UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 4 

Ms. Sheila C. Holman 

Director 

Division of Air Quality 

North Carolina Department of 

Environment and Natural Resources 

1641 Mail Service Center 

Raleigh, North Carolina 27699-1641 

Dear Ms. Holman: 

ATLANTA FEDERAL CENTER 

61 FORSYTH STREET 

ATLANTA, GEORGIA 30303-8960 

NOV 2 5 2013J 

Thank you for submitting the state ofNorth Carolina's 2013 annual ambient air monitoring network 

plan (Network Plan), dated July 2, 2013. The Network Plan is required by 40 Code of Federal 

Regulations (CFR) §58.10. The Network Plan covers the ambient air monitoring network for the North 

Carolina Division of Air Quality (NC-DAQ) and the local air quality agencies in North Carolina. 

The U.S. Environmental Protection Agency understands that the NC-DAQ provided a 30-day public 

comment period and did not receive any public comments. According to 40 CFR §58.10(a)(2), since 

public inspection and comment have already been solicited, the EPA is not required to offer another 

comment period. The EPA approves North Carolina's 2013 Network Plan. 

Thank you for working with us to monitor air pollution and promote healthy air quality in North 

Carolina and the nation. If you have any questions or concerns, please contact Gregg Worley at 

(404) 562-9141 or Ryan Brown at (404) 562-9147. 

Enclosure 

cc: Mr. Donnie Redmond 

Ambient Monitoring Section Chief, NC-DAQ 

Mr. Leslie Rhodes 

Director, Mecklenburg County Land Use and 

Environmental Services Agency 

Sincerely, 

;J~hA· ~-rr anne M. Gettle, 

'A;i~g Director 

Air, Pesticides and Toxics 

Management Division 

Internet Address (URL) • http://www.epa.gov 

Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer) 
Mr. William M. Barnette, Director 

Forsyth County Environmental Affairs Department 

Mr. David Brigman, Director , 

Western North Carolina Regional Air Quality Agency 
FY 2013 State ofNorth Carolina Ambient Air Monitoring Network Plan 

U.S. EPA Region 4 Comments and Recommendations 

This document contains the U.S. EPA comments and recommendations on the state ofNorth Carolina's 

2013 ambient air monitoring network plan (Network Plan). Ambient air monitoring rules, which include 

regulatory requirements that address network plans, data certification, and minimum monitoring 

requirements, among other requirements, are found in 40 CFR Part 58. Minimum monitoring 

requirements for criteria pollutants are listed in 40 CFR Part 58, Appendix D. Minimum monitoring 

requirements are listed for ozone (03), particulate matter less than 2.5 microns (PM2.s), particulate 

matter less than 10 microns (PMw), nitrogen dioxide (N02), sulfur dioxide (S02), carbon monoxide 

(CO), and lead (Pb). 

The minimum monitoring requirements are based on core based statistical area (CBSA) boundaries as 

defined by the U.S. Office ofManagement and Budget, July 1, 2011, population estimates from the U.S. 

Census Bureau, and historical ambient air monitoring data. Minimum monitoring requirements for 03, 

PM2.5, PM10, only apply to metropolitan statistical areas (MSAs), which are a subset ofCBSAs. OMB 

currently defines 17 MSAs in the state ofNorth Carolina. On February 1, 2013, OMB redefined the 

CBSA boundaries based on 2010 census data. In North Carolina, there are two newly defined MSA's: 

Myrtle Beach-Conway-North Myrtle Beach, SC-NC and New Bern, NC that were previously defined as 

micropolitan CBSAs. Additionally, some MSA populations changed due to the inclusion and/or 

exclusion of counties from OMB's February 2013 MSA delineations. The 2009 and 2013 defined MSAs 

and the respective July 1, 2011, and 2012 population estimates from the U.S. Census Bureau are shown 

in Table 1. 

Table 1: Metropolitan Statistical Areas and Populations 

MSAName 

Charlotte-Concord-Gastonia, NC-SC 

Virginia Beach-Norfolk-Newport News, V A-NC 

Raleigh, NC 

Greensboro-High Point, NC 

Winston-Salem, NC 

Durham-Chapel Hill, NC 

Asheville, NC 

Myrtle Beach-Conway-North Myrtle Beach, SC-NC 

Fayetteville, NC 

Hickory-Lenoir-Morganton, NC 

Wilmington, NC 

Jacksonville, NC 

Greenville, NC 

Burlington, NC 

Rocky Mount, NC 

NewBem,NC 

Goldsboro, NC 

*previously micropolitan CBSA 

2011 Population 

2009 MSA definition 

1,795,472 

1,679,894 

1,163,515 

730,966 

482,025 

512,979 

429,017 

NA* 

374,157 

369,685 

364,567 

192,690 

179,719 

153,291 

152,157 

NA* 

123,697 

2012 Population 

2013 MSA definition 

2,296,569 

1,699,925 

1,188,564 

736,065 

647,697 

522,826 

432,406 

394,542 

374,585 

363,627 

263,429 

183,263 

172,554 

153,920 

151,662 

128,119 

124,246 
Minimum 0 3 Monitoring Requirements 

40 CFR Part 58, Appendix D, Table D-2 

The state of North Carolina's proposed 0 3 monitoring network meets the minimum requirements found 

in 40 CFR Part 58, Appendix D, Table D-2 for all MSAs, except the Myrtle Beach-Conway-North 

Myrtle Beach MSA. 

Due to changes·that OMB made to MSA boundaries in February of2013, Brunswick County, North 

Carolina has been added to the Myrtle Beach-Conway-North Myrtle Beach, SC-NC MSA. This change 

has triggered the requirement for an 03 monitor in 'this MSA. The 2013 Network Plan indicates that NCDAQ has entered into discussions with the SC Department of Health and Environmental Control (SC 

DHEC) and other stakeholders to identify an appropriate location for a new monitoring site. Once a 

suitable monitoring location is identified, information regarding the site can be provided either as an 

amendment to the current Network Plan or in next year's Network Plan. 

The Network Plan also proposes to shutdown the 03 monitor at the Enochville site (AQS ID 37-159-

0022). EPA approves the shutdown of this monitor. The EPA reviewed historical data and other 

information to make this determination. The 0 3 monitor at the Rockwell site (AQS ID 37-159-0021) is 

in the same county and has recorded similar values compared to the Enochville monitor over the last 

five years. After the Enochville monitor is shutdown, the Charlotte-Concord-Gastonia, NC-SC MSA 

would still meet the minimum monitoring requirements found in 40 CFR Part 58, Appendix D. 

Additionally, the Network Plan proposes to relocate two 03 monitoring sites: Waggin Trail (AQS ID 37-

003-0004) and Bent Creek (AQS ID 37-021-0030). The EPA approved the relocation of the Bent Creek 

ozone site in a letter to the Western North Carolina Regional Air Quality Agency dated April29, 2013. 

The new Bent Creek location is less than a mile from the previous site and has the same AQS ID. 

The EPA also approves the relocation of the W aggin Trail site to a new location that will be named 

Taylorsville 2013 with an AQS ID of37-003-0005. The EPA has reviewed the North Carolina Division 

of Air Quality's (NC-DAQ) request to relocate the Waggin Trail 03 site and determined that this 

monitor meets the relocation requirements of 40 CFR § 58.14(c)(6). The Taylorsville 2013 site is nearby 

the Waggin Trail site and should be representative ofthe same spatial scale as the Waggin Trail site. 

Minimum PM10 Monitoring Requirements 

40 CFR Part 58, Appendix A, 3.3.1 

40 CFR Part 58, Appendix D, Table D-4 

The state ofNorth Carolina's current PM10 primary monitoring network meets the minimum 

requirements for all areas. All PM10 collocation requirements for manual methods found in 40 CFR Part 

58, Appendix A, 3.3.1 are currently being met. These include the requirement that fifteen percent of 

each network of manual PM10 methods (at least one site) must be collocated. 

Minimum PM2.s Monitoring Requirements 

40 CFR Part 58, Appendix A, 3.2.5 

40 CFR Part 58, Appendix D, Table D-5 

The state ofNorth Carolina's current PM2.s monitoring network meets the minimum requirements found 

in 40 CFR Part 58, Appendix D, Table D-5 for all MSAs. Manual PM2.s collocation requirements are 
found in 40 CFR Part 58, Appendix A, 3.2.5. These include the requirement that fifteen percent of each 

network of manual PM2.s methods (at least one site) must be collocated. The manual collocation 

requirements for PM2.s are currently being met in the Network Plan. 

The Network Plan proposes to shut down three PM2.5monitors at the end of2013: Finely Farm (AQS ID 

37-183-0020), Springfield Rd (AQS ID 37-065-0004), and Lenoir Community College (AQS ID 37-

1 07-0004). The design values for all three PM2.s monitors have been trending down in recent years and 

are all well below the NAAQS. The most recent design values (2009-2012) for these monitors are 9.3, 

8.9, and 9.0 micrograms per cubic meter, respectively. After the shutdown of these PM2.s monitors, the 

state's network would still meet the minimum monitoring requirements found in 40 CFR Part 58, 

Appendix D. Therefore, the EPA approves the shutdown of the Finley Farm, Springfield Rd, and Lenoir 

Community College PM2.s monitors. 

After submission of the Network Plan, NC-DAQ sent a formal request, dated October 1, 2013 to 

relocate the Spruce Pine (AQS ID 37-121-0001) PM2.s monitor. The EPA has reviewed ND-DAQ's 

request to relocate the Spruce Pine PM2.s monitor and determined that this monitor meets the relocation 

requirements of 40 CFR § 58.14( c)( 6). The proposed BRR Hospital site is nearby the existing Spruce 

Pine site and should be representative of the same spatial scale as the Spruce Pine site. The EPA 

approves the relocation of the Spruce Pine PM2.s monitor to the proposed BRR Hospital site, which will 

have the AQS ID of37-121-0004. 

PM2.s Continuous Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.7.2 

Regulatory requirements for continuous PM2.s monitoring require that " ... State, or where appropriate, 

local agencies must operate continuous PM2.s analyzers equal to at least one-half(round up) the 

minimum required sites listed in Table D-5 of this appendix. At least one required continuous analyzer 

in each MSA must be collocated with one of the required FRM/FEM/ARM [federal reference 

method/federal equivalent method/approved regional method] monitors, unless at least one of the 

required FRMIFEM/ ARM monitors is itself a continuous FEM or ARM monitor in which case no 

collocation requirement applies." These minimum continuous PM2.s monitoring requirements are 

currently met in the all MSAs in the state. Also, the continuous PM2.s collocation requirements are 

currently met in all MSAs. Therefore, the continuous PM2.s monitoring network described in the 2013 

Network Plan meets all of the design criteria of 40 CFR Part 58. 

PM2.s Background and Transport Sites 

40 CFR Part 58, Appendix D, 4.7.3 

40 CFR Part 58, Appendix D, 4.7.3 requires that "each State shall install and operate at least one PM2.5 

site to monitor for regional background and at least one PM2.s site to monitor for regional transport." 

The Network Plan identifies six PM2.s sites as general background sites that include: Mendenhall (AQS 

ID: 37-081-0013), Cherry Grove (AQS ID: 37-033-0001, Kenansville (AQS ID: 37-061-0002), Boone 

(AQS ID: 37-189-0003), Candor (AQS ID: 37-123-0001), and Jamesville (AQS ID: 37-117-0001). The 

Network Plan identifies three regional transport sites for PM2.s identified as: Cherry Grove (AQS ID: 

37-033-0001), Jamesville (AQS ID: 37-117-0001), and Bryson City (AQS ID: 37-173-0002). Therefore, 

NC-DAQ has satisfied the requirements of 40 CFR Part 58 for background and transport sites. 

3 
Pb Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.5 

40 CFR Part 58, Appendix D, 4.5 requires that "At a minimum, there must be one source-oriented 

SLAMS [state and local air monitoring station] site located to measure the maximum Pb concentration 

in ambient air resulting from each non-airport Pb source which emits 0.50 or more tons per year and 

from each airp_ort which emits 1.0 or more tons per year ... " 

Section 4.5(a)(ii) of Appendix D to 40 CFR Part 58 provides the following provisions for a waiver of the 

Pb monitoring requirements: 

"(ii) The Regional Administrator may waive the requirement in paragraph 4.5(a) for monitoring 

near Pb sources if the State or, where appropriate, local agency can demonstrate the Pb source 

will not contribute to a maximum Pb concentration in ambient air in excess of 50% of the 

NAAQS (based on historical monitoring data, modeling, or other means). The waiver must be 

renewed once every 5 years as part of the network assessment required under 58.10(d)." 

In its approval of the state's 2011 Network Plan, pursuant the provisions of the above section, The EPA 

granted the waivers of the source-oriented ambient air monitoring requirements at two sources: Blue 

Ridge Paper Products, Inc. in Canton, North Carolina and Saint Gobain Containers in Wilson, North 

Carolina. The waivers must be renewed every five years as part of the network assessment required 

under40 CFR §58.10(d). 

40 CFR Part 58, Appendix D, 3(b) requires that "NCore sites in CBSA with a population of 500,000 

people (as determined in the latest Census) or greater shall also measure Pb either as Pb-TSP or PbPMw." This monitoring was required to begin December 27, 2011. The Network Plan indicates that PbPMw sampling is ongoing at the Charlotte NCore site (AQS ID: 37-119-0041) and the Raleigh NCore 

site (AQS ID: 37-183-0014). As a result, the Pb monitoring network described in the Network Plan 

meets all of the design criteria of 40 CFR Part 58. 

S02 Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.4 

Ambient air monitoring network design criteria for S02 are found in Section 4.4 of Appendix D to 40 

CFR Part 58. This section requires that "The population weighted emissions index (PWEI) shall be 

calculated by States for each core based statistical area (CBSA)." As a result, the S02 monitoring site(s) 

required in each CBSA will satisfy minimum monitoring requirements if the monitor(s) is sited within 

the boundaries of the parent CBSA and is one of the following site types: population exposure, 

maximum concentration, source-oriented, general background, or regional transport. An S02 monitor at 

a NCore station may satisfy minimum monitoring requirements if that monitor is located within a CBSA 

with minimally required monitors consistent with Appendix D, 4.4. 

4 
Table 2 shows the required S02 monitors based on the 2012 PWEI. Existing S02 monitoring sites 

described in the Network Plan meet the minimum requirements of 40 CFR Part 58. 

Table 2: PWEI and S02 Required Monitors in North Carolina 

CBSAName 

Virginia Beach-Norfolk-Newport News, V A-NC 

Charlotte-Gastonia-Concord, NC-SC 

Durham,NC 

Wilmington, NC 

N02 Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.4 

July 2012 PWEI Values 

78,540 

34,426 

16,885 

10,045 

July 2012 PWEI Required 

Monitors 

1 

Ambient air monitoring network design criteria for NOz are found in Section 4.3 of Appendix D to 40 

CFR Part 58. There are three types of required N02 monitoring: near-road, area-wide, and Regional 

Administrator required. These types ofN02 monitoring are described in sections 4.3.2, 4.3.3, and 4.3.4 

respectively. 

Any CBSA with a population of 500,000 or more persons is required to have a near-road N02 

monitoring station that monitors expected maximum hourly concentrations near a major road. Any 

CBSA with a population of2,500,000 or more persons or that has one or more roadway segments with a 

250,000 or greater annual average daily traffic (AADT) count is required to have an additional near-road 

N02 monitoring station. The Near-road NOz Monitoring Technical Assistance Document (TAD) 

provides guidance to state and local agencies in selecting an appropriate near-road N02 monitoring 

location. This document can be found on the internet at 

http://www.epa.gov/ttnamtil/files/nearroad/NearRoadTAD.pdf. 

Ambient air monitoring network design criteria for area-wide N02 sites are found in Section 4.3.3 of 

Appendix D to 40 CFR Part 58. Any CBSA with a population of 1,000,000 or more persons is required 

to monitor a location of expected highest N02 concentrations representing the neighborhood or larger 

spatial scales. 

Ambient air monitoring network design criteria for Regional Administrator required N02 monitoring, 

often referred to as RA-40 monitoring, are found in Section 4.3.4 of Appendix D to 40 CFR Part 58. 

This section states that ''the Regional Administrators, in collaboration with States, must require a 

minimum of forty additional N02 monitoring stations nationwide in any area, inside or outside of 

CBSAs, above the minimum monitoring requirements, with a primary focus on siting these monitors in 

locations to protect susceptible and vulnerable populations. The Regional Administrators, working with 

States, may also consider additional factors ... to require monitors beyond the minimum network 

requirement." 

The EPA Region 4 approves the selection ofthe Triple Oak (AQS ID 37-183-0021) site in fulfillment of 

the near-road N02 requirement for the Raleigh, NC CBSA. In the Network Plan, Mecklenburg County 

Air Quality (MCAQ) proposed two potential sites to meet the requirement for the near-road N02 

requirement in the Charlotte-Concord-Gastonia, NC-SC. In July of2013, the EPA Region 4 staff visited 

MCAQ's proposed location on Remount Road. MCAQ communicated that due to site access and siting 

issues the proposed site near Remount Road would be preferable to the proposed site locate_d on Toomey 

5 
Avenue. The EPA approves the selection ofthe near-road site on Remount Road (AQS ID 37-119-0045) 

in fulfillment of the near-road N02 requirement. As discussed in the Network Plan, the Greensboro-High 

Point, NC; Winston-Salem, NC; and Durham-Chapel Hill, NC CBSAs will be required to have nearroad N02 monitoring by January 1, 2017. 

The EPA approves the selection ofthe Garinger (AQS ID: 37-119-0041) and Millbrook (AQS ID: 37-

183-0014) sites in fulfillment of the area-wide N02 monitoring requirement for the Charlotte-GastoniaRock Hill and Raleigh-Cary CBSAs. 

The EPA selects the Hattie Avenue site (AQS ID 450-045-0015) operated by Forsyth County Office of 

Environmental Assistance and Protection as a location for a Regional Administrator required N02 

monitor to help protect susceptible and vulnerable populations. The full list ofN02 monitors identified 

by the EPA's Regional Administrators can be found on the EPA's website at 

http://www.epa.gov/ttnamtil/svpop.html. 

Air Quality Index (AQI) Reporting 

40 CFR §58.50 

AQI reporting is required in MSAs with populations over 350,000. There are 10 MSAs in the state of 

North Carolina required to report an AQI: Charlotte-Gastonia-Concord, Virginia Beach-NorfolkNewport News, Raleigh-Cary, Greensboro-High Point, Durham-Chapel Hill, Winston-Salem, Asheville, 

Hickory-Lenoir-Morganton, Fayetteville, and Wilmington. NC-DAQ meets these AQI reporting 

requirements. 

Monitoring Network Changes Proposed by NC-DAQ 

NC-DAQ has proposed several monitoring network changes in its 2013 Network Plan. Monitors 

proposed for discontinuation or relocation are summarized in Table 3. 

Table 3: Monitors Proposed for Discontinuation/Relocation 

AQS ID Site Name PoUutant 

37-159-0022 Enochville 0 3 

37-003-0004 Waggin Trail 

37-183-0020 Finley Farm PM2.s 

3 7-065-0004 Springfield Rd PM2.s 

37-107-0004 Lenoir Community PM25 

College 

37-121-0001 Spruce Pine PM2.s 

6 

Type 

SLAMS 

SLAMS 

SLAMS 

SLAMS 

SLAMS 

SLAMS 

Comments 

Approved: Monitor will be 

shutdown at the end of the 

20 13 0 3 season 

Approved: Monitor will 

shutdown at the end of the 

20 13 0 3 season and will be 

replaced with a nearby 0 3 

monitor - Taylorsville 20 13 

(AQS ID 37-003-0005) 

Approved: Monitor will shut 

down 12/31/20 13 

Approved: Monitor will shut 

down 12/31/2013 

Approved: Monitor will shut 

down 12/31/2013 

Approved: Monitor will be 

relocated less than a mile 

from the existing site and will 

have a new AQS ID 37-121-

0004 
The EPA reviewed these requests for monitor discontinuation or relocation and detennined that they all 

meet the requirements of 40 CFR §58.14(c) for monitor discontinuation and relocation. The minimum 

monitoring requirements for PM2.s and 03 found in Appendix D to 40 CFR Part 58 will continue to be 

met for the respective MSAs after these monitors are discontinued or relocated. 

The EPA also has reviewed and approves the location for the startup of the all monitors listed in Table 4. 

Table 4: Monitors Proeosed for Startue 

AQSID Site Name Pollutant Tiee Comments 

37-183-0021 Triple Oak N02 SLAMS - near-road Approved: site establishment 

for near-road N02 monitoring 

37-119-0045 Remount Road N02 SLAMS - near-road Approved: site establishment 

for near-road N02 monitoring 

37-003-0005 Taylorsville 2013 Ozone SLAMS Approved: will replace 

Waggin Trail site 

37-121-0004 BRR Hospital PM2.s SLAMS Approved: will replace the 

SEruce Pine site 

National Core (NCore) Monitoring Network 

Ambient air monitoring network criteria for NCore sites are found in Section 3 of Appendix D to 40 

CFR Part 58. NC-DAQ designated two NCore sites in the 2013 Network Plan. The first site (AQS ID 

37-183-0014) is located at the East Millbrook Middle School site in Raleigh, NC. The second site (AQS 

ID 37-119-0041) is located at the Garinger site in Charlotte, NC and is operated by MCAQ. Official The 

EPA approval was granted for these sites on October 30, 2009. The 2013 Network Plan meets the 

minimum monitoring requirements for NCore sites. 

7