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

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# SEP 062011

Mr. Bruce Louks Air Quality Manager Idaho Department ofEnvironmental Quality 1410 North Hilton Boise, Idaho 83706-1255 DearMr. Louks: We have evaluated the 20II Idaho Ambient AirMonitoring Network Plan, which describes the Idaho monitoring network for 2011-12. The EPA has the following comments on proposed changes to the network in this network plan: I. PM 10-2.5 monitoring (PMcoarse) was initiated at the Meridian St. Luke's NCore site on 1/1/20II (160010010). IDEQ is operatingthree lo-vol R&P 2025 FRM samplers for PM 10-2.S determinations. One sampleris configured to capture PM2.5 and the otherto capture PM 10. The primary pairofPM2.5 and PM 10 samplers run every third day (1/3) and the second PM 10 sampler runs every twelfth day (1/12) to assess the lo-vol PM 10 precision. PM10-2.5 is calculated by difference ofPM 10 PM2.5. TheEPA approves this change. 2. The MetOne BAM 1020PM2.S monitor was terminated at the S1. Maries (1600900I0) site on 09127/2010. It was replaced by a PM2.5 TEOM. IDEQevaluated the relationship ofthe BAM 24­ hour data to the filter data collectedon the FRMover a one yearperiod. The relationship did not meet the statistical criteria for a Class III FEM (40 CFR Part 53.35). Because the BAM is designated FEM by the EPA, and following the evaluation period allowed by the EPA for IDEQ to perform this assessment, the data would then become regulatory data and used for determining NAAQS compliance. IDEQ decided to continue utilizing the FRM filter-based method as the primary regulatory monitor at this site and redeploy a PM2.5 continuous monitorfor air quality forecasting and AQIdeterminations. The EPA approves this change. 3. The Met One BAM at the Pinehurst (160790017) site was terminated on 12/3112010 for the same reason stated above. IDEQ chose to designate the TEOM-FDMS the primary monitorat the Pinehurst site and report daily (III) 24-hour averaged data, initiated on 11112011. TheTEOM-FDMS is an FEM and data can be used for determining NAAQS compliance in addition to airquality forecasting and AQI. IDEQevaluated the relationship ofthe TEOM-FDMS 24-hour data compared to the filterbased FRM values over a period ofone year, and the statistical criteriafor Class III FEM monitors was satisfIed. The two co-located filter-based FRM PM2.S monitors at this site are running every sixth day in order to assess precision for IDEQ's PM2.5 FRM network. The EPA approves this change. 4. The MetOne BAM at the Salmon site (160590004) was designated as the primary monitor for the purpose ofdaily sampling for NAAQS compliance, in addition to air quality forecasting and AQI. The PM2.S FRM is operating on a1/6 schedule for determiningprecision ofthe BAM 24-hollf averaged PM2.S data. TheEPA approvesthis change. 

# o Prfnf«lonRecyct(J(JPaper5.The Met One BAM at the Nampa Fire Station (160270002) site was terminated on 9/30/2010 for the reason stated above. The existing PM2.5 TEaM will continue to be used for the purpose of air quality forecasting and AQI determination. The EPA approves this change. 6. The MetOne BAM at the Meridian St. Luke's site (160010010) was terminated on 12/30 2010 for the reason stated above. Theexisting PM2.5 TEaM will continue to be used for the purpose ofair quality forecasting and AQI determination. The EPA approves this change. 7. Othercomment: IDEQ has within their network 17 SPM "NR" (non-regulatory) PM2.5 samplers (16 TEOMs and I BAM) that are non-FRM and non-FEM. Overthe past couple years TDEQ had been evaluating a numberofBAMs atdifferent sites and determined in mostcases that they do not meet Class III FEM status, therefore IDEQ is replacing them with TEaMs. For most all ofthese sitesthe use ofa non-FRM, or non-FEM, sampler is appropriate for non-regulatory purposes (such as AQI and burn ban purposes). However, ofall these PM2.5 monitors, the only monitorthatthe EPA recommends to be an FRM, orFEMcontinuousPM2.5 monitor, is the PM2.5 monitor at the Meridian NCore site, since it would be desirable to compare the PM2.5 values measured at this site to the NAAQS. The following monitors are designated "core" monitorsbecause they are either: I)required by 40CFR Part 58, Appendix 0, 2) have a design value nearor above the new PM2.5 24-hour standard of

### 35ug/m3, or 3) they are essential monitoring parameters at NCore sites: I. PM2.5 FRMs (or Approved Regional Method): a) Nampa(primary and co-located) b) Meridian/St. Luke'sHospital c) Pinehurst d) Salmon e) Franklin f) St Maries 2. PM2.5 speciation monitors and pre-cursorgas monitors at the Meridian/St. Luke's Hospital 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 IDEQ's discretion with any remaining federal funds orState funds. Ifyou have anyquestions about our approval ofthe Idaho monitoring network, please contact Keith Rose at (206) 553-1949. Sincerely,

RobertElleman, Acting Unit Manager State and Tribal Air ProgramsUnit

cc: MikeMcGown, lao Keith Rose, OAWT Chris Hall, OEA 

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