y

, 

Bureau of Air Quality Control 

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 2010 annual ambient air 

monitoring network plan (Network Plan) and five-year ambient air monitoring network 

assessment (Network Assessment), dated July 1,2010. The Network Plan and Network 

Assessment are required by 40 Code of Federal Regulations (CFR) 558.10. 

The Environmental Protection Agency (EPA) Region 4 understands that the South 

Carolina Department of Health and Environmental Control (DHEC) provided the public a 30-day 

review period. The only comment received was from the National Park Service which expressed 

appreciation to DHEC for the time and expenses it put into operating a monitoring site at the 

Cowpens National Battlefield. 

Based upon our review of the Network Plan and Network Assessment, EPA Region 4 has 

determined that the documents satisfy the applicable requirements of 40 CFR Part 58. Also, the 

State was found to have adequately considered the additional factors specified by EPA Region 4 

in conducting the Network Assessment. The Network Plan is approved. Comments and 

recommendations on both documents are enclosed. 

Thank you for your work with us to monitor air pollution and promote healthy air quality 

- in South Carolina and the nation. If you have any questions or concerns, please contact Doug 

Neeley at (404) 562-9097 or David McNeal at (404) 562-9102. 

Sincerely, 

/I%& 

Gwendolyn Keyes Fleming 

Regional Administrator 

Enclosure 

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

Recycled/Recyclable *Printed wlh Vegetable On Based Inks on Recyded Paper (Mlnbnum 30% Postconsumer) 
Mr. Thomas Flynn, 

Manager, Air Data Analysis and Support Section, 

SC DHEC 
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) multipollutant monitoring 

station, and/or a state implementation plan. However, new national ambient air quality standards 

(NAAQS) were promulgated this year for nitrogen dioxide (N@) and sulfur dioxide (SO2) with 

minimum monitoring requirements effective January 1,20 13. Minimum monitoring 

requirements are listed for ozone (03), particulate matter less than 2.5 microns (PM2.5), 

particulate matter less than 10 microns (PMlo), 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 from the U.S. Census Bureau and historical ambient air monitoring data. 

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

July 1,2009, population estimates from the U.S. Census Bureau are shown in Table 1. 

Table 1: Metropolitan Statistical Areas and Populations 

MSA Name Population 

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

Columbia, SC 744,730 

Charleston-North Charleston-Surnmerville, SC 659,191 

Greenville-Mauldin-Easley, SC 639,617 

Augusta-Richmond Couuty, GA-SC 539,154 

Spartanburg, SC 286,822 

Myrtle Beach-Conway-North Myrtle Beach, SC 263,868 

Florence, SC 200,653 

Anderson, SC 184,901 

, Sumter, SC 104,495 

Minimum Ozone Monitoring Requirements 

40 CFR part 58, appendix D, table D-2 

Region 4 has determined that the ozone monitoring network outlined in the Network Plan 

meets the minimum requirements found in 40 CFR part 58, appendix D, table D-2 for all MSAs. 
Minimum PM2j Monitoring Requirements 40 CFR part 58, appendix A, 3.25 40 CFR part 58, appendix D, table D-5 ' 

Region 4 has determined that the PM2.5 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 PM2.5 collocation requirements are met. 

PMns Continuous Monitoring Requirements 

40 CFR part 58, appendix D, 4.7.2 

Regulatory requirements for continuous PM25 monitoring require that "...State, or where 

appropriate, local agencies must operate continuous 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 Federal 

Reference Method (FRM)/Federal Equivalent, Method (FEM)/Approved Regional Method 

(ARM) 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 outlined network Region 4 has determined that the proposed PM25 continuous 

monitoring network meets or exceeds the minimum requirements in the all of the MSAs in the 

State. Also, the continuous PM2.S collocation requirements are met in all MSAs. 

PM2j Background and Transport Sites 

40 CFR part 58, appendix D, 4.73 

40 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, DHEC has satisfied the requirements 

of 40 CFR part 58 for regional background and transport sites. 

Pb Monitoring Requirements 

40 CFR part 58, appendix D, 4.5 

DHEC's Network Plan identifies the following Pb monitoring sites that were added to the 

network to satisfy population based monitoring requirements in part 58, appendix D: 
changes to its Pb monitoring requirements. Under these proposed changes, population-based 

monitors will not be required and EPA has advised states not to expend any resources planning 

or installing them. The Network Plan indicates that monitoring at the above sites may be 

terminated, pending the promulgation of the proposed changes to EPA's Pb monitoring 

requirements. In addition, the Network Plan indicates that a new Pb monitor will be added to the 

Parklane (AQS ID 45-079-0007) NCore site in anticipation of the changes to the Pb requirements 

in 40 CFR part 58. Based upon our review, all of the Pb monitoring provisions in the Network 

Plan are acceptable. 

Air Quality Index (AQI) Reporting 

40 CFR 958.50 

AQI reporting is required in MSAs with populations over 350,000. There are three 

MSAs in the State of South Carolina required to report an AQI: Greenville-Spartanburg, 

Columbia, and Charleston-North Charleston. The Network PI* on page 3 indicates that the 

daily AQI for these areas is available on EPA's AIRNow web site. This satisfies the AQI 

reporting requirements. 

Monitoring Network Changes Proposed by DHEC 

DHEC has proposed several monitoring network changes in the Network Plan which are 

summarized in Table 3. 

---J 

AQS ID Pollutant Comments 

45-007-0004 PMzJ SPM Site discontinued 

45-045916 P& SPM Addition to existing site 

45-083-0010 PMzJ SLAMS Move within MSA 

45-043-0006 PMIO SPM Site discontinued 

45-043-0012 PMto SPM Site discontinued 

45-019-xxxx pMz.5 SPM New site 

45-O~PXXXX Black carbon Non-regulatory New site 

45-0 19-0049 pM2.5 SLAMS Move within MSA 

45-0 19-0049 Speciated PMlo SPM Site to be discontinued 

45-041-0002 pM2.5 SLAMS Move within MSA 

The State of South Carolina has proposed to move three of its PM2.5 monitoring sites. 

One move would involve relocating a monitor in the Spartanburg MSA from the Westview 

(AQS ID 45-083-0010) site to the T. K. Gregg (AQS ID 45-083-001 1) site and another move 

would involve relocating a monitor in the Florence MSA from the H. L. Sneed Middle School 

(AQS ID 45-041-0002) site to the Williams (AQS ID 45-041-0003) site. According to the 
The proposal to move the PM2.5 monitoring site at the Charleston Public Works (AQS ID 

45-019-0049) site has been made pending identification of a suitable replacement site and 

collection of data demonstrating that the proposed site is representative of the current site. EPA 

will make a determination regarding the acceptability of this move once DHEC provides the 

results of simultaneous monitoring at the existing site and the proposed site. 

Since none of the special purpose monitoring sites that DHEC proposes to shutdown are 

used for meeting the minimum monitoring requirements in appendix D of 40 CFR part 58, the 

proposal to discontinue these monitors is acceptable. 

National Core (NCore) Monitoring Network 

DHEC proposed Parklane (AQS ID 45-079-00047) and Chesterfield (AQS ID 45-025- 

0001) as NCore sites in its 2010 Network Plan. EPA's Office of Air Quality Planning and 

Standards granted approval of the sites in a letter dated October 30,2009. Following approval, 

DHEC decided not to operate Chesterfield as an NCore site. However, DHEC will continue to operate regional transport, regional background, and air toxics monitors at this site. According 

to the Network Plan, monitors for all required NCore species are expected to be operational at 

the Parklane site by the January 1,201 1, deadline. The only change identified for the NCore site 

in the Network Plan is the addition of a Pb monitor. This monitor is being added in anticipation 

of revisions to the Pb monitoring requirements in part 58. 

Five-Year Ambient Air Monitoring Network Assessment 

In addition to the Network Plan, DHEC submitted a five-year Network .Assessment. This 

assessment is required under provisions in 40 CFR §58.10(d) and DHEC submitted it by the 

Julyl, 2010, deadline. At a minimum, the Network Assessment must consider whether the 

monitoring network meets the objectives outlined in appendix D to 40 CFR part 58, whether new 

sites are needed, whether existing sites can be terminated because they are no longer needed, and 

whether new technologies are appropriate for incorporation into the ambient air monitoring 

network. The assessment must also consider the ability of the existing and proposed sites to 

support air quality characterization for areas with relatively high populations of susceptible 

individuals (e.g., children with asthma) and for any sites proposed for discontinuation, the effect 

on data users other than the agency itself, such as nearby states or tribes or health effects studies. 

For PM2.5, the assessment must also speclfy needed changes to population-oriented sites. 

Region.4 required its state and local agencies to consider the following additional factors 

in their network assessments: 
needs. 

DHEC evaluated its existing monitoring network using tools provided by EPA and the 

assessment explained that these tools work best for higher density networks with wide spatial 

distribution. Because the State's ozone and PM25 networks have the largest number of monitors 

and are the most widely distributed, the networks for these pollutants received greater emphasis 

in the Network Assessment. Using the EPA tools and a weighting system that considers a 

number of factors, DHEC ranked its existing monitoring sites in order of importance. The 

weighting system assigned greater importance to ambient concentration levels, the likelihood of , 

national ambient air quality standard (NAAQS) violations, and the population of individuals 

either less than 19 or more than 64 years of age. Although these factors received the highest 

weighting, DHEG's analysis also considered the area served by the monitor, pollutant emission 

levels, population changes, the number of people living below the poverty level, the length of 

time a monitor has been in service, and the number of monitors at the site. 

In addition to ranking ihe importance of it existing monitors, DHEC identified areas 

where additional monitors would provide the most value. The assessment also notes, that due to 

EPA's review of many NAAQS and their associated monitoring requirements, it is not feasible 

to make significant changes to the State's ambient air monitoring network at this time. Another 

issue discussed in the Network Assessment is the need for better evaluation tools that could be 

made available now for use in the annual planning process. According to the assessment, this 

would help avoid duplication of effort as DHEC prepares for the next five-year assessment 

which will be due on July 1,201 5.