UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seattle, WA98101-3140

OFFICE OF AIR, WASTE AND TOXICS March 10,2014

Mr. Bruce Louks Air QualityManager Idaho Department ofEnvironmental Quality 1410 Notih Hilton Boise, ID 83706-1255

Dear Mr. Louks:

EPA has evaluated the Idaho Department ofEnvironmental Quality's (IDEQ's) 2013 AmbientAir Monitoring Network Plan (Plan), which describes Idaho's ambient air monitoring network for 2013-14. In the Plan, Idaho proposed the following changes to its monitoring network. EPA evaluated the proposed changes to the Idaho monitoring network in accordance with 40 C.F.R. 

### § 58.14(c), and with consideration ofthe appropriate monitor siting requirements in 40 C.F.R. Part 58, Appendix D.

I. TheMeridianN02 near-road site (16-001-0023) was added to IDEQ's network as a State

or Local Air Monitoring Site (SLAMS) site on January I, 2013. IDEQ will continue monitoring carbon monoxide (CO) and oxides ofnitrogen (N02, NO and NOx) at this site. EPA finds that this sitemeets the requirement ofAppendix D 4.3.2 for an N02 nearroadwaymonitoring 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 Idaho N02 monitoring network as meeting the requirements of40 C.F.R. 

### § 58.13(c).

2. IDEQ proposed to shut down the PM10 SLAMS monitors at the U.S. ForestService (USFS) site in Sandpoint and to relocate this PM10 monitorto the University ofldaho (U of!) site in Sandpoint, where a 10-metermeteorological station is currently operating. Sandpoint is a PM10 maintenance area, but the maintenanceplan for this area does not specify a specific monitor location to trigger contingencymeasures. Further, both monitoring sites are within the Sandpoint PM10 maintenance area, and IDEQ has collected one year ofdata simultaneously at both sites and found thatthe PM10 data are well correlated. Based onthe above reasons, EPAbelieves that the U of! site adequately represents the conditions at the USFS site and would be an appropriate substitute for that site. Therefore, EPA has determined that this relocation satisfies the criteria of40 C.F.R. 

### § 58.14(b) and approves the relocation ofthe PM10 monitor from the USFS site to the U ofI site in Sandpoint.

3. IDEQ proposed to relocate the PM2.s SLAMS monitor at the St. Maries site approximately 450 feet to the north northwest ofits current location at the USFS office. IDEQ needs to move the site due to remodeling ofthe USFS building and associated restrictions in access to this site. EPA finds that this proposed relocation satisfies the criteria in 40 C.F.R. 

### § 58.14(c)(6) because logistical problems beyond the state's controlmake it impossible to continue the operation ofthemonitor in its current location. Accordingly, EPA approves this relocation.

4. IDEQ hasbeen operating two 

### PMz.s Federal Reference Monitors (FRMs) and one Tapered Element OscillatingMonitor (TEOM) at the Pinehurst site. TheTEOM is designated as the primaryreporting monitor at this site. The two FRMs are used for assessingprecision ofthe TEOM. However, EPA's AQS system cannot accommodate two precision measurements at one site. IDEQ proposes to move one of the FRMs atPinehurst to the St. Luke's National Core (NCore) site. Relocatingthis monitorto the St. Luke's NCore sitemeets the network quality check requirements of Part 58, Appendix A, Section 3.2.5. Therefore, EPA approves therelocation ofthis monitor.

With this letter, EPA is approving the 2013 Planbecause it contains the necessaryinfonnation about the network's existing andproposed sites, as specified at 40 C.F.R. 

### § 58.10(b).

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

cc: Mike McGown, IOO Keith Rose, OA WT Chris Hall, OEA ClaudiaVaupel, OA WT Sincerely,

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