UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10 1200 Sixth Avenue, Suite 900 Seattle, WA 98101·3140
In. OF AIR WASTE. AND TOXICS 

# OCT 052011
Ms. BarbaraTrost Air and Water Quality Division Alaska DepartmentofEnvironmenlal Conservation 555 Cordova Street Anchorage, Alaska 99501-2617 DearMs. Trost: We have evaluated the 2011 Alaska Ambient Air Monitoring Network Plan, which describes the Alaska monitoring network for 2011-12. EPA has the following comments on this network plan. The primary change to the Alaska air monitoring network this year was the addition ofthe Fairbanks NCore monitoring site, which was supposed to be fully operation onJanuary 1,2011. As oqhat date, only the required PM2.5 and meteorological monitoringequipment had been initiated. However, ADEC has provided adequatejustification in its final plan explainingthat some ofthe gaseous monitors at this site were not in operation until mid-Septemberbecause ofinstrument problems requiring factory repair. Also, ADEC provided a description ofthe Fairbanks NCore site selection process in Appendix G ofthe plan, which explains whyADEC believes the site is properly located. EPAconcurs with the selection ofthe Fairbanks NCore monitoring site. As requested byEPA, ADEC added a footnote in Appendix E that explains that the.2009 PM2.5 98 percentile value, and the 2008-10 design value, provided in the tables for the Fairbanks State Office Building Site, are contingent on EPA concurring on the five high flagged exceptional event days for 2009. The Municipality ofAnchorage(MOA) will discontinue collection ofa PM2.5 FRM monitor at the Garden site (AQS ID: 02-020-0018) after06/30/11. MOA will continue collection ofPM2.5 data at this site with an FEM BAM1 020monitor which is also designated as SLAMS for PM2.5. EPA approves this change. MOAreplaced the primary PMIO FRM samplers (operating on a 1:3 frequency) at theTudor site with a BAM1020operating continuously, in accordance with 40CFR, Part 50, Appendix K, Section 3.1 (f). EPA approves this change. MOAdiscontinued COmonitoring at the Turnagain site effective 03/31111. CO monitors will continue to operate at three otherlocations in Anchorage (the Garden, Parkgate, and DHHS sites). EPA approves this change.

() Pt1ntlKlonRecycledPaperThe following monitors are designated "core" monitors because they are either: I) required by 40 CFR Part 58, Appendix D; 2) have a design value near or above the new PM2.5 24-hour standard of 

### 35ug/m3 or; 3) they are essential monitoring parameters at NCore sites: 1. PM2.5 FRMs (or Approved Regional Method): a) Fairbanks (primary and secondary) b) Juneau c) Butte 2. PM2.5 speciation and precursor gas monitoring at the Fairbanks NCore site. "Core" monitors are those monitors in the network that must be operated with available PM2.5 monitoring funds. The "non-core" PM2.5 monitors in the State's network can be operated at ADEC'sdiscretion with any remaining federal funds orState funds. Ifyou have anyquestions about ourapproval ofthe Alaska monitoring network, pleasecontact Keith Rose at (206) 553-1949. Sincerely,

Robert Elleman, Acting Manager State and Tribal Programs Unit
cc: Chris Hall, OEA



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