UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

75 Hawthorne Street

San Francisco, CA 94105

November 1, 2010

Mr. Lewis Wallenmeyer, Director

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. Wallenmeyer:

Thank you for your submittal of the 2010 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 all of the requirements set forth under 40 CFR Part 58.10. We 

have included comments and recommendations for next year’s network plan. While this 

letter serves as an official approval of the annual network plan, it does not constitute 

approval of the future system modifications that are proposed in the plan. Pending the 

gathering of further information that DAQEM has proposed, EPA will continue to work 

with your district to review system changes as they proceed on a case-by-case basis.

We also want to thank you for your timely submission of the 2010 Network 

Assessment required under 40 CFR Part 58.10. We recognize that preparing the network 

assessment was a significant project and we appreciate your efforts. EPA plans to 

provide feedback regarding network assessments during the winter of 2011.

If you have any questions regarding this letter, 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

Enclosures

cc: Mike Sword, Engineering Manager, DAQEM

Yousaf Hameed, Monitoring Supervisor, DAQEM
Comments on 2010 Network Plan for Clark County DAQEM

Please implement the following recommendations for next year’s network plan:

Major:

Mention of comments received/not received during public inspection of plan (pp.4): Any 

comments received during the public inspection period that is required of the annual 

monitoring network plan (40 CFR 58.10 (a) (1)) should be included along with the plan. 

In the event that no comments are received, a statement reflecting this should be included

in the plan. DAQEM includes a section regarding the public inspection process, however 

there is no mention of whether comments were received or not.

Statement of purpose for each monitor at site (pp.17-18): 40 CFR 58.10 (a) (1) requires 

that a statement of purpose for each monitor be included in the annual monitoring 

network plan. This may be addressed in the form of a descriptive site overview as long 

as the purpose of each monitor is mentioned. In general, Clark County DAQEM has 

done a good job addressing this requirement. Nonetheless, for the following sites, a more 

detailed description should be considered: Boulder City, J.D. Smith, East Sahara, 

Mesquite, Orr, Winterwood. These site descriptions should elaborate further on the 

purpose for each of the monitors. A more elaborate description would include things like 

primary pollution concerns, historical context, and relevant regulations.

Minor:

Inconsistency of Apex spatial scale reporting (pp.10-11, 24): It was noted that DAQEM 

initially had their Apex site PM10 and PM2.5 continuous monitors classified as Regional 

spatial scales (pp.10-11). The detailed site section for this station (pp.24) reports these 

two monitors as representative of a Neighborhood scale. EPA believes that the 

neighborhood spatial scale is the appropriate one and recommends that DAQEM correct 

this discrepancy so as to avoid confusion in future plans.

Unclear figures (pp.51, 53-55, 57-60, 62): DAQEM has provided several pages of very 

useful figures that represent the various pollutant specific monitoring locations. A few of 

the figures were difficult to decipher (Figures 20, 22-24, 26-29, and 31). It is 

recommended that DAQEM ensure that each of the included figures are published in a 

higher resolution, such as that seen in Figures 21, 25, and 30 of the report.