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 of Ecology 

P.O. Box 47600 

Olympia, W A 98504-7600 

Dear Mr. Ragan: 

March 10,2014 

EPA has evaluated the Washington Department of Ecology's (Ecology's) 2013 Ambient Air 

Monitoring Network Plan (Plan), which describes Washington's ambient air monitoring network 

for 2013-14. In the Plan, Ecology proposed the following three changes to the Washington 

monitoring network. EPA evaluated the proposed changes to the network in accordance with 40 

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

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

I. Ecology proposes to locate its first N02 near-roadway monitor at a location near 

Tenth and Weller streets in Seattle, and to begin operation of this monitor onJanuary 

1, 2014, the regulatory startup date for the N02 near-roadway monitors. This 

segment of roadway has one of the highest combined Average Annual Daily Traffic 

count of vehicle 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 monitor meets 

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 meeting the 

requirements of 40 C.F .R. § 58. 13( c). As of the date of this letter, this new N02 nearroadway monitor was scheduled to begin operation by the end of February. 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 oscillating monitor (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 of a SPM monitor is not required, so EPA approval of 

the discontinuation of the Alaska Street monitor is not required. The TEOM at the 

Wenatchee Fifth Street site will monitor at same scale as the Alaska Street monitor, a 

neighborhood scale as specified in Appendix D 4.7. l(c)(3), and will meet all 

applicable criteria in Appendices A, C, D, and E. For these reasons, EPA approves 

the siting of the TEOM at the at the Wenatchee 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 now 
using a PM2.5 PRM to monitor to determine compliance with the 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 Plan because it contains the necessary 

information about the network's existing and proposed sites, as specified at 40 C.P.R. § 

58.10(b). 

If you have any questions about our approval of the 2013 Annual Monitoring Network Plan, 

please contact Keith Rose at (206) 553-1949. 

cc: Chris Hall, OEA 

Keith Rose, OA WT 

Jeff Hunt, OAWT 

Claudia Vaupel, OA WT 

2 

Sincerely, 

Ol. r, , ~-, , ~!A.-

Debra Suzuki, Manag r 

Air Planning Unit 

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