NA
 

NCDENR
 

North Carolina Department of Environment and Natural Resources 

Beverly Eaves Perdue, Governor Dee Freeman, Secretary 

October 28, 2011 

Gwendolyn Keyes Fleming 

Regional Administrator 

USEPA, Region 4 

Sam Nunn Federal Center 

61 Forsyth Street, SW 

Atlanta, Georgia 30303-8960 

Dear Ms. Fleming: 

Pursuant to the requirements ofthe federal Clean Air Act and on behalf of Governor Beverly E. 

Perdue, I am submitting to you and your colleagues at the U.S. Environmental Protection Agency 

(EPA) the State of North Carolina's revised recommendations for boundaries delineating the areas 

in the S~te that either attain or do not attain the March 12,2008 8-hour standard for ozone. We 

believe the boundaries described in the enclosed package are the most effective way to achieve the 

goals ofthe Clean Air Act. We look forward to discussing these recommendations with you after 

EPA has had the opportunity to review and comment on them. 

The federal Clean Air Act requires EPA to designate areas as attainment Of nonattainment 

following promulgation of a new national ambient air quality standard. The EPA has asked states 

for their recommendations for nonattainment boundaries by October 28, 2011. Please note that 

North Carolina plans to certify its 2011 ambient air quality data for ozone by the end of2011 so 

that this data may be used in determining nonattainment boundaries for the March 12,2008 8-hour 

standard for ozone. 

Based on extensive public discussion of our initial boundary recommendations for the 2008 ozone 

standard submitted in March 2009 and analysis ofthe current ambient air quality data through 

2011, we are recommending that six entire counties and one partial county in the CharlotteGastonia-Salisbury metropolitan area be designated as nonattainment for the 2008 8-hour ozone 

standard and all remaining areas be designated as attainment. The proposed nonattainment area is 

consistent with the area that was designated nonattainment for the 1997 8-hour ozone standard. 

North Carolina was able to attain the 1997 8-hour ozone standard using this recommended 

nonattainment boundary area. 

North Carolina learned ofthe need to update the boundary recommendations in a call with EPA 

Region 4 staff on September 29, 2011. As a result, the state has not had sufficient time to consult 

with local elected officials and other partners prior to this submittal. North Carolina reserves the 

right to further amend these recommendations as we have the opportunity to do that over the 

1601 Mail Service Center, Raleigh, North Carolina 27699-1601 

Phone: 919-733-4984/ FAX: 919-715-3060/lntemet: www.enr.state.nc.us/ENR 

N~rthCarohna
Ms. Fleming 

October 28,2011 

Page 2 

coming weeks. Any changes in the state's recommendations will be communicated during the 120 

day process that will follow EPA's response to these initial recommendations. 

North Carolina has been working hard to address ozone pollution in conjunction with our many 

local, state, and national partners. Over the past decade, North Carolina has implemented 

substantial, progressive emissions reductions that have resulted in attainment ofthe 1997 8-hour 

ozone standard statewide. Under the North Carolina legislature's Clean Air Bill of 1999, the 

State's vehicle inspection and maintenance program was changed to an on-board diagnostic (OBD) 

program that now covers 48 counties. In addition to implementation ofthe NOx SIP Call rules, in 

2002 North Carolina's General Assembly also enacted the landmark multi-pollutant legislation 

known as the Clean Smokestacks Act which continues to result in significant sulfur dioxide and 

nitrogen oxides (NOx) emissions reductions from the State's two largest electric utility companies. 

As demonstrated by these and other actions, North Carolina is committed to improving air quality. 

North Carolina believes that good air quality is vital to the health of our citizens, the state's 

environment, and future economic growth and quality of life. We look forward to continuing to 

work with EPA and our other partners to develop strategies to attain the 2008 8-hour ozone 

standard. More detailed information and supporting data are included in the enclosed 

recommendation package. Thank you for your consideration ofthese recommendations. 

Sincerely, 

?~e~~---"/) Secretary 

DF:lab 

Enclosure 

c:	 The Honorable Beverly E. Perdue 

The Honorable Steve Troxler 

The Honorable Gene Conti 

The Honorable J. Keith Crisco 

Sheila C. Holman 
Supplement to the
 

State ofNorth Carolina's
 

Recommendation on Boundaries
 

For the 2008 8-Hour Ozone Standard
 

March 12, 2009
 

Revised October 28, 2011
 

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 7 I

Charlotte-Gastonia'-Salisbury Metropolitan Area Discussion 7 

EPA's Presumpti~e 8-Hour Ozone Nonattainment Boundary: ; 7 

North Carolina's R.ecommended 8-Hour Ozone Nonattainment Boundary: 7 

Charlotte-Gastonia-Salisbury CSA 8-Hour Ozone Design Values: 7 

Anson County 8 

Cleveland County 11 

Iredell County 12 

Stanly County 14 

Table of Figures 

Figure 1: North Carolina's 2009-2011 8-Hour Ozone Design Values Map 2 

Figure 2: North Carolina's Revised Recommendation For 8-Hour Ozone Nonattainment Area 

Boundaries 3 

Figure 3: Charlotte-Gastonia-Salisbury Regional 2009-2011 8-Hour Ozone Design Values 8 

Figure 4. Population Density Map for the Charlotte-Gastonia-Salisbury CSA based on the 2010 

Census 10 

Figure 5. Percent Growth Between 2000 and 2010 for Iredell County 13 

table of Tables 

Table 1: North Carolina Boundary Recommendation for 8-Hour Ozone Standard 3 

Table 2: Charlotte-Gastonia-Salisbury Regional Ozone Design Value Table 7 

Table of Appendices 

Appendix A: North Carolina's 2009-2011 8-Hour Ozone Design Values Map & Table 
(I'his Page Is Intentionally Blank) 
Introduction 

The purpose ofthis document is to provide the State ofNorth Carolina's revised 

recommendations on boundaries for the 2008 8-hour ozone standard. 

On March 12,2008, the United States Environmental Protection Agency (EPA) promulgated 

a revised 8-hour ozone National Ambient Air Quality Standard (NAAQS) of75 parts per billion 

(Ppb). On March 12, 2009, the State ofNorth Carolina submitted its boundary recommendation for 

nonattainment areas based on the ambient air quality data for 2006-2008. However, in September 

2009, the EPA announced that they were going to reconsider the 2008 ozone standard and 

postponed implementation of this standard. It was announced that the reconsideration ofthe 2008 

ozone standard would be withdrawn on September 2, 2011. 

The EPA is now moving forward with the implementation of the 2008 ozone standard. 

Since most states had submitted boundary recommendations in 2009, the EPA has advised states 

that they will use the boundary recommendations previously submitted and update them based on 

the 2008-2010 ambient air quality data. The EPA has requested states wishing to revise their 

boundary recommendations to submit them by October 28, 2011. The EPA also agreed to use 

2009-2011 ambient air quality data for the designation process if a state planned to certify their 

2011 data early. 

North Carolina has elected to certify the 2011 ambient air quality data early and has made its 

revised boundary recommendations based on the 2009-2011 data. 

Background 

The Clean Air Act (CAA) requites the EPA to designate areas as attainment or 

nonattainmeilt 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 the 

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 maximUIi1 8-holir average ozone value for each ofthe 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, the EPA revised the 8-houf ozone standard 

to 75 ppb. Therefore, a monitored three-year average of75 ppb is considered to meet or attain the 

standard, while a three-year average of 76 ppb or greater is considered to violate the ambient 

standard. 

North Carolina has evaluated the ozone monitoring data for the State for the three-year 

period of 2009-201 1, and has determined that a total of4 out of40 monitors currently violate the 

2008 8-hour ozone standard based on the pre-certified data for 2011. Figure 1 displays a map ofthe 

2009-2011 8-hour ozone design values for North Carolina. This map and a table used for 

calculating the respective design values are included in Appendix A. The four violating monitors 

are all located in the Charlotte-Gastonia-Salisbury metropolitan area. 

1 
Statewide 8-Hour Ozone 

Design Values 

2009-201!1 8-Hour Ozone Design Values 

o Attaining (75 ppb or less)
 

@ Nonattaining (76 ppb or gre,ater)
 

Figure 1: North Carolina's 2009-2011 8-Hour Ozone Design Values Map 

(Please Note That All Design Value Concentrations Presented Above Are In Parts Per Billion (Ppb) and 

that the 2011 ambient air quality data has not been certified) 

2 
Summary of Recommendations 

The State ofNorth Carolina's revised recommendations for the designation of areas ofthe state for the 

2008 8-hour ozone standard is nonattainment for Cabarrus, Gaston, Lincoln, Mecklenburg, Rowan, Union 

Counties, a partial county nonattainment recommendation for Iredell County; and attainment designation for the 

remaining areas in North Carolina. The nonattainment area boundary recommendation for the CharlotteGastonia-Salisbury metropolitan area is displayed in Figure 2. This is the same area in North Carolina that was 

designated nonattainment for the 1997 8-hour ozone standard for the Charlotte-Gastonia-Salisbury metropolitan 

area. Table 1 summarizes North Carolina's recommendation of areas as nonattainment or attainment for the 

2008 8-hour ozone NAAQS. 

Figure 2: North Carolina's Revised Recommendation For 8-Hour Ozone Nonattainment Area
 

Boundaries
 

Table 1 is North Carolina's revised recommendation of areas as nonattainment or attainment under the revised 

8-hour ozone standard. 

Table 1: North Carolina Boundary Recommendation for 8-Hour Ozone Standard 

Designated Area Designation Type 

Charlotte-Gastonia-Salisbury Area: 

Cabarrus County 

Gaston County 

Iredell County (part) 

Davidson Township 

Coddle Creek Township 

Lincoln County 

Mecklenburg County 

Rowan County 

Union County 

Rest of State 

Alamance County . 

Nonattainment 

Attainment 

3
 
Table 1: North Carolina Boundary Recommendation for 8-Hour Ozone Standard 

Designated Area Designation Type 

Alexander County Attainment 

Alleghany County Attainment 

Anson County Attainment 

Ashe County Attainment 

Avery County Attainment 

Beaufort County Attainment 

Bertie County Attainment 

Bladen County Attainment 

Brunswick County Attainment 

Buncombe County Attainment 

Burke County Attainment 

Caldwell County Attainment 

Camden County Attainment 

Carteret County Attainment 

Caswell County Attainment 

Catawba County Attainment 

Chatham County Attainment 

Cherokee County Attainment 

Chowan County Attainment 

Clay County Attainment 

Cleveland County Attainment 

Columbus County Attainment 

Craven County Attainment 

Cumberland County Attainment 

Currituck County Attainment 

Dare County Attainment 

Davidson County Attainment 

Davie County Attainment 

Duplin County Attainment 

Durham County Attainment 

Edgecombe County Attainment 

Forsyth County Attainment 

Franklin County Attainment 

Gates County Attainment 

Graham County Attainment 

Granville County Attainment 

Greene County Attainment 

Guilford County Attainment 

Halifax County Attainment 

Harnett County Attainment 

Haywood County Attainment 

Henderson County Attainment 

Hertford County Attainment 

Hoke County Attainment 

Hyde County Attainment 

4
 
Table 1: North Carolina Boundary Recommendation for 8-Hour Ozone Standard 

Designated Area Designation Type 

Iredell County (part) Attainment 

Barringer Township Attainment 

Bethany Township Attainment 

Chambersburg Township Attainment 

Concord Township Attainment 

Cool Springs Township Attainment 

Eagle Mills Township Attainment 

Fallstown Township Attainment 

New Hope Township Attainment 

Olin Township Attainment 

Sharpesburg Township Attainment 

Shiloh Township Attainment 

Statesville Township Attainment 

Turnersburg Township Attainment 

Union Grove Township Attainment 

Jackson County Attainment 

Johnston County Attainment 

Jones County Attainment 

Lee County Attainment 

Lenoir County Attainment 

Macon County Attainment 

Madison County Attainment 

Martin County Attainment 

McDowell County Attainment 

Mitchell County Attainment 

Montgomery County Attainment 

Moore County Attainment 

Nash County Attainment 

New Hanover County Attainment 

Northampton County Attainment 

Onslow County Attainment 

Orange County Attainment 

Pamlico County Attainment 

Pasquotank County Attainment 

Pender County Attainment 

Perquimans County Attainment 

Person County Attainment 

Pitt County Attainment 

Polk County Attainment 

Randolph County Attainment 

Richmond County Attainment 

Robeson County Attainment 

Rockingham County Attainment 

Rutherford County Attainment 

Sampson County Attainment 

5
 
Table 1: North Carolina Boundary Recommendation for 8-Hour Ozone Standard 

Designated Area Designation Type 

Scotland County Attainment 

Stanly County Attainment 

Stokes County Attainment 

Surry County Attainment 

Swain County Attainment 

Transylvania County Attainment 

Tyrrell County Attainment 

Vance County Attainment 

Wake County Attainment 

Warren County Attajnment 

Washington County Attainment 

Watauga County Attainment 

Wayne County Attainment 

Wilkes County Attainment 

Wilson County Attainment 

Yadkin County Attainment 

Yancey County Attainment 

6
 
Area Specific Recommendations on Boundaries for 8-hour Ozone Nonattainment 

The revised recommendations address the designation area boundary 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". 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. 

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

considering boundaries less than the full Core Based Statistical Area (CBSA) or Combined Statistical Area 

(CSA) for nonattainment designation. The remaining documentation only addresses in detail those areas where 

North Carolina's revised recommendation is less than the full CBSA or CSA. 

Charlotte-Gastonia-Salisbury Metropolitan Area Discussion 

EPA's Presumptive 8-Hour Ozone Nonattainment Boundary: 

The EPA's presumptive nonattainment boundary would include Anson, Cabarrus, Cleveland, Gaston, 

Iredell, Lincoln, Mecklenburg, Rowan, Stanly, and Union Counties. 

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

North Carolina's recommended nonattainment boundary includes Cabarrus, Gaston, Lincoln, 

Mecklenburg, Rowan and Union Counties and the Townships of Davidson and Coddle Creek in Iredell County. 

Charlotte-Gastonia-Salisbury CSA 8-Hour Ozone Design Values: 

Table 2 below contains the design values for the monitors located in the Chadotte-Gastonia-Salisbury 

CSA, along with the fourth highest 8-hour average ozone concentrations for 2009 through 2011 which are used 

to calculate the design values. Figure 3 displays the design values in the monitor locations. 

Ta e bl 2 : Ch ar I0 tte-G as t . onla-SarISb ury R' ee;lona10 zone DeSlgn . V I T a ue able 

Annual4tn Highest 8-hr Average I Design Value Monitoring Sites County 1,1 

i.' • 

2009 ~- "-" . -- ....... " .
 

.. 

Lincoln 0.065 

Mecklenburg 0.068 III 

Mecklenburg 0.071 

Crouse

Arrowood

County Line 

Garinger (Plaza) 

Enochville

Rockwell

Monroe 

l .

I. 

Mecklenburg Ij 0.069 JI 

Rowan Ii. 0.073 

Rowan 0.071 

Union 0.067 • ..' '. 

2010 2011 2009-2011 , .-.,. .. ._.­

. . .- . _.. ._. - . 

0.072 0.077 0.071 

0.078 0.082 :. 0.076

0.082 0.083 f. 0.078 

0.082 0.088 i. 0.079

0.078 0.078 :. 0.076 

0.077 0.077 0.075 

0.071 0.073 0.070 

7
 
Cleveland 

Regional 8-Hour Ozone 

Design Values 

Unim 70

• Anson 

2009-2011 9-Hour Ozone Oooign Values 

• Altaining (75 ppb or less) 

• Nonattalning (76 ppb or rrcre) 

o Metrolina County Borders 

Figure 3: Charlotte-Gastonia-Salisbury Regional 2009-2011 8-Hour Ozone Design Values 

Four of the monitors in the Charlotte-Gastonia-Salisbury metropolitan area currently measure the 

highest ozone values in the State. North Carolina recommends that the whole counties of Cabarrus, Gaston, 

Lincoln, Mecklenburg, Rowan and Union and the partial county of Iredell be designated as nonattainment. This 

is the same area in North Carolina that was designated nonattainment for the 1997 8-hour ozone standard for the 

Charlotte-Gastonia-Salisbury metropolitan area. Additionally, North Carolina effectively attained the 19978­

hour ozone standard with this recommended nonattainment boundary area. 

The counties not recommended and the partial county recommendation are discussed below, along with 

the 9 criteria the EPA identified in their nonattainment boundary guidance that should be addressed. 

Anson County 

This is a Micropolitan Statistical Area county within the Charlotte-Gastonia-Salisbury CSA, and 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 ofthe CSA. Therefore, North Carolina is recomniending no portion ofthe county 

be designated as nonattainment. 

Air Quality Data: 

As shown in Figure 3 above, this area has 7 monitors with design values ranging from 70 to 79 ppb. 

The monitor located nearest Anson County is in neighboring Union County in Monroe with a design 

value of 70 ppb. On days when this monitor has the highest readings, the winds generally are out ofthe 

southwest. Since Anson County is east ofthis monitor, the emissions from this county are not expected 

to impact the air quality on days when this monitor would observe an exceedance ofthe 2008 ozone 

standard. 

8 
Emissions Data: 

Based on 2009 emissions inventories, Anson County has annual point source emissions of 129 tons and 

66 tons of nitrogen oxides (NOx) and volatile organic compounds (VOCs), respectively. There are no 

major point sources located within the county. 

Population Density and Degree of Urbanization: 

26,948 people live in Anson County. The northern portion of Anson County is a largely rural county 

with no census tracts having a population density greater than 250 people per square mile. Figure 4 

below displays the population density map for the Charlotte-Gastonia-Salisbury CSA. 

Traffic and Commuting Patterns: 

Anson County has 828,400 Daily VMT, according to 2009 data. Anson County contributes less than 

halfof 1 percent ofthe commuters who drive into Mecklenburg County to work each day. Based upon 

historic trends over the last ten years, the VMT are not expected to change significantly over the next ten 

years. 

Growth Rates and Patterns: 

The population in Anson County increased by 6.6% from 2000 to 2010, contrary to the 2000 census 

prediction that the population would decrease by 1.7% during this time period. However, even with the 

population increase, this is a very modest growth rate compared to the more urban areas ofNorth 

Carolina and Anson County remains a very rural area. The population is expected to slightly increase 

from 2010 to 2020 by 1.9%. This county is not expected to grow enough to become a significant 

contributor to ozone exceedances in the Charlotte-Gastonia-Salisbury CSA. 

Meteorology: 

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

pattern, the emissions in the county are not expected to impact the ambient air quality in the CSA. 

Geographyffopography: 

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 recommendations for nonattainment areas under the 2008 8-hour ozone 

standard. 

Level of control of emissions sources: 

There are no major point sources to consider controls within the county. Mobile sources are another 

source ofNOx emissions. The combined Federal and state control programs for mobile sources address 

these emissions. Anson County does not currently have an on-board diagnostic (OBD) based inspection 

and maintenance (lIM) program, but requires an annual visual inspection of emissions equipment. Lowsulfur gasoline is required statewide. . 

9
 
" 

" legeod

t:J Metrolina countyBorders, 

MetroUl1a Populatiori20:1(). 

'Density (per SCiuaremlfeJ, 

D(}-50 -

,050-100 

o 10()c25O ,

CJ 25(}-500' " ' • " 

o 5O(}-1000'" 

0 1000-2500 

02500-5000' 

C:]'5000+ 

,Anson. 

,J. ..... '1 <._-".,-~... > 

Population DataSouTce,: U.S. Census Bureau (2010) 

Figure 4. Population-Density Map for the Charlotte-Gastonia-Salisbury CSA based on the 2010 Census 

10
 
Cleveland County 

This is a Micropolitan Statistical Area county within the Charlotte-Gastonia-Salisbury CSA, and 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 ofthe CSA. Therefore, North Carolina is recommending no portion ofthe county 

be designated as nonattainment. 

Air Quality Data:
 

As shown in Figure 3 above, this CSA has 7 monitors with design values ranging from 70 to 79 ppb.
 

The monitor located nearest Cleveland County is in neighboring Lincoln County in Crouse with a design
 

value of7l ppb. On days when this monitor has the highest readings, the winds generally are out ofthe
 

southwest. Portions ofCleveland County are located southwest ofthis monitor, however, since there are
 

no major NOx sources located in Cleveland County and this monitor is attaining the 2008 ozone
 

standard, it is not likely that emissions from this county would contribute to a violation ofthe 2008
 

standard in the CSA.
 

Emissions Data:
 

Based on 2009 emissions inventories, Cleveland County has annual point source emissions of 150 tons
 

and 412 tons ofNOx and VOC, respectively. There is one major VOC point source in the county and no
 

major sources ofNOx.
 

Population Density and Degree of Urbanization:
 

98, 078 people live in Cleveland County. Cleveland County is predominantly a rural county with eleven
 

large census tracks with 250 people or less per square mile. In Shelby, located in central Cleveland
 

County, the population density ranges from 250 to 2500 people per square mile. In Kings Mountain,
 

located in southeast Cleveland County, the population density is 500 to 1000 people per square mile.
 

(See Figure 4)
 

Traffic and Commuting Patterns:
 

Cleveland County has 2,709,540 Daily VMT, according to 2009 data. Cleveland County contributes
 

less than 1 percent ofthe commuters who drive into Mecklenburg County to work each day. Based on
 

the historic trends, the VMT are expected to increase by less than one percent annually over the next ten
 

years.
 

Growth Rates and Patterns:
 

The population ofCleveland Country grew by 1.9% between 2000 and 2010. The population in
 

Cleveland County is expected to grow slightly between 2010 and 2020, with an increase of3.2%. These
 

are very small growth rates compared to other parts ofNorth Carolina. This county is not expected to
 

grow enough to become a significant contributor to ozone exceedances in the Charlotte-Gastonia­


Salisbury CSA.
 

Meteorology:
 

Winds across Cleveland County are climatologically from the southwest, which is in the direction ofthe
 

closest monitor located in Lincoln County. However, the Lincoln County monitor is attaining the 2008
 

ozone standard and there are no major NOx sources located in Cleveland Co.unty. Therefore, it is not
 

likely that emissions from Cleveland County would contribute to a violation ofthe 2008 ozone standard.
 

11
 
Geographyffopography:
 

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 recommendations for nonattainment areas under the 2008 8-hour
 

ozone standard.
 

Level of control of emissions sources:
 

Cleveland County currently has one major VOC point source and no major NOx sources. Since North
 

Carolina is NOx limited with respect to ozone formation, controlling man-made VOC sources does not
 

reduce ozone concentrations. Therefore, the level of control for this VOC source should not be of
 

consideration for nonattainment boundary designation. Mobile sources are another source ofNOx
 

emissions. The combined Federal and state control programs for mobile sources address these
 

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

required statewide.
 

Iredell County 

This is a Micropolitan Statistical Area county within the Charlotte-Gastonia-Salisbury CSA, and it does 

not have a monitor located in the county. This is a high commuter county into the Charlotte area along the 1-77 

corridor. The northern portion ofthe 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 ofIredell County, Coddle Creek and 

Davidson Townships, be designated as nonattainment. 

Air Quality Data:
 

As shown in Figure 3 above, this CSA has 7 monitors with design values ranging from 70 ppb to 79 ppb.
 

The monitor located closest to Iredell County is in neighboring Rowan County in Enochville with a
 

design value of76 ppb. However, on days when this monitor has the highest readings, the winds are
 

generally out ofthe southwest, indicating that the emissions from the northern portion ofIredell County
 

are not likely to contribute to the Enochville monitor's high ozone levels since this area is north and east
 

this monitor. Since a significant amount of commuter traffic from the southern two townships travel
 

into Mecklenburg County, the lower two townships may be impacting the ambient air quality data in this
 

CSA. Therefore, North Carolina is recommending just the two lower townships be designated
 

nonattainment.
 

Emissions Data:
 

Based on 2009 emissions inventories, Iredell County has annual point source emissions of 2,087 tons
 

and 927 tons ofNOx and VOC, respectively. 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:
 

159,437 people live in Iredell County and 65,385 people live in the two townships recommended as
 

nonattainment, which is 41% ofthe County's population. The northern, eastern and western portions of
 

Iredell County have low population density with 16 census tracks containing 250 people or less per
 

square mile. Statesville, located in central Iredell County, has population density ranging from 250 to
 

2500 people per square mile. The southern portion ofIredell County, where Mooresville is located, is
 

12 
more densely populated. Mooresville's population density ranges from 1000 to 2500 people per square
 

mile (see Figure 4). This more densely populated area is located in the two townships being
 

recommended for nonattainment.
 

Traffic and Commuting Patterns:
 

Iredell CoUnty has 5,762,800 average daily vehicle miles traveled (VMT), according to 2009 data.
 

Iredell County contributes 2.02 percent ofthe commuters who drive into Mecklenburg County to work
 

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

expected to increase to approximately 7,300,000 by 2020.
 

Growth Rates and Patterns:
 

The population in Iredell County grew considerably from 2000 to 2010, increasing by 30%, and an
 

additional growth of 17.2% is expected between 2010 and 2020. The majority ofthis growth occurred
 

in the two southern townships being recommended for nonattainment. Figure 5 displays the percent
 

growth between 2000 and 2010 for each township. Davidson Township's population growth was 90
 

percent and Coddle Creek Township's growth was 43 percent. All other townships were less than 40
 

percent with most being less than 20 percent.
 

Legend 

Iredell Townships 

Population growth in percent, 2000-2010 

10% or less 

0 10-20% 

0 20-40% 

0 40-50% 

CJ More than 60% 

Figure 5. Percent Growth Between 2000 and 2010 for Iredell County 

Meteorology: 

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

pattern, the emissions in the county are more likely to impact areas outside ofthe CSA. However, the 

13
 
commuter traffic emissions from the southern two townships would still impact the air quality in the 

CSA even with southwest winds. Therefore, North Carolina is recommending just the two lower 

townships be designated nonattainment. On days when the winds are from the north, the emissions will 

add to the Charlotte area's pollution. 

Geographyffopography: 

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 ofIredell 

County, and is consistent with North Carolina's recommendations for nonattainment areas under the 

2008 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. The 

natural gas pumping station, located in Davidson Township, is subject to the NOx SIP Call and has 

taken permit limits to address the requirements ofthe NOx SIP Call. The other large NOx source is a 

glass manufacturer located just outside ofthe recommended nonattainment area, which bums only 

natural gas, a lower emitting fossil fuel. Mobile sources are another source ofNOx emissions. The 

combined Federal and state control programs for mobile sources address these emissions. Iredell 

County currently has an OBD based liM program and low-sulfur gasoline is required statewide. 

Stanly County 

This is a Micropolitan Statistical Area county within the Charlotte-Gastonia-Salisbury CSA, and 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 ofthe CSA. Therefore, North Carolina is recommending no portion ofthe county be 

designated as nonattainment. 

Air Quality Data: 

As shown in Figure 3 above, this CSA has 7 monitors with design values ranging from 70 to 79 ppb. 

The monitor located nearest Stanly County is in neighboring Rowan County in Rockwell with a design 

value of75 ppb. On days when this monitor has the highest readings, the winds are generally out of the 

southwest. Since Stanly County is located south and east ofthis monitor and there are no large NOx 

sources located in this county, it is not likely that the emissions from this county would impact the air 

quality in the CSA when this monitor observes an exceedance ofthe 2008 ozone standard. 

Emissions Data: 

Based on 2009 emissions inventories, Stanly County has annual point source emissions of269 tons and 

371 tons ofNOx and VOC, respectively. There is one major VOC point source and no major sources of 

NOx emissions in Stanly County. 

Population Density and Degree of Urbanization: 

60,585 people live in Stanly County. Stanly County is a predominantly rural area with most ofthe 

county having a population density of250 people or less per square mile. Albemarle, located in 

northeast Stanly County, is the only populous area with a population density of 1000 to 2500 people per 

square mile (Figure 4). 

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Traffic and Commuting Patterns: 

Stanly County has 1,342,620 Daily VMT, according to 2009 data. Stanly County contributes less than 1 

percent ofthe commuters who drive into Mecklenburg County to work each day. Based on historic 

trends, the VMT are expected to increase by less than 0.5% annually over the next ten years. 

Growth Rates and Patterns: 

The population in Stanly County increased slightly from 2000 to 2010 by a rate of 4.3%, with a further 

population increase of 7.3% expected from 2010 to 2020. This is a very modest growth rate compared 

to the more urban areas ofNorth Carolina and Stanly County remains predominantly a rural area. This 

county is not expected to grow enough to become a significant contributor to ozone exceedances in the 

Charlotte-Gastonia-Salisbury CSA. 

Meteorology: 

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

pattern, the emissions in the county are not expected to impact the air quality in the CSA. 

Geographyffopography: 

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 recommendations for nonattainment areas under the 2008 8-hour ozone 

standard. 

Level of control of emissions sources: 

Stanly County currently has one major VOC point source and no major NOx sources. Since North 

Carolina is NOx limited with respect to ozone formation, controlling man-made VOC sources does not 

reduce ozone concentrations. Therefore, the level of control for this VOC source should not be of 

consideration for nonattainment boundary designation. Mobile sources are another source ofNOx 

emissions. The combined Federal and state control programs for mobile sources address these 

emissions. Stanly CoUnty does not currently have an OBD based 11M program, but requires an annual 

visual inspection of emissions equipment. Low-sulfur gasoline is required statewide. 

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