UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 4 ATLANTA FEDERAL CENTER 61 FORSYTH STREET ATLANTA, GEORGIA 30303·8960 

## NOV 06 

## 2013 Ms. Myra Reece Chief, Bureau ofAir Quality Control South Carolina Department ofHealth and

Environmental Control 2600 Bull Street Columbia, South Carolina 29201 Dear Ms. Reece: Thank you for submitting the State ofSouth Carolina's 2013 annual ambient air monitoring network plan (Network Plan) dated July 3, 2013
. The Network Plan is required by 40 Code ofFederal Regulations §58
. 10. The U.S. Environmental Protection Agency Region 4 understands that 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 provided that following changes are made: 1. Ozone (OJ) 

### and sulfurdioxide (802 ) 

### monitoring sites need to be established in the Myrtle Beach-Conway-North Myrtle Beach, SC-NC metropolitan statistical area (MSA). 2. The proposed discontinuation ofthe 03 

### monitor at the Clemson site (AQS ID 45

-072-0002) in the Greenville-Anderson-Mauldin MSA is not approved. The EPA would be willing to consider approving the discontinuation ofa different ozone monitoring site in the MSA to help meet the stated goal ofconserving resources. 3. The designations for the S02 monitoring sites in three MSAs needs to be switched from special purpose monitor (SPM) to state and local air monitoring station (SLAMS)
. 4
. Air Quality Index reporting for the Myrtle Beach-Conway-North Myrtle Beach, SC-NC MSA needs to be initiated once an 03 monitoring site is established
. S. The designation for the nitrogen dioxide (NOz) 

### monitor at the Greenville Employment Security Commission site (AQS ID 045-045-0015) needs to be changed from SPM to SLAMS
. The EPA Region 4 has selected Greenville ESC to be among the Regional Administrator required N02 monitoring sites intended to help protect susceptible and vulnerable populations.

Internet Address (URL) • http://www.epa.gov Recyled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled**P<~per** (Minimum 30% Postconsumer)Details regarding the basis for the changes summarized above are provided in the enclosed comments regarding the Network Plan
. Thank you for working withus to monitor air pollution and promotehealthy air quality in South Carolina. Ifyou have any questions or concerns, please contact Gregg Worley at (404) 562-9141 or David McNeal at (404) 562-9102
.

# ~~**%** d'reaneanne M
. Gettle Acting Director

Enclosure

cc: LauraAckerman, SESD Lynorae Benjaman, APB Mr. Robert Brown Division Director, Air Planning Development and Outreach, SC DHEC Mr. Scott Reynolds Air, Pesticides andToxics Management Division

Director, Division ofAir Quality Analysis, SC DHEC Mr. Thomas Flynn Manager , Air Data Analysis and Support Section, SC DHEC The Honorable William Harris Chiefofthe Ca tawba Indian Nation Darin Steen, Environmental Services Director Catawba IndianNation

## CY 2013 State ofSouth 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 on the state ofSouth 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 CFRpart 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 (PMto), nitrogen dioxide 

### (N02), sulfur dioxide (S02 ), carbon monoxide (CO), and lead (Pb). The minimum monitoringrequirements arebased on core based statistical area (CBSA) boundaries as defined by the U
.S. Office ofManagement and Budget (OMB), July 1, 2012, population estimates from the U.S
. Census Bureau, and historical ambient air monitoring data. Minimum monitoring requirements for 0 3, PM2 .5, PM 10, only apply to metropolitan statistical areas (MSAs), which are a subset ofCBSAs. OMB currently defines 10 MSAs in the state ofSouth Carolina. These MSAs and the respective July 1, 2012, population estimates from the U
.S. Census Bureau are shown in Table 1. Table 1: Metropolitan Statistical Areas and Populations MSAName Charlotte-Gastonia-Concord NC-SC Greenville-Anderson-Mauldin, SC Columbia, SC Charleston-North Charleston-Summerville, SC Augusta-Richmond County, GA-SC Myrtle Beach-Conway-NorthMyrtle Beach, SC-NC Spartanburg, SC Florence, SC Hilton Head Island-Bluffion-Beaufort, SC Sumter, SC 

### Minimum 

### 03Monitoring Requirements 

### 40 CFR

### part 58, appendix D, table D-2 Population 2,296,569

842,853 784,745 697,439 575,898 394,542 316,997 206,087 193,882 108,052

Region 4 has detennined that the ozone monitoring network outlined in theNetwork Plan meets the minimum requirements found in 40 CFR part 58, appendix D, table D-2 for nine ofthe MSAs in South Carolina. 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 ozone monitor in the MSA, and the 2013 Network Plan indicates that the SC Department ofHealth and Environmental Control (SC DHEC) has entered into discussions with North Carolina and other stakeholders to identify an appropriate location for a new monitoring site. Once a suitable monitoring location is identified, infonnation regarding the site can be provided either as an amendment to the current Network Plan or in next year's Network Plan.



### 1TheNetwork Plan includes a proposal to discontinue 

### 03 monitoring at the Clemson site (AQS ID 45- 072-0002). At this time we do not approve the proposal. Please see the section ofthis letter titled "Proposed MonitoringNetwork Changes" for further discussion regarding this issue. 

### Minimum PMto 

### Monitoring Requirements 40 CFRpart 58, appendix A, 3.3.1 40 CFRpart58, appendix D, table D-4 Region 4 has determined that the PM10 monitoring network outlined in theNetwork Plan meets or exceeds the minimum requirements found in 40 CFR part 58, appendix 0, table 0-4 for all MSAs. Also, 

### all manual PM1o collocation requirements are met. 

### Minimum PMz.s Monitoring Requirements 40 CFRpart58, appendix A, 3.2.5 40 CFRpart 58, appendix D, 

### table D·S Region 4 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 0-5 for all MSAs
. Also, all PMz.s collocation requirements are met. 

### Pl\'lz.s Continuous 1\'lonitoring Requirements 40 CFR part 58, appendix D, 4.7.2 Regulatory provisions for continuous PM25 monitoring require that 'The State, orwhere appropriate, local agencies must operate continuous PM2
.s analyzers equal to at least one-half(round up) ofthe minimum required sites listed in TableD-5 ofthis appendix. At least one required continuous analyzer in each MSA must be collocated with one ofthe required FRMIFEMIARM [Federal Reference Method/Federal Equivalent Method/Approved Regional Method] monitors, unless at least one ofthe required FRM/FEMJARM monitors is itselfa continuous FEM orARM monitor in which case no collocation requirement applies." After revi ew ofthe Network Plan, Region 4 has determined that the proposed PM2
.s continuous monitoring network meets orexceeds the minimum requirements in all of the MSAs in the state. Also, the continuous PM2.5 collocation requirements are met in all MSAs. The Network Plan includes a request that data from the continuous PM2
.smonitor at the Greenville Employment Security (ESC) site (AQS ID 045-045-00 15) not be used for comparison to the national ambient air quality standards (NAAQS)
. This request is made under provisions in 40 CFR 58
. ll(e) and the Network Plan includes data demonst rating that, under performance criteria in40 CFR part 53, Table C-4, the monitor at the Greenville ESC can be excluded for NAAQS reporting purposes. Therefore, the request for the continuous PM2
.smonitor at the Greenville ESC site is acceptable. Please update the monitor type to "Non-Regulatory" in the Air Quality System (AQS). 

### PMz.s Background andTransportSites 40 CFRpart 58, appendix D, 4
.7.3 40 CFR part 58, appendix 0, 4
.7.3 requires that " Each State shall install and operate at least one PM25 site to monitor for regional background levels and n t least one PM2
.s site to monitor for regional 

### 2transport." The 2013 Network Plan identifies Ashton {AQS ID 45-029-0002) 

### in Colleton County as a regional background site and Chesterfield {AQS ID 45-025-0001) inChesterfield County as a regional transport site
. Therefore, SC DHEC has satisfied the requirements of40 CFR part 58 for regional background and transport sites. 

### Pb MonitoringRequirements 40 

### CFRpart 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 ormore tons per year and from each airport which emits 1
.0 ormore tons per year..." Although South Carolinahas 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 ofa 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. 40 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 Pb either as Pb-TSP or PbPM10." The Network Plan indicates that a Ph sampler is located at the Parklane NCore site (AQS ID 45- 079-0007). The Pb monitoring network described in the Network Plan meets all ofthe design criteria of40 CFR part 58
. 

### Sulfur Dioxide (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 ofAppendix D to 40 CFRpart 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 ifthe monitor(s) is sited within the boundaries ofthe parent CBSA and is ofthe following site types: population exposure, maximum concentration, source-oriented, general background, orregional transport
. An S02monitor at an NCore station may satisfy minimum monitoring requirements ifthat monitor is located within a CBSA with minimally required monitors consistent with Appendix D, section 4.4. Based upon PWEis calculated using the latest population estimates and emission inventory data, the minimum number of monitors required for the CBSAs in South Carolina is summarized inTable 2
.



### 3Table 2: S02 Monitoring System Status SLAMS Exist ing CBSAName required SLAMS Au;_ usta-Richmond County, GA-SC 1 1 Charleston

-North Charleston-Summerville, SC Charlotte-Gastonia-Concord NC

-SC 2 Columbia, SC 1 Greenville-Anderson-Mauldin. SC 0 Myrtle Bench-Conwa y-North Myrtle Beach, SC

-NC 0 

### Based upon the infonnation summarized above, three additional SLAMS will be needed in order to sa

tisfy the minimum S02 monitoring requirements for the CBSAs in South Carolina Both the CharlotteGastonia-Concord and Greenville-Anderson-Mauldin CBSAs have existing S02monitoring sites whose designation canbe changed from SPM to SLAMS to meet the minimum monitoring requirements. In the Charlotte-Gastonia-Concord CBSA, the existing monitor is locat ed at the York site (AQS ID 45-091- 0006) and in the Greenville-Anderson-Mauldin CBSA, the existing monitor is located at the Greenville ESC site (AQS ID 45-045-00t5)
. Due to changes that OMB made to MSA boundaries, 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 S02 monitor in the MSA and the 2013 

### Network Plan indicates that SC DHEC has entered into discussions with North Carolina 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
. One additional comment that we have regarding S02 monitoring involves the designation for the monitor at the Jenkins Avenue Fire Station site (AQS ID 45-019-0046) in the Charleston-North Charleston CBSA. In ourcomments on last year's Network Plan, we indicated that the designation for one ofthe two S02sites in the CBSA should be changed from SPM to SLAMS in order to meet the minimum monitoring requirements in 40 CFR part 58. Although the Network Plan submitted July 3 identifies both ofthe S02 sites in the CBSA as SPMs, the monitor at the Jenkins Avenue site is designated as a SLAMS in EPA's AQS. Therefore, the monitor designation in theNetwork Plan should be revised so that it is consistent with the information in AQS. This can either bedone as a correction to this year's plan or in next year's plan. 

### N02 MonitoringRequirements 40 CFR part58, appendix D, 4.3 Ambient air monitoring network design criteria for N02 are found in Section 4.3 ofappendix D to 40 CFR part 58. There are three types ofrequired NOz

### monitoring: near-road, area-wide, and Regional Administrator required. These types ofN02monitoring are described in sections 4.3
.2, 4.3
.3 and 4.3.4, respectively. Ambient air monitoring design criteria for near-road N02monitoring sites are found in section 4.3.2 of appendix D to 40 CFR part 58. Any CBSAwith a population of500,000 or more persons is required to 4have a near-road N<h site that monitors expected maximumhourly concentrations near a majorroad. Any CBSA with a population of2,500,000 ormore persons orthat has one ormoreroadway segments with a 250,000 or greater annual average daily traffic (AADT) count is required to have an additional near-road N02 monitoring station. TheNear-roadN02 Monitoring TechnicalAssistanceDocument (TAD) provides guidance to state and local agencies in selecting an appropriate near-roadN02 monitoring location. This document can be found on the internet at http://www.epa.gov /ttnamti 1/tiles/nearroad /NearRoadTAD.pdt: The requirement for near-road monitoring in the Charlotte-Gastonia-Concord NC-SC CBSA will be met using a site operated by Mecklenburg County's Land Use and Environmental Services Agency (MCLUESA) in Charlotte, North Carolina. MCLUESA is presently working to establish the Charlotte near-road N02monitoring site. No other CBSA in South Carolina is currently required to have near-road N02 monitoring. By January, 1 2017, South Carolina CBSA's with populations over 500,000 will berequired to operate near-road N0 2 monitoring
. Ambient air monitoring network design criteria for area-wide 

### ND! sites are found in section 4.3.3 of appendix D to 40 CFRpart 58. Any CBSA with a population of 1,000,000 ormore persons is required to monitor a location ofexpected highest N02concentrations representing the neighborhood or larger spatial scales
. The Garinger High School (AQS ID 37-119-0041) currently operated by MCLUESA will be used for fulfilling the area-wide N02 monitoring requirement for the Charlotte-Gastonia-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 section 4.3.4 ofappendix D to 40 CFR part 58. This section states that "the Regional Administrators, in collaboration with States, must require a minimum of forty additional N02monitoring stations nationwide in any area, inside or outside ofCBSAs, 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." As part ofourreview oflast year's Network Plan and through correspondence with SC DHEC, Region4 selected the Greenville ESC site (AQS ID 450-045-0015) as one ofthe locations for a Regional Administrator required N02 monitor to help protect susceptible and vulnerable populations
. The full list ofN02 monitors identified by EPA's Regional Administrators can be found on EPA's website at http://www.epa.gov/ttnamti 1 /svpop.html. This selection ofthe Greenville ESC site is mentioned in this year's plan, but the designation for the N02 monitor at the Greenville ESC is still identified as an SPM in the Network Plan. This designation needs to be switched from SPM to SLAMS in orderfor it to operate as a Regional Administrator required N02monitor
. 

### 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. The Network Plan on Page 3 indicates that 

### 5

### the daily AQI for all ofthese areas except Myrtle Beach-Conway-North Myrtle Beach is available on EPA's AIRNow web site. Prior to the addition ofBrunswick County, North Carolina to the Myrtle Beach-Conway-North Myrtle Beach
. the population for the MSA did not exceed the threshold for AQI reporting. As discussed previously in our comments, 

### 03 and S02 monitors will need to beadded to the MSA in order to satisfy the minimum requirement in 40 CFR part 58. Once these monitors are installed and operating, AQI reporting should also be provided for the Myrtle Beach-Conway-North Myrtle Beach MSA
. 

### Proposed Monitoring Network Changes SC DHEC has proposed seven monitoring network changes which are summarized in Table 3. Table 3: Proposed Monitoring Network Changes

AQS ID Pollutant Type Comments 45-019-0049 PMu continuous SPM Editorial correction 45-083-0011 PM2J continuous SPM Editorial correction 45-091-0006 

## so1 SLAMS Change designation 45-045-0015 

## co SLAMS Discontinue monitoring 45-072-0002 03 SLAMS Discontinue monitoring 45-029-0002 PM2
.s SPM Ch
. ange·designation 45-073-0001 PM2s SLAMS Change designation 

### The first two changes listed inTable 3 are beingmade to correct errors in a previous Network Plan. The continuous PM25 monitors at the Charleston Public Works (CPW) site (AQS ID 45-019-0049) and the T.K. Gregg site (AQS ID 45-083-0011) have been in operation since 2008 but were incorrectly deleted from a previous Network Plan. Since the proposed changes for the Charleston CPW and the T.K. Gregg sites are beingmade so the Network Plan will reflect the monitors currently in operation, the changes are acceptable
. TheNetwork Plan proposes to switch the designation for the S02 monitor at the York site (AQS ID 45- 091-0006) from SLAMS to SPM. The rationale for this change is that calculations performed during the review oflast year's Network Plan indicated that the minimum monitoring requirements for the Charlotte-Gastonia-Concord MSA could be met without an S02SLAMS at the York site. However, based upon calculations using the latest population and emission inventory data, an S02 SLAMS at the York site will be needed in orderto meet the minimum monitoring requirements for the CharlotteGastonia-Concord MSA. Therefore, the proposed change in the designation for the S02 monitor at the York site is not acceptable. The Network Plan indicates that CO monitor was discontinued at the Greenville ESC site (AQS ID 450- 045-0015) in July 2012. According to 40 CFR § 

### 58.14(c), a request for discontinuation ofa SLAMS monitor will be approved ifthe monitor meets any ofthe criteria under 40 CFR 

### § 58.14( c)( 1) through (6). The requested CO monitor meets the requirement of40 CFR § 

### 58.14(c)(l). The monitor has shown attainment ofthe CO NAAQS during the previous five years and has a probability ofless than 10 percent ofexceeding 80 percent ofthe applicable NAAQS during the next three years. Also, since the CO monitor at this site is not needed in orderto meet the minimum monitoring requirements under 40 CFR part 58, the monitor shutdown is acceptable. 6TheNetwork Plan proposes to discontinue 

### 03monitoring at the Clemson site (AQS ID 45-072-0002) in Pickens County in order to redirect limited resources to program priorities. The Greenville-AndersonMauldinMSA includes Greenville, Anderson, Laurens, and Pickens Counties and under 40 CFR part 58, two 0 3monitors are required in the MSA. Currently, there are five 0 3monitors in operation in the MSA. These include the Clemson site which has been in operation since 1979 and four newer sites which were established between 2008 and 2010. These newer sites are the Big Creek (AQS ID 45-007-0005) site in Anderson County, Famoda Farms (AQS ID 45-045-1003) and Hillcrest Middle School sites (AQS ID 45-045-0016) in Greenville County, and the WolfCreek site (AQS ID 45-077-0003) in Pickens County. The Network Plan states that, basedupon an evaluation ofthe data from the 0 3 sites in the GreenvilleAnderson-Mauldin MSA, SC DHEC has concluded that the WolfCreek site is a more appropriate site than the Clemson site for representing 

### 03 concentrations in the portion ofthe MSA where the sites are located. Based upon our review of

### 03 concentration data from the two sites, we do not agree with the proposal to shut down the Clemson site. The basis for this decision is that the available data show that peak 0 3 concentrations are consistently higher at the Clemson site than they are at the WolfCreek site, and the Clemson site is representative ofa more densely populated area than the area represented by the WolfCreek site. Below is a summary ofseveral comparisons between the monitoring results at the two sites which show that 

### 03 concentrations are higher at the Clemson site: 1. During 2011 and 2012, the Clemson site had either the highest or second highest 0 3 design value in the Greenville-Anderson-Mauldin MSA. Since two 

### 03 monitoring sites are required in the MSA, it will be difficult tojustify shutting down the Clemson site unless there are at least two other sites in the MSA that have a higher design value than the Clemson site. 2. During 2012, the 

### 03 concentrations used for calculating design values (i.e., the fourth max concentration) were significantly higher at the Clemson site [0.068 parts per million {ppm)] than they were at the WolfCreek site (0.062 ppm). 3. During the years when monitoring data are available for both the Clemson and WolfCreek sites (2010- 2012), there were three days during which the OJ concentrations exceeded the NAAQS at the Clemson site while there were no days when the 0 3 concentrations at the WolfCreek site exceeded the NAAQS. · 

### 4. Figure 3 in the Network Plan shows that the 

### 03 con_centrations at the Clemson site are consistently higher than the concentrations at the WolfCreek site. Figure 3 is a graph ofthe highest 8-hour OJ concentrations for the years 201 0 through 2012. This graph demonstrates that for three ofthe four months with the highest OJ concentrations, the concentrations at the Clemson site were higher than at the WolfCreek site. 5. Figure 4 is a graph ofthe diurnal one-hour OJ concentrations for the June through August period during 2011 and 2012. This graph demonstrates, that for the peak OJ hours during the day, concentrations were higher at the Clemson site than they were at the WolfCreek site. Although the information summarized above shows that, based upon the data currently available, the WolfCreek site is not a suitable replacement for the Clemson site, we do understand that operating five monitors in an MSA where only two sites are required imposes a resource burden on the SC DHEC.

7In orderto reduce this resource burden, we would be willing to consider a request to shutdown another site in the MSA that is oflower value than the Clemson site. The Network Plan proposes to change the designation for the continuous PM2
.s monitor at the Aston site (AQS ID 45-083-0011) from SPM to SLAMS to reflect the fact that the monitor is used for satisfying the requirement for a regional background site. This change is acceptable. TheNetwork Plan proposes to change the designation for the continuous PM2
. s monitor at the Long Cr eek (AQS ID 45-073-0001) site from SLAMS to SPM due to inadequate performance ofthe FEM that was installed in order to replace a FRM at the site. Since a PM2
.s SLAMS is not needed at the Long Creek site in order to meet the minimum monitoring requirements under 40 CFR part 58, the proposed change in monitoring designation is acceptable. 

### National Core (NCore) Monitoring Network 40 CFR part58, appendix D, 3 A requirement that each state operate at least one NCore site is found in section 3 ofappendix D. The SC DHEC proposed Parklane (AQS ID 45-079-00047) as an NCore site in its 2009 Network Plan. EPA's Office ofAir Quality Planning and Standards granted approval for this site in a letter dated October 30, 2009. Following this approval, Pb monitoring was added to the site in 2010. No additional changes are pr oposed for the site in the 2013 Network Plan.



### 8