Ms. Sheila C. Holman 

Director Division of Air Quality 

North Carolina Department of 

Environment and Natural Resources 

1 64 1 Mail Service Center 

Raleigh, North Carolina 27699-1 641 

Dear Ms. Holman: Thank you for submitting the State of North Carolina's 201 1 annual ambient air monitoring network 

plan (Network Plan), dated July 1,201 1. The Network Plan is required by 40 Code of Federal 

Regulations (CFR) 558.10. The Network Plan covers the ambient air monitoring network for the North 

Carolina Division of Air Quality and its local agencies. The U. S. Environmental Protection Agency Region 4 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, EPA Region 4 is not required to offer 

another comment period. Based upon our review of the Network Plan, EPA Region 4 has determined that the plan satisfies the 

applicable requirements of 40 CFR part 58. Therefore the Network Plan is approved. 

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 Doug Neeley at 

(404) 562-9097 or Katherine Snyder at (404) 562-9840. 

Gwendolyn Keyes Fleming 

Regional Administrator 

Enclosures 

Internet Address (URL) http://www.epagov 

ABcvcled/Recvclable . Printad with Vpnatahln nil R~COA hkc onmrrhr( DI-A- /anr:-..- n--.-.- .. -. 
Mr. Don R. Willard 

Director, Mecklenburg County Land Use and Environmental Services Agency 

Mr. William M. Barnette, Director 

Director, Forsyth County Environmental Affairs Department 

Mr. David Brigman 

Director, Western North Carolina Regional Air Quality Agency 
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 do not exist for carbon monoxide (CO) unless required by the establishment 

of a National Core (NCore) multi-pollutant monitoring station, andlor a state implementation plan., 

However, new national ambient air quality standards (NAAQS) were promulgated in 201 0 for nitrogen 

dioxide (NO2) and sulfur dioxide (SOz) with minimum monitoring requirements effective January 1, 

201 3. Minimum monitoring requirements for nitrogen dioxide (NO2) will be addressed in the 2012 

network plans. Minimum monitoring requirements are listed in this document for ozone (03), 

particulate matter less than 2.5 microns (PM~s), particulate matter less than 10 microns (PMlo), sulfur 

dioxide (SOz), and lead (Pb). 

The minimum monitoring requirements are based on metropolitan statistical area (MSA) boundaries as 

defined by the U.S. Office of Management and Budget (OMB), July 1,2009, population estimates fiom 

the U.S. Census Bureau, and historical ambient air monitoring data. OMB currently defines 15 MSAs 

in the State of North Carolina. These MSAs and the respective July 1,2009, population estimates fiom 

the U.S. Census Bureau are shown in Table 1. 

Table 1: Metropolitan Statistical Areas and Populations 

MSA Name Population 

Charlotte-Gastonia-Concord, NC-SC 1,745,524 

Virginia Beach-Norfolk-Newport News, VA-NC 1,674,498 Raleigh-Cary, NC 1,125,827 Greensboro-High Point, NC 714,765 

Durham-Chapel Hill, NC 50 1,228 Winston-Salem, NC 484,921 

Asheville, NC 412,672 

Hickory-Lenoir-Morganton, NC 365,364 

Fayetteville, NC 360,355 

Wilmington, NC 354,525 Greenville, NC 179,715 

Jacksonville, NC 173,064 

Burlington, NC 150,358 

Rocky Mount, NC 146,536 

Goldsboro, NC 113,811 

Minimum Ozone Monitoring Requirements 

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

The network described in the 201 1 Network Plan meets the minimum O3 monitoring requirements 

specified by 40 CFR Part 58, Appendix D, Table D-2 in all areas except for the Asheville and Hickory 

MSAs. The Asheville and Hickory MSAs each have the correct number of required ozone monitors 
seeking to shutdown the Frying Pan monitor (AQS ID: 37-087-0035) 2-3 weeks prior- to October 3 1. 

The Frying Pan monitor is operated year round by the National Park Service (NPS) in Great Smoky 

Mountains National Park. The NPS wants to shutdown the monitor because it needs to replace the 

- monitor's shelter. Replacing the shelter needs to be done before winter weather in the mountainous 

area makes the task too difficult. Getting this work done in October will help ensure that the monitor is 

operational by the beginning of the 2012 ozone monitoring season. EPA concurs that this is necessary 

and any impact to data completeness during this time frame will be noted appropriately by EPA. 

Minimum PMlo Monitoring Requirements 

40 CFR Part 58, Appendix A, 3.3.1 

40 CFR Part 58, Appendix D, Table D-4 The State of North Carolina's current PMlo primary monitoring network meets the minimum 

requirements for all areas. All PMlo 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 PMlo methods (at least one site) must be collocated. 

Minimum PM2.5 Monitoring Requirements 40 CFR Part 58, Appendix A, 3.2.5 

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

The State of North Carolina's current PM2.5 monitoring network meets the minimum requirements 

found in 40 CFR Part 58, Appendix D, Table D-5 for all MSAs. Manual PM2.5 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 PM2.5 methods (at least one site) must be collocated. The manual collocation 

requirements for PM2.5 are currently being met in the Network Plan. 

PMz.5 Continuous Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.7.2 

Regulatory requirements for continuous PM2.5 monitoring require that ". . .State, or where appropriate, 

local agencies must operate continuous PM2.5 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, unlkss at least one of the 

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

collocation requirement applies." These minimum continuous PM2.5 monitoring requirements are 

currently met in the-all of the MSAs in the State. Also, the continuous PM2.5 collocation requirements 

are currently met in all MSAs. Therefore, the continuous PM2.5 monitoring network described in the 

201 1 Network Plan meets all of the design criteria of 40 CFR Part 58. 
g

p

(AQS ID: 3 7-08 1-001 3), Cherry Grove (AQS ID: 37-033-0001), Springfield Road (AQS ID: 37-065- 

0004), Kenansville (AQS ID: 37-061 -0002), Boone (AQS ID: 37- 189-0003), Candor (AQS ID: 37- 123- 

0001), and Jamesville (AQS ID: 37-1 17-0001). The Network Plan identifies three regional transport 

sites for PM2.5 identified as: Cherry Grove (AQS ID: 37-033-0001), Jamesville (AQS ID: 37-1 17- 

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. 

Lead Monitoring Requirements 

40 CFR Part 58, kppendix D, 4.5 

EPA recently revised the monitoring requirements for Pb found at 40 CFR Part 58, Appendix D, 

Section 4.5 (see 75 Federal Register 81 126). These revisions reduced the emissions threshold for 

facilities near which source oriented Pb monitoring is required from 1.0 tons per year (tpy) to 0.5 tpy. 

The rule also removed population-based monitoring requirements for Pb and replaced them with a 

requirement to monitor for Pb at urban NCore sites. 

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 airport which emits 1.0 or more tons per year.. ." 

In its network plan, North Carolina has requested that EPA grant a waiver of source-oriented Pb 

monitoring requirements for two sources. 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 58.1O(d)." 

North Carolina has submitted air modeling indicating that the following sources will not contribute to a 

maximum Pb concentration in the ambient air in excess of 50% the NAAQS: 

Blue Ridge Paper Products, Inc. 

Canton, North Carolina 

Saint Gobain Containers 

Wilson, North Carolina 
North Carolina has also requested that EPA considerrevised emissions data related to source-oriented 

Pb monitoring requirements. North Carolina has submitted information indicating that the actual Pb 

emissions from the following sources are below 0.50 tpy: 

Duke Energy Carolinas, LLC 

Belews Creek Steam Station 

Belews Creek, NC 

Progress Energy 

Roxboro Plant 

Semora, NC 

Duke Energy Carolinas, LLC Royal Development Co 

Marshall Steam Station High Point, NC 

Terrell, NC 

U.S. Army Fort Bragg 

Duke Energy Carolinas, LLC Cumberland County, NC 

Allen Steam Station 

Belmont, NC U.S . Marine Corps Camp Lej eune 

Onslow County, NC 

EPA has reviewed this information and concurs that the actual Pb emissions from these sources are 

below 0.50 tpy. Therefore, ambient air monitoring is not required at these sources. Population oriented 

monitoring is still required at urban NCore sites beginning on December 27,201 1. Based on the 201 1 

Network Plan, North Carolina will satisfL the minimum monitoring requirements for Pb. ' 

Sulfur Dioxide Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.4 

Ambient air monitoring network design criteria for SO2 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 SO2 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 SO2 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. The SOz network is to be operational beginning January 1,20 13. The Charlotte-Gastonia-Concord 

CBSA is required to have a total of two SO2 monitors. Currently, there is only one operating SO2 

monitor in the CBSA, located at the Garinger site (AQS ID: 37-1 19-0041). In an e-mail dated 

September 20,201 1, South Carolina Department of Health and Environmental Control committed to 

establishing a SO2 monitor at the York site (AQS ID: 45-091-0006) to assist in meeting the minimum 

monitoring requirements for this CBSA. Once the SO2 monitor at the York monitoring site in South 
Air Quality Index (AQI) Reporting 

40 CFR 858.50 

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-Gasonia-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 201 1 Network Plan. Monitors 

proposed for discontinuation are summarized in Table 2. 

Table 2: Monitors proposed for discontinuationAocation change 

AQS ID Pollutant Type Comments 

37-183-001 8 Carbon Monoxide SLAMS Will use the FRM CO monitor 

at the Millbrook site to fulfill 

the SIP requirements 

37- 173-0002 pM2.5 SLAMS - Regional Monitor will be shut down at 

transport completion of 20 month BAM 

study (5120 1 1) 

EPA has reviewed these requests for discontinuation or monitor relocation and determined that all of the 

requested monitors, in Table 2, meet the requirements of 40 CFR §58.14(~)(6) for monitor 

discontinuation. The minimum monitoring requirements for PM2.5 and O3 found in Appendix D to 40 

CFR Part 58 will continue to be met for the respective MSAs after these monitors are discontinued. 

NC-DAQ also requested to change the monitoring frequericy at AQS IDS 37-081 -001 3,37-07 1-001 6, 

37-05 1-0009, and 37-00 1-0001 to 1 in 6 day for PM2.5 sampling. At this proposed fkequency, the 

monitors will meet the PM2.5 operating schedule requirements under 40 CFR $58.12(d)(l)(i). Therefore, 

EPA approves the change in monitoring frequency at these sites. 

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 has designated two NCore sites in the 201 1 Network Plan. The first site (AQS 

ID 37-1 83-0014) is located at the East Millbrook Middle School site in Raleigh, NC. The second site 

(AQS ID 37-1 19-0041) is located at the Garinger site in Charlotte, NC and is operated by the 

Mecklenburg County Land Use and Environmental Services Agency. Official EPA approval was 

granted for these sites on October 30,2009. The 201 1 Network Plan meets the minimum monitoring 

requirements for NCore sites. 
in AQS. Monitors that are listed as "other" will be treated as a SLAMS monitor for regulatory 

evaluations. For a monitor to count toward the minimum monitoring requirement (e.g. ozone 

requirements above), it must be classified as a SLAMS monitor in AQS, thus the monitor classifications 

should be updated in AQS (Waggin Trail AQS ID: 37-003-0004). 

Also, the State should verify that monitor types in AQS match those in the Network Plan. For example, 

the ozone monitor at Waynesville (AQS ID 37-087-0004) is listed as a SLAMS monitor in the Network 

Plan, but as "other" in AQS. In addition, there are discrepancies in monitor type in AQS and the 

Network Plan for the following sites, AQS IDS: 3 1 - 159-002 1-42 10 1 - 1,37- 159-002 1-4420 1 - 1, and 37- 

l79-OO3-#2Ol-l. 

In addition, the State should verify the PM2.5 background monitor designations in AQS. There are two 

sites in AQS designated as PM2.5 background sites that are not designated in the network plan as 

background sites. These sites include: Pittsboro (AQS ID: 37-037-0004) and West Johnston (AQS ID: 

37-101-0002).