UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

REGION IX

75 Hawthorne Street

San Francisco, CA 94105

November 1, 2010

Mr. Larry Greene

Air Pollution Control Officer

Sacramento Metro Air Quality Management District

777 12th Street

Sacramento, CA 95814

Dear Mr. Greene:

Thank you for your submission of the Sacramento Metropolitan Air Quality Management 

District’s (SMAQMD) 2009 Annual Monitoring Network Plan in July, 2010. We have reviewed 

the submitted document and have found that it meets the minimum requirements set forth under 

40 CFR Part 58.10. 

On June 30, 2010, we received your request for approval to terminate SO2 sampling at the 

North Highlands site. Based on the information presented in your letter, EPA finds that your 

request meets the requirements of 40 CFR 58.14 and approves termination. Specifically, your 

analysis showed that this SO2 sampler does not affect the District’s compliance with Appendix 

D network design requirements and, based on measured concentrations, is not expected to exceed 

the NAAQS in the next three years as stated in 40 CFR 58.14(c)(1).

While this letter serves as official approval of the annual network plan and this specific 

modification, it does not constitute approval of the other system modifications that are proposed 

in the plan for the future. We will continue to work with your district to review system changes 

as they proceed.

Enclosed, please find our comments on the plan. If you have any questions regarding this 

letter or the enclosed comments, please feel free to contact me at (415) 972-3851 or Kate Hoag at 

(415) 972-3970.

Sincerely,

/S/

Matthew Lakin, Manager

Air Quality Analysis Office

Air Division

Enclosure

cc: Brigette Tollstrup, SMAQMD

John Ching, SMAQMD
Comments on 2009 Data Year Network Plan for Sacramento Metropolitan AQMD 

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

1. The network plan does not list a CO monitor at the T Street site (see Table 1, page 

5 and Table 3, page 6), but Appendix B, page 61 lists CO in the site description. 

Please correct these references to be consistent.

2. The design values used for determining minimum monitoring requirements should 

include the most recent complete data year. For example, for your next Annual 

Monitoring Network Plan, the design values should be calculated using 2008-

2010 data. 

3. Page 10 indicates that the District is evaluating discontinuing CO monitoring at 

several sites including the maximum concentration microscale site at El 

Camino/Watt. Since EPA is currently reviewing the CO NAAQS, please consider 

as part of your evaluation that the CO monitoring requirements may change.

4. Page 11 lists the date for required submittal of annual data certifications as June 

2010. The correct date for this requirement is May 1 of each year (40 CFR 

§58.15(a)(2)).

5. Appendix B – Detailed Site Information

a. The question of whether the data from a PM2.5 monitor is suitable for 

comparison to PM2.5 NAAQS is not answered for all PM2.5 monitors

b. Please list FRM/FEM/non-FEM type and method code for all particulate 

monitors and the POC for sites with multiple monitors for the same 

pollutant.

c. Branch Center #2 Site: This site is described on page 14 as a source 

oriented site to monitor PM10 from nearby aggregate operations, but the 

purpose of the monitor is to measure representative concentrations.

d. Please include a description on page 51 of why the O3, CO and NO2

monitors at North Highlands-Blackfoot site are SPMs.

e. Since the Sloughhouse monitoring site is potentially an important ozone 

site for characterizing peak concentrations in the District, it would be 

helpful to describe the decision to keep the site as a SPM rather than a 

SLAMS. The plan also describes siting issues since there is a tree within 

6m of the inlet, which may be important to address if this continues to be

one of the highest ozone sites in the District. 

f. Please include the site type for the PM2.5 BAM at the T Street site on age 

63.