UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 4 

Ms. MayaRao 

Chief 

Mississippi Department of 

Environmental Quality 

P.O. Box 2249 

Jackson, Mississippi 39225-2261 

Dear Ms. Rao: 

ATLANTA FEDERAL CENTER 

61 FORSYTH STREET 

ATLANTA, GEORGIA 30303-8960 

November 22, 2013 

Thank you for submitting the annual ambient air-monitoring network plan (Network Plan) for the state 

ofMississippi, dated June 26, 2013, and the Addendum to the Network Plan, dated August 27, 2013. 

The Network Plan is required by 40 Code ofFederal Regulations (CFR) §58.10. The Network Plan 

covers ambient air monitoring networks operated by the Mississippi Department of Environmental 

Quality. 

The cover letter submitted with the MDEQ Network Plan indicated that the public was provided a 

comment period and that MDEQ did not receive public comments regarding the plan. While the letter 

did not indicate that the comment period was 30-days in length, it is our understanding from subsequent 

conversations with your staff that the comment period was 30-days in length as required. 

After review of the plan, the EPA approves the MDEQ's Network Plan with the exception of the 

proposal to discontinue the Meridian ozone monitoring site. The EPA believes that the Meridian site is 

important to preserve the spatial representation of the ozone-monitoring network in the southern 

Mississippi and southern Alabama area. 

The EPA approves the Pascagoula (Jackson Co. 28-059-0006) site to be among the Regional 

Administrator required nitrogen dioxide (N02) monitors intended to help protect susceptible and 

vulnerable populations. The full list ofN02 monitors identified by the Regional Administrators can be 

found on the EPA's website at http://www.epa.gov/ttnamtil/svpop.html. 

Enclosed is a summary of our analysis and comments that may be useful in understanding the EPA's 

decisions and in developing next year's plan. Please contact us if you have any questions related to our 

comments. 

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

Recycled/Recyclable • Printed with Vegetable Oil Based Inks on Recycled Paper (Minimum 30% Postconsumer) 
Thank you for working with us regarding air quality and monitoring air pollution in Mississippi. If you 

have questions or concerns, please contact Gregg Worley at (404) 562-9141 or Phyllis Warrilow at (404) 

562-9198. 

Enclosure 

cc: Mr. Jerry Beasley, 

MDEQ, Air Standards and Planning 

Mr. Michael Jordan, 

Sincerely, 

-{)~ ~---J eaneanne M. Gettle 

Acting Director 

Air, Pesticides and Toxics 

Management Division 

Mississippi Department of Environmental Quality 
CY 2013 State of Mississippi Ambient Air Monitoring Network Plan 

U.S. EPA Region 4 Comments and Recommendations 

The EPA reviewed the Mississippi Department of Environmental Quality annual air monitoring network 

plan (Network Plan). Ambient air monitoring rules are found in 40 CFR Part 58, which include 

regulatory requirements regarding network plans, data certification, and minimum monitoring 

requirements. Minimum monitoring requirements for critical pollutants are listed in 40 CFR Part 58, 

Appendix D. New national ambient air quality standards (NAAQS) for carbon monoxide (CO) with 

minimum monitoring requirements are effective January 1, 2015, and January 1, 2017. Minimum 

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

particulate matter less than 10 microns (PM10), nitrogen dioxide (NOz) sulfur dioxide (SOz), 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 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, and PM10 only apply to metropolitan statistical areas (MSAs), which are a subset ofCBSAs. The 

state's four MSAs and respective population estimates from the U.S. Census Bureau are shown in 

Table 1. 

Table 1: Metropolitan Statistical Areas and July 1, 2012 Population Estimates 

Name Population 

Hattiesburg, MS 146,766 

Memphis, TN-MS-AR 1,341,690 

After review ofMDEQ's Network Plan with respect to the applicable requirements, the EPA makes the 

following comments and recommendations: 

Minimum 03 Monitoring Requirements 

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

Based on population figures and current design values, MDEQ is required to have two 0 3 monitors in 

each of the Gulfport-Biloxi-Pascagoula and Jackson MSAs. The Gulfport-Biloxi-Pascagoula MSA 

currently has two 0 3 monitor(s) and Jackson MSA has two 03 monitors. 

The Memphis MSA is also required to have two 0 3 monitors; however, MDEQ's memorandum of 

agreement (MOA) with Arkansas, Tennessee, and the Shelby County Health Department allows 

Mississippi to meet the 03 requirement for the Memphis MSA with the single 03 monitor in DeSoto 

County. The 0 3 network described in the 2013 Network Plan meets the minimum monitoring 

requirements specified by 40 CFR Part 58, Appendix D, Table D-2 in all areas. 
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 of 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), ... " S02 monitors should be sited within 

CBSA boundaries and be of the following site types: population exposure, maximum concentration, 

source-oriented, general background, or regional transport. 

An S02 monitor at an NCore station may satisfy minimum monitoring requirements if that monitor is 

located within a CBSA that is required to have a monitor under Appendix D, 4.4. MDEQ's S02 

monitors are at the Jackson NCore (28-049-0020) station and at the Pascagoula (Jackson Co. 28-059-

0006) monitoring site. The S02 monitoring network design proposed in the Network Plan meets the 

minimum requirements of 40 CFR Part 58. 

NOz Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.4 

Ambient air monitoring network design criteria for N02 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. 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 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 N02 Monitoring Technical Assistance Document 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 riteria 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, "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." 

For the Memphis CBSA, the requirement for near-road N02 monitoring will be met by a near-road site 

operated by Memphis/Shelby County Health Department, Air Pollution Control Program, in Memphis, 

TN. Additionally, the Marion (Crittenden Co. 05-035-0005) site in Arkansas fulfills the area-wide N02 

monitoring requirement for the Memphis CBSA. No other CBSA in Mississippi is currently required to 
have area-wide NOz monitoring or near-road NOz monitoring. The Jackson, MS CBSA will be required 

to have one near-road NOz monitor operating by January 1, 2017. 

The EPA approves the Pascagou~a (Jackson Co. 28-059-0006) site to be among the Regional 

Administrator required NOz monitors intended to help protect susceptible and vulnerable populations. 

The full list ofN02 monitors identified by the Regional Administrators can be found on the EPA's 

website at http://www.epa.gov/ttnamtillsypop.html. 

Minimum PM1o Monitoring Requirements 

40 CFR Part 58, Appendix D, 3.3.1 

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

The state of Mississippi's current PMw monitoring network meets the minimum requirements found in 

40 CFR Part 58, Appendix D, Table D-4 for all MSA's. All PMw collocation requirements for manual 

methods found in 40 CFR Part 58, Appendix A, Section 3.3.1 are also currently being met. Fifteen 

percent of each network of manual PMw methods (at least one site) must be collocated. MDEQ will 

meet this requirement by having both regular and collocated federal reference method (FRM) PM10 

samplers at the relocated NCore site in the Jackson MSA. The new Air Quality System (AQS) 

identification number is Hinds Co. 28-049-0020. 

Minimum PM2.s Monitoring Requirements 

4il CFR Part 58, Appendix A, 3.2.5 

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

The state of Mississippi's PMz.s monitoring network meets the minimum requirements found in 40 CFR 

Part 58, Appendix D, Table D-5 for all MSAs. The following MSA's are required to have one PM2.5 

monitor: Gulfport-Biloxi-Pascagoula; Hattiesburg, and Jackson. The Memphis MSA is required to have 

two PMz.s monitors. MDEQ's MOA with Arkansas and Memphis-Shelby County, TN allows 

Mississippi to meet the PMz.s requirements for the Memphis MSA with the single PM2.5 monitor in 

DeSoto County. 

MDEQ's primary PMz.s monitoring network as described in the Network Plan meets the minimum 

requirements found in 40 CFR Part 58, Appendix D, table D-5 for all MSAs. 

PM2.s Continuous Monitoring Requirements 

40 CFR Part 58, Appendix D, 4.7.2 

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

local agencies must operate continuous PMz.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 FRM or ARM monitor in which case no 

collocation requirements applies." These minimum continuous PMz.s monitoring requirements are being 

met in all MSAs. Therefore, the continuous PM2.5 monitoring network described in the 2013 Network 

Plan meets all design criteria of 40 CFR Part 58. 

3 
PM2.5 Continuous Federal Equivalent Methods 

40 CFR § 58.10(e) 

As part of the recent revisions to the PM2.s NAAQS, the EPA created new procedures for handling data 

collected using continuous PM2.5 FEMs. These procedures are found at 40 CFR § 58.10(e). If an agency 

can demonstrate that the FEM data are not of sufficient comparability to a collocated FRM, then the 

monitoring agency may request that the FEM data not be used in comparison to the NAAQS. 

In the Network Plan addendum submitted on August 27,2013, MDEQ has demonstrated that the PM2.s 

continuous FEM at the new Jackson NCore site (Hinds Co. 28-049-0020) is not of sufficient 

comparability to a collocated FRM. The EPA approves Mississippi's request that this monitor not be 

considered comparable to the PM2.s NAAQS. 

MDEQ is requested to report the data from this monitor to the AQS parameter code 88502. This 

approval also includes the historical data collected at this monitor, so the historical data can be 

reassigned to parameter code 88502 as well. Also, the minimum PM2.s monitoring requirements will 

continue to be met for the Jackson MSA without counting this monitor. 

PM2•5 Background and Transport Sites 

40 CFR Part 58, Appendix D, 4. 7.3 

Regulatory requirements in 40 CFR Part 58, Appendix D, 4.7.3 require that "each state shall install and 

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

for regional transport." The Grenada (Grenada Co. 28-043-0001) PM2.s monitor is identified as a 

background monitor and the PM2.5 monitor in Hernando (DeSoto Co. 28-033-0002) is identified as the 

transport monitor. Therefore, MDEQ has satisfied the requirements of 40 CFR Part 58 for background 

and transport sites. 

Pb Monitoring Requirements 

40 CFR Part 58, Appendix D, 4. 7.3 

40 CFR Part 58, Appendix D, 3(b) 

Ph monitoring requirements are found in 40 CFR Part 58, Appendix D, 4.5. This states "At a minimum, 

there must be one source-oriented SLAMS [State and Local Air Monitoring Station] site located to 

measure the maximum Ph concentration in ambient air resulting from each non-airport Ph source which 

emits 0.50 or more tons per year and from each airport which emits 1.0 or more tons per year ... " There 

are currently no stationary Ph sources requiring ambient air lead monitoring. 

Furthermore, 40 CFR Part 58, Appendix D, 3(b) requires that "NCore sites in CBSAs with populations 

of 500,000 people (as determined in the latest census) or greater shall measure Ph either as Ph-TSP or 

Pb-PMw." This monitoring was required to begin December 27, 2011. MDEQ has chosen to monitor 

lead at the NCore site in Jackson (Hinds Co. 28-049-0019). The EPA has determined that the Ph 

monitoring network described in the Network Plan meets all design criteria of 40 CFR Part 58. 

4 
Air Quality Index (AQI) Reporting 

40 CFR Part 58.50 

Air Quality Index (AQI) reporting is required in MSAs with populations over 350,000. The GulfportBiloxi-Pascagoula, MS, Jackson, MS, and Memphis, TN-MS-AR MSAs are required to report an AQI. 

The Network Plan includes a link on Page 3 directing users to the MDEQ web site where AQI 

information is available. This satisfies the AQI reporting requirements. 

Monitoring Requirements for Multi-State CBSAs 

40 CFR Part 58 Appendix D, 2(e) 

As mentioned previously, MDEQ has a MOA with the state of Arkansas and Tennessee and with the 

Shelby County Health Department for sharing responsibility to meet the minimum monitoring 

requirements in the Memphis CBSA. The EPA's review ofthe Network Plan found that the monitoring 

required in the Memphis CBSA meets the minimum requirements found in 40 CFR Part 58, 

Appendix D 2(e). 

National Core (NCore) Monitoring Network 

The EPA approved the move ofMDEQ's NCore site to 232 E. Woodrow Wilson Drive, Jackson, MS. 

This location is approximately one mile from the former location near the University of Mississippi 

Medical Center. Due to the site being almost one mile away (0.9 mile) and being out of service for 

almost a year, a new site number was agreed upon for the NCore site (Hinds Co. 28-049-0020). 

Additional Monitoring Network Changes 

MDEQ has proposed several monitoring changes in the Network Plan. MDEQ is proposing to 

discontinue its 0 3 monitor at the Meridian site. The monitor is reading concentrations less than 85% of 

the NAAQS with a 2010-2012 design value of 63 parts per billion. The EPA believes, however, that this 

0 3 site has significant value in preserving the spatial representativeness of the ozone monitoring network 

in the southern Mississippi and southern Alabama area. Currently, there are no other 03 monitoring sites 

located near the Meridian site. The closest sites are 80 - 130 miles away, depending on the direction. 

For this reason, the EPA is not approving this monitor for discontinuation and requires MDEQ to 

continue its operation. 

MDEQ has requested approval to relocate the Jackson, Mississippi Metro site (Hinds Co. 28-049-0010) 

to Hinds Community College property due to security concerns at the current site. Members of the EPA 

Science and Ecosystem Support Division have visited the proposed site and determined that the new site 

meets siting criteria. The EPA approves the relocation of this site. 

5