UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seattle, WA 98101-3140

OFFICE OF AIR, WASTE AND TOXICS

Mr. Mike Ragan· Air Monitoring Coordinator Air Quality Program W A Department ofEcology P.O. Box 47600 Olympia, W A 98504-7600

Dear Mr. Ragan: March 10,2014

EPA has evaluated the Washington Department ofEcology's (Ecology's) 2013 Ambient Air Monitoring Network Plan (Plan), which describes Washington's ambient air monitoring network for 2013-14. In the Plan, Ecologyproposed the following three changes to the Washington monitoringnetwork. EPA evaluated the proposed changes to the network in accordance with 40

. C.F.R. Part 58.14(c), and with consideration ofthe applicable requirements identified in 40

C.F.R. Part 58, Appendix D.

I. Ecologyproposes to locate its first N02 near-roadway monitor at a location near Tenth and Weller streets in Seattle, and to begin operation ofthis monitor onJanuary 1, 2014, theregulatory startup date for the N02 near-roadway monitors. This segment ofroadway has one ofthe highest combined Average Annual Daily Traffic count ofvehicle traffic in Seattle. EPA finds that this site meets the requirement of Appendix D 4.3 .2 for an N02 near-roadway monitoring site, and the monitormeets all applicable criteria in 40 C.F.R. Part 58, Appendices A, C, D, and E. For these reasons, EPA approves the Washington N02 monitoring network as meetingthe requirements of40 C.F.R. 

### § 58. 13(c). As ofthe date ofthis letter, this new N02 nearroadway monitor was scheduled to begin operationbythe end ofFebruary. Please inform us when this monitor actually starts operation.

2. Ecology discontinued the Special Purpose Monitor (SPM) PM2.s at the Wenatchee Alaska Street site and replaced it with a tapered-element oscillatingmonitor (TEOM) SPM at the Wenatchee Fifth Street site. Ecology will operate this TEOM as a nonregulatory monitor for two years. According to 40 C.F.R. § 58.20(f), prior EPA approval for discontinuation ofa SPM monitor is not required, so EPA approval of the discontinuation ofthe Alaska Street monitor is not required. The TEOM at the Wenatchee Fifth Street site will monitor at same scale as the Alaska Streetmonitor, a neighborhood scale as specified in Appendix D 4.7.l(c)(3), and will meet all applicable criteriain Appendices A, C, D, and E. Forthesereasons, EPA approves the siting ofthe TEOM at the at theWenatchee Fifth Street site.

3. Ecology discontinued the PM2.s Federal Reference Method (FRM) State or Local Air Monitoring Site (SLAMS). monitor at the Vancouver 4'11 and Plain site and is nowusing a PM2.5 PRMto monitorto determine compliance withthe

### PMz.s NAAQS that location. This modification complies with 40 C.P.R.§ 58.14(b), therefore EPA approves this modification at the Vancouver site.

With this letter, EPA is approving the 2013 Planbecause it contains the necessary information about the network's existing and proposed sites, as specified at 40 C.P.R. § 58.10(b).

Ifyou have any questions about our approval ofthe 2013 Annual MonitoringNetwork Plan, please contact Keith Rose at (206) 553-1949.

cc: Chris Hall, OEA Keith Rose, OA WT JeffHunt, OAWT ClaudiaVaupel, OA WT

2 Sincerely, 

# Ol. r, ,**~-,**

## ,**~!A.-** Debra Suzuki, Manag r Air Planning Unit



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