UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION4 

Ms. Myra Reece 

Chief 

Bureau of Air Quality Control. 

ATLANTA FEDERAL CENTER 

61 FORSYTH STREET 

ATLANTA, GEORGIA 30303-8960 

NOV 1 9 2015 

South Carolina Department of Health and 

Environmental Control 

2600 Bull Street 

Columbia, South Carolina 29201 

Dear Ms. Reece: 

Thank you for submitting the state of South Carolina's 2015 annual ambient air monitoring network plan 

(Network Plan) dated July 20, 2015. The Network Plan is required by 40 Code of Federal Regulations 

(CFR) §58.1 0. 

The U.S. Environmental Protection Agency Region 4 understands that the South Carolina Department of 

Health and Environmental Control (SC DHEC) provided the public a 30-day review period for its draft 

Network Plan. Comments on the draft plan were submitted by three stakeholders and the final Network 

Plan includes the SC DHEC response to these comments. 

With this letter, the EPA Region 4 is approving the Network Plan with the following exceptions: 

1. The EPA does not approve the proposed discontinuation of the ozone (OJ) monitor at the 

Clemson site (AQS ID 45-072-0002) in the Greenville-Anderson-Mauldin Metropolitan 

Statistical Area (MSA). At this time the information provided does not adequately support that 

the Clemson monitor is duplicative. In its Network Plan, SC DHEC indicated that additional 

information on it shutdown request would be provided in its monitoring network assessment 

document; however the assessment has not yet been submitted. When it is submitted, the EPA 

will reconsider its position on the request and discuss it with SC DHEC staff. The monitoring 

network assessment is required by 40 CFR 58.1 0( d). We look forward to receiving the additional 

information for further review and consideration. Please note that the EPA is willing to consider 

the discontinuation of a different, lower value ozone monitoring site(s) in this MSA. 

2. An 03 monitoring site must be established and approved by the EPA in the Myrtle BeachConway-North Myrtle Beach, SC-NC MSA by the beginning of the 2016 03 monitoring season. 

The 2015 Network Plan identifies a site name (Coastal Carolina), location, and AQS ID (45-051-

0008) for this site; however, insufficient information was provided for the EPA to approve this 

location. The EPA requests that SC DHEC submit a Network Plan addendum with a complete 

site proposal containing, at minimum, the information required by 40 CFR §58.10(b). In addition 

to the information on the new site, this addendum may also include a formal proposal to relocate 

the York (AQS ID 45-091-0006) ozone monitor. By this letter, the EPA is approving a 

temporary shutdown for this monitor in 2016 while SC DHEC relocates the monitoring site. As a 

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

Recycled/Recyclable • Prinled with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer) 
reminder, every addendum to the Network Plan must undergo a public inspection process before 

being submitted to the EPA. 

3. Monitor siting criteria, as described in 40 CFR Part 58, Appendix E must be evaluated and met at 

each site operating a regulatory monitor. Ideally, each site in the monitoring network should be 

evaluated annually for compliance with Appendix E siting criteria. The EPA Science and 

Ecosystem Support Division found SC DHEC monitoring sites which were not meeting 

regulatory monitor siting criteria in its July 2015 technical systems audit of the SC DHEC air 

monitoring program. The EPA requests that SC DHEC submit documentation of monitor siting 

evaluations, determinations, and corrective actions for all of its regulatory monitoring sites in the 

next annual Network Plan. 

Details regarding the EPA's review of the Network Plan are provided in the enclosed comments. 

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

Carolina. If you have any questions or concerns, please contact Gregg Worley at (404) 562-9141 or 

Ryan Brown at (404) 562-9147. 

Sincerely, 

0.everly H. Banister-'1n 

Director . U 

Air, Pesticides and Toxics Management Division 

Enclosure 

cc: Mr. Robert Brown 

Division Director, Air Planning Development and Outreach, SC DHEC 

Mr. Scott Reynolds 

Director, Division of Air Quality Analysis, SC DHEC 

Mr. Thomas Flynn 

Manager, Air Data Analysis and Support Section, SC DHEC 

The Honorable William Harris 

Chief of the Catawba Indian Nation 

Mr. Darin Steen 

Director, Environmental Services, Catawba Indian Nation 
CY 2015 State of South Carolina Ambient Air Monitoring Network Plan 

The U.S. EPA Region 4 Comments and Recommendations 

This document contains the U.S. EPA Region 4 comments and recommendations regarding the state of 

South Carolina's 2015 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 (PM1o), 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 of Management and Budget (OMB), July 1, 2014, population estimates from 

the U.S. Census Bureau, and historical ambient air monitoring data. Minimum monitoring requirements 

for OJ, PM2.s, and PM1o only apply to metropolitan statistical areas (MSAs) which are a subset of 

CBSAs. OMB currently defines 10 MSAs in the state of South Carolina. These MSAs and the respective 

July 1, 2014, population estimates from the U.S. Census Bureau are shown in Table 1. 

Table I: Metropolitan Statistical Areas and Populations 

MSAName Population u 

Charlotte-Gastonia-Concord NC-SC 2,380,314 

Greenville-Anderson-Mauldin, SC 850,965 

Columbia, SC 800,495 

Charleston-North Charleston-Summerville, SC 727,689 

Augusta-Richmond County. GA-SC . 583,632 

Myrtle Beach-Conway-North Myrtle Beach, SC-NC 417,668 

Spartanburg, SC 321,418 

Florence, SC 207,030 

Hilton Head Island-Bluffton-Beaufort, SC 203,022 

Sumter, SC 107,919 

Proposed Monitoring Network Changes 

The EPA's rationale for approval or disapproval of specific network changes can be found below in the 

pollutant sections of this document. Monitors proposed for discontinuation and the EPA's determination 

are summarized in Table 2. 

Table 2: Monitors Proposed for Discontinuation 

AQSID Site Name Pollutant Tipe Comments 

45-072-0002 Clemson o, SLAMS Not AJ!Eroved 

Temporary shutdown 

45-091-0006 YorkCMS OJ SLAMS approved for 20 16, will be 

relocated in 2017 

45-045-0015 Greenville ESC PM1.' speciation SPM Shutdown. No longer funded 

b the EPA 
The Network Plan also mentioned relocation or possible relocation of the monitors summarized in Tabte 

3. For EPA to approve any of these relocations, SC DHEC must submit these requests in a future 

Network Plan or as part of a Network Plan addendum with all the requisite information required by 40 

CFR §58.10(b). 

Table 3: Monitors Proposed for Relocation or Possible Relocation 

AQSID Site Name 

45-091-0006 York 

45-015-0002 Bushy Park Pump 

Station 

45-063-0008 

Operating Schedules 

40 CFR § 58.12 

lrmo 

Pollutant 

o, 

PM:u /other 

Type 

SLAMS 

Comments 

Will be relocated in 2017. SC 

DEHC must submit a site relocation 

request as part of the next Network 

Plan or a Network Plan addendum. 

SLAMS Possible relocation - tree 

encroachment 

SLAMS/other Possible relocation - possible 

changes in property use by land 

owner 

The monitoring network proposed in the Network Plan meets the required operating schedules for all 

continuous analyzers and all manual Pb, PM10, PMH. and PM2.s Speciation Trends Network (STN) 

monitors. SC DHEC has not proposed any changes to its operating schedules in the Network Plan. 

Air Quality Index (AQI) Reporting 

40 CFR §58.50 

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

South Carolina required to report an AQI: Greenville-Anderson-Mauldin, Columbia, Charleston-North 

Charleston, and Myrtle Beach-Conway-North Myrtle Beach, SC-NC MSAs. The Network Plan indicates 

that the daily AQI for all of these areas except the Myrtle Beach-Conway-North Myrtle Beach, SC-NC 

MSA is available on the EPA's AIRNow web site. Once an OJ monitoring site is approved and 

operating in this MSA in order to satisfy the minimum requirements in 40 CFR Part 58, AQI reporting 

should also be provided for the Myrtle Beach-Conway-North Myrtle Beach, SC-NC MSA. 

National Core {NCore) Monitodng Network 

40 CFR Part 58, Appendix D, 3 

A requirement that each state operate at least one NCore site is found in 40 CFR Part 58, Appendix D, 3. 

The state's approved NCore site is located in Columbia at the Parklane site (AQS ID 45-079-00047) and 

the SC DHEC has not proposed any changes for the site in its Network Plan. 

OJ Monitoring Requirements 

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

The Network Plan includes a proposal to discontinue OJ monitoring at the Clemson site (AQS ID 45-

072-0002). The EPA does not approve this proposal at this time. The Network Plan stated that the 

Clemson site is duplicative, but no information justifying that position was included. The SC DI-IEC 

indicated in the Network Plan that additional rationale for discontinuing this site would be contained in 

the SC DHEC monitoring network assessment document. However, the SC DHEC has not yet submitted 
the assessment to the EPA. Thus, the infonnation provided to EPA does not adequately support the 

position that the Clemson monitor is duplicative. 

The available data show that peak and average 03 concentrations are consistently higher at the Clemson 

site than they are at other sites in the Greenville area. Forty CFR Part 58, Appendix D, 4.l(b) requires 

that "Within an OJ network, at least one 03 site for each MSA, or CSA if multiple MSAs are involved, 

must be designed to record the maximum concentration for that particular metropolitan area." Based on 

EPA's analysis of the data, the Clemson site is required as the maximum concentration site in the MSA. 

Also, the Clemson site is representative of a more densely populated area than other sites in the 

Greenville area. We look forward to receiving the additional infonnation for further review and 

consideration. Please note that, the SC DHEC is currently operating five Q3 monitors in this MSA where 

two are required at a minimum. The EPA is willing to consider a request to shut down other site(s) in the 

MSA that are oflower value than the Clemson site. 

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 

triggered the requirement for an 03 monitor in the MSA based on the population in the new MSA. The 

2015 Network Plan identifies a site name (Coastal Carolina), location, and AQS ID (45-051-0008) for 

this monitor, however insufficient infonnation was provided for the EPA to approve this location. The 

EPA requests that SC DHEC submit a Network Plan addendum with a complete site proposal with all 

the requisite infonnation required by 40 CFR §58.1 O(b ). This addendum must undergo a public 

inspection process before being submitted to the EPA. 

The Network Plan also includes a proposal to temporarily discontinue 03 monitoring at the York CMS 

site (AQS ID 45-091-0006) for the 2016 03 season and that this site will be relocated to a nearby 

location. The York monitor is an upwind site for the Charlotte-Concord-Gastonia NC-SC MSA and 

typically reads lower than the other 03 monitors in the MSA. The EPA approves the temporary 

shutdown ofthe York monitor for 2016. Once SC DHEC has identified a suitable replacement site for 

the York monitor, the EPA requests that SC DHEC submit a Network Plan addendum with a complete 

site proposal including all the requisite infonnation required by 40 CFR §58.10(b). This addendum must 

undergo a public inspection process before being submitted to the EPA. 

With the exception of the Myrtle Beach-Conway-North Myrtle Beach, SC-NC MSA, the EPA has 

detennined that the 03 monitoring network outlined in the Network Plan meets the minimum 

requirements found in 40 CFR Part 58, Appendix D, Table D-2 for the other MSAs in South Carolina. 

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 40 CFR Part 58, 

Appendix D. 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 SOz 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 of the following site types: population exposure, 

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

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

CBSA with minimally required monitors consistent with Appendix D, Section 4.4. Based upon PWEis 

3 
calculated using the latest population estimates and emission inventory data, the minimum number of 

monitors required for the CBSAs in South Carolina is summarized in Table 4. 

Table 4: SO: Monitoring System Status 

CBSAName 

Augusta-Richmond Counry, GA-SC 

Charleston-North Charleston-Summerville, SC 

Charlotte-Gastonia-Concord NC-SC 

Columbia, SC 

Greenville-Anderson-Mauldin, SC 

SLAMS 

Required 

SLAMS 

Present 

Based upon the information summarized in Table 4, the S02 monitoring network outlined in the 

Network Plan meets the S02 PWEI requirements specified in 40 CFR Part 58, Appendix D, Section 4.4. 

The EPA finalized the S02 Data Requirements Rule (ORR) (see 80 Federal Register, No. 162) on 

August 21 , 2015. This rule will require characterization of the air quality near sources with S02 

emissions greater than 2,000 tons per year by conducting ambient air monitoring or modeling. We 

encourage SC DHEC to begin having conversations with affected sources in the state to determine an 

agreed upon approach for meeting the ORR requirements. By January 15, 2016, SC DHEC must submit 

a final list to the EPA Region 4 identifying the sources around which SOz air pollution must be 

characterized. For sources that SC DHEC decides to evaluate using ambient air monitoring, new site 

proposals must be included in the 2016 Network Plan. The location ofthese monitoring sites should be 

selected using the process outlined in the S02 NAAQS Designations Source-Oriented Monitoring 

Technical Assistance Document1

• 

N02 Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.3 

Ambient air monitoring network design criteria for NOz are found in 40 CFR Part 58, Appendix D, 4.3. 

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. 

Ambient air monitoring design criteria for near-road N02 monitoring sites are found in 40 CFR Part 58, 

Appendix D, 4.3.2. The requirement for near-road monitoring in the Charlotte-Gastonia-Concord NCSC CBSA will be met using the Remount site (AQS ID 37-119-0045) operated by Mecklenburg 

County's Land Use and Environmental Services Agency (MCLUESA) in Charlotte, North Carolina. No 

other CBSA in South Carolina is currently required to have near-road N02 monitoring. By January J, 

2017, South Carolina CBSA's with populations over 500,000 will be required to operate near-road N02 

monitoring. South Carolina has four CBSAs in this range: Greenville-Anderson-Mauldin, SC; 

Columbia, SC; Charleston-North Charleston-Summerville, SC, and Augusta-Richmond County, GA-SC. 

As a result of the 5-year NAAQS review cycle, the N02 monitoring requirements may be modified in 

2016. The N02 near-road monitoring requirements may change for CBS As with populations between 

500,000 and 1,000,000 people, such as the South Carolina CBSAs listed above. 

1 S02 NAAQS Designations Source-Oriented Monitoring Technical Assistance Document. U.S. EPA Office of Air Quality 

Planning and Standards Air Quality Assessment Division, Draft December 20 13. 

btm://www3 .epa.g.ov/airgual ity/su lfurdjoxide!pdfs/S02 Monitoring. TAD .pdf 

4 
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. The Garinger High School (AQS ID 37-119-0041) currently operated 

by MCLUESA will be used for fulfilling the area-wide NOz monitoring requirement for the CharlotteGastonia-Concord NC-SC CBSA. No other CBSA in South Carolina is required to have area-wide N02 

monitoring. 

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

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

provisions, Regional Administrators must require a minimum of forty additional N02 monitoring 

stations nationwide, with a primary focus on siting these monitors in locations to protect susceptible and 

vulnerable populations. Previously, Region 4 selected the Greenville ESC site (AQS ID 450-045-0015) 

as a location for an RA-40 NOz monitoring site. The full list ofNOz monitors identified by EPA's 

Regional Administrators can be found on EPA's website at httt>://www.epa.gov/ttnamtillsvoop.html. 

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

Although SC DEC has no sources that exceed the thresholds for Pb monitoring, the Johnson Control 

Battery Group conducts source-based ambient Pb monitoring at three sites around the Florence 

Recycling Center in Florence, South Carolina. The company is conducting this monitoring under terms 

of a settlement agreement reached with several petitioners who commented on the construction permit 

for the facility. Locations for the monitoring sites were selected based upon an agreement between the 

company and the stakeholders. 

Forty CFR Part 58, Appendix D, 3(b) requires that "NCore sites in CBSAs with a population of500,000 

people (as determined in the latest Census) or greater shall also measure Ph either as Ph-TSP or PbPM!o." The Network Plan indicates that a Pb sampler is located at the Parklane NCore site (AQS ID 45-

079-0007). The Pb monitoring network described in the Network Plan meets all of the design criteria of 

40 CFR Part 58. 

PM to Monitoring Requirements 

40 CFR Part 58, Appendix A, 3.3.1 

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

Region 4 has determined that the PM1o monitoring network outlined in the Network Plan meets or 

exceeds the minimum requirements found in 40 CFR Part 58, Appendix D, Table D-4 for all MSAs. 

Also, all manual PM10 collocation requirements are met. 

5 
PMz.s Monitoring Requirements 

40 CFR Part 58, Appendix A, 3.2.5 

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

The EPA has determined that the PM2.s monitoring network outlined in the Network Plan meets or 

exceeds the minimum requirements found in 40 CFR Part 58, Appendix D, Table D-5 for all MSAs. 

Also, all PM2 s collocation requirements are met. 

PMz.s Continuous Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.7.2 

Regulatory provisions for continuous PM2 s monitoring require that "The State, or where appropriate, 

local agencies must operate continuous PM2.s analyzers equal to at least one-half(round up) of 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/AR.¥ [Federal Reference 

Method/Federal Equivalent Method/Approved Regional Method] monitors, unless at least one of the 

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

collocation requirement applies." After review of the Network Plan, the EPA has determined that the 

proposed PM2.s continuous monitoring network meets or exceeds the minimum requirements in all of 

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

PMz.s Background and Transport Sites 

40 CFR Part 58, Appendix D, 4.7.3 

Forty CFR Part 58, Appendix D, 4.7.3 requires that "Each State shall install and operate at least one 

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

transport." The Network Plan identifies Ashton (AQS ID 45-029-0002) in Colleton County as a regional 

background site and Chesterfield (AQS ID 45-025-0001) in Chesterfield County as a regional transport 

site. Therefore, the SC DHEC has satisfied the requirements of 40 CFR Part 58 for regional background 

and transport sites. 

PM2.s Chemical Speciation Network (CSN) 

40 CFR Part 58, Appendix D, 4.7.4 

The EPA conducted an assessment of the CSN in an effort to optimize the network and create a network 

that is sustainable going forward. As a result of this assessment, the EPA de funded a number of 

monitoring sites, eliminated the CSN PM2 s mass measurement, reduced the frequency of carbon blanks, 

reduced sample frequency at monitoring sites, and reduced the number of icepacks in shipments during 

the cooler months of the year. 

The EPA defunded two CSN monitors at sites in South Carolina: Chesterfield (AQS ID 45-025-0001) 

and Greenville ESC (AQS ID 45-045-0015). The Network Plan indicates that the Chesterfield CSN 

monitor has been discontinued due to lack of EPA funding and the Greenville ESC speciation monitor 

will continue to operate with state funding. 

6 
Photochemical Assessment Monitoring Station (PAMS) 

40 CFR Part 58, Appendix D, 5.0 

With the recent passage of a new ozone NAAQS on October 1, 2015, the EPA also finalized changes to 

PAMS. By June 1, 2019, the NCore site in Columbia will be required to implement PAMS monitoring. 

The EPA realizes there are several implementation challenges to work through and is committed to 

working closely with SC DHEC to identify efficiencies and minimize the burden of implementing this 

new monitoring program. However, at this time the PAMS requirement is being met by the state. 

Monitoring Siting Criteria 

40 CFR Part 58, Appendix E 

Monitor siting criteria, as described in 40 CFR Part 58, Appendix E, must be met and continually 

evaluated at each site operating a regulatory monitor. Ideally, each site in the monitoring network should 

be evaluated annually for compliance with regulatory siting criteria. The EPA Science and Ecosystem 

Support Division (SESD) found many of the SC DHEC monitoring sites were not meeting regulatory 

monitor siting criteria in the July 2015 technical systems audit (TSA) of the SC DHEC air monitoring 

program. The final TSA report, dated November 17, 2015, describes this audit finding in greater detail. 

The SC DHEC was provided an opportunity to comment on the draft TSA report. The EPA requests that 

the SC DHEC submit documentation of monitor siting evaluations, determinations, and corrective 

actions for all of its regulatory monitoring sites in the next annual Network Plan. 

7