UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX 

75 Hawthorne Street 

San Francisco, CA 94105 

February 28, 2013

Mr. Mike Sword, Engineering Manager

Clark County Department of Air Quality

4701 W. Russell Road, Suite 200

Las Vegas, Nevada 89118

Dear Mr. Sword:

Thank you for your submission of the Clark County Department of Air Quality’s (DAQ) Annual 

Network Plan Report 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. While 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 recognize 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 information should be included or revised in next year’s 

plan.

Please note that we cannot approve portions of the 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.

In addition to the checklist and list of specific plan elements where EPA Region 9 is not taking 

action, enclosed are additional detailed comments on the plan (Attachment C). All of the 

comments in Attachments A, B, and C should be addressed in next year’s network plan. If you 
have any questions regarding this letter or the enclosed comments, please feel free to contact me 

at (415) 972-3851 or Elfego Felix at (415) 947-4141.

Sincerely,

/s/

Matthew Lakin, Manager

Air Quality Analysis Office

Enclosures:

A. Annual Air Monitoring Network Plan Checklist

B. Elements where EPA is Not Taking Action

C. Additional Detailed Comments

cc: Yousaf Hameed, DAQ

Tina Gingras, DAQ
Attachment B: Annual Air Monitoring Network Plan Items where EPA is Not Taking 

Action

We are not acting on the portions of annual network plans 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.

 NCore and the plan for NO2 monitoring require EPA Administrator approval. Per 40 CFR 

58.11(c), NCore is subject to approval of the EPA Administrator and per 40 CFR 

58.10(a)(5) plans for establishing NO2 monitoring sites are submitted to the EPA 

Administrator for action. Therefore, we are not acting on these items.

 System modifications (e.g., site closures or moves) are subject to approval per 40 CFR 

58.14(c). Information provided in the plan was insufficient for EPA to approve the 

following system modifications listed in the plan per the applicable requirement:

o Relocation or shut down of the Walter Johnson and/or Green Valley sites to bring 

into 40 CFR 58, Appendix E compliance (Options 3-4, page 13)

o Termination of CO monitoring at J.D. Smith, Orr, and Winterwood sites (page 54)

o Termination of Jean site (page 54)

o Termination of additional sites (page 54)

Therefore, we are not taking action on these items 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

Identification of maximum 

concentration ozone 

monitor(s)

68 Insufficient information to judge

Distance from trees 92 Insufficient information to judge in some 

instances, not meeting requirement in some 

instances

Distance from supporting 

structure

89 Insufficient information to judge in some 

instances, not meeting requirement in one 

instance

Obstructions not on roof 91 Insufficient information to judge

Dates of last two semi-annual 

flow rate audits for Pb 

45 Insufficient information to judge
monitors

Frequency of one-point flow 

rate verification for Pb 

samplers audit.

41 Insufficient information to judge

Operating schedule for each 

monitor

26 Insufficient information to judge in some 

instances

Monitoring objective for each 

instrument

58 Insufficient information to judge

Obstructions on roof 90 Insufficient information to judge

Additional information for each of these items is in included in Attachment A.
Attachment C: Additional Detailed Comments

 [Item 13] Although EPA Region 9 is not taking action on the NO2 portions of the plans 

this year, for next year, please identify sites fulfilling the NO2 area-wide and RA40 

requirements.

 [Item 23] The Paul Meyer (p.33) and Walter Johnson (p.36) AQS site IDs list an 

incorrect county code that should be corrected to 003 rather than 002. EPA suggests that 

DAQ report the AQS site ID for Winterwood (p.37) formatted as XX-XXX-XXXX 

rather than XX-XXXX-XXX. SPM using FRM, FEM, or ARM methods are required to 

report to AQS site IDs in the network plan.

 [Item 25] Sampling and analysis methods are discussed in various sections of DAQs plan. 

EPA recommends that DAQ consolidate the reporting of sampling and analysis methods 

into the detailed site description tables found on pages 22-37. The sampling and analysis 

method should be reported on an individual instrument by instrument basis. For FEM and 

FRM instruments, reporting the method code fulfills this requirement. Please also ensure 

to report the sampling and analysis method for Pb, NOy, and any new monitoring that 

may be reported in next year’s plan.

 [Item 35] EPA recommends that DAQ incorporate a public review process for changes to 

the PM2.5 network even in the case when a lease is lost or notice to vacate is received. 

 [Items 43 & 44] Although most of the Annual Performance Evaluations for gaseous, and 

semi-annual flow rate audits for PM instruments were reported, EPA found a few 

instances where the information was missing. An ozone evaluation at Jerome Mack and 

an NO2 evaluation at Joel Neal were not found for 2011. Each of the PM10 sites at Palo 

Verde, Boulder City, and Jerome Mack only reported one flow audit for 2011, and 

similarly for continuous PM2.5 at Jerome Mack, only one flow audit was reported. Please 

report all required annual performance evaluations and semi-annual flow are audits in 

next year’s plan. If an evaluations or audit did not occur in a particular year, please 

provide this clarification in the network plan.

 [Item 56] Please report start dates for seasonal (Apex, Mesquite) monitors in the annual 

network plan.

 [Item 57] Currently DAQ has monitor type listed as “Type” in the detailed site section of 

the network plan (p.22-37). This “Type” should be relabeled to read monitor type and 

should be reported for each instrument at each of the sites, rather than on a per site basis. 

There is an inconsistency for the PM2.5 continuous sites that are also listed as SPMs in 

p.18 since a monitor type cannot be both an SPM and a SLAMS.

 [Item 59] Site types are found throughout the plan labeled as “Objective” and “Monitor 

Objective Type.” Please change these to read site type.
 [Items 60 & 61] Although most parameter and parameter occurrence codes are reported 

on page 19, a few were not found. Those not found include: Pb and PM10-2.5 at Jerome 

Mack, seasonal ozone at Apex and Mesquite. Please report parameter and parameter 

occurrence codes for all instruments in next year’s plan. 

 [Item63] For PM2.5 please clarify the season in which monitoring takes place. EPA 

recommends that sampling frequency and season information gets incorporated into the 

detailed site tables of pages 22-37.

 [Items 67, 72, 74, 75, 79, 83] Although EPA recognizes that DAQ in all cases meets or 

exceeds all minimum monitoring requirements, please include the representative area 

(e.g. MSA, CBSA) population when describing minimum monitoring requirements.

 [Items 85 & 86] Please report the distance and traffic counts for the nearest roads from 

the Apex and Mesquite sites. It is recommended that a credible traffic count from the 

nearest road is reported for all sites.

 [General] Although not required, EPA recommends that for special studies where 

monitoring has occurred in at least two consecutive years, such as the Spring Mountain 

Youth Camp site, DAQ consider including the following additional information (as 

applicable) in the annual monitoring network plan that will allow for a better 

understanding of the studies conducted:

o AQS Site Identification

o Location: street address and geographic coordinates

o Sampling and analysis method

o Operation schedule: sampling frequency and season

o Scale of representativeness

o Start date

o Instrument monitor type, monitoring objective, and site type

o Parameter code

o Parameter occurrence code

 [General] EPA recommends that DAQ report detailed information for meteorology 

parameters on a per site basis and incorporate the details into the site tables found on 

pages 22-37. Examples of helpful detailed site information to provide include: instrument 

manufacturer and model, start date, siting, and QA/QC information, as applicable.