State of North Carolina’s 

Recommendation on Boundaries 

of 8-Hour Ozone 

Nonattainment Areas 

March 12, 2009 

Governor Beverly Perdue
(This Page Is Intentionally Blank)
Table of Contents

Introduction..................................................................................................................1

Background...................................................................................................................1

Summary of Recommendations..................................................................................3

Area Specific Recommendations on Boundaries for 8-hour Ozone 

Nonattainment............................................................................................................10

Area Specific Recommendations on Boundaries for 8-hour Ozone 

Nonattainment............................................................................................................11

Snow Bird Mountains – Joyce Kilmer-Slickrock Wilderness Area Nonattainment Area 

Discussion.......................................................................................................................................12

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................12 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................12 

Discussion:...................................................................................................................................12 

Emissions Data: ...........................................................................................................................13 

Population Density And Degree Of Urbanization:......................................................................14 

Traffic And Commuting Patterns: ...............................................................................................14 

Growth Rates And Patterns: ........................................................................................................14 

Geography / Topography:............................................................................................................14 

Jurisdictional Boundaries: ...........................................................................................................15 

Level of Control of Emission Sources:........................................................................................15

Great Smoky Mountains National Park Nonattainment Area Discussion..............................16

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................16 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................16 

Discussion:...................................................................................................................................16 

Air quality data: ...........................................................................................................................17 

Emissions Data: ...........................................................................................................................17 

Population Density And Degree Of Urbanization:......................................................................17 

Traffic And Commuting Patterns: ...............................................................................................18 

Growth Rates And Patterns: ........................................................................................................18 

Meteorology: ...............................................................................................................................18 

Geography / Topography:............................................................................................................18 

Jurisdictional Boundaries: ...........................................................................................................19 

Level of Control of Emission Sources:........................................................................................19

Great Balsam Mountains – Shining Rock Wilderness Area Nonattainment Area Discussion

.........................................................................................................................................................20

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................20 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................20 

Discussion:...................................................................................................................................20 
Emissions Data: ...........................................................................................................................21 

Population Density And Degree Of Urbanization:......................................................................22 

Traffic And Commuting Patterns: ...............................................................................................22 

Growth Rates And Patterns: ........................................................................................................22 

Meteorology: ...............................................................................................................................22 

Geography / Topography:............................................................................................................22 

Jurisdictional Boundaries: ...........................................................................................................23 

Level of Control of Emission Sources:........................................................................................23

Black Mountains Nonattainment Area Discussion ....................................................................24

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................24 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................24 

Air quality data: ...........................................................................................................................25 

Emissions Data: ...........................................................................................................................25 

Population Density And Degree Of Urbanization:......................................................................26 

Traffic And Commuting Patterns: ...............................................................................................26 

Growth Rates And Patterns: ........................................................................................................26 

Geography / Topography:............................................................................................................26 

Jurisdictional Boundaries: ...........................................................................................................27 

Level of Control of Emission Sources:........................................................................................27

Hickory-Lenoir-Morganton Nonattainment Area Discussion..................................................28

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................28 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................28 

Air quality data: ...........................................................................................................................28 

Emissions Data: ...........................................................................................................................29 

Population Density And Degree Of Urbanization:......................................................................29 

Traffic And Commuting Patterns: ...............................................................................................29 

Growth Rates And Patterns: ........................................................................................................30 

Meteorology: ...............................................................................................................................30 

Geography / Topography:............................................................................................................30 

Jurisdictional Boundaries: ...........................................................................................................30 

Level of Control of Emission Sources:........................................................................................30

Charlotte-Gastonia-Rock Hill Nonattainment Area Discussion...............................................32

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................32 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................32 

Iredell County ..............................................................................................................................33 

Cleveland County ........................................................................................................................34 

Anson County ..............................................................................................................................36 

Stanly County ..............................................................................................................................37 

Greensboro-Winston-Salem-High Point Nonattainment Area Discussion..............................39

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................39 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................39 

Stokes County..............................................................................................................................40 

Yadkin County.............................................................................................................................41 

Surry County................................................................................................................................42 

Randolph County.........................................................................................................................43 

Orange County.............................................................................................................................45 
Raleigh-Durham-Cary Nonattainment Area Discussion ..........................................................46

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................46 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................46 

Harnett County ............................................................................................................................47 

Johnston County ..........................................................................................................................48 

Chatham County ..........................................................................................................................49 

Orange County.............................................................................................................................51 

Fayetteville Nonattainment Area Discussion..............................................................................53

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................53 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................53 

Greenville Nonattainment Area Discussion................................................................................56

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................56 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................56 

Pitt County...................................................................................................................................58 

Greene County.............................................................................................................................59 

Virginia Beach-Norfolk-Newport News Nonattainment Area Discussion...............................61

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: ......................................................61 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary:...............................61 

Currituck County .........................................................................................................................62 

Table of Figures 

Figure 1: North Carolina’s 2006-2008 8-Hour Ozone Design Values Map (Please Note That All 

Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.)...................................................................................2 

Figure 2: North Carolina’s Recommendation On 8-Hour Ozone Nonattainment Area Boundaries...5 

Figure 3: Potential 8-hour Ozone Nonattainment Areas Map Following EPA’s Presumptive Full 

CSA/MSA and Full County Boundaries (As Presented at Governmental and Public Meetings)

.....................................................................................................................................................10 

Figure 4: North Carolina’s Proposed 8-hour Ozone Nonattainment Areas Map (As Presented at 

Governmental and Public Meetings) ...........................................................................................10 

Figure 5: Recommended Nonattainment Areas. Snow Bird Mountains – Joyce Kilmer-Slickrock 

Wilderness Area nonattainment area shaded in orange...............................................................12 

Figure 6: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That 

All Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.).................................................................................13 

Figure 7: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites) .15 

Figure 8: Recommended Nonattainment Areas. Great Smoky Mountains National Park 

nonattainment area shaded in orange...........................................................................................16 

Figure 9: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That 

All Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.).................................................................................17 

Figure 10: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)19 
Figure 11: Recommended Nonattainment Areas Great Balsam Mountains – Shining Rock 

Wilderness Area nonattainment area shaded in orange...............................................................20 

Figure 12: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That 

All Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.).................................................................................21 

Figure 13: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)23 

Figure 14: Recommended Nonattainment Areas. Black Mountains nonattainment area shaded in 

orange. .........................................................................................................................................24 

Figure 15: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That 

All Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.).................................................................................25 

Figure 16: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)27 

Figure 17: Recommended Nonattainment Area................................................................................28 

Figure 18: Unifour Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All 

Design Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve 

Space On The Map. 76 ppb = 0.076 ppm.).................................................................................29 

Figure 19: Metrolina NC Regional 2006-2008 8-Hour Ozone Design Values Map ........................32 

Figure 20: Triad NC Regional 2006-2008 8-Hour Ozone Design Values Map................................39 

Figure 21: Triangle NC Regional 2006-2008 8-Hour Ozone Design Values Map...........................46 

Figure 22: Fayetteville NC Regional 2006-2008 8-Hour Ozone Design Values Map .....................53 

Figure 23: Greenville NC Regional 2006-2008 8-Hour Ozone Design Values Map .......................56 

Figure 24: Three-year design values of monitors surrounding the Greenville area..........................56 

Figure 25: Spatially allocated modeled design values for 2009........................................................57 

Figure 26: Currituck NC Regional 2006-2008 8-Hour Ozone Design Values Map.........................61 

Table of Tables 

Table 1: North Carolina – Ozone (8-Hour Standard)..........................................................................6 

Table 2: Snow Bird Mountains – Joyce Kilmer-Slickrock Wilderness Area Regional Ozone Design 

Value Table..................................................................................................................................13 

Table 3: Great Smoky Mountains National Park Regional Ozone Design Value Table ..................17 

Table 4: Great Balsam Mountains – Shining Rock Wilderness Area Regional Ozone Design Value 

Table ............................................................................................................................................21 

Table 5: Black Mountains Regional Ozone Design Value Table .....................................................25 

Table 6: Hickory Regional Ozone Design Value Table....................................................................29 

Table 7: Charlotte/Metrolina Regional Ozone Design Value Table .................................................32 

Table 8: Greensboro-Winston-Salem-High Point (Triad) Regional Ozone Design Value Table.....39 

Table 9: Raleigh-Durham-Cary (Triangle) Regional Ozone Design Value Table............................46 

Table 10: Fayetteville Regional Ozone Design Value Table............................................................53 

Table 11: Greenville Regional Ozone Design Value Table..............................................................57 

Table 12: Fayetteville Regional Ozone Design Value Table............................................................61 
Table of Appendices 

Appendix A: North Carolina’s 2006-2008 8-Hour Ozone Design Values Map & Table 

Appendix B: Local Government and Public Comments Received 

Appendix C: U.S. National Park Service and U.S. Forest Service Comments Received 

Appendix D: Area Designations for the 2008 Revised Ozone National Ambient Air Quality 

Standards – December 2008 U.S. EPA Memorandum 

Appendix E: North Carolina’s Existing and Previous Nonattainment Areas Boundaries Map 

Appendix F: North Carolina’s Vehicle Emissions Testing (OBD) and Safety Inspection Map 

Appendix G: North Carolina’s Jurisdictional Information: 

North Carolina County Map 

Core Base Statistical Area (CBSA) and Combined Statistical Area (CSA) Map 

North Carolina Regional and Metropolitan Planning Organizations (RPO & MPO) Map 

Select County Township Maps and Statewide County Township Population Table 

Appendix H: North Carolina’s 2006 NOx and VOC Emissions Data Maps and Tables 

Appendix I: North Carolina’s 2000 Population and Population Density Maps 

Appendix J: North Carolina’s 2007 & 2020 Daily Vehicle Miles Traveled Maps and Table 

Appendix K: Commuting Patterns for Larger Urbanized Counties in North Carolina 

Appendix L: North Carolina’s Population Growth Rates and Projections Description 

Appendix M: Backward Wind Trajectories and Wind Roses On 8-Hour Ozone Exceedance Days 
Introduction 

 The purpose of this document is to provide the State of North Carolina’s recommendations 

on boundaries for the 8-hour ozone standard nonattainment areas. This package is in response to 

the promulgation of a revised 8-hour ozone national ambient air quality standard (NAAQS) by the 

United States Environmental Protection Agency (EPA) on March 12, 2008. 

 EPA has instructed the States to submit their recommendations for nonattainment 

boundaries for any monitors violating this revised 8-hour ozone standard by March 12, 2009. EPA 

will then provide comments back to the States by no later than November 12, 2009. These written 

comments from EPA begin a 120-day period during which the States and EPA will attempt to work 

out any issues on the nonattainment boundaries. EPA will make the final decision on boundaries by 

March 12, 2010. This final decision on 8-hour ozone nonattainment areas will subsequently be 

published in the Federal Register and codified in 40 CFR 81. 

Background 

 The Clean Air Act (CAA) requires EPA to designate areas as attainment or nonattainment 

following the promulgation of a new NAAQS. The nonattainment boundaries are to be based on 

the data collected at the ambient air monitoring stations. The State and local air programs operate 

the ozone monitoring sites. The data is quality assured, and then submitted to EPA where it 

becomes part of a national database. The CAA requires that the monitoring data be evaluated to 

determine which monitors meet the standard and which monitors violate the standard. For the 8-

hour ozone standard, three years worth of data for each monitor is evaluated. The fourth highest 

daily maximum 8-hour ozone value for each of the three years is averaged together, and the 

resulting average is then compared to the standard. The three-year average is referred to as the 

design value. With their action on March 12, 2008, EPA revised the 8-hour ozone standard to 0.075 

parts per million (ppm). Therefore, a monitored three-year average of 0.075 ppm is considered to 

meet or attain the standard, while a three-year average of 0.076 ppm or greater is considered to 

violate the ambient standard. 

 North Carolina has evaluated the ozone monitoring data for the State for the most recent 

three-year period of 2006-2008, and has determined that a total of 27 out of 40 monitors currently 

violate the new 8-hour ozone standard. Additionally, the discontinuation of a monitor in western 

Pitt County in 2007 and the subsequent establishment of a new monitor in central Pitt County in 

2008 have resulted in insufficient data to calculate an appropriate 2006-2008 design value at either 

location and therefore these sites are unclassifiable at this time. A map showing the 8-hour ozone 

design values across North Carolina is included as Figure 1. This map and a table used for 

calculating the respective design values are included in Appendix A. The highest design value in 

the State at 0.094 ppm is observed at a monitor located in northeastern Mecklenburg County. The 

lowest design value in the State at 0.065 ppm is observed at the Bryson City monitor in central 

Swain County. The higher design values tend to occur along the I-85/I-40 corridor stretching 

throughout the Piedmont Crescent from Charlotte through the Triad and to the Triangle. This is the 

most heavily urbanized and industrialized region of North Carolina. There are also four monitors in 

the North Carolina Mountains that are minimally violating the standard. All of the violating 

monitors in the mountains are located above 4500 feet and experience the highest ozone 

concentrations during the middle of the night, which is indicative of transported pollution and not 

the result of local emissions sources. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 1 
Figure 1: North Carolina’s 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design Value Concentrations Pre

Per Billion (ppb) To Conserve Space On The Map. 76 ppb = 0.076 ppm.)

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 2 
Summary of Recommendations 

 The State of North Carolina’s recommendations for the designation of areas of the state for 

the new 8-hour ozone standard is demonstrated in the attached map entitled, “North Carolina’s 

Proposal on Potential 8-hour Ozone Nonattainment Boundaries” (Figure 2). The recommendations 

include: full county nonattainment designation for Alamance, Alexander, Cabarrus, Caswell, 

Catawba, Cumberland, Davidson, Davie, Durham, Edgecombe, Forsyth, Franklin, Gaston, 

Granville, Guilford, Lincoln, Mecklenburg, Nash, Orange, Person, Rockingham, Rowan, Union, 

and Wake Counties; partial county nonattainment designation for Buncombe, Burke, Caldwell, 

Chatham, Cherokee, Graham, Haywood, Henderson, Iredell, Jackson, Johnston, Madison, 

McDowell, Randolph, Swain, Transylvania, and Yancey Counties; unclassifiable designation for 

Pitt County, and attainment designation for the remaining full or partial counties in North Carolina. 

These various designation recommendations are further reflected in Table 1. 

 From November 2008 through February 2009, 22 meetings or presentations were held 

across North Carolina with local government elected officials, local and regional transportation 

planners, other State agencies, and Federal agencies. Additionally, five public meetings were 

conducted in each of the five most populous regions of North Carolina in January and early 

February 2009. At all of these meetings, background information concerning the promulgation of 

the revised 8-hour ozone standard and the implications to North Carolina based on current 

monitoring data were presented. Central to the discussion during these meetings were two maps: 

one map demonstrating the potential nonattainment areas following EPA’s presumptive boundaries 

of full county designations of entire Core Based Statistical Areas (CBSA - which is either a 

metropolitan or micropolitan statistical area) or entire Combined Statistical Areas (CSA - which is a 

combination of adjacent CBSA’s) with monitors violating the ozone standard, counties outside of a 

CBSA or CSA with violating monitors, and counties believed to contribute to the ozone problem 

(Figure 3); and one map demonstrating the potential nonattainment areas based on a proposal by the 

North Carolina Division of Air Quality (Figure 4). 

 This designation recommendation takes into consideration comments received during the 22 

governmental meetings, during the five public meetings, and during the public comment period that 

ended on February 9, 2009. Appendix B contains the comments received. The basic rationale for 

the designation recommendations is that in the core urban areas of a CBSA or CSA, whole counties 

are selected where the violating ozone design values are observed. In the less urbanized areas of a 

CBSA or CSA, partial counties are selected where the population and vehicle miles traveled are 

relatively low and where the monitoring data demonstrates attainment of the 8-hour ozone standard. 

In most instances, the partial county designations were represented by Metropolitan Planning 

Organization (MPO) or township boundaries that are immediately connected with the core of the 

CBSA or CSA. In the mountain areas (Buncombe, Cherokee, Graham, Haywood, Henderson, 

Jackson, Madison, McDowell, Swain, Transylvania, and Yancey Counties), the North Carolina 

portion of the Great Smoky Mountains National Park, the North Carolina portion of the Joyce 

Kilmer-Slickrock Area, the Shining Rock Wilderness Area, and elevations above 4000 feet in the 

Snow Bird, Great Balsams, and Black Mountains are being recommended for designation. This is 

due to the before mentioned violations occurring only at high elevation monitors in these areas. A 

letter from the U.S. National Park Service is attached in Appendix C supporting the nonattainment 

boundary recommendation for the Great Smoky Mountains National Park. This letter was 

submitted in 2000 during an earlier boundary recommendation process, but recent discussions with 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 3 
the U.S. National Park Service revealed that they continue to believe that the entire Great Smoky 

Mountains National Park should be designated as nonattainment. Additionally, a correspondence 

from the U.S. Forest Service is attached in Appendix C supporting the nonattainment boundary 

recommendations for both the Joyce-Kilmer – Slickrock and the Shining Rock Wilderness Areas. 

The full discussion of the partial county designations, including a discussion on the mountain area 

designations, is provided later. 

 These recommendations address the designation area boundaries criteria laid out in the 

December 4, 2008 memo from Robert J. Meyers, Principal Deputy Assistant Administrator entitled, 

“Area Designations for the 2008 Revised Ozone National Ambient Air Quality Standards”. This 

guidance is attached in Appendix D. The designation recommendations are also consistent with the 

methodology behind the establishment of all existing and previous 8-hour ozone nonattainment area 

boundaries in North Carolina. A map of North Carolina’s existing and previous nonattainment area 

boundaries is provided in Appendix E. 

 The final designation by EPA of the nonattainment areas is only the first step in the 

implementation of the revised 8-hour ozone standard. The next major requirement is the 

development of the State Implementation Plan that contains the necessary strategies to be 

implemented by the state so that all areas can attain the standard by the attainment date. In order to 

accomplish this requirement, North Carolina is in the process of beginning a modeling analysis to 

conclude what control strategies are necessary to address the current 8-hour violations in the State. 

This modeling analysis will be coordinated through a collaboration amongst states throughout the 

Southeast, Midwest, and Mid-Atlantic. This multi-state and multi-region collaboration ensures that 

North Carolina is accurately projecting future emissions and air quality scenarios in the modeling 

analysis and is appropriately developing control strategies that will ultimately lead to expeditious 

statewide attainment of the revised 2008 8-hour ozone standard. 

 North Carolina has already undertaken substantial and progressive emissions reduction 

strategies over the past decade. These strategies have allowed North Carolina to achieve almost 

statewide attainment of the 1997 8-hour ozone standard. The North Carolina General Assembly 

adopted the Clean Air Bill of 1999 that changed the State’s vehicle inspection and maintenance 

(I/M) program to an on-board diagnostic (OBD) program and expanded the program to 48 counties 

that captured greater than 80% of the vehicles in North Carolina. This OBD based I/M program is 

one of the most expansive in the country. Appendix G contains a county map of where the I/M 

program is currently required for cars and light-duty trucks. Additional actions taken by North 

Carolina include the adoption of the NOx SIP call rules and the North Carolina General Assembly 

approval of an aggressive multi-pollutant bill (Clean Smokestacks Act) in 2002 that has resulted in 

significant reductions in sulfur dioxide, as well as year round reductions in nitrogen oxides from the 

State's two largest utilities. Both of the legislative actions demonstrate North Carolina’s willingness 

and statutory authority to establish emissions control programs regardless of a Federal 

nonattainment designation status. Finally, North Carolina maintains a nationally recognized air 

quality action day program in the six most populous regions of the state. This program advises 

citizens of upcoming air quality events so that the public can better protect their health and take 

action to reduce their own emission producing activities. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 4 
Figure 2: North Carolina’s Recommendation On 8-Hour Ozone Nonattainment Area Boundaries

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 5 
Following in Table 1 is North Carolina’s recommendation of areas as nonattainment, unclassifiable, 

or attainment under the revised 8-hour ozone standard. 

Table 1: North Carolina – Ozone (8-Hour Standard) 

Designated Area Designation 

 Type 

Classification 

Type 

Snow Bird Mountains – Joyce KilmerSlickrock Wilderness Area: 

Graham County 

Above 4000 feet elevation in the Snow 

Bird Mountains range 

Joyce Kilmer-Slickrock Wilderness 

Area boundary 

Cherokee County 

Above 4000 feet elevation in the Snow 

Bird Mountains range 

Great Smoky Mountains National Park: 

Haywood County 

Park boundary 

Swain County 

Park boundary 

Great Balsam Mountains – Shining Rock 

Wilderness Area: 

Buncombe County 

Above 4000 feet elevation in this 

mountain range 

Haywood County 

Above 4000 feet elevation in this 

mountain range 

Shinning Rock Wilderness Area 

boundary 

Henderson County 

Above 4000 feet elevation in this 

mountain range 

Jackson County 

Above 4000 feet elevation in this 

mountain range 

Transylvania County 

Above 4000 feet elevation in this 

mountain range 

Nonattainment 

Nonattainment 

Nonattainment 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 6 
Designated Area Designation 

 Type 

Classification 

Type 

Black Mountains: 

Buncombe County 

Above 4000 feet elevation in this 

mountain range 

Madison County 

Above 4000 feet elevation in this 

mountain range 

McDowell County 

Above 4000 feet elevation in this 

mountain range 

Yancey County 

Above 4000 feet elevation in this 

mountain range 

Hickory-Lenoir-Morganton Area: 

Alexander County 

Burke County 

Unifour Metropolitan Planning 

Organization boundary 

Caldwell County 

Unifour Metropolitan Planning 

Organization boundary 

Catawba County 

Charlotte-Gastonia-Salisbury Area: 

Cabarrus County 

Gaston County 

Iredell County 

Davidson Township 

Coddle Creek Township 

Lincoln County 

Mecklenburg County 

Rowan County 

Union County

Nonattainment 

Nonattainment 

Nonattainment 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 7 
Designated Area Designation 

 Type 

Classification 

Type 

Greensboro-Winston-Salem-High Point 

Area: 

Alamance County 

Davidson County 

Forsyth County 

Guilford County 

Caswell County 

Davie County 

Orange County

Burlington-Graham Metropolitan 

Planning Organization boundary 

Randolph County 

High Point Metropolitan Planning 

Organization boundary 

Rockingham County 

Raleigh-Durham-Cary Area: 

Chatham County 

Baldwin Township 

Center Township 

New Hope Township 

Williams Township 

Durham County 

Franklin County 

Granville County 

Johnston County 

Capital Area Metropolitan Planning 

Organization boundary 

Orange County 

Outside Burlington-Graham 

Metropolitan Planning Organization 

boundary 

Person County 

Wake County 

Fayetteville Area: 

Cumberland County 

Nonattainment 

Nonattainment 

Nonattainment 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 8 
Designated Area Designation 

 Type 

Classification 

Type 

Rocky Mount Area: 

Edgecombe County 

Nash County 

Greenville Area: 

Pitt County 

Rest of State 

Nonattainment 

Unclassifiable 

Attainment 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 9 
Figure 3: Potential 8-hour Ozone Nonattainment Areas Map Following EPA’s Presumptive Full CSA/MSA and 

Full County Boundaries (As Presented at Governmental and Public Meetings) 

Figure 4: North Carolina’s Proposed 8-hour Ozone Nonattainment Areas Map (As Presented at Governmental 

and Public Meetings) 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 10 
Area Specific Recommendations on Boundaries for 8-hour Ozone 

Nonattainment 

 The purpose of the remainder of this document is to address the criteria that EPA established 

for considering boundaries less than the full CBSA or CSA for nonattainment designation. These 

criteria are outlined in the before mentioned “Area Designations for the 2008 Revised Ozone 

National Ambient Air Quality Standards” memo, which is attached in Appendix D. The remaining 

documentation only addresses in detail those areas where North Carolina’s recommendation is less 

than the full CBSA or CSA, where additional areas beyond a CBSA or CSA are recommended for 

nonattainment designation, or where there is incomplete air quality data and an unclassifiable 

designation is recommended. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 11 
Snow Bird Mountains – Joyce Kilmer-Slickrock Wilderness Area 

Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Graham County 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Elevations above 4000 feet elevation in the Snow Bird Mountains range (Cherokee and 

Graham Counties) and the Joyce Kilmer-Slickrock Wilderness Area (Graham County) 

Discussion: 

 Graham County is not a portion of a CBSA or CSA. There are not any major urban areas 

within Graham County, and it is considered one of North Carolina’s most rural counties. There is 

only one ozone monitor in Graham County (reference Figure 6), and this site is located above 4000 

feet elevation in the Snow Bird Mountains range that straddles the Cherokee and Graham County 

line. This monitoring site was originally established to help understand the air quality impacting the 

nearby Joyce Kilmer-Slickrock Wilderness Area without having to disturb land specifically within 

this Wilderness Area. With this in mind, the nonattainment boundary recommendation includes all 

of the Joyce Kilmer-Slickrock Wilderness Area despite being geographically separated from the 

violating monitor (see Figure 5). The additional rationale for the recommended 8-hour ozone 

nonattainment boundary is outlined in the following 9 factors. 

Figure 5: Recommended Nonattainment Areas. Snow Bird Mountains – Joyce Kilmer-Slickrock Wilderness 

Area nonattainment area shaded in orange 

.

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 12 
Air quality data: 

The Joanna Bald monitor, located above 4000 feet, at elevation 4688 feet, in the Snow Bird 

Mountains has a design value of 0.078 ppm. The readings at the ridge top monitors experience the 

highest ozone concentrations during the middle of the night, which is indicative of transported 

pollution. The Bryson City monitor, located in a valley at 2159 feet just east of Graham County and 

outside of the recommended nonattainment area, has a design value of 0.065 ppm, the lowest design 

value in the state. The readings at the valley monitors below 4000 feet show that local precursor 

sources are not significantly contributing to the ozone violations at monitors above 4000 feet. 

Figure 6: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design 

Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve Space On The Map. 76 ppb 

= 0.076 ppm.)

Table 2: Snow Bird Mountains – Joyce Kilmer-Slickrock Wilderness Area Regional Ozone 

Design Value Table 

Emissions Data: 

 There are minimal emissions sources of either precursor pollutants (NOx and VOC) in the 

recommended nonattainment area. The surrounding region has minimal anthropogenic emissions 

sources of either precursor pollutants (NOx and VOC). The only significant point emissions source 

in Graham County is Stanley Furniture, with 21 tons/year of NOx and 337 tons/year of VOC. 

2005 2006 2007 2008 05-07 06-08

Snow Bird 

Mountains - Joyce 

Kilmer-Slickrock 

Wilderness Area

Joanna Bald 37-075-0001 0.079 0.076 0.081 0.078 0.078 0.078

Region Annual 4th Highest 8-Hour Average Design Value Monitoring Sites AIRS ID

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 13 
Population Density And Degree Of Urbanization: 

Graham County has a population of 8,144 (2007 estimate) and a population density of 27 

people per square mile. This is one of the least densely populated counties in North Carolina and 

the entire eastern United States. Surrounding counties also have low population density. Nearby 

valley monitors below 4000 feet have design values well below the NAAQS, which shows that 

local precursor sources are not significantly contributing to the ozone violations at monitors above 

4000 feet. The recommended nonattainment area has very low population, estimated around 350 

people and possibly as low as 0-5 people. (Please see Appendix I for maps of population density) 

Traffic And Commuting Patterns: 

 There are not any significant roadways within the recommended nonattainment area. 

Practically all of the VMT in Graham County is outside of the recommended nonattainment area 

boundary. 

Growth Rates And Patterns: 

Population growth in Graham County from 2000-2010 is 2.7% and from 2010-2020 is 1.6%. 

The population growth in the recommended nonattainment area is expected to be negligible. 

Meteorology: 

The violating ridge top monitors are located above the nocturnal boundary layer and are near 

or within the subsidence inversion at the top of the daytime mixed layer. Because of this 

stratification, the air at elevations above 4000 feet is characterized by long range transport and has 

different diurnal patterns than locations within the valleys. Backward trajectories in Appendix M 

show that air parcels on days with ozone at or above 76 ppb originate from areas outside the region 

including the western piedmont of North Carolina, Tennessee, and the Ohio River Valley, 

suggesting that the inclusion of elevations below 4000 feet in the nonattainment area would have 

little impact on the violating monitors located above 4000 feet. 

Geography / Topography: 

 The Joanna Bald ozone monitor is considered a high-elevation or ridge top monitor. Much 

like all the other ridge top ozone monitors in Western North Carolina, Joanna Bald does not have a 

normal diurnal ozone response profile similar to ozone monitors in the valleys of the Mountains and 

throughout the balance of the Piedmont, Sandhills, and Coastal Plains. Instead of recording 

exceedances of the 8-hour ozone standard during the middle of the afternoon when ozone 

production and photochemistry is at a maximum, the ozone exceedances at Joanna Bald and other 

ridge top monitors occur during the nighttime hours. This timing of the exceedances is indicative of 

transport and not local generation of ozone, since the ozone chemistry stops once the sun sets. 

Figure 7 demonstrates a typical comparison between a mountain ridge top monitor (red line), a 

mountain valley monitor (blue), and a large metropolitan area monitor (yellow). 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 14 
Figure 7: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)

Jurisdictional Boundaries: 

Parts of the Qualla Boundary, also known as the Eastern Cherokee Indian Reservation, are 

located in Graham County. These sections of the Qualla Boundary are non-contiguous and are 

separate from the primary part of the Qualla Boundary located in Swain and Jackson counties. The 

Cherokees who live in Graham County form the Snowbird Cherokee community. Although there 

are the described tribal lands in Graham County, the Snowbird Mountains at elevation 4000 feet and 

above that are recommended to be designated nonattainment are not on any tribal lands. Also the 

area recommended to be designated nonattainment has never been part of a nonattainment area, is 

not in a CSA, and does not have an MPO. 

Level of Control of Emission Sources: 

 No OBD-based I/M program exists in this county; however, an annual visual inspection of 

emissions equipment for tampering is required. Other Federal and state (North Carolina and 

surrounding states) mobile and point strategies to reduce emissions will have a much greater impact 

in reducing ozone levels below the NAAQS above 4000 feet. 

• DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment strategy, 

regardless of designation. North Carolina believes this is an important consideration for 

setting nonattainment boundaries. The new inspection and maintenance program that 

requires on-board diagnostic testing in 48 counties (phased in between 2002 and 2006) is an 

example of North Carolina’s ability to control sources in counties regardless of the 

nonattainment designations. The new I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 15 
Great Smoky Mountains National Park Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Haywood County (as a part of a larger Asheville nonattainment area also including 

Buncombe, Henderson County, Madison, Transylvania, and Yancey Counties) 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Haywood County 

Park boundary 

 Swain County 

Park boundary 

Discussion: 

 The Great Smoky Mountains National Park is not a portion of a CBSA or CSA. There are 

not any major settlements within the park, and being a national park it can be considered an 

undeveloped tract of land. There is only one ozone monitor within the park boundaries in the North 

Carolina portion of the park (reference Figure 6), and this site is located above 4000 feet elevation 

in Haywood County. Since nearby low elevation sites are in attainment, North Carolina agrees with 

the presumptive nonattainment boundary of the Great Smoky Mountains National Park (see Figure 

8). The additional rational for the recommended 8-hour ozone nonattainment boundary is outlined 

in the following 9 factors. 

Figure 8: Recommended Nonattainment Areas. Great Smoky Mountains National Park nonattainment area 

shaded in orange. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 16 
Air quality data: 

The Purchase Knob monitor, located above 4000 feet at elevation 5085 feet in the Great 

Smoky Mountains National Park, has a design value of 0.077 ppm. The nearest monitors to the 

Park outside of the recommended nonattainment area are at Waynesville, with a design value of 

0.071 ppm, and Bryson City, with a design value of 0.065 ppm. The readings at the ridge top 

monitors experience the highest ozone concentrations during the middle of the night, which is 

indicative of transported pollution. 

Figure 9: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design 

Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve Space On The Map. 76 ppb 

= 0.076 ppm.)

Table 3: Great Smoky Mountains National Park Regional Ozone Design Value Table 

Emissions Data: 

 There are minimal emissions sources of either precursor pollutants (NOx and VOC) in the 

recommended nonattainment area. The surrounding region has minimal anthropogenic emissions 

sources of either precursor pollutant (NOx and VOC). 

Population Density And Degree Of Urbanization: 

There are approximately 183 people, which is less than 0.3 percent of the total population in 

the counties where the recommended nonattainment area is located, living in the North Carolina 

2005 2006 2007 2008 05-07 06-08

Purchase Knob (Ridge Top) 37-087-0036 0.084 0.073 0.078 0.080 0.078 0.077

Waynesville (Valley) 37-087-0004 0.074 0.069 0.074 0.071 0.072 0.071

Bryson (Valley) 37-173-0002 0.070 0.063 0.066 0.068 0.066 0.065

Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average Design Value

Great Smoky 

Mountains National 

Park

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 17 
portion of the Great Smoky Mountains National Park. (Please see Appendix I for maps of 

population density) 

Traffic And Commuting Patterns: 

 The minimal amount of the VMT within the recommended nonattainment area is associated 

with the US441. Given the remote nature of the Great Smoky Mountains National Park, the vast 

majority of the VMT in Haywood and Swain Counties is outside of the Park jurisdictional boundary 

and the recommended nonattainment area boundary. 

Growth Rates And Patterns: 

Population growth within the Great Smoky Mountains National Park is projected to be minimal. 

Meteorology: 

The violating ridge top monitors are located above the nocturnal boundary layer and are near 

or within the subsidence inversion at the top of the daytime mixed layer. Because of this 

stratification, the air at elevations above 4000 feet is characterized by long range transport and has 

different diurnal patterns than locations within the valleys. Backward trajectories in Appendix M 

show that air parcels on days with ozone at or above .076 ppm originate from areas outside the 

region including the western Piedmont of North Carolina, Tennessee, and the Ohio River Valley, 

suggesting that the inclusion of elevations below 4000 feet in the nonattainment area would have 

little impact on the violating monitors located above 4000 feet. 

Geography / Topography: 

 The Purchase Knob ozone monitor is considered a high-elevation or ridge top monitor. 

Much like all the other ridge top ozone monitors in Western North Carolina, Purchase Knob does 

not have a normal diurnal ozone response profile similar to ozone monitors in the valleys of the 

Mountains and throughout the balance of the Piedmont, Sandhills, and Coastal Plains. Instead of 

recording exceedances of the 8-hour ozone standard during the middle of the afternoon when ozone 

production and photochemistry is at a maximum, the ozone exceedances at Purchase Knob and 

other ridge top monitors occur during the nighttime hours. This timing of the exceedances is 

indicative of transport and not local generation of ozone, since the ozone chemistry stops once the 

sun goes sets. Figure 10 demonstrates a typical comparison between a mountain ridge top monitor 

(red line), a mountain valley monitor (blue), and a large metropolitan area monitor (yellow). 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 18 
Figure 10: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)

Jurisdictional Boundaries: 

The Great Smoky Mountains National Park defines the boundary of the nonattainment area. 

Haywood County, one of the counties where the Park is located, was one of the counties in the 

Mountain Early Action Compact (EAC) under the 1997 8-hour ozone standard. Haywood and 

Swain counties are currently attaining the standard and a redesignation submittal is in process. 

Level of Control of Emission Sources: 

 Other Federal and state (North Carolina and surrounding states) mobile and point strategies 

to reduce emissions will have a much greater impact in reducing ozone levels below the NAAQS 

above 4000 feet. Haywood County currently has an OBD based I/M program. Swain County does 

not have an OBD-based program, but requires an annual visual inspection of emissions equipment 

for tampering. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment strategy, 

regardless of designation. North Carolina believes this is an important consideration for 

setting nonattainment boundaries. The new inspection and maintenance program that 

requires on-board diagnostic testing in 48 counties (phased in between 2002 and 2006) is an 

example of North Carolina’s ability to control sources in counties regardless of the 

nonattainment designations. The new OBD based I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 19 
Great Balsam Mountains – Shining Rock Wilderness Area Nonattainment Area 

Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Buncombe, Haywood, Henderson, and Transylvania Counties (as part of a larger Asheville 

nonattainment area also including Madison and Yancey Counties) 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Elevations above 4000 feet elevation in the Great Balsam Mountains range (includes 

portions of Buncombe County, Haywood County, Henderson County, Jackson County, 

Transylvania County) and all of the Shining Rock Wilderness Area 

Discussion: 

 The Great Balsam Mountains and Slick Rock Wilderness area are part of the Asheville CSA. 

There are 5 ozone monitors in the Asheville area (reference Figure 12), and one located nearby 

(Purchase Knob). All of the violating monitors are located above 4000 feet with all monitors below 

4000 feet easily within attainment. The different ozone distribution with elevation and 

corresponding back trajectory analysis shows that ozone is generated outside the Asheville area and 

transported into the region above 4000 feet with the upper level winds primarily from Tennessee, 

Georgia, Northern South Carolina, and central North Carolina. Additionally, ozone and ozone 

precursors may be transported longer distances from major sources within the Ohio River Valley. 

Since very little ozone is generated locally, we recommend the nonattainment boundary 

encompassing areas above 4000 feet around the violating monitor, in this case the Frying Pan 

monitor. The additional rationale for the recommended 8-hour ozone nonattainment boundary is 

outlined in the following 9 factors. 

Figure 11: Recommended Nonattainment Areas Great Balsam Mountains – Shining Rock Wilderness Area 

nonattainment area shaded in orange. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 20 
Air quality data: 

The Frying Pan monitor, located above 4000 feet at elevation 5200 feet in the Great Balsam 

Mountains, has a design value at 0.078 ppm. The Waynesville monitor, located in a valley at 2641 

feet in Haywood County to the west outside of the recommended nonattainment area, has a design 

value of 0.071 ppm. The Bent Creek monitor, located in a valley at 2215 feet in Buncombe County 

to the east outside of the recommended nonattainment area, also has a design value of 0.071 ppm. 

The readings at the ridge top monitors experience the highest ozone concentrations during the 

middle of the night, which is indicative of transported pollution. The readings at the valley 

monitors below 4000 feet show that local precursor sources are not significantly contributing to the 

ozone violations at monitors above 4000 feet. 

Figure 12: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design 

Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve Space On The Map. 76 ppb 

= 0.076 ppm.)

Table 4: Great Balsam Mountains – Shining Rock Wilderness Area Regional Ozone Design 

Value Table 

Emissions Data: 

 There are minimal emissions sources of either precursor pollutants (NOx and VOC) in the 

recommended nonattainment area. There are 3 NOx sources above 100 tons/year in Buncombe and 

Haywood Counties outside the recommended nonattainment area. There are 6 VOC sources above 

2005 2006 2007 2008 05-07 06-08

Frying Pan (Ridge Top) 37-087-0035 0.082 0.079 0.077 0.080 0.079 0.078

Waynesville (Valley) 37-087-0004 0.074 0.069 0.074 0.071 0.072 0.071

Bryson (Valley) 37-173-0002 0.070 0.063 0.066 0.068 0.066 0.065

Design Value Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average

Great Balsam 

Mountains - Shining 

Rock Wilderness 

Area

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 21 
100 tons/year and 2 sources from 50-100 tons/year in Buncombe, Haywood, and Henderson 

Counties outside the recommended nonattainment area. Trajectory analysis in Appendix M shows 

that these nearby sources have little impact on days with ozone violations. 

Population Density And Degree Of Urbanization: 

The recommended nonattainment area contains at most 2,074 people, though it may be as 

low as 100 people. Most of the surrounding area has low population density, with the cities of 

Asheville and Hendersonville having the highest population densities in the region. Valley 

monitors below 4000 feet located in and near these cities have design values well below the 

NAAQS, which shows that local precursor sources in the higher density areas are not significantly 

contributing to the ozone violations at monitors above 4000 feet. (Please see Appendix I for maps 

of population density) 

Traffic And Commuting Patterns: 

 The minimal amount of the VMT within the recommended nonattainment area is associated 

with the Blue Ridge Parkway, NC Route 215, and US Route 276. Given the remote nature of the 

Great Balsam Mountains – Shining Rock Wilderness Area, the vast majority of the VMT in 

Buncombe, Haywood, Henderson, and Transylvania Counties is outside of the recommended 

nonattainment boundary. 

Growth Rates And Patterns: 

 Population growth within the Great Balsam Mountains and the Shining Rock Wilderness 

area is projected to be negligible. Growth in surrounding counties ranges from 5-15%. 

Meteorology: 

The violating ridge top monitors are located above the nocturnal boundary layer and are near 

or within the subsidence inversion at the top of the daytime mixed layer. Because of this 

stratification, the air at elevations above 4000 feet is characterized by long range transport and has 

different diurnal patterns than locations within the valleys. Backward trajectories in Appendix M 

show that air parcels on days with ozone at or above .076 ppm originate from areas outside the 

region including the western piedmont of North Carolina, Tennessee, and the Ohio River Valley, 

suggesting that the inclusion of elevations below 4000 feet in the nonattainment area would have 

little impact on the violating monitors located above 4000 feet. 

Geography / Topography: 

 The Frying Pan ozone monitor is considered a high-elevation or ridge top monitor. Much 

like all the other ridge top ozone monitors in Western North Carolina, Frying Pan does not have a 

normal diurnal ozone response profile similar to ozone monitors in the valleys of the Mountains and 

throughout the balance of the Piedmont, Sandhills, and Coastal Plains. Instead of recording 

exceedances of the 8-hour ozone standard during the middle of the afternoon when ozone 

production and photochemistry is at a maximum, the ozone exceedances at Frying Pan and other 

ridge top monitors occur during the nighttime hours. This timing of the exceedances is indicative of 

transport and not local generation of ozone, since the ozone chemistry stops once the sun goes sets. 

Figure 13 demonstrates a typical comparison between a mountain ridge top monitor (red line), a 

mountain valley monitor (blue), and a large metropolitan area monitor (yellow). 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 22 
Figure 13: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)

Jurisdictional Boundaries: 

Haywood and Buncombe counties are part of the Mountain Area Early Action Compact 

(EAC) under the 1997 8-hour ozone. Shining Rock Wilderness Area boundary defines a portion of 

the recommended nonattainment area. 

Level of Control of Emission Sources: 

 Mobile emissions are the largest anthropogenic source in the recommended nonattainment 

area. Henderson, Buncombe, and Haywood Counties all have OBD-based I/M programs. Jackson 

and Transylvania counties do not have OBD-based I/M programs, but an annual visual inspection of 

emission equipment is required. Other Federal and state (North Carolina and surrounding states) 

mobile and point strategies to reduce emissions will have a much greater impact in reducing ozone 

levels below the NAAQS above 4000 feet. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment strategy, 

regardless of designation. North Carolina believes this is an important consideration for 

setting nonattainment boundaries. The new inspection and maintenance program that 

requires on-board diagnostic testing in 48 counties (phased in between 2002 and 2006) is an 

example of North Carolina’s ability to control sources in counties regardless of the 

nonattainment designations. The new I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 23 
Black Mountains Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Yancey County (as part of a larger Asheville nonattainment area also including Buncombe, 

Haywood, Henderson, Madison, and Transylvania Counties) 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Elevations above 4000 feet elevation in the Black Mountains range (Buncombe, McDowell, 

Madison, and Yancey Counties). 

Discussion: 

 The Black Mountains area is part of the Asheville CSA. There are 5 ozone monitors in the 

Asheville area (reference Figure 15), and 2 located nearby (Purchase Knob and Barnett Knob). All 

of the violating monitors are located above 4000 feet with all monitors below 4000 feet easily 

within attainment. The different ozone distribution with elevation shows that ozone is generated 

outside the Asheville area and transported into the region above 4000 feet with the upper level 

winds primarily from Tennessee, Georgia, Northern South Carolina, and central North Carolina. 

Additionally, ozone and ozone precursors may be transported longer distances from major sources 

within the Ohio River Valley. Since very little ozone is generated locally, we recommend the 

nonattainment boundary encompassing areas above 4000 feet within the Black Mountains around 

the violating monitor, in this case the Mount Mitchell monitor (see Figure 14). The additional 

rational for the recommended 8-hour ozone nonattainment boundary is outline in the following 9 

factors. 

Figure 14: Recommended Nonattainment Areas. Black Mountains nonattainment area shaded in orange. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 24 
Air quality data: 

The Mount Mitchell monitor, located above 4000 feet at elevation 6502 feet in the Black 

Mountains, has a design value at 0.077 ppm. The readings at the ridge top monitors experience the 

highest ozone concentrations during the middle of the night, which is indicative of transported 

pollution. The Bent Creek monitor, located in a valley at 2215 feet in Buncombe County to the 

southwest outside of the recommended nonattainment area, also has a design value of 0.071 ppm. 

The Linville monitor, located at 3238 feet in Avery County to the northeast outside of the 

recommended nonattainment area, has a design value of 0.067 ppm. The readings at the valley 

monitors below 4000 feet show that local precursor sources are not significantly contributing to the 

ozone violations at monitors above 4000 feet. 

Figure 15: Western NC Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design 

Value Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve Space On The Map. 76 ppb 

= 0.076 ppm.) 

Table 5: Black Mountains Regional Ozone Design Value Table 

Emissions Data: 

 There are minimal emissions sources of either precursor pollutants (NOx and VOC) in this 

region. 

2005 2006 2007 2008 05-07 06-08

Mt. Mitchell (Ridge Top) 37-199-0004 0.080 0.075 0.079 0.078 0.078 0.077

Bent Creek (Valley) 37-021-0030 0.079 0.071 0.073 0.071 0.074 0.071

Annual 4th Highest 8-Hour Average Design Value Region Monitoring Sites AIRS ID

Black Mountains

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 25 
Population Density And Degree Of Urbanization: 

Approximately 2500 people live in the recommended nonattainment area. Most of the 

surrounding area has low population density. The city of Asheville has the highest population 

density in the region. Valley monitors below 4000 feet located in and near Asheville are well below 

the NAAQS, which shows that local precursor sources are not significantly contributing to the 

ozone violations at monitors above 4000 feet. (Please see Appendix I for maps of population 

density) 

Traffic And Commuting Patterns: 

 Most of the traffic within the recommended nonattainment area is associated with the Blue 

Ridge Parkway. Yancey County, which includes the largest portion of the nonattainment area, has 

454,640 Daily VMT and contributes 0.62% of the commuters that drive to Buncombe County to 

work each day. This pattern shows that the Black Mountains above 4000 feet nonattainment area 

should not be expanded to include wider area. 

Growth Rates And Patterns: 

Population growth within the Black Mountains is projected to be negligible. Growth in 

surrounding counties ranges from 5-15%. 

Meteorology: 

The violating ridge top monitors are located above the nocturnal boundary layer and are near 

or within the subsidence inversion at the top of the daytime mixed layer. Because of this 

stratification, the air at elevations above 4000 feet is characterized by long range transport and has 

different diurnal patterns than locations within the valleys. Backward trajectories in Appendix M 

show that air parcels on days with ozone at or above 0.076 ppm originate from areas outside the 

region including the western Piedmont of North Carolina, Tennessee, and the Ohio River Valley, 

suggesting that the inclusion of elevations below 4000 feet in the nonattainment area would have 

little impact on the violating monitors located above 4000 feet. 

Geography / Topography: 

 The Mount Mitchell ozone monitor is considered a high-elevation or ridge top monitor. 

Much like all the other ridge top ozone monitors in Western North Carolina, Mount Mitchell does 

not have a normal diurnal ozone response profile similar to ozone monitors in the valleys of the 

Mountains and throughout the balance of the Piedmont, Sandhills, and Coastal Plains. Instead of 

recording exceedances of the 8-hour ozone standard during the middle of the afternoon when ozone 

production and photochemistry is at a maximum, the ozone exceedances at Mount Mitchell and 

other ridge top monitors occur during the nighttime hours. This timing of the exceedances is 

indicative of transport and not local generation of ozone, since the ozone chemistry stops once the 

sun goes sets. Figure 16 demonstrates a typical comparison between a mountain ridge top monitor 

(red line), a mountain valley monitor (blue), and a large metropolitan area monitor (yellow). 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 26 
Figure 16: Diurnal Ozone Profile Comparison (Ridge Top, Valley, and Large Metropolitan Sites)

Jurisdictional Boundaries: 

Buncombe County is one of the counties in the Mountain Area Early Action Compact 

(EAC) under the 1997 8-hour standard. The recommended nonattainment area is defined by the 

elevation of 4000 feet in the counties where the Black Mountains are located (Buncombe, 

McDowell, and Yancey). These counties have not previously been designated nonattainment. 

Level of Control of Emission Sources: 

 Buncombe County, which encompasses the western portion of the recommended 

nonattainment area, has an OBD-based I/M program. McDowell and Yancey counties do not have 

an OBD-based I/M program, but annual visual inspection of emissions equipment is required. 

Other Federal and state (North Carolina and surrounding states) mobile and point strategies to 

reduce emissions will have a much greater impact in reducing ozone levels below the NAAQS 

above 4000 feet. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment strategy, 

regardless of designation. North Carolina believes this is an important consideration for 

setting nonattainment boundaries. The new inspection and maintenance program that 

requires on-board diagnostic testing in 48 counties (phased in between 2002 and 2006) is an 

example of North Carolina’s ability to control sources in counties regardless of the 

nonattainment designations. The new I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 27 
Hickory-Lenoir-Morganton Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Alexander, Burke, Caldwell, and Catawba Counties 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 The Unifour Metropolitan Planning Organization Planning Boundary within Burke and 

Caldwell Counties, and the whole of Catawba and Alexander Counties 

Discussion: 

 Point and mobile emissions are sparse outside the Metropolitan Planning Organization 

(MPO) boundary within in western Burke and Caldwell Counties. Additionally, population density 

is substantially lower in the same area compared to areas within the MPO. An analysis of 

trajectories shows little impact from western Burke and Caldwell Counties on high ozone days. 

Thus, we recommend that areas outside the MPO boundaries in western Caldwell and Burke 

Counties be designated attainment. 

Figure 17: Recommended Nonattainment Area. 

Air quality data: 

There are two monitoring sites located in the Hickory-Lenoir-Morganton MSA, one in 

Lenoir in Caldwell County and one in Taylorsville in Alexander County. The Taylorsville site has a 

marginal violation at 0.076 ppm, while the Lenoir site is under the NAAQS at 0.075 ppm. A site 

close to the western border of Burke county in Linville is well under the NAAQS, at 0.067 ppm. A 

wind analysis suggests that on the majority days with higher ozone at these monitors, Charlotte is 

having the most impact on these sites. There are also a number of days when these sites are 

impacted by transport from the west and northwest, and that pollution comes over the mountains 

and mixes down into the valleys where the monitors are located. For these reasons, we recommend 

a smaller area than the full MSA. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 28 
Figure 18: Unifour Regional 2006-2008 8-Hour Ozone Design Values Map (Please Note That All Design Value 

Concentrations Presented Above Are In Parts Per Billion (ppb) To Conserve Space On The Map. 76 ppb = 0.076 

ppm.)

Table 6: Hickory Regional Ozone Design Value Table 

Emissions Data: 

 There are no significant point sources in western Burke and Caldwell counties, outside the 

MPO boundary. Hence, the recommended nonattainment boundary should not include areas 

outside the MPO boundary in western Burke and Caldwell Counties. 

Population Density And Degree Of Urbanization: 

As of July 2007 estimates, there are 153,404 people in Catawba County, 88,439 people in 

Burke County, 79,376 in Caldwell County, and 36,656 in Alexander County. North Carolina’s 

recommended nonattainment boundary captures 318,837 people, of the total 357,875 people living 

in the four county MSA, or 89 percent of the population is represented in the MPO planning 

boundary. In the recommended partial counties (Burke and Caldwell), the MPO boundary captures 

69.8% or 61,466 people and 84.8% or 67,311 people in Burke and Caldwell counties, respectively. 

Population density is much lower outside the MPO boundary in western Burke and Caldwell 

Counties (see Appendix I). 

Traffic And Commuting Patterns: 

 Caldwell County has 1,699,900 Daily VMT and contributes 8.45% of the commuters that 

drive to Catawba County to work each day. Daily VMT are expected to increase to 1,904,030 in 

2005 2006 2007 2008 05-07 06-08

Waggin Trail 37-003-0004 0.080 0.076 0.081 0.076 0.079 0.077

Lenoir 37-027-0003 0.075 0.076 0.077 0.072 0.076 0.075

Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average Design Value

Unifour

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 29 
2020. Burke County has 2,685,230 Daily VMT and contributes 8.83% of the commuters that drive 

to Catawba County to work each day. Daily VMT are expected to increase to 2,938,960 in 2020. 

The amount of daily commuters originating from western Burke and Caldwell counties and outside 

the MPO is small. 

Growth Rates And Patterns: 

Population growth from 2000-2007 is 4.7%, well below the statewide average of 8.3%. 

Catawba county population is projected to grow 11.5% from 2000-2010, and 12.6% from 2010 to 

2020. Burke county population is projected to decline 0.9% from 2000-2010, and 0.7% from 2010 

to 2020. Caldwell county population is projected to grow 3.2% from 2000-2010, and 2.0% from 

2010 to 2020. Alexander county population is projected to grow 11.9% from 2000-2010, and 8.0% 

from 2010 to 2020. 

Meteorology: 

On the days when these monitors exceed the 8-hour standard, they appear to be measuring 

pollution from several other areas, mainly Charlotte and the Triad but also including eastern 

Tennessee, and the Ohio River Valley. As the pollution in these areas is reduced, these monitors 

should observe lower ozone levels. Currently, the design value for the Lenoir monitor is 0.075 ppm 

and the Taylorsville monitor is 0.076 ppm. The trajectory analysis included in Appendix K shows 

that the last 5-6 hours of the trajectories cross eastern portions of the 4 counties. Very few 

trajectories pass through western Burke and Caldwell Counties on their way to the monitors. 

Geography / Topography: 

 The mountains in the western part of the Burke and Caldwell Counties need to be factored in 

to the nonattainment designation. These areas coincide with areas within the Pisgah National 

Forest. 

Jurisdictional Boundaries: 

The western parts of Burke and Caldwell Counties are within the Pisgah National Forest. 

The recommended nonattainment area matches the MPO boundaries in Burke and Caldwell 

Counties. Alexander, Burke, Caldwell and Catawba counties make up the Unifour Early Action 

Compact (EAC) Area under the 1997 8-hour ozone. 

Level of Control of Emission Sources: 

The majority of the emissions are generated from mobile sources. An OBD-based 

inspection and maintenance program is active in Catawba, Caldwell, and Burke Counties. Although 

Alexander County does not have and OBD based I/M program, annual visual inspection of emission 

equipment is required. Other Federal and state mobile strategies will also reduce these emissions. 

Low sulfur diesel and gasoline is required statewide. The Marshall Steam Station in Catawba 

County is now required to reduce the NOx emissions to meet the NOx SIP Call and the Clean 

Smokestacks Act. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment strategy, 

regardless of designation. North Carolina believes this is an important consideration for 

setting nonattainment boundaries. The new inspection and maintenance program that 

requires on-board diagnostic testing in 48 counties (phased in between 2002 and 2006) is an 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 30 
example of North Carolina’s ability to control sources in counties regardless of the 

nonattainment designations. The new I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 31 
Charlotte-Gastonia-Rock Hill Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

The whole counties of Iredell, Mecklenburg, Lincoln, Gaston, Cleveland, Union, Anson, 

Stanly, Cabarrus, and Rowan. 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

The whole counties of Cabarrus, Gaston, Lincoln, Mecklenburg, Rowan and Union and the 

partial county of Iredell. 

Figure 19: Metrolina NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Table 7: Charlotte/Metrolina Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

County Line 37-119-1009 0.090 0.093 0.096 0.093 0.093 0.094

Enochville 37-159-0022 0.088 0.089 0.095 0.082 0.090 0.088

Rockw ell 37-159-0021 0.086 0.085 0.096 0.084 0.089 0.088

Garinger 37-119-0041 0.088 0.091 0.093 0.085 0.090 0.089

Crouse 37-109-0004 0.082 0.082 0.085 0.079 0.083 0.082

Monroe 37-179-0003 0.082 0.080 0.082 0.080 0.081 0.080

Arrow ood 37-119-1005 0.085 0.078 0.087 0.073 0.083 0.079

York (South Carolina) 45-091-0006 0.079 0.078 0.080 0.075 0.079 0.077

Annual 4th Highest 8-Hour Average Design Value Region Monitoring Sites AIRS ID

Metrolina

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 32 
The monitors in the Charlotte-Gastonia-Rock Hill MSA currently measure the highest ozone values 

in the State. North Carolina recommends, relative to the North Carolina counties, that the whole 

counties of Cabarrus, Gaston, Lincoln, Mecklenburg, Rowan and Union and the partial county of 

Iredell be designated as nonattainment. The counties not recommended and the partial county 

recommendations are discussed below, along with the 9 criteria EPA identified in their 

nonattainment boundary guidance that should be addressed. 

Iredell County 

This is an MiSA county within the Charlotte-Gastonia-Salisbury CSA, but it does not have a 

monitor located in the county. This is a high commuter county into the Charlotte area along the I77 corridor. The northern portion of the county is rural, so the recommendation is for a smaller area 

than the entire county. 

The recommendation is that the two townships in the southern portion of Iredell County, Coddle 

Creek and Davidson Townships, as defined by the 2000 Census, be designated as nonattainment.

Air Quality Data: 

As shown in Figure 19 above, this area has 7 monitors with design values ranging from 

0.079 ppm to 0.094 ppm. The monitor located nearest Iredell County is in neighboring 

Rowan County in Enochville with a design value of 0.088 ppm. However, on days when 

this monitor has the highest readings, the winds are generally out of the southwest, 

indicating that the emissions from southern Iredell County are not likely to contribute to the 

Enochville monitor’s high ozone levels. 

Emissions Data: 

Based on 2005 emissions inventories, Iredell County has 2012.88 tons per year of pointsource NOx and the county has 768.55 tons per year of point-source VOC. There are some 

industrial sources in the county, including a natural gas pumping station, which is subject to 

the NOx SIP call. 

Population Density and Degree of Urbanization: 

122,660 people live in Iredell County, 39,885 people live in the two townships 

recommended as nonattainment. The northern portion of Iredell County has low population 

density, with 2 tracts containing 50-100 people per square mile, and 5 tracts with 100-250 

people per square mile. The northern portion also includes Statesville, with 1 tract 

containing 250-500 people per square mile, and 5 small tracts with 500-2500 people per 

square mile. The portion that is recommended to be designated nonattainment has 1 tract 

with 250-500 people per square mile, and 2 small tracts with 500-1000 people per square 

mile. (Please see Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Iredell County has 5,208,390 Daily VMT, according to 2007 data. Iredell County 

contributes 2.02 percent of the commuters who drive in to Mecklenburg County to work 

each day. Iredell ranks number 5 in the commuting counties into Mecklenburg. These 

VMT are expected to increase to 6,236,920 by 2020. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 33 
Growth Rates and Patterns: 

The population in Iredell County is expected to grow between 2000 and 2010, with a total 

increase of 32.0%. 

Meteorology: 

Winds across Iredell County are climatologically from the southwest. With this 

climatological wind pattern, the emissions in the southern part of the county will likely 

impact the Triad area. On days when the winds are from the north, the emissions will add to 

the Charlotte area’s pollution. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The existing 1997 8-hour ozone standard nonattainment area includes the southern portion 

of Iredell County, which is also included in North Carolina’s recommendation as 

nonattainment for the new 8-hour ozone standard. 

Level of control of emissions sources: 

Iredell County currently has 2 major point sources for NOx and one major point source for 

VOCs. One fuel pumping station is subject to the NOx SIP Call. However, controls for 

additional large point sources are handled on a case-by-case basis. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Iredell County currently has an OBD based I/M program and 

low-sulfur gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment 

strategy, regardless of designation. North Carolina believes this is an important 

consideration for setting nonattainment boundaries. The new inspection and 

maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Cleveland County 

This is an MiSA county within the Charlotte-Gastonia-Salisbury CSA, but it does not have a 

monitor located in the county. This is a mostly rural county with a low impact from commuting 

traffic into the urbanized core of the CSA. Therefore, North Carolina is recommending no portion 

of the county be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 19 above, this area has 7 monitors with design values ranging from 

0.079 ppm to 0.094 ppm. The monitor located nearest Cleveland County is in neighboring 

Lincoln County in Crouse with a design value of 0.082 ppm. However, on days when this 

monitor has the highest readings with winds generally out of the southwest, Cleveland 

County has no additional impact on the air quality within the CSA. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 34 
Emissions Data: 

Based on 2005 emissions inventories, Cleveland County has 184.87 tons per year of pointsource NOx and the county has 793.60 tons per year of point-source VOC. There are two 

major point sources in the county (1 each for NOx and VOC). 

Population Density and Degree of Urbanization: 

96,408 people live in Cleveland County. The northern portion of Cleveland County has low 

population density, with 9 tracts of less than 250 people per square mile. Two small tracts 

of 250-1000 people per square mile and 3 smaller tracts of 1000-2500 people per square 

mile are in the southeastern portion of the county. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Cleveland County has 2,727,700 Daily VMT, according to 2007 data. Cleveland County 

contributes less than 1 percent of the commuters who drive in to Mecklenburg County to 

work each day. These VMT are expected to increase to 3,087,880 by 2020. 

Growth Rates and Patterns: 

The population in Cleveland County is expected to grow slightly between 2000 and 2010, 

with a total increase of 0.8%. 

Meteorology: 

Winds across Cleveland County are climatologically from the southwest. With this 

climatological wind pattern, the emissions in the southern part of the county will likely not 

impact the air quality within the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The existing 1997 8-hour ozone standard nonattainment area does not include Cleveland 

County and it is not included in North Carolina’s recommendation as nonattainment for the 

new 8-hour ozone standard. 

Level of control of emissions sources: 

Cleveland County currently has 1 major point source for NOx and one major point source 

for VOCs. However, these sources are non-EGUs and controls for each facility will be 

handled on a case-by-case basis. Additional NOx emissions are from mobile sources, and 

the combined Federal and state control programs will address these emissions. Cleveland 

County currently has an OBD based I/M program and low-sulfur gasoline is required 

statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 35 
control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Anson County 

This is an MSA county within the Charlotte-Gastonia-Salisbury CSA, but it does not have a 

monitor located in the county. This is a mostly rural county with a low impact from commuting 

traffic into the urbanized core of the CSA. Therefore, North Carolina is recommending no portion 

of the county be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 19 above, this area has 7 monitors with design values ranging from 

0.079 ppm to 0.094 ppm. The monitor located nearest Anson County is in neighboring 

Union County in Monroe with a design value of 0.080 ppm. However, on days when this 

monitor has the highest readings with winds generally out of the southwest, Anson County 

has no additional impact on the air quality within the CSA. 

Emissions Data: 

Based on 2005 emissions inventories, Anson County has 171.82 tons per year of pointsource NOx and the county has 58.61 tons per year of point-source VOC. There are no 

major point sources located within the county. 

Population Density and Degree of Urbanization: 

25,321 people live in Anson County. The northern portion of Anson County is a largely 

rural county with no tracts having a population density fewer than 250 people per square 

mile. (Please see Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Anson County has 829,870 Daily VMT, according to 2007 data. Anson County contributes 

less than half of 1 percent of the commuters who drive in to Mecklenburg County to work 

each day. These VMT are expected to increase to 944,060 by 2020. 

Growth Rates and Patterns: 

The population in Anson County is expected to decrease slightly between 2000 and 2010, 

with a total decrease of 1.7%. A further decrease is expected from 2010 to 2020, falling by 

4.3%. 

Meteorology: 

Winds across Anson County are climatologically from the southwest. With this 

climatological wind pattern, the emissions in the southern part of the county will have no 

impact on the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The existing 1997 8-hour ozone standard nonattainment area does not include Anson County 

and it is not included in North Carolina’s recommendation as nonattainment for the new 8-

hour ozone standard. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 36 
Level of control of emissions sources: 

There are no major point sources to consider controls within the county. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Anson County does not currently have an OBD based I/M 

program, but requires an annual visual inspection of emissions equipment. Low-sulfur 

gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999.

Stanly County 

This is an MiSA county within the Charlotte-Gastonia-Salisbury CSA, but it does not have a 

monitor located in the county. This is a mostly rural county with a low impact on commuting traffic 

into the urbanized core of the CSA. Therefore, North Carolina is recommending no portion of the 

county be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 19 above, this area has 7 monitors with design values ranging from 

0.079 ppm to 0.094 ppm. The monitor located nearest Stanly County is in neighboring 

Rowan County in Rockwell with a design value of 0.088 ppm. However, on days when this 

monitor has the highest readings with winds generally out of the southwest, Stanly County 

has no additional impact on the air quality within the CSA. 

Emissions Data: 

Based on 2005 emissions inventories, Stanly County has 363.74 tons per year of pointsource NOx and the county has 340.35 tons per year of point-source VOC. There is one 

major point source of NOx emissions in Stanly County. 

Population Density and Degree of Urbanization:

58,277 people live in Stanly County. The northern portion of Stanly County is a largely 

rural county with 7 tracts having a population density fewer than 250 people per square 

mile, 2 tracts with a density of 250-500 people per square mile and 1 tract each of 500-1000 

and 1000-2500 people per square mile. (Please see Appendix I for maps of population 

density) 

Traffic and Commuting Patterns:

Stanly County has 1,418,410 Daily VMT, according to 2007 data. Stanly County 

contributes less than 1 percent of the commuters who drive in to Mecklenburg County to 

work each day. These VMT are expected to increase to 1,495,570 by 2020. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 37 
Growth Rates and Patterns:

The population in Stanly County is expected to increase slightly between 2000 and 2010, 

with a total decrease of 2.3%. 

Meteorology: 

Winds across Stanly County are climatologically from the southwest. With this 

climatological wind pattern, the emissions in the southern part of the county will have no 

additional impact on the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The existing 1997 8-hour ozone standard nonattainment area does not include Stanly County 

and it is not included in North Carolina’s recommendation as nonattainment for the new 8-

hour ozone standard. 

Level of control of emissions sources: 

There is one major point source to consider within the county, but this source is not subject 

to the NOx SIP Call. Therefore, controls are handled on a per-case basis. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Stanly County does not currently have an OBD based I/M 

program, but requires an annual visual inspection of emissions equipment. Low-sulfur 

gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina General 

Statute allows sources anywhere in the state to be controlled under an attainment 

strategy, regardless of designation. North Carolina believes this is an important 

consideration for setting nonattainment boundaries. The new inspection and 

maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 38 
Greensboro-Winston-Salem-High Point Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Surry, Stokes, Rockingham, Caswell, Yadkin, Forsyth, Guilford, Alamance, Davie, Davidson and Randolph 

Counties 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Forsyth, Guilford, Alamance, Davidson, Caswell, Davie, Rockingham and the partial counties of Randolph and 

Orange 

Figure 20: Triad NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Table 8: Greensboro-Winston-Salem-High Point (Triad) Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

Cooleemee 37-059-0002 0.084 0.080 0.085 0.081 0.083 0.082

Mendenhall 37-081-0013 0.082 0.080 0.086 0.081 0.082 0.082

Union Cross 37-067-1008 0.080 0.082 0.083 0.078 0.081 0.081

Hattie Ave. 37-067-0022 0.074 0.082 0.082 0.081 0.079 0.081

Bethany 37-157-0099 0.078 0.075 0.082 0.084 0.078 0.080

Cherry Grove 37-033-0001 0.076 0.075 0.082 0.080 0.077 0.079

Clemmons 37-067-0030 0.075 0.077 0.078 0.078 0.076 0.077

Shiloh Church 37-067-0028 0.078 0.067 0.076 0.077 0.073 0.073

Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average Design Value

Triad

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 39 
The monitors in the Greensboro/ Winston Salem/High Point CSA currently measure the second 

highest ozone values in the State. North Carolina recommends that the whole counties of Forsyth, 

Guilford, Alamance, Davidson, Caswell, Davie, Rockingham and the partial counties of Randolph 

and Orange be designated as nonattainment. Counties for which recommendations differ from 

EPA’s presumptive boundaries are discussed below, along with the 9 criteria EPA identified in their 

nonattainment boundary guidance that should be addressed. 

Stokes County 

 This is an MSA county within the Greensboro-Winston Salem-High Point CSA, but there is 

no monitor located here. This is a rural county, so the recommendation is that no portion of the 

county be designated nonattainment. 

Air Quality Data: 

As shown in Figure 20 above, the Triad area has 8 monitors with design values ranging from 

0.073 ppm to 0.082 ppm. While Stokes County has no monitor, the nearest is located in 

Forsyth County with a design value of 0.073, and the second nearest monitor is located in 

Rockingham County with a design value of 0.080. 

Emissions Data: 

Based on 2002 emissions inventories, Stokes County has 21017.08 tons per year of NOx and 

the county has 95367.89 tons per year of VOC (anthropogenic only). The large source of 

NOx emissions are from the Duke Energy Belews Creek facility, which has reduced and will 

continue to reduce the NOx emissions to about 31 tons per day under the NOx SIP call. 

Population Density and Degree of Urbanization: 

44,711 people live in Stokes County. The county in general has a relatively low population 

density, with most tracts having 250 or fewer people per square mile. Two small tracts have 

a population density of 250-500 people per square mile. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Stokes County has 889,040 Daily VMT and contributes 6.03 percent of the commuters that 

drive to Forsyth County to work each day. These VMT are expected to increase to 

1,039,980 in 2020. 

Growth Rates and Patterns: 

The population in Stokes County is expected to grow slightly between 2000 and 2010, with 

a total increase of 5% or less. 

Meteorology: 

Winds across Stokes County are climatologically from the southwest. With this 

climatological wind pattern, the county is not in an upwind sector that would routinely have 

an impact on air quality in any portion of the CSA or North Carolina. The exception is in 

the case of northerly winds. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 40 
Jurisdictional Boundaries: 

Stokes County is one of several counties in the Triad Early Action Compact area under the 

1997 8-hour ozone standard. The counties in the Triad EAC were designated attainment 

April 15, 2008. 

Level of control of emissions sources: 

Currently there is one major point source in Stokes County to control and this facility is 

subject to the NOx SIP call. The remaining NOx emissions are from mobile sources, and 

the combined Federal and state control programs will address these emissions. Stokes 

County currently has an OBD-based I/M program and low-sulfur gasoline is required 

statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The OBDbased I/M program was adopted in 1999. 

Yadkin County 

 This is an MSA county within the Greensboro-Winston Salem-High Point CSA, but there is 

no monitor located here. This is a rural county, so the recommendation is that no portion of the 

county be designated nonattainment. 

Air Quality Data: 

As shown in Figure 20 above, this area has 8 monitors with design values ranging from 

0.073 ppm to 0.082 ppm. There is no monitor in Yadkin County, but the closest monitor is 

located in Forsyth County and has a design value of 0.077 ppm. 

Emissions Data: 

There are no large point sources in the county.

Population Density and Degree of Urbanization: 

36,348 people live in Yadkin County. The county in general has a relatively low population 

density, with most tracts having 100 or fewer people per square mile. Two small tracts have 

a population density of 100-250 people per square mile. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Yadkin County has 1,381,260 Daily VMT as of 2007. Yadkin County contributes 3.23 

percent of the commuters that drive to Forsyth County to work each day. These VMT are 

expected to increase to 1,635,170 by 2020. 

Growth Rates and Patterns: 

The population in Yadkin County is expected to grow moderately between 2000 and 2010, 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 41 
with a total increase of 6.1%. 

Meteorology: 

Winds across Yadkin County are climatologically from the southwest. With this 

climatological wind pattern, the majority of the county is not in an upwind sector that would 

routinely have an impact on air quality in the urban portion of the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

Yadkin County is one of several counties in the Triad Early Action Compact area under the 

1997 8-hour ozone standard. The counties in the Triad EAC were designated attainment 

April 15, 2008. 

Level of control of emissions sources: 

There are no major point sources in the county needing control. The remaining NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Yadkin County currently has no OBD-based I/M program, but 

it has an annual safety inspection program requiring a visual check of emissions control 

devices for tampering. Low-sulfur gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Surry County 

 This is not an MSA county but rather a Micropolitan Statistical Area (MiSA) within the 

Greensboro-High Point-Winston Salem CSA and there is no monitor located here. This is a rural 

county, so the recommendation is that no portion of the county be designated nonattainment. 

Air Quality Data: 

As shown in Figure 20 above, this area has 8 monitors with design values ranging from 

0.073 ppm to 0.082 ppm. There is no monitor in Surry County, but the closest monitor is 

located in Forsyth County and has a design value of 0.073 ppm. 

Emissions Data: 

Based on 2002 point source emissions inventories, Surry County has 326.49 tons per year of 

NOx and the county has 1222.35 tons per year of VOC. The largest point sources in Surry 

County are the True Textiles, Weyerhaeuser Company and Vaughan-Bassett Furniture 

Company manufacturing facilities.

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 42 
Population Density and Degree of Urbanization: 

71,219 people live in Surry County. The entire County has fairly low population density, 

with 2 tracts containing 50-100 people per square mile, 6 tracts containing 100-250 people 

per square mile, 3 small tracts containing 250-1000 people per square mile and one minor 

tract containing 1000-2500 people per square mile. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Surry County has 2,396,290 Daily VMT. Surry County contributes 2.54 percent of the 

commuters that drive to Forsyth County to work each day. These VMT are expected to 

decrease to 2,359,680 by 2020. 

Growth Rates and Patterns: 

The population in Surry County is expected to grow between 2000 and 2010, with a total 

increase of 4.0%. 

Meteorology: 

Winds across Surry County are climatologically from the southwest. With this 

climatological wind pattern, the northwestern portion of the county is not in an upwind 

sector that would routinely have an impact on air quality in the urban portion of the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

Surry County is one of several counties in the Triad Early Action Compact area under the 

1997 8-hour ozone standard. The counties in the Triad EAC were designated attainment 

April 15, 2008. 

Level of control of emissions sources: 

As discussed there are 3 non-EGU major point sources in Surry County. Controls for nonEGUs are regulated on a case-by-case basis. The remaining NOx emissions are from mobile 

sources, and the combined Federal and state control programs will address these emissions. 

Surry County currently has an OBD-based I/M program and low-sulfur gasoline is required 

statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Randolph County 

 This is an MSA county within the Greensboro-Winston Salem-High Point CSA, but it does 

not have a monitor and is a mostly rural county. Therefore, North Carolina’s recommendation is for 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 43 
a smaller area of the county to be designated as nonattainment. 

The recommendation is that the High Point Metropolitan Planning Organization portion of 

Randolph County be designated as nonattainment.

Air Quality Data 

As shown in Figure 20 above, this area has 8 monitors with design values ranging from 

0.073 ppm to 0.082 ppm. The nearest monitor to this region is in southeastern Forsyth 

County with a design value of 0.081 ppm. 

Emissions Data: 

Based on 2002 point-source emissions inventories, Randolph County has 55.09 tons per year 

of NOx and the county has 747.49 tons per year of VOC. The largest point source (VOC 

emissions) in the county is the Oliver Rubber Company. 

Population Density and Degree of Urbanization: 

130,454 people live in Randolph County. Much of the County has low population density, 

with 10 tracts of 250 people or less per square mile, 5 tracts containing 250-500 people per 

square mile, 3 small tracts of 500-1000 people per square mile and 5 smaller tracts 

containing 1000-2500 people per square mile. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Randolph County has 3,742,370 Daily VMT. Randolph County contributes 7.54 percent of 

the commuters that drive to Guilford County to work each day. These VMT are expected to 

increase to 4,253,460 by 2020. 

Growth Rates and Patterns: 

The population in Randolph County is expected to grow moderately between 2000 and 

2010, with a total increase of 9.2%. 

Meteorology: 

Winds across Randolph County are climatologically from the southwest. With this 

climatological wind pattern, the portion of the county to be excluded from designation as 

nonattainment would not serve as an upwind sector that would routinely have an impact on 

air quality in the urban portion of the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

Randolph County is one of several counties in the Triad Early Action Compact area under 

the 1997 8-hour ozone standard. The counties in the Triad EAC were designated attainment 

April 15, 2008. The High Point Metropolitan Planning Organization boundary as of March 

12, 2009, defines the portion of Randolph County that is recommended to be designated 

nonattainment. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 44 
Level of control of emissions sources: 

As discussed there are 3 non-EGU major point sources (VOC) in Randolph County with no 

major NOx point sources. Controls for non-EGUs are regulated on a case-by-case basis. 

The remaining NOx emissions are from mobile sources, and the combined Federal and state 

control programs will address these emissions. Randolph County currently has an OBDbased I/M program and low-sulfur gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Orange County 

 This is not a county within the Triad CSA; however, a portion of the county is part of the 

Burlington-Graham Metropolitan Planning Organization. In order to avoid duplication of 

transportation conformity exercises, this portion of Orange County is recommended to be 

considered part of the Triad nonattainment area. Because the bulk of the county is included in the 

Raleigh-Durham-Cary CSA, the nine factors are addressed in the Raleigh-Durham-Cary Area 

discussion rather than here. 

The recommendation is that the Burlington-Graham Metropolitan Planning Organization portion of 

Orange County be designated as nonattainment for the Greensboro-Winston-Salem-High Point 

Nonattainment Area for the purposes of transportation conformity.

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 45 
Raleigh-Durham-Cary Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Wake, Johnston, Harnett, Orange, Durham, Chatham, Person, Granville and Franklin Counties. 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Wake, Orange, Durham, Person, Granville, and Franklin counties and the partial counties of Chatham and 

Johnston. 

Figure 21: Triangle NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Table 9: Raleigh-Durham-Cary (Triangle) Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

Millbrook 37-183-0014 0.082 0.078 0.084 0.078 0.081 0.080

Butner 37-077-0001 0.085 0.076 0.083 0.081 0.081 0.080

Durham Armory 37-063-0015 0.076 0.078 0.080 0.076 0.078 0.078

Franklinton 37-069-0001 0.080 0.074 0.080 0.078 0.078 0.077

Bushy Fork 37-145-0003 0.079 0.075 0.079 0.078 0.077 0.077

W. Johnston 37-101-0002 0.083 0.072 0.078 0.076 0.077 0.075

Fuquay-Varina 37-183-0016 0.085 0.073 0.080 0.078 0.079 0.077

Pittsboro 37-037-0004 0.079 0.070 0.075 0.072 0.074 0.072

Annual 4th Highest 8-Hour Average Design Value Region Monitoring Sites AIRS ID

Triangle

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 46 
The monitors in the Raleigh-Durham-Cary CSA currently measure the third highest ozone values in 

the State. North Carolina recommends that the whole counties of Wake, Orange, Durham, Person, 

Granville, and Franklin counties and the partial counties of Chatham and Johnston be designated as 

nonattainment. In addition North Carolina recommends that portions of Orange County be 

associated with two different nonattainment areas for the purposes of transportation conformity. The 

counties not recommended and the partial county recommendations are discussed below, along with 

the 9 criteria EPA identified in their nonattainment boundary guidance that should be addressed. 

Harnett County 

 This is an MiSA county within the Raleigh-Durham-Cary CSA, but it does not have a 

monitor located in the county. This is a mostly rural county with no large commuting impact on the 

urbanized core. Therefore, North Carolina is recommending no portion of the county be designated 

as nonattainment. 

Air Quality Data 

As shown in Figure 21 above, this area has 8 monitors with design values ranging from 

0.072 ppm to 0.080 ppm. The monitor located nearest Harnett County is in neighboring 

Wake County in Fuquay with a design value of 0.077 ppm. Though the winds are 

climatologically out of the southwest, the limited emissions from this county are such that 

they do not significantly impact the air quality within the CSA. 

Emissions Data: 

Based on 2005 emissions inventories, Harnett County has 1.08 tons per year of point-source 

NOx and the county has 34.43 tons per year of point-source VOC. There are no major point 

sources of either NOx or VOC throughout the county. 

Population Density and Degree of Urbanization: 

91,085 people live in Harnett County as of 2000. The county is almost entirely rural, with 

no tracts with population density greater than 250 people per square mile. (Please see 

Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Harnett County has 2,541,190 Daily VMT, according to 2007 data. Harnett County 

contributes 2.45 percent of the commuters who drive in to Wake County to work each day. 

These VMT are expected to increase moderately to 2,946,700 by 2020. 

Growth Rates and Patterns: 

The population is expected to increase by 23.5% by 2010 and by 20.1% between 2010 and 

2020. These high percentages are exaggerated because of the small base population. 

Meteorology: 

Winds across Harnett County are climatologically from the southwest. Even with this 

climatological wind pattern, emissions from Harnett County are such that they have no 

significant impact on air quality degradation within the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 47 
Jurisdictional Boundaries: 

Harnett County is not included in any existing nonattainment area nor has it previously been 

designated nonattainment. The recommendation is that no portion within the county 

boundary be designated nonattainment. 

Level of control of emissions sources: 

Harnett County has no major point sources for NOx and VOC emissions. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Harnett County currently has an OBD-based I/M program and 

low-sulfur gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Johnston County 

 This is an MSA county within the Raleigh-Durham-Cary CSA with an attaining monitor 

located in the more populated, far western portion of the county. Most of the eastern portion of 

Johnston County is rural, with the western portion commuting into Wake County. Therefore, North 

Carolina is recommending that a smaller portion than the entire county be designated as 

nonattainment. 

The recommendation is that the area within the Capital Area Metropolitan Planning Organization 

boundary be designated as nonattainment.

Air Quality Data 

As shown in Figure 21 above, this area has 8 monitors with design values ranging from 

0.072 ppm to 0.080 ppm. The monitor located within the county currently has a design 

value of 0.075 ppm, which is attainment both for the previous and current 8-hour ozone 

standard. 

Emissions Data: 

Based on 2005 emissions inventories, Johnston County has 43.35 tons per year of pointsource NOx and the county has 253.87 tons per year of point-source VOC. There are no 

major point sources of NOx or VOC. 

Population Density and Degree of Urbanization: 

121,965 people live in Johnston County as 2000, 60,605 of which live in the portion 

recommended for nonattainment. The eastern portion of the county is mostly rural with 7 

tracts of 250 or fewer people per square mile and 1 small tract of 1000-2500 people. The 

area recommended for nonattainment is more urbanized with 4 tracts of population density 

between 100-500 people per square mile. (Please see Appendix I for maps of population 

density) 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 48 
Traffic and Commuting Patterns: 

Johnston County has 5,225,390 Daily VMT, according to 2007 data. Johnston County 

contributes 6.56 percent of the commuters who drive in to Wake County to work each day, 

most of which live in the western portion of the county. These VMT are expected to 

increase to 6,131,270 by 2020. 

Growth Rates and Patterns: 

The population in Johnston County is expected to grow between 2000 and 2010, with a total 

increase of 40.1%. An increase of 31.1% is expected between 2010 and 2020. 

Meteorology: 

Winds across Johnston County are climatologically from the southwest. With this 

climatological wind pattern, the limited emissions from the county have no significant 

impact on the degradation of the air quality within the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The Capital Area Metropolitan Planning Organization includes the Wilders, O’Neal, 

Clayton, Cleveland, Pleasant Grove and Elevation Townships. These areas were part of a 

previous ozone nonattainment area that was redesignated as attainment December 26, 2007. 

Level of control of emissions sources:

Johnston County currently has no major point source of NOx or VOCs. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Johnston County currently has an OBD-based I/M program 

and low-sulfur gasoline is required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

Chatham County 

 This is an MSA county within the Raleigh-Durham-Cary CSA with one attaining monitor 

located in the northwest portion of the county. This is a mostly rural county with a low impact on 

commuting traffic into the urbanized core of the CSA. Therefore, North Carolina is recommending 

a smaller portion than the entire county be designated as nonattainment. 

The recommendation is that the Baldwin, Center, New Hope and Williams Townships be 

designated as nonattainment.

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 49 
Air Quality Data: 

As shown in Figure 21 above, this area has 8 monitors with design values ranging from 

0.072 ppm to 0.080 ppm. The monitor located within Chatham County currently has the 

lowest design value of 0.072 ppm, which is in attainment for both the previous and current 

8-hour ozone standards. 

Emissions Data: 

Based on 2005 emissions inventories, Chatham County has 2494.81 tons per year of pointsource NOx and the county has 239.23 tons per year of point-source VOC. There are 2 

major point sources of NOx emissions and 2 major point sources for VOC emissions. One 

of the point sources is Progress Energy’s Cape Fear plant, which is subject to the NOx SIP 

Call. 

Population Density and Degree of Urbanization: 

49,329 people live in Chatham County, with 21,320 people living in the area recommended 

for nonattainment. The county is largely rural, with the area recommended for 

nonattainment having 3 tracts, all with 250 people or fewer per square mile. The western 

portion of the county has 1 small tract with 500-1000 people per square mile. (Please see 

Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Chatham County has 1,906,160 Daily VMT, according to 2007 data. Chatham County 

contributes less than 1 percent of the commuters who drive in to Wake County to work each 

day. These VMT are expected to increase to 2,502,830 by 2020. 

Growth Rates and Patterns: 

The population in Chatham County is expected to increase between 2000 and 2010, with a 

total decrease of 27.3%. A further increase is expected from 2010 to 2020, growing by 

22.3%. 

Meteorology: 

Winds across Chatham County are climatologically from the southwest. With this 

climatological wind pattern, only the emissions in the eastern portion of the county would 

have significant impact on the air quality within the CSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The Baldwin, Center, New Hope and Williams townships define the area recommended as 

the nonattainment boundary. These areas were part of a previous ozone nonattainment area 

that was redesignated as attainment December 26, 2007. 

Level of control of emissions sources: 

There are 2 major point sources of NOx and 2 major point sources for VOC emissions. The 

largest NOx point source is Progress Energy’s Cape Fear plant, which as mentioned before, 

is subject to the NOx SIP Call and Clean Smokestacks Act. Other major non-EGU source 

controls are handled on a case-by-case basis. Additional NOx emissions are from mobile 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 50 
sources, and the combined Federal and state control programs will address these emissions. 

Chatham County currently has an OBD-based I/M program. Low-sulfur gasoline is required 

statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999.

Orange County 

 This is an MSA county within the Raleigh-Durham-Cary CSA; however, a portion of the 

county is under the jurisdiction of the Burlington-Graham Metropolitan Planning Organization. In 

order to avoid duplication of transportation conformity exercises, this portion of Orange County is 

recommended to be considered part of the Triad nonattainment area that has a higher design value. 

The remainder of the county is recommended to be considered part of the Raleigh-Durham-Cary 

nonattainment area because a portion of the remainder of the county is covered by the DurhamChapel Hill-Carrboro Metropolitan Planning Organization. Because the county is included in the 

Raleigh-Durham-Cary CSA, the nine factors are addressed here for the whole county rather than 

duplicated in the Greensboro-Winston Salem-High Point discussion. 

The recommendation is that the Burlington-Graham Metropolitan Planning Organization portion of 

Orange County be designated as nonattainment for the Greensboro-Winston-Salem-High Point 

Nonattainment Area for the purposes of transportation conformity.

Air Quality Data: 

As shown in Figure 21 above, this area has 8 monitors with design values ranging from 

0.073 ppm to 0.082 ppm. The monitor nearest to this region is in southwestern Person 

County and has a design value of 0.077 ppm. 

Emissions Data: 

Based on 2002 point-source emissions inventories, Orange County has 561.28 tons per year 

of NOx and the county has 152.08 tons per year of VOC. The largest point source of NOx 

emissions in the county is not within the Burlington-Graham MPO, but exists in the 

southeastern portion of the county at the University of North Carolina at Chapel Hill. 

Population Density and Degree of Urbanization: 

118,227 people live in Orange County. Much of the County has low population density, 

with 8 tracts of 250 people or less per square mile, 2 tracts containing 250-500 people per 

square mile, 2 small tracts of 500-1000 people per square mile, 6 smaller tracts containing 

1000-2500 people per square mile, and 4 minor tracts containing more than 5000 people per 

square mile. Most of the densely populated tracts are located in the southeastern portion of 

Orange County. (Please see Appendix I for maps of population density) 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 51 
Traffic and Commuting Patterns: 

Orange County has 3,921,360 Daily VMT. Orange County contributes 1.17% of the 

commuters that drive to Wake County daily and 9.92% of the commuters that drive to 

Durham County daily. These VMT are expected to increase to 4,653,190 by 2020. Orange 

County contributes 0.2% of the commuters that drive to Guilford County in the GreensboroWinston Salem-High Point CSA daily and 0.05% to Forsyth County in the same CSA. 

Growth Rates and Patterns: 

The population in Orange County is expected to grow moderately between 2000 and 2010, 

with a total increase of 13.7%. 

Meteorology: 

Winds across Orange County are climatologically from the southwest. Most of the 

emissions within the county will have an impact on the northern portion of the RaleighDurham-Cary nonattainment. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

Orange County was part of a previous ozone nonattainment area that was redesignated as 

attainment December 26, 2007. 

Level of control of emissions sources: 

The major NOx point source in Orange County is the University of North Carolina, which is 

not within Burlington-Graham MPO. The remaining NOx emissions are from mobile 

sources and the combined Federal and state control programs will address these emissions. 

Orange County currently has an OBD based I/M program and low-sulfur gasoline is 

required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999.

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 52 
Fayetteville Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Cumberland and Hoke Counties 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Cumberland County 

Figure 22: Fayetteville NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Table 10: Fayetteville Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

Wade 37-051-0008 0.084 0.072 0.080 0.075 0.078 0.075

Golfview 37-051-1003 0.091 0.074 0.082 0.075 0.082 0.077

Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average Design Value

Fayetteville

The monitors in the Fayetteville MSA currently measure the fourth highest ozone values in the 

State. North Carolina recommends that the whole county of Cumberland be designated as 

nonattainment. Cumberland County was one of four Early Action Compact areas under the 1997 8-

hour ozone standard and was designated attainment April 15, 2008. The county not recommended is 

discussed below, along with the 9 criteria EPA identified in their nonattainment boundary guidance 

that should be addressed. 

Hoke County 

 This is a Fayetteville MSA county, but it does not have a monitor located in the county. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 53 
This is a minor commuting county into the urbanized core and is also mostly rural. Therefore, 

North Carolina is recommending no portion of the county be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 22 above, this area has 2 monitors with design values of 0.075 ppm to 

0.077 ppm. The monitor located nearest Hoke County is in Cumberland County in 

Golfview with a design value of 0.077 ppm. Though the winds are climatologically out of 

the southwest, the limited emissions from this county are such that they do not significantly 

impact the air quality within the Fayetteville MSA. 

Emissions Data: 

Based on 2005 emissions inventories, Hoke County has 63.38 tons per year of point-source 

NOx and the county has 10.18 tons per year of point-source VOC. There are no major point 

sources of either NOx or VOC throughout the county. 

Population Density and Degree of Urbanization: 

33,646 people live in Hoke County as of 2000. The county is almost entirely rural, with 4 

tracts with population density of 100 people or fewer per square mile. One small tract with 

population density of 500-1000 is in the center of the county. (Please see Appendix I for 

maps of population density) 

Traffic and Commuting Patterns: 

Hoke County has 807,740 Daily VMT, according to 2007 data, with no major commuting 

contribution to the Fayetteville MSA. These VMT are expected to increase moderately to 

1,140,050 by 2020. 

Growth Rates and Patterns: 

The population is expected to increase by 40.0% by 2010 and by 31.3% between 2010 and 

2020. This growth rate is exaggerated by the small base population. 

Meteorology: 

Winds across Hoke County are climatologically from the southwest. Even with this 

climatological wind pattern, emissions from Hoke County are such that they have no 

significant impact on air quality degradation within the Fayetteville MSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The Fort Bragg Military Reservation extends from northwestern Cumberland Ccounty 

through the northern half of Hoke County. There is also the Fayetteville Metropolitan 

Planning Organization covering Cumberland County and a portion of southern Harnett 

County and eastern Hoke County. The previous 8-hour ozone nonattainment area North 

Carolina’s recommended nonattainment area. 

Level of control of emissions sources: 

Hoke County has no major point sources for NOx and VOC emissions. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 54 
will address these emissions. Hoke County currently does not have an OBD-based I/M 

program, but a visual check of emissions equipment is required. Low-sulfur gasoline is also 

required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 55 
Greenville Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Pitt and Greene Counties 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 Unclassifiable, defer designation. 

Figure 23: Greenville NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Figure 24: Three-year design values of monitors surrounding the Greenville area. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 56 
Figure 25: Spatially allocated modeled design values for 2009. 

Table 11: Greenville Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

Farmville 37-147-0099 0.080 0.072 0.079 0.077

Pitt County Ag Center 37-147-0006 0.077

Lenoir College (Nearby) 37-107-0004 0.081 0.071 0.077 0.074 0.076 0.074

Jamesville (Nearby) 37-117-0001 0.079 0.070 0.075 0.074 0.074 0.073

Region Monitoring Sites AIRS ID Annual 4th Highest 8-Hour Average Design Value

Greenville

This area has a single ozone monitor, which was relocated prior to the start of the 2008 ozone 

season. Its fourth highest value in 2008 was 0.077 ppm; however, it is recommended that 

classification of the area be deferred until after the ozone season of 2010 when three consecutive 

years of data will be available at this monitor. This area has never been designated nonattainment, 

there are no major NOx sources in the area, an OBD-based I/M program was implemented in Pitt 

County by 2006, and the nearest upwind and downwind monitors are both in attainment of the new 

ozone standard (see Lenoir County and Martin County, respectively, in Figure 23) and both are 

trending downward (cleaner). Additionally, future-year 8-hour ozone State Implementation Plan air 

quality modeling has shown that the area under consideration is expected to be within attainment by 

2009. If a request for deferral is denied, North Carolina recommends Pitt County be designated as 

nonattainment and no portion of Greene County is designated as nonattainment. The counties 

associated with the request for deferral and those not recommended are discussed below, along with 

the 9 criteria EPA identified in their nonattainment boundary guidance that should be addressed. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 57 
Pitt County 

This is a Greenville MSA county with one monitor. This is a mostly rural county with an urbanized 

core. The monitor within the county has recently moved approximately 14.5 miles, which is 

beyond the distance that would allow the data from the two monitoring sites to be considered a 

continuous record. 

Air Quality Data 

As shown in Figure 23 above, this area has 1 monitor with no calculable design value. The 

monitor was previously located in Farmville, but has moved to the Pitt County Ag Center, in 

the western part of the county. As shown in Figure 24, monitoring trends at the surrounding 

ozone monitors indicate a downward progression in the design values, within attainment. 

Additionally, air quality modeling data shown in Figure 25 indicates the Greenville area will 

be within attainment by 2009. This future-year modeling has proven to be highly accurate at 

recreating design values for a given area. Using this information, North Carolina expects 

the Greenville area monitor to show attainment upon obtaining sufficient data for a design 

value to be calculated. 

Emissions Data: 

Based on 2005 emissions inventories, Pitt County has 139.59 tons per year of point source 

NOx from and the county has 623.40 tons per year of point source VOC from 9 sources. 

There is one major point source of VOC located in the southeastern part of the county. 

Population Density and Degree of Urbanization: 

134,107 people live in Pitt County as of 2000. The county is largely rural, with the 

exception of the urbanized core in Greenville. There are 9 tracts of 250 or fewer people per 

square mile, 4 tracts of 250 to 500 people per square mile, 1 tract of 500 to 1000 people per 

square mile, 3 tracts of 1000-2500 people per square, 4 small tracts of 2500-5000 people per 

square mile and 1 smaller tract of more than 5000 people per square mile. This dense urban 

core can mostly be attributed to East Carolina University, located in downtown Greenville. 

(Please see Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Pitt County has 3,377,830 Daily VMT, according to 2007 data, with most commuting 

occurring within the county. These VMT are expected to increase moderately to 4,065,700 

by 2020. 

Growth Rates and Patterns: 

The population is expected to increase by 19.9% between 2000 and 2010 and by 16.3% 

between 2010 and 2020. 

Meteorology: 

Winds across Pitt County are climatologically from the southwest. On days where the 

monitor experiences the highest levels of ozone, this is mostly attributable to recirculation of 

emissions within the county. Additional emissions from an EGU downwind also aids in 

high ozone concentrations. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 58 
Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The Greenville Metropolitan Planning Organization is located within the central portion of 

Pitt County. This MPO is also within the larger Mideast Rural Planning Organization. Pitt 

County was not previously designated as nonattainment. 

Level of control of emissions sources: 

Pitt County has no major point sources for NOx, but does have one major point source for 

VOC. Large point sources that are non-EGUs are controlled on a case-by-case basis. 

Additional NOx emissions are from mobile sources, and the combined Federal and state 

control programs will address these emissions. Pitt County currently has an OBD-based I/M 

program. Low-sulfur gasoline is also required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was enacted in 1999 by the General Assembly. 

Greene County 

 This is a Greenville MSA county, but there is no monitor located within this county. This 

county is entirely rural, with no large commuting impact on the urbanized core. The monitor 

nearest the county has recently moved beyond the distance that would allow the data from the two 

monitoring sites to be considered a continuous record. The second nearest monitor is located in 

Lenoir County at Lenoir Community College in Kinston, with a design value of 0.074 ppm. Based 

on the rural characteristics, lack of emissions and surrounding monitors indicating attainment, North 

Carolina recommends no portion of Greene County be designated nonattainment. 

Air Quality Data: 

As shown in Figure 23 above, this area has 1 monitor with no calculable design value. The 

monitor was previously located in Farmville, but has moved to the Pitt County Ag Center, in 

the western part of Pitt County. Monitoring trends at the surrounding ozone monitors 

indicate a downward progression in the design values, within attainment. Upon obtaining 

sufficient data for a design value to be calculated for the monitor located in Greene County, 

North Carolina expects this monitor to also show attainment. 

Emissions Data: 

Based on 2005 emissions inventories, Greene County has 1.4 tons per year of point-source 

NOx and the county has 0.07 tons per year of point-source VOC. There are no major point 

sources in this county. 

Population Density and Degree of Urbanization: 

18,976 people live in Greene County as of 2000. The county is entirely rural. There are no 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 59 
tracts with population densities greater than 250 people per square mile. (Please see 

Appendix I for maps of population density) 

Traffic and Commuting Patterns: 

Greene County has 585,250 Daily VMT, according to 2007 data, comprising 2.98% of the 

commuting traffic into Pitt County for work. These VMT are expected to increase 

moderately to 731,000 by 2020. 

Growth Rates and Patterns: 

The population is expected to increase by 13.5% between 2000 and 2010 and by 8.8% 

between 2010 and 2020. 

Meteorology: 

Winds across Greene County are climatologically from the southwest. Given the lack of 

emissions within the county, North Carolina asserts that this county has no appreciable 

impact on the air quality within the Greenville MSA. 

Geography/Topography: 

There are no special geography or topography issues to consider in this region. 

Jurisdictional Boundaries: 

The Eastern Carolina Rural Planning Organization includes the counties of Greene, Wayne, 

Lenoir and Duplin. Greene County has never been designated nonattainment. 

Level of control of emissions sources: 

Greene County has no major point sources for either NOx or VOCs. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Greene County currently has no OBD-based I/M program, but 

a visual inspection of emissions equipment is required. Low-sulfur gasoline is also required 

statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was enacted in 1999 by the General Assembly. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 60 
Virginia Beach-Norfolk-Newport News Nonattainment Area Discussion 

EPA Presumptive 8-Hour Ozone Nonattainment Boundary: 

 Currituck County 

North Carolina’s Recommended 8-Hour Ozone Nonattainment Boundary: 

 No portion of Currituck County designated as nonattainment 

Figure 26: Currituck NC Regional 2006-2008 8-Hour Ozone Design Values Map 

Table 12: Fayetteville Regional Ozone Design Value Table 

2005 2006 2007 2008 05-07 06-08

Jamesville (Nearby) 37-117-0001 0.079 0.070 0.075 0.074 0.074 0.073

Sulfolk (Virginia) 51-800-0005 0.078 0.071 0.078 0.078 0.075 0.075

Sulfolk (Virginia) 51-800-0004 0.077 0.077 0.076 0.077 0.076 0.076

Hampton (Virginia) 51-650-0004 0.078 0.076 0.076 0.079 0.076 0.077

Annual 4th Highest 8-Hour Average Region Monitoring Sites AIRS ID

Currituck County, 

Tidewater VA

Design Value

EPA is recommending Currituck County be included in the 8-hour ozone nonattainment boundary 

within the Virginia Beach-Norfolk-Newport News nonattainment area. North Carolina 

recommends not designating any portion of Currituck County as nonattainment. The county not 

recommendation is discussed below, along with the 9 criteria EPA identified in their nonattainment 

boundary guidance that should be addressed. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 61 
Currituck County 

 This is an MSA county, but it does not have a monitor located in the county. This is a 

mostly rural county with no impacts on commuting into the urbanized core of the Virginia BeachNorfolk-Newport News MSA. Therefore, North Carolina is recommending no portion of the 

county be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 26 above, this area has 3 monitors with design values ranging from 

0.075 ppm to 0.077 ppm. The monitor located nearest Currituck County is in Suffolk 

County in Holland with a design value of 0.075 ppm. On days where this area experiences 

its highest ozone concentrations, winds are predominantly out of the north, whereas 

Currituck County is located downwind of the Virginia Beach-Norfolk-Newport News MSA 

Emissions Data: 

Based on 2005 emissions inventories, Currituck County has 10.59 tons per year of pointsource NOx and the county has 0.22 tons per year of point-source VOC. There are no major 

point sources of either NOx or VOC throughout the county. 

Population Density and Degree of Urbanization: 

18,297 people live in Currituck County as of 2000. The county is entirely rural, with all 

tracts having 100 or fewer people per square mile. (Please see Appendix I for maps of 

population density) 

Traffic and Commuting Patterns: 

Currituck County has 971,830 Daily VMT, according to 2007 data, with no major 

commuting contribution to the Virginia Beach-Newport News-Norfolk MSA. These VMT 

are expected to increase moderately to 1,571,790 by 2020. 

Growth Rates and Patterns: 

The population is expected to increase by 41.7% by 2010 and by 30.4% between 2010 and 

2020. This high rate is exaggerated by the small base population. 

Meteorology: 

Winds across Currituck County are climatologically variable from the west-southwest and 

east-northeast. However, on days where ozone values in the county are highest, the winds 

are generally northerly, indicating Currituck County is downwind of the Virginia BeachNewport News-Norfolk MSA. Therefore, Currituck County has no impact on the 

nonattainment of the aforementioned MSA. 

Geography/Topography: 

Currituck County is located in close proximity to the Atlantic Ocean. As such, the county is 

subject to the diurnal shifts in wind direction. Also, because of the variability of wind 

direction, the atmosphere is typically kept clean and well-mixed. 

Jurisdictional Boundaries: 

The Albemarle Rural Planning Organization encompasses the northeast portion of the North 

Carolina coastline. The Hampton Roads (VA) Metropolitan Planning Organization includes 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 62 
the aforementioned nonattainment area. Currituck County has not been designated 

nonattainment previously. 

Level of control of emissions sources: 

Currituck County has no major point sources for NOx and VOC emissions. Additional NOx 

emissions are from mobile sources, and the combined Federal and state control programs 

will address these emissions. Currituck County currently does not have an OBD-based I/M 

program, but a visual check of emissions equipment is required. Low-sulfur gasoline is also 

required statewide. 

DENR’s ability to control sources throughout the state: The North Carolina 

General Statute allows sources anywhere in the state to be controlled under an 

attainment strategy, regardless of designation. North Carolina believes this is an 

important consideration for setting nonattainment boundaries. The new inspection 

and maintenance program that requires on-board diagnostic testing in 48 counties 

(phased in between 2002 and 2006) is an example of North Carolina’s ability to 

control sources in counties regardless of the nonattainment designations. The new 

I/M program was adopted in 1999. 

State of North Carolina’s Recommendation 

on Boundaries for 8-Hour Ozone Nonattainment Areas 

 63