UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX
75 Hawthorne Street San Francisco, CA 94105

April 18, 2013

Ted Schade

Air Pollution Control Officer

Great Basin Unified Air Pollution Control District

157 Short Street Bishop, California 93514

Dear Mr. Schade :

Thank you for your submission of the Great Basin Unified Air Pollution Control District’s (GBUAPCD’s) 2012 Ambient Air Monitoring Network Plan in June 2012

. Based on the information provided in the plan, EPA approves all portions of the network plan except those specifically identified below.

Annual network plans are important documents for regulatory purposes (e.g., State Implementation Plans, designations and redesignations ) and public information, in addition to the myriad uses by the air districts. EPA is revising the review process for annual network plans to specifically check and document the comprehensive set of items that are required to be included in the annual network plans per 40 CFR 58.10 in a consistent manner. We have created

a checklist that lists all these items and have included it as Attachment A. W hile the items in the checklist are required by EPA regulations , we acknowledge that we have not specifically requested some of this information in previous annual network plan reviews . We r ecognize that your plan may not have all the items that we have currently identified and hope to work with you on the inclusion of these items in future plans. To facilitate these changes, EPA has provided

detailed feedback in the checklist where informati on should be included or revised in next year’s plan.

Please note that we cannot approve portions of th e annual network plan for which the information in the plan is insufficient to judge whether the requirement has been met, or for

which the information , as described, does not meet the requirements as specified in 40 CFR 58.10 and the associated appendices. EPA Region 9 also cannot approve portions of the plan for which the EPA Administrator has approval authority. Accordingly, we are not acting on the specific portions of your agency ’s annual network plan listed in Attachment B

.

All of the comments in Attachments A , B, and C should be addressed in next year’s network plan. Also, GBUAPCD received comments from the Los Angeles Department of Water and

Pow er (LADWP) on specific portions the annual network plan during the public comment period. GBUAPCD’s responses to these comments were included with the network plansubmittal. EPA also received separate comments on the annual network plan outside of the

com ment period. EPA has determined that GBUAPCD’s responses to the substantive comments are adequate and has provided supplemental responses to the substantive comments in

Attachment D. If you have any questions regarding this letter or the enclosed comments, please

feel free to contact me at (415) 972

- 3851 or Michael Flagg at (415) 972

- 3372

.

Sincerely,

/s/

Matthew Lakin, Manager Air Quality Analysis Office

Enclosure s : A. Annual Air Monitoring Network Plan Checklist

B. Elements where EPA is Not Taking Action

C. Additional Detailed Comments

D. Response to Comments

cc: Christopher Lanane, GBUAPCD Karen Magliano, CARBAttachment B : Annual Air Monitoring Network P lan I tems where EPA is N ot Taking

A cti on

We are not acting on the portions of annual network plan s where either EPA Region 9 lacks the authority to approve specific items of the plan, or EPA has determined that a requirement is either not met or information in the plan is insufficient to judge whether the requirement has

been met.

 NCor e monitoring require s EPA Administrator approval . Per 40 CFR 58.11(c), NCore network design and changes are subject to approval of the EPA Administrator

. Therefore, we are not acting on these items.

 System modifications (e.g., site closures or moves) are subject to approval per 40 CFR58.14(c). Information provided in the pl an was insufficient for EPA to approve the following system modification listed in the plan per the applicable requirement:

relocation of the Flat Rock PM 10 SLAMS site . Therefore, we are not taking action on this item as part of this year’s annual network plan.

 EPA identified items in you agency’s annual network plan where a requirement was not being met or information in the plan was insufficient to judge whether the requirement was being met based on 40 CFR 58.10 and the associated appendices. Therefore

, we are not acting on of the following items:Item Checklist Row (Attachment A) Issue

Distance to roadway 62 Insufficient information to judge

Traffic count 63 Insufficient information to judge Scale of representation 16 Insufficient information to judge

Distance between collocated

monitors 33 Insufficient information to judge

Distance from supporting

structure 66 Insufficient information to judge

PM 2.5 monitors represent community wide air quality at neighborhood scale 54 Insufficient information to judge

Population

- oriented PM 2.5 site in area of expected max

concentration 5 5 Insufficient information to judge

PM 2.5 background/transport

site 58 Insufficient information to judge

Document how agency will provide for the review of changes to PM 2.5 network 22 Insufficient information to judge

Precision and accuracy reports 23 Insufficient information to judge

Data certification 2 4 Insufficient information to judge

Parameter occurrence code 43 Insufficient informatio n to judge Sampling and analysis method 13 Insufficient information to judge in some

instances

Method code 37 Insufficient information to judge in some

instances

Monitor start date 38 Insufficient information to judge Monitor type 39 Insufficient information to judge Monitoring objective 40 Insufficient information to judge

Parameter code 42 Insufficient information to judge Statement of purpose 2 Insufficient information to judge

NCore site information 7 Insufficient information to judge Frequency of 1

- pt QC checks 28 Insufficient information to judge

Date of annual PE audits 29 Insufficient information to judge

Probe material 72 Insufficient information to judge

Residence time 73 Insufficient information to judge

Additional information for each of these items is in included in Attachment A

.Attachment C : Additional Detailed C omments

 The Coso Junction PM 10 site is characterized as “regional scale” on p.7, but listed as “neighborhood” in the site report in Appendix A. Therefore, please correct this discrepanc y in next year’s plan.

 While some of the dates for PM 10 semi

- annual flow audits are missing from the Appendix A site reports, EPA has reviewed information provided by the district and has confirmed that this requ irement is currently being met. Please provide the dates of the semi

- annual

flow audits for each monitor in next year’s plan

.

 The PM 10 monitors in the network are currently monitoring at the correct frequency, but information included in the plan is unclear. Please provide the specific operating schedules for each monitor in next year’s plan.

 While the collocation requirement for manual PM 10 monitors is currently being met, please include more detailed information concerning the PM 10 collocation requirement and specific information on the operating schedules for manual PM 10 monitors at the

Keeler site.Attachment D : Response to Comments

The Los Angeles Department of Water and Power (LADWP) submitted comments to the Great Basin Unified Air Pollution Control District (GBUAPCD) on May 16, 2012, during the comment period held by GBUAPCD on its proposed 2012 annual network plan (2012 ANP). GBU ACPD responded to these comments in a memorandum dated May 23, 2012, which was included with

the final 2012 ANP submitted to EPA on June 29, 2012. LADWP subsequently sent a letter to

EPA on September 28, 2012 expanding upon the comments made in the May 16, 2012 letter, and providing responses to GBUAPCD’s responses in the May 23, 2012 memorandum. LADWP sent further comments on January 8, 2013 supplement ing the ir comments submitted on September 28,

2012.

Comment: LADWP acknowledges that GBUAPCD’s state or l ocal air monitoring stations (SLAMS) 1 network is covered under an approved California Air Resources Board (ARB) Quality Assurance Plan (QAP). However, LADWP contends that the ARB QAP does not cover the use of the data used to identify supplemental dust con trol areas on Owens Lake because the ARB QAP does not properly assure quality for all the instrument systems that are used in the dust source identification process. LADWP also notes that some of the instrument system elements that are not covered by the Q AP (e.g. sand motion monitoring and video monitoring) are described in the 2012 ANP. LADWP also requests that GBUAPCD update its PM 10 and

PM 2.5 Quality Assurance Project Plans (QAPPs) for particulate matter with an aerodynamic diameter less than or equal t o a nominal 10 micrometers (PM 10 ) and particulate matter with an aerodynamic diameter less than or equal to a nominal 2.5 micrometers (PM 2.5 ) to include all of the instrument systems that are required to implement the procedures described in the 2008

Owens Valley State Implementation Plan (2008 SIP), and have those QAPPs approved in a public proceeding.

Response: The requirements contained in 40 CFR Part 58 Appendix A, including the requirements for QAPPs, are applicable to SLAMS air monitoring data and Prevention of Significant Deterioration (PSD) data. 2 These requirements also apply to all special purpose monitor (SPM) 3 stations using a federal reference method (FRM), a federal equivalent method (FEM), or an approved regional method (ARM), which meets t he requirements of 40 CFR Part 58 Appendix E. 4 LADWP’s initial comments on the 2012 ANP and their subsequent September 28, 2012 letter both acknowledge that the GBUACPD’s SLAMS network is covered by ARB’s QAP. As the additional instrument systems mentioned by LADWP in their comments are not SLAMS and do not use FRM, FEM or ARM methods, information pertaining to the operation of

1 “The SLAMS make up the ambient air quality monitoring sites that are primarily needed for NAAQS comparisons, but may serve other data purposes. SLAMS exclude special purpose monitor (SPM) stations and include NCore, PAMS, and all other State or locally op erated stations that have not been designated as SPM stations.” 40 CFR 58.1.

2 40 CFR 58.11(a)(1); 40 CFR Part 58, Appendix A, § 1.

3 “An SPM is defined as any monitor included in an agency's monitoring network that the agency has designated as a special purpose monitor in its annual monitoring network plan and in AQS, and which the agency does not count when showing compliance with the minimum requirements of this subpart for the number and siting of monitors of various types.” 40 CFR 58.20(a).

4 40 CF R 58.20(b); 40 CFR Part 58, Appendix A, § 1.those instruments and the subsequent data use in the dust source identification process is not

required to be included in QAPPs und er 40 CFR 58 Appendix A

. Furthermore, there are no requirements that QAPPs must undergo a public review process prior to submission and approval by EPA or the PQAO (primary quality assurance organization).

Comment: The current GBUAPCD monitoring network d esign is problematic because it focuses on Owens Lake and does not adequately assess contributions from other source areas. LAWDP also requests that GBUAPCD identify the major off

- lake source areas and monitor them for both

sand motion and dust emissions.

Response: Comments concerning which sources are influencing specific monitors are beyond the scope of what EPA is required to review and approve as part of the annual network plan process. Generally, ambient air monitoring network design is performed by the State or local air districts and there are no specific requirements in 40 CFR Part 58 Appendix D, 4.6 that mandate

a PM 10 network capture influences from specific sources. Currently, the PM 10 network in the Owens Lake nonattainment area meets the appli cable requirements in 40 CFR 58 Appendix D.

Comment: The Keeler PM 2.5 and PM 10 monitors, and the North Beach PM 10 monitor appear to violate the EPA siting criteria contained in 40 CFR Part 58 Appendix E, §3(a) due to their close proximity to a number of unpaved roads.

Response: As explained in 40 CFR 58 Appendix E, §3(a), it is important to understand the monitoring objective for a particular location in order to interpret the requirement for spacing

from minor sources. The Keeler and North Beach mon itoring sites are characterized as having population oriented 5 (population exposure) and source impact (source oriented) site types, respectively. 6 40 CFR 58 Appendix E, §3(a) explains that if the objective for a monitoring site is to investigate local PM 1 0 sources, then the site is likely to be properly located nearby. Furthermore, in these instances, capturing the influence of emissions from nearby unpaved roads may be important, and moving these monitors away from such sources may underestimate the popul ation’s exposure to harmful levels of PM 10 and PM 2.5 . Due to the monitoring objectives of these sites and their distance from roadways, the presence of nearby unpaved roads does not violate EPA’s siting criteria in 40 CFR 58 Appendix E.

Comment: The 2012 ANP does not adequately explain the April 2011 discontinuation and

relocation of the Flat Rock PM 10 monitor to the Mill Site.

Response: EPA agrees that there was insufficient information included in the 2012 ANP concerning the shutdown and relocation of the Flat Rock PM 10 monitor. System modifications to the SLAMS network must meet specific criteria outlined in 40 CFR 58.14 and be subsequently approved by EPA. As there was not enough information to judge whether the shutdown and relocation of the Flat Rock monitor was appr opriate, EPA is not taking action at this time on the

5 Population

- oriented monitoring (or sites) means residential areas, commercial areas, recreational areas, industrial areas where workers from more than one company are located, and other areas where a substantial number of people may spend a significant fraction of their day.

6 2012 ANP, Table 2.modification and will work closely with GBUAPCD to appropriately document the shutdown

and relocation.

Comment: The 2012 ANP does not provide documentation that siting issues at the Coso Junction

moni toring site have been corrected and data from the site cannot be used to assess the

contributions from Owens Lake.

Response: While the documentation of the siting issue at Coso Junction was discussed in 75 FR

54031 and in subsequent correspondence, EPA ag rees that the ANP should contain a statement that describes the actions taken to address previously identified siting issues at the Coso Junction monitoring site. In regards to the data , a n assessment of whether the data from a specific monitor

is influenc ed by a particular source is beyond the scope of what EPA is required to review and approve as part of the annual network plan process. Generally, ambient air monitoring network design is performed by the State or local air districts and there are no speci fic requirements in 40 CFR Part 58 Appendix D, 4.6 that mandate a PM 10 network capture influences from specific sources. In the 2012 ANP, the Coso Junction is appropriately characterized as a population oriented (population exposure) and pollutant transpor t (regional transport) regional scale monitoring site.

Comment: Information concerning the proposed new locations of the T

- 4 and T

- 23 non

regulatory SPMs is not included in the 2012 ANP.

Response: As described in the 2012 ANP and GBUACPD’s responses to LADWP’s comments,

the T

- 4 and T

- 23 monitors are non

- regulatory special purpose monitors that are being used to

measure PM 10 emissions near the remaining source areas on the lakebed and to further refine the District’s Dust Identification Program model. As these monitors are only being used in short

term special studies, EPA generally does not require information for such monitors to be included as part of the ANP. Furthermore, while EPA approval is required for addition and discontinuation of SLAMS, no such approval is required for changes in SPM stations. 7

Comment: EPA cannot approve the 2012 network plan

, because it includes monitors that are no longer part of GBUACPD ’ s network a s a result of LADWP’s termination of the Dirty Socks,
Mill Site, and North Beach monitor licenses

. GBUACPD must withdraw the current 2012 Network Plan from EPA and amend the plan to remove these monitoring stations from its

network.

Response : GBUAPCD is not required to withdraw and resubmit the 2012 ANP due to changes in

the n etwork after submittal to EPA. T he shutdown of the Dirty Socks, Mill Site, and North

Beach PM 10 monitors were not approved by EPA in accordance with 40 CFR 58.14

. ANPs are the appropriate mechanism to document changes to the network. EPA expects that infor mation pertaining to the shutdown of these monitors will be included in future ANPs

.

7 40 CFR 58.10(e), 58.11(c).