UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX 

75 Hawthorne Street 

San Francisco, CA 94105 

November 1, 2011

Mr. Mike Sword, Engineering Manager

Clark County Department of Air Quality and Environmental Management

500 S Grand Central Parkway, 1st Floor

P.O. Box 555210

Las Vegas, NV 89155-5210

Dear Mr. Sword:

Thank you for your timely submittal of the 2011 Annual Monitoring Network Plan for the Clark County 

Department of Air Quality and Environmental Management (DAQEM). EPA has reviewed the 

submitted document and found that it is complete, informative, very detailed and meets the requirements 

set forth under 40 CFR Part 58.10. We also appreciate your addressing in full our comments to last 

year’s 2010 Network Plan. While this letter serves as an official approval of the annual network plan, it 

does not constitute approval of future nor previous network modifications that are identified in the plan. 

EPA will continue to work with DAQEM to review system changes as they proceed on a case-by-case 

basis and will respond separately to requests already submitted.

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

Air Division

Enclosure

cc: Yousaf Hameed, Monitoring Supervisor, DAQEM
Comments on 2011 Network Plan for Clark County DAQEM

Please update next year’s network plan to reflect the following comments:

1. 40 CFR 58.10(b)(3) requires that the sampling and analysis method(s) for each parameter 

measured be reported. EPA found that DAQEM’s current method for reporting this requirement 

is either lacking or unclear for multiple sites. In order to clarify and facilitate the reporting of 

this requirement, please implement the following:

o Remove this information from the overall site description section (located just beneath the 

site photographs) and incorporate it into the tables that include monitor specific information.

o To report appropriate FRM/FEM sampling and analysis method(s), please refer to the tables 

listed towards the end of the List of Designated Reference and Equivalent Methods. A link to 

the latest List of Designated Reference and Equivalent Methods can be found at 

http://www.epa.gov/ttn/amtic/criteria.html. For the sampling method, please report the 

appropriate instrument name and model found under the table column labeled method. For 

the analysis method, please report the designation number found under the column heading 

Designation No. 

o For non-FRM/non-FEM instruments, please report the full instrument name and model as the 

sampling method, and describe (or provide a reference to) the analysis method used.

2. 40 CFR 58.10 (b)(8) requires the MSA, CBSA, CSA or other area represented by each monitor 

be reported. DAQEM’s 2011 Network Plan addresses this requirement on page 5 in the section 

titled “Metropolitan Statistical Area.” In order to clarify the content of this section and to better 

address the requirement, EPA recommends the following be implemented:

o Include a statement that clarifies that each of the monitors operated by DAQEM are 

contained within the Las Vegas-Paradise Metropolitan Statistical Area.

o Remove the statement that reads: “the Cities of Mesquite and Boulder City, do not qualify as 

Metropolitan Statistical Areas.” This statement is inaccurate given that the Metropolitan 

Statistical Area encompasses all of Clark County. Since each of these cities resides within 

the boundaries of Clark County, they are each representative of this same MSA.

3. 40 CFR 58.10(b)(12) requires the identification of newly required NO2 monitors based on the 

2010 NAAQS revision to the primary NO2 standard. Although DAQEM includes a discussion 

(pp.61) of new upcoming NO2 monitoring in Clark County, an analysis for the actual number of 

required sites based on most recent information is not included. Please ensure this analysis is 

included in next year’s plan.