or instrumentality of the Federal government shall enga ge in, support in any wa y or provide financial assistance for, license or permit, or approve any activity that does not conform to the South Carolina Air Quality Implementation Plan (SIP). The transportation conform ity rule requires Federal agencies to determine, prior to taking any acti on on transportation plans, programs, and projects, that such action will
conform to the SIP to maintain the National Ambient Air Quality Standards (NAAQS). The transportation conformity regulation applies onl y to areas that are designated nonattainment or maintenance for any of the criteria pollutants (oz one, carbon monoxide, fine particulate matter, sulfur dioxide, nitrogen dioxide, or lead).

On August 15, 1997 (62 FR 43780), April 10, 2000 (65 FR 18911), and August 6, 2002 (67 FR 50808), the EPA promulgated amendments to the trans portation conformity rule to streamline and clarify the criteria and procedures for determining the conformity of transportation plans, programs, and projects. The State was required by 40 CFR Part 51 Subpart T Section 51.390 to amend the SIP by specifically removing any previously applicable implementation plan transportation conformity requirements and submitting a revision to the SIP that addresses all requi rements of 40 CFR Part 93 Subpart A. A Notice of General Public Interest was pub lished on August 25, 2000. This SI P revision was delayed by the timeconsuming task of gathering the necessary signature s for a MOA. A staff-conducted public hearing was held on the proposed revision on September 22, 2003. The SIP amendment was published as final in the State Register on October 24, 2003, and subsequently submitted to the EPA for final approval on November 14, 2003. The EPA published approval of the SIP revision in the Federal Register (69 FR 4245) on January 29, 2004.

In accordance with these requirements, the SC DHEC incorporated into the SIP a new MOA to implement Section 176 of the Clean Air Act (CAA), as amended (42 U.S.C. 7401, et seq .), the related requirements of 23 U.S.C. 109(j), and regulations un der 40 Code of Federal Re gulations (CFR) Part 93, Subpart A. The parties to this MOA are as follo ws: each of the South Carolina Metropolitan Planning Organizations (MPOs), the SCDHEC, the SCDOT, th e Federal Highway Administration South Carolina Division Office (FHWA), the Federal Transit Administ ration (FTA), the EPA Region 4 (EPA), and local publicly-owned transit agencies not represented by aforementioned MPOs in nonattainment and
maintenance areas. The “South Carolina Criteria and Interagency Consultation Procedures for the Determination of the Conformity of Transporta tion Plans, Programs, and Projects” provides for interagency consultation, resolution of conflicts, and public consultation procedures. The parties to this79 MOA agreed to conduct transportation conformity dete rminations in accordance with the provisions of 40 CFR Part 93 Subpart A.

The SIP amendment consisted of the following documents:

1: South Carolina Transportation Conformity Memorandum of Agreement as endorsed by all parties.

2: South Carolina State Register “Notice of Amendment to th e South Carolina Air Quality Implementation Plan” - Published on October 24, 2003.

3: Notice of Public Hearing published in the State Register on August 22, 2003.

4: Copy of the verbatim transcript of the September 22, 2003, Public Hearing.

5: South Carolina’s Legal Authority (Excerpt from the EPA-approved SIP).

2. Conformity Interagency Consultation - York County/RFATS MPO

On April 15, 2004, the EPA issued designations and classifications based on the severity of the 8- hour ozone NAAQS in each state with an effective da te of June 15, 2004. This included the RFATS MPO boundary for the York County area along with conti guous portions of North Carolina. In making the boundary and classification determinations, the EPA utilized 8-hour ozone monitoring data from the 2001-2003 calendar years. Although the monitor in Yo rk County during that time was below the 8-hour ozone standard of 0.085 parts per million (ppm), the EPA determined that a portion of York County contributed to violating monitors in nearby North Carolina. The nonattainment area was classified under Subpart 2 of the Clean Air Act as being a “moderate ” nonattainment area for ozone. This was decided based upon a monitored ozone value of 0.10 0 ppm in Rowan County, North Carolina.

As a minimum requirement, no later than J une 15, 2005, the RFATS area was required to demonstrate transportation conformity to ensure that all projects utilizing federal funds do not have an adverse impact on the area’s air quality. Transpor tation Conformity consultation procedures as outlined in the South Carolina Transportation Conformity Me morandum of Agreement and endorsed by all parties enabled the nonattainment area to immediately be gin the process. The York County Interagency Consultation process, which included representatives fro m the RFATS, the SCDHEC, the SC Department of Transportation, the EPA Region 4, the SC Divisi on Office of Federal Highways, the Federal Transit Authority, the City of Rock Hill, and York Count y, was initiated on May 14, 2004, and is ongoing. Specific information regarding this process is included in Appendi x F3 Section 4.1.

3. RFATS - CMAQ Projects

The Congestion Mitigation and Air Quality Impr ovement Program (CMAQ) was created by the Intermodal Surface Transportation Equity Act (ISTEA) in 1991, was reauthorized by the Transportation Equity Act for the Twenty-First Century (TEA-21), and was subsequently reauthorized by the Safe Accountable, Flexible Efficient Transportation Equi ty Act - a Legacy for Users (SAFETEA-LU). The CMAQ program provides funding for projects designed to help achieve and maintain the NAAQS. South Carolina receives an annual minimum apportionmen t, which in 2006 was a little over $10 million. A mandatory portion of that, nearly $2 million, was requir ed to be used in the RFA TS area. To be eligible for the mandatory funding, projects must advance ai r quality goals. New roads or lanes that would potentially increase traffic are not elig ible for CMAQ funding. A variety of eligible project types include traffic control signalization, traffic flow improveme nts, alternative fuel programs, transit projects,80 carpooling programs, and bicycle and pedestrian projects.

The RFATS MPO announced its approved list of CMAQ projects for the funding years 2004 through 2006 at a press conference on January 26, 2007. The York County interagency consultation group, which includes the RFATS MPO, the SCDHEC, the SCDOT, EPA Region 4, the FHWA, and the FTA, has been meeting for several years to address transportation conformity and the attainment SIP. This group approved the methodology used in determining air quality benefits for the selected projects. All RFATSsponsored CMAQ projects are included in the RF ATS 2030 Long Range Transportation Plan. The project list includes signalization improvements, turn lanes, bicycle paths, a hybrid trolley, alternative fuel vehicles, and an idle reduction and awareness program for schools. Of the ten projects on the list, seven are fully-funded. Project sponsors include the City of Rock Hill, RFATS, RFATS Congestion Management System, SCDOT District 4, York County, and the Catawba Regional Council of Governments (COG). Local matches were provided by the City of York, the City of Rock Hill, York County, the Catawba COG, the SC Energy Office, the Rock Hill School District, and the Museum of York County. Emissions reductions over the lifetim es of the currently-funded projects are estimated at 1,999 tons of VOCs, 8,659 tons of CO, and 1,678 tons of NO

x . Matching funding for the three additional projects will need to be identified before they can proceed. These projects, when funded, will produce
additional reductions of 61 tons of VOC s, 266 tons of CO, and 52 tons of NO

x .

B. Highway Mobile Source VOC Insignificance

Section 93.109(k), in the Transportation Confor mity Rule Amendments for the new 8-hour ozone and fine particulate matter NAAQS, addresses areas with insignificant motor vehicle emissions. The rule suggests that such a finding would be based on a number of factors, including the percentage of motor
vehicle emissions in the context of the total SIP inve ntory, the current state of air quality as determined by monitoring data for that NAAQS, the absence of SIP motor vehicle control measures, and historical trends and future projections of the growth of mo tor vehicle emissions. Although there is a vehicle control measure (inspection and maintenance) program in place in the North Carolina counties of the Metrolina area, it was established for additional reductions in NO

x emissions. There are incidental VOC emissions reductions as a result of this program; how ever, it is not believed the reduction of VOC
emissions has resulted in decreased ozone levels.

The SCDHEC has examined the NCDAQ’s study to determine sources of VOC emissions and their
contribution to ozone formation in the Metrolina area . Due to the generally warm and moist climate of the Carolinas, vegetation abounds in many forms, and fo rested lands naturally cover much of each state. The NCDAQ has found that, as a result, the biogenic sector is the most abundant source of VOC emissions in the Carolinas, accounting for approx imately 90% of the total VOC emissions. The overwhelming abundance of biogenic VOC emissions ma kes the majority of North and South Carolina, including the Metrolina area, a NO

x -limited environment for the formation of ozone.

Additionally, the SCDHEC has reviewed a number of modeling sensitivity runs performed by the NCDAQ that were designed to determine the impact of highway mobile sour ce VOCs on ozone formation
in the Metrolina area. The results of these sensitivities indicate no change in future ozone concentrations in the Metrolina area when highway mobile VO C emissions are significantly changed (e.g., 50% decrease). These sensitivities are discussed in more detail in Appendix F.3.

The SCDHEC agrees with the NCDAQ findings th at highway mobile VOCs are insignificant
contributors to ozone formation in the Metrolin a nonattainment area. Emission estimates indicate highway mobile VOC is a small percentage of the to tal VOC emissions inventor y. Highway mobile VOC emissions are projected to decrease in the future , notwithstanding VMT increases. Emission sensitivity modeling indicates no change in future ozone con centrations when VOC emissions are significantly81 changed. For these reasons, neither the NCDA Q nor the SCDHEC set a MVEB for VOC for the
Metrolina nonattainment area in their 2007 SIP am endments. The SCDHEC consulted with its interagency transportation partners prior to reaching th is conclusion. Both agencies planned to revisit the setting of MVEB for VOC if there was any future i ndication that the Metrolina area has become VOCsensitive for ozone formation.

However, the EPA indicated by email on October 6, 2009, by phone on October 21, 2009, and again on December 9, 2009, that it does not agree that on- road mobile VOCs are insignificant contributors to ozone formation. Although SCDHE C disagrees with EPA’s assessment, SCDHEC is submitting a VOC MVEB for the South Carolina portion of the Metrolina nonattainment area for the 1997 ozone
standard . Further discussion of the VOC insignificance is sue can be found in the supplement to this
attainment demonstration.

C. Motor Vehicle Emission Budgets

The MVEBs will be set for the attainment year 200 9. By the time the MVEBs are found adequate or approved by the EPA, the next trans portation conformity regional emissi ons analysis should be for years 2009 and beyond. Therefore, MVEBs will not be set for the baseline year 2002.

Although emissions are usually expressed in terms of tons per day, the MVEBs will be set in terms of kilograms (kg) per day. The reason for the ch ange is because the MOBILE model generates emission factors in grams per mile. In past conformity exer cises, there have been some issues with conversion to tons per day, as well as concerns with how MVEB s were rounded to the hundredth place. Setting the MVEBs in kilograms per day will avoid these issues in future conformity determinations. During the development of the MVEBs, the interagency part ners for the York County nonattainment area were
consulted.

Table VII-1 shows the York County on-road mobile NO

x and VOC emissions expressed in tons per day and the corresponding kilograms per day values for 2009.

Table VII-1: 2009 Highway Mobile Source NO

x and VOC Emissions York County Nonattainment Area Pollutant Tons/day Kg/day
NO

x 8.01 7,299 VOC 4.563 4,141

Upon the EPA’s affirmative adequacy finding for the partial county MVEBs, as shown in Table VII2, they will become the applicable MVEBs fo r the nonattainment portion of York County.

Table VII-2: York County Nonattainment Area
NO

x and VOC MVEBs for 2009 Pollutant MVEB (Kilograms/day)
NO

x 7,299
VOC 4,141