UNIT ED STATES ENVIRONMENTAL PROTECTION AGENCY

Ref: 8P-AR Ms. Cara Keslar Monito ring Section Supervisor RE GION 8 1595 Wynkoop Street DENVER, CO 80202-1129 Ph one 800-227-8917 http://www.epa.gov/region08 

# FEB 2 9 2012

Wyoming Department of Env ironmental Quality 122 West 25 th Street. 2

- E C he yenne, Wyoming 82002 Dear Ms. Keslar: Thank you for submitting t he 2010 and 201 1 W yo ming Ambient Ai r Mon ito rin g Annual Network Plans, both of wh ic h we r e subm itted under lett rs dated June 27, 2011. This lette r pre se nt s our comments on the plans and documents our approva l. R eg ion 8 also reviewed the Wyoming Ambient Monitoring Network Assessment 2010, which was subm itted under a letter dated July 15,2011. Althoug h regulations do not require formal concurrence on a network assessment by the Region, we find the assessment very useful and appreciate the effort tha t the Air Qual ity Division put into thi s effort. The network plans describe new ai r monito rin g station s that have been added to the network since the netwo rk plan of September 2009. Excepl for the Nat ion al Core multi pollutant monitorin g (NCore) stati on in C hey enne, these stat ion s have not been doc ume nted in netwo rk modification forms submitted to Region 8. Netwo r k modification requ st fo rm s describ e the instruments to be installed in a station and the statio n ·s elevation, probe siting

. nearb y land use and related details. The inf ormati o n on the forms augments the network planning an d asse s ment processes de sc ribed in 40 CFR 58

. 1 0. An example of a s tation with incomp lete docum entation in Region 8's fi les is the Boulder special purpose monitor (SPM) station in Sublette Co unty, with AQS identifi cation number 56-035-009 9. Th is statio n , which ha s been running s ince 2005, monitors the criteria po llutants nitrogen dioxide, ozone and PM 10
. I3oulder is the sta ti on most frequently report ing the maximum co ncentration of ozo ne in Sublette Co unty. Si nce the Boulder SPMs have run for more than two years, their data may be used for comparison to the Nationa l Ambie nt Ai r Quality Standard, consistent w ith 40 CFR 58.20. However, the network plan docs not state that the I3ou ld er stati on me ets probe s iting criteria an d ot h e rwi se meets criteri a for regulatory mon itoring

. r urth er ·mor e, Reg io n 8 does not have s upportin g docume ntation from the Air Q u a lity Division ( such as in a s ite file or complete site and monitor data in AQS). Although it contains some exemptions for SPMs, 40 CFR 58 sta te s that, with respect to State and Local Air Monitoring Stations (SLAMS), NCo re, SPM and speciation sta ti ons, a network plan ' ·shall include a state ment or pu rposes lor each monitor ahd ev idence that sit in g and operation of each mon itor m eets the requi r ements o f appendices A, C, D, and E of this part, where applicable." We recommend th at futurenetwork plans include evidence that the air monitoring sta tions. including SPMs. meet regulatory criteri a equivalent to SLAMS. This evidence may be shown conci se ly

### ~ modifying the table in append ix A or the plan, inc ludi ng a n appendix of recent network modification

## ~q**ue st**  forms , a sepa rate tile or si milar documentation. Section 40 CFR 58

. 20 states that, "The monitoring agency must also submit to AQS an ind ication or whether each SPM reporting data to AQS monitor meet s the requirement s of append ice s A and E to this part." We s ugge st that the AQD enter the required info r mation in AQS for the spec i al purpose mon itors as well as the SLAMS. This would include information frequenqy mi ss ing from the Division's monitor and si te informati on in AQS. s uch as probe height. probe location , measurement scale. sample residence time and unrestricted air flow. The network m od ification form was designed to include these essential regu l atory monitoring criteria, so that the information recorded oh the network modification form is then readily available for AQS input. We understand that the AQD is work ing to bring site Iiles up to date by comp le ting network modi tication forms, consistent with the Wyoming/ EPA Performance Partnership Agreement, Fiscal Year 2012. We a l so unders tand that the AQD will be prepared to address s ite documentation during the systems audit that Region 8 plans to c nduct in Wyoming this year. One of the air monitoring stations in Pinedale discussed in section 2.2

. 8 of the 20 II network plan is on the west side of City Park and Pine Creek and has the AQS identification number 56-035-0 I0 I. This station houses a continuous PM 2

. s analyzer, an analyzer measuring ozone and another measuring oxides of nitrogen. The continuous PM2. s analyzer is a Met One Instruments, Inc. BAM-I 020 Beta Attenuation Mass Monitor with a very sharp cut cyclone particle size separatbr (EPA equivalency designation EQPM-0308-170). With re spect to this continuous PM 2
.5 analyzer, section 2.2.8 ref e rs to the .July 24, 2008 EPA memorandum, "Implementing Continuous PM 2
. 5 Federal Eq uivalent Methods (FEMs) and Approved Regional Methods (A RMs) in State or Local Air Monitor in g Station (SLAMS) Netwo rk s:· The J\QD correctly cites the memorandum as giving gu idance for long-teny evaluat ion of an FEM, and Region 8 s upports the AQD's evaluation of the beta-attenuation method iq Pinedale. Data collected in 20 I I by this PM 2 .5 ana lyzer in Pinedale were coded in AQS as both "special purpose· ' and "non-regulator y: · Consistent with EPA's 2008 memorandum, Region 8 concurs in thi s rep o rtin g convention. Also consistent with that memo. we would support the AQD's revi s iting the monitor type in the 2012 monitoring plan. The 20 II network plan showed the BAM-I 020 in use to monitor PM2 .s at three perma n ent ai r monitoring stations in Wyoming (as well as in the three mobile air monitoring station s); accordingly , we also encoW"age the AQD se lect a s ite for

## colloc~~ing a referenc e-method PM2.s sample r with this method. Ir you have any questions or comments, contact me at (303) 312-6431 or .Joe Delwiche of my staff at (303) 312-6448

. Sincerely, 

### ,/-**,.~** 

# i\_**-~c~~** Deirdre

## Ro**hery ,**  Chief (j · Air Permitting, Mon i to ring

. 

### & Modeling Unit