Mr. Richard C. Chism UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGIONS 1445 ROSS AVENUE, SUITE 1200 DALLAS TX 75202-2733 

# OCT 2 6 20 15
Director, Monitoring Division (MC 165) Texas Commission on

Environmental Quality Post Office Box 13087 Austin, TX 78711-3087 Dear Mr. Chism: Thank you for your correspondence submitting the Texas Commission on Environmental Quality' s (TCEQ) 2015 Annual Monitoring Network Plan. Thank you also for your letter dated April 7, 2015, regarding your air monitoring network. The U.S. Environmental Protection Agency (EPA) has completed its review of the TCEQ's 2015 Annual Monitoring Network Plan to ensure it meets the requirements of 40 Code ofFederal Regulations (CFR) Part 58 that are under the oversight ofthe Regional Administrator. At EPA Region 6, approval authority for annual monitoring network plan s is delegated to the Associate Director for Air Programs. We appreciate your cooperation and work to submit your 2015 network plan. The network assessment process presents an opportunity for the EPA Region 6 and the TCEQ to collaborate on the air monitoring network design. See 40 CFR Part 58 Appendix D, Section 1.1.2. I am pleased to inform you that your 2015 amb ient air monitoring network plan is approved in accordance with 40 CFR §58.1 0
. Also, as requested in your Five Year Ambient Monitoring Network Assessment, your requests to renew lead waivers for the Lower Colorado River Authority Fayette Power Plant in Fayette County and t he United States Department of the Army Fort Hood facility near Killeen are approved. We note an are a in your PM network requiring immediate attention: the need for a continuous PM2.s monitor in Texarkana. Details of our revi ew of your air monitoring network plan are provided in the enclosure. The EPA appreciat es the TCEQ's use of the revised Metropolitan Statistical Area definitions and 2014 population estima t es from the U.S. Census Bureau. We look forward to our continued collaborative work with the TCEQ on your 2016 ambient air monitoring network plan. If you have any questions , or if you would like to d iscuss our comments, please contact me at (214) 665-7548, or your staff may c o ntact Ms. Frances Verhal en, Air Quality Analysis Section Chief, at (214) 665-2172.

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I •**~**Texas Commission on En vironmental Quality 20 15 Annual Ambient Air Monitoring Network Plan Technical Comments
The 2015 Texas Annual Monitoring Network Plan (AMNP), dated June 30, 20 15 , was received on July 1 , 2015. This plan will be referred to as the "20 15 Plan" throughout the remainder of this do cumen t. In accordance with the requirements of 40 Code of Federal Regulations (CFR) Part 58 and its appendices, the U.S. Environmental Protection Agency (EPA) bas reviewed the 2015 Plan and our comments are provided below. The comments bel ow reflect the EPA 's efforts in collaboration w ith the Texas Commission on Environmental Quality (TCEQ) to maintain an accurate and efficient amb ie nt air monitoring network.


### General Comments We appreciate the TCEQ 's annual air monitoring network review for 2015, and acknowledge the TCEQ's finding that "After cons ideration ofthe fe d eral regulations, 2014 U.S. Census Bureau population data, and 20 1 5 design values, the TCEQ will meet or exceed all monitoring requirements with the above mentioned recommendations for next year." We note that in order to meet federal monitoring requirements, there is a need for a continuous PM2
.s monitor in Texarkana. This is di scu ssed further in the section "Particulate Matter (PM) Monitoring" below. We request that the TCEQ continue to include an assessment of its plan's conformance with 40 CFR58 and its appendices in next year's review, and references to t he CFR for network changes. For future p l ans , at the time the proposal become s availab le for public review, we request that a web link to the annual monitoring network propo sal be provided to Ms. France s Verhalen at verhal en.frances@epa.gov and Ms. Ellen Belk at belk.ellen@epa.gov. Also, we appreciate that the TCEQ has been providing an electronic versio n ofthe AMNP and encourage you to continue to provide an electronic version in addition to the hardcopy. For future plans, we ask that the TCEQ also provide an Excel spreadsheet of its site list, which for the 20 15 Plan was provided in Appendix A: TCEQ SLAMS, PAMS, NATTS, NCore, and SPM Site List. Electronic copies may be sent to Ms. France s Verhalen and Ms. Ellen Belk at the email addresses above. 

### Nitrogen Dioxide (N02) 

### Monitoring Area-wide N02 Monitors The EPA Region 6 acknowledges that the N02 area-wide monitors for the Houston-The Woodl andsSugarland [C linton , Air Quality System (AQS) #48-201-1 035], Dallas-Fort Worth-Arlington (Hinton , AQS Site ID: 48-113 -0 069), San Antonio-New Braunfels (Northwest, AQS Site ID: 48-029-003 2), and Aus tin-Round Rock (Northwest, AQS Site ID: 48-453-0014) core-based s tati stical areas, as requ ired by the 40 CFR, Part 58, Appendi x D, Section 4.3.3, were approved in the 20 1 3 AMNP response letter from EPA Region 6 dated May 28 , 2014. 

### Regional Administrator Required Monitoring (RA40) 

### Monitors The EPA Region 6 acknow ledges that the N02 monitors (i.e. El Paso Ascarate, AQS Site ID:48-141-0055, Houston Clinton, AQS Site ID: 48-201-1035, Arlington Municipal Airport, AQS S ite ID: 48-439-3011 and Beaumont Nederland High School, AQS Site ID: 48-245-1 035) for use to help pro tect susceptible and vulnerab le populations under the "RA40" national requirement (40 CFR Part 58, Appendix D , Section 4.3.4) were approved in the 20 1 3 AMNP response letter from EPA Region 6 dated May 28, 2014. 

### Near

- Road Monitoring Sites In an email dated December 3, 2014, the EPA Region 6 approved the phase II near-road site locati ons for Dallas-Fort Worth (i.e. the Fort Worth California Parkway North site, AQS Site ID: 48-439 -1 0 53) and for Houston (i.e. the Houston North Loop site, AQS Site ID: 48 -201-1052). Both sites were deployed in 2015 as required by 40 CFR Part 58, Appendix D, Section 4.3. 2. We acknowledge that the Fort Worth California Parkway North and Hous ton North Loop sites also house, in addition to the required N02 monitors, required PM2.s and CO monitors in accordance with 40 CFR Part 58, Appendix D, Sections 4.7 and 4.2.1. Additional PM2.s and CO monitors will be required to be deployed by January 1, 2017, at the existing near-road sites in Austin and San Antonio.


### Sulfur Dioxide (S02) Monitoring The TCEQ operates 25 S02 monitors, 3 of which are at National Core multipollutant monitoring stat ion sites. No additional monitors are required according to the S02 Population Weighted Emission Index
. The TCEQ is meeting the network design requirements for ambient air quality monitoring for S02. See 40 CFR Part 58, Appendix D Section 4.4.


### Lead (Pb) Monitoring Pb Waivers The TCEQ has submitted five Pb waivers for source-oriented monitoring since 2010, and all have been granted by EPA Region 6. Three ofthese waivers are no longer required because source emissions have decreased below the 0.50 tons per year threshold. Requests to renew Pb waivers for the Lower Colorado River Authority (LCRA) Fayette Power Pl ant in Fayette County, Texas, and the United States Department of the Army Fort Hood facility near K illee n were included in the TCEQ's Five Year Network Assessment, submitted to EPA Region 6 on June 30, 2015. Based on the data and modeling discussion provided by TCEQ in Appendix E of the Five Year Network Assessment, these Pb waiver renewal requests are approved. For the LCRA facility, the sources were mo deled in 2009; since then there have been no changes to the modeled source parameters and the reported emissions were lower in 2013 than in 2009, which woul d correspond with lower predicted Pb concentrations than previously modeled. For the Fort Hood facility, the sources were modeled in 2012; since that time there have been no changes to the modeled source parameters and the 2015 permit all o wable emission rates were shown to correspond with a maximum predicted modeled concentration of less than half the Pb NAAQS. 

### Pb Collocation The TCEQ is curre ntly operating thirteen Pb monitoring sites, three of which have collocation. The TCEQ is current ly exceeding the required number of collocated Pb monitors as detailed in 40 CFR Part 58, Appendix A, Section 3.3.4.3. With collocation at the Frisco Eubanks site (AQS Site ID: 24 8-08 5-0 009) , th e requirement for collocation at the highest concentratio n s ite is currentl y being met. Because the desi gn va lue (DV) of this site i s expected to drop dramati ca lly in 2016, please ensure the co llocation requirements continue to be met.


### Ozone (03) Mon itoring T he EPA Region 6 acknowledges that no changes occurred in the Texas ozone monitoring network in 2 015
. 

### Ca rbon Monoxide (CO) Monitoring E PA Region 6 acknowledges the following end dates in AQS for the nine CO monitors approve d for discontinua tion in the 20 1 3 AMNP response letter from the EPA Region 6 dated May 28, 2014. According to AQS, the end date for CO monitoring was June 30, 2014, for the Houston Aldine sit e (AQS S ite ID: 48-201-0024), the Arlington Municipal Airport site (AQS Site 10: 48-439-3011) , and the Austin Northwest site (AQS Site ID: 48-453-0014)
. Also in AQS, the end date for CO monitoring was December 31 , 2014, for the E l Paso UTEP site (AQS Site ID : 48-141-003 7) , the El Paso Skyline s ite (AQS S ite ID : 48-141

- 005 8 ), the Houston Lang site (A QS S ite ID : 48-201-0047), the Houston Texas Avenue s it e (AQ S Site ID : 48-201-0075), and the Houston Park Place site (AQS S ite ID: 48 -20 1-0416). The Fort Worth Northwest site (AQS Site ID : 4 8-4 39 -1 002) has an end date in AQS of October 31,2014.


### Particulate Matter (PM) Monitoring Particulate Matter of 10 Microns or More (PM10) EPA Regi on 6 n ote s that in the letter responding to your 20 14 Plan (d ate d January 14 , 20 15) , the E PA approved the proposa l to deploy the required State or local air monitoring station s PM to monitor a t the Brownsville (AQ S S ite 10 : 48

- 061-0006) site in the Brownsville-Harlingen M etropolitan Statistic al Area (MSA) and at the Edinburg East Freddy Gonzale z Drive (AQS Site ID : 48-215-1046) site in the McAllen-Edinburg-Mission MSA as meeting the requirements of 40 CFR Part 58, Appendix D , Section 4.6. Please notify E PA Region 6 which PMto monitoring method is used at these sites and when the monitors were dep loyed and became operational. Please ensure this information is reflected in the TCEQ's 2016 AMNP. EPA Region 6 acknowledges that the fo ll owing PM to m onitors were repl ace d with PM 10 metho d 062 monitors as n oted in AQS: Socorro Hueco (AQS #48-141-0057) prima ry and collocated QA samplers and Laredo Vid aurri (AQS# 48-479

- 0016) primary and collocated Q A samplers. · For the Tyler M S A, the table in Appendix H indicates that there are 0 required PM10 monitors and 1 exis ting moni tor. The EPA agrees that no PM10 monitors are required in the area but notes a discrepancy wi th Appe ndix A , which does not list any PMto monitors in the Ty ler area. Please v er ify the number of existin g PM 10 monitors, and update App endi x A or Appendix H as appropriate. 

### PM10 Collocation Based on rev ie w ofthe number of collocated PMto monitors , the EPA clarified that collocation i s requi red for 15 % ofthe entire manual network
. Based on the current network of27 monitors , the TCEQ


### 3is required to ha v e 4 collocated monitors and currently operates 8. The EPA is open to discussion s or proposals for reducing the number of collocated monitors.
Particulate Matter of 2.5 Microns or Less (PMz.s) In the El Paso MSA, the table in Appendix I indicates that there are 3 required monitors and 2 existing monitors. Popul a tion and design value requirements would support a finding that 2 National Amb ient Air Quality Stand ard PM2 .s monitors are needed in the El Paso area. Please verify the number of required and exis ting PM2
.s monitors, and update Appendix I as appropriate. In the 2014 AMNP, the TCEQ proposed to operate the Brownsville PM2
. s monitor on a 116 schedule. The EPA did not approve of this schedule due to lack of current data and the TC EQ agreed in the response letter, dated April 7, 2015, to operate this monitor on a 1/3 schedule. Examination ofthe data indicates that thi s monitor is running on a 1/3 schedule but in Appendix A the operating schedule is listed as 1/6. Ple as e verify the operating schedule ofthis monitor. After TCEQ has submitted their PM2.s network evaluation, including the PM2.s tapered element oscillating microbalance (TEOM) network, as part ofthe 20 15 T CEQ Five Year Network Assessment, changes in the sampling schedule ofthe se monitors can be requested after consideration of factors including, but not limited to, the historical PM2
.s data quali ty asse ss ments, the location of current PM2.s DV sites, and th e ir regulatory data needs as 

### provided by 40 CFR 

### §58.12(d)(l)(ii). · PMz.s Collocation The TCEQ depl o yed 4 new Phll.s Federal reference method (FRM) monitors which increases the number o f moni to rs to 25: Fort Worth California Parkway North (AQS 484391053), Houston North Loop (AQS 4820 11052), Edinburg East Freddy Gonzalez Drive (AQS 482151046), and Brownsville (AQS 48061000 6) using sampling method 145. According to 40 CFR Part 58, Appendix A, Section 3.2.5, 15% ofthe primary monitors for each sampling method are required to be collocated. The TCE Q currently has three collocated monitors to meet the 15% collocation requirements for method 145. These monitors are at the following sites: the Dallas Hinton site (AQS #48-113-0069), the Houston Clinton site (AQS #48-201-1035) and the Corpus Christi Huisache site (AQS #48-355

- 0032). However, the addition of the PM2.s FRM sites proposed for deployment in the Brownville-Harlingen and the McAllen-Edinb urg -Mission MSAs and the two near-road PM2
.s monitors now require the TCEQ t o have an additional co ll ocated monitor. The EPA concurs with the TCEQ recommendation ofthe additio n of a PM2.s FRM gravimetric sampler to the El Paso Chamizal (AQS 48

- 141

- 0044) site to meet t he collocation requirement. PMz.s Continuous Network For the Texarkana MSA, according to 40 CFR Part 58, Appendix D , Section 4.7.2, the TCEQ is required to opera te continuous PM2 .s monitors equal to at least one-half the minimum required sites listed in Table D-5 of40 CFR Part 58, Appendix D. Since the TCEQ operates a SLAMS PM2.s FRM at the Texarkana site (A QS #48-037-0004), the TCEQ is also required to operate a continuous monitor within the Texarkana MSA. We understand that the TC E Q is unable to deploy a TEOM monitor at the Texarkana site (A QS #48-037-0004) due to logistical issues. Based on a conversation between Frances Verhalen and Patti de Ia Cruz on October 5, 2015, we understand that the TCEQ plans to relocate the monitoring stati o n in fiscal year 2016 and install a continuous PM2.s monitor by December 31, 2015. Please notify EPA Region 6 where the TCEQ is planning to locate the PM2.s continuous monitor and whi ch method w i ll b e used. Once EPA Region 6 has approved the site location and method in 4

### accordance with 40 CFR Part 58 and it s appendices, the TCEQ will need to notify EPA Region 6 when the monitor is deployed and operational. Please ensure that this change is reflected in the TCEQ' s 2016 AMNP and also in AQS. In accordance with 40 CFR Part 58, Appendix D, Section 4.7, during the transition to the new sit e we r equest tha t the TC E Q continue to operate the PM2
.s FRM monitor at the Texarkana sit e (AQ S #48-037-0004), which will continue to sample once every third day, f or continuity ofdata. The TCE Q is als o required to operate PM2
.s monitors for the Air Quality Index system for any M S A with a population exceeding 350;000. 

### See 40 CFR §58.50(b). The TCEQ's continuous PM2
.s network currently meets, and in some cases, exceeds this requirement. We suggest the TCEQ reassess their continuous PM 2
. s network for efficiency and coverage. Further discussion will be needed before c hanges are made to the TCEQ continuous PM2.s network. We note that the PM2. s TEOM at the Wichita Falls site (AQS #48-485-0315) was approved for discontinuation in an email to the TCEQ on March 31, 2014 , and acknowledge the end date of February 24,2015, as provided in your letter dated April 7, 2015. In the Laredo MSA, the table in Appendix I indicates that there are 0 required monitors and 2 ex is ting moni tors. The EPA agrees that no continuous PM2.s monitors are required in the area but notes a disc r epancy with Appendix A, which lists only 1 continuous PM2.s monitor in the Laredo area. Please verify the number ofexisting PM2
.s monitors, and update Appendix A or Appendix I as appropriate.
Volatile Organi c Compounds (VOCs) , Carbonyls and Meteoro logy 

### The EPA Region 6 acknowl e dges that no changes occurred in the TCEQ Automated Gas Chromatograph ( Auto-GC), canister, carbonyl and meteorology networks in 2015.
Phot och emic al A ssessm ent Mo ni to r in g Sta tio n s (P AMS) 

### In Appendix A there are some Photochemical Air Monitoring Station (PAMS) meteorological parameters that need to be changed from Special purpose monitor (SPM) to PAMS under the column titled "AQS Net w ork & 

### Monitor Type". Please make the following changes in Appendix A and the AQS for the following four monitors: 1. Relative Humidity needs to be changed from SPM to PAMS at the Dallas Hinton site (AQ S Site ID: 48- 1 1 3-0069) 2. UV Radiation nee ds to be changed from SPM to PAMS at the El Paso UTEP site (AQS Site ID: 48-141-0037) 3
. Solar R a diation needs to be changed from SPM toP AMS at the El Paso Chamizal site (AQ S Site ID: 4 8- 141-0044) 4. Re lative Humidity needs to be changed from SPM to PAMS at the Houston Aldine site ( AQS Site ID: 4 8-201-0024). The f ollowing changes to the PAMS network were approved by the E PA by lette r dated January 29, 20 1 5: 5• The decommissioning of the Reactive Oxides of Nitrogen (NO x) monitor at the SETRPC 4 0 Sabine Pas s site (AQS Site ID: 48-245-0101 ). • There-de si gnation of the carbonyl monitors at the Fort Worth N orthwest site (AQS Site ID: 48- 439-1002 ) and the El Paso Ascarate Park SE site (AQS Site ID: 48-141-0055) from PAMS to SPM. • There

- desig nation ofthe radar profiler at the EJ Paso UTEP site (AQS Site ID: 48-141-00 3 7) from PAMS to SPM. The EPA previous ly concurred with there-designation of the dew point monitors to SPMs in the 2 013 AMNP response letter from EPA date d May 28,2014. We appreciate t he TCEQ updating AQS w ith these SPM desig nations beginning with a start date ofJuly 1, 2014.

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