UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION 10



### Dick Pedersen, Director 1200 Sixth Avenue, Suite 900 Seattle, Washington 98101-3140 

## JUN 29 2012

Oregon Department ofEnvironmental Quality 811 SW Sixth Avenue Portland, Oregon 97204 Dear Mr. Pedersen: OFFICE OF THE REGIONAL ADMINISTRATOR



### This letter responds to the Oregon Department ofEnvironmental Quality's March 21, 2012 submittal regarding the 24-hour PM2.5

### National Ambient Air Quality Standardexceedance at the Klamath Falls Peterson School site in Klamath County on September 25, 2009. The ODEQ has requested that the EPA concurthat this exceedance was due to a wildfire exceptional event. Therecorded 24-hour PM2.5 

### level at the site was 62.5 J..tg/m3

. 

### Ourresponse to the ODEQ'srequest is governed bythe "Treatment ofData InfluencedbyExceptional Events" rule (72 FR 13560, March 22, 2007). After careful consideration ofthe informationprovided, we concur with the State's exceptional events flag. Thebasis for ourdecision is set forth inthe enclosed document. The ODEQ included exceptional events documentation for several other flagged exceedances in southern Oregon inits March 21, 2012 submittal. This letter covers the September25, 2009 Klamath Falls exceedancebecause ofits potential impact on air quality decisions for the Klamath Falls PM2.5 

### nonattainment area. Our concurrence on the September 25, 2009 Klamath Falls exceedance is not intended to indicate the EPA's views on concurrence ornon concurrence with any other flagged exceedances contained in the March 21, 2012 submittal. Note that the EPA's decisions on exceptional event exclusions are not considered final agency action until they are acted upon as part ofa final regulatory action, such as in an action concludingthat the affected datamaybeexcluded from use in a designation ordetermination ofattainment, whichis subject to public notice and comment. Thank you for yourtimely submittal ofthis exceptional event documentation and for respondingto our comments and questions about the documentation. Ifyou have any questions orwishto discuss this matter further, please contact me orhave your staffcontact Debra Suzuki, Manager ofthe State and Tribal AirPrograms Unit in the Office ofAir, Waste and Toxics at (206) 553-0985.

Enclosure Dennis 

### J. McLerran Regional Administrator

### cc: Andy Ginsberg Oregon Department ofEnvironmental Quality David Collier Oregon Department ofEnvironmental Quality Anthony Bamack Oregon Department ofEnvironmental Quality

### EPA Region 10 Review ofExceptional Event Request Klamath Falls, OR 24-hour PM2.s NAAQS
Background On March 22, 2007, the EPA adopted a final rule, Treatment**l~{**Data Influenced by Exceptional Events' (Exceptional Events Rule or EER) to govern the review and handling ofcertain air quality monitoring data for which the normal planning and regulatory processes are not appropriate. Under the EER, the EPA may exclude data from use in determinations ofNational Ambient Air Quality Standard (NAAQS) exceedances and violations ifa state demonstrates that an "exceptional event'' caused the exceedances. Before the EPA can exclude data from these regulatory determinations, the state must flag the data in the EPA's Air Quality System (AQS) database and, after notice and opportunity for public comment, submit a demonstration tojustify the exclusion. After considering the weight ofevidence provided in the demonstration, the EPA decides whether or not to concur with each flag.2 ODEQ's Request ODEQ requested concurrence on a flagged exceedance ofthe 24-hour PM2.5 NAAQS (35**[.tg/m~)** that occurred in Klamath Falls, Oregon on September 25, 2009, at the Klamath Falls Peterson School site (AQS site 41-035-0004). The recorded 24-hour PM2.5 level at the site was 62.5**[.lg/m~.** Prior to and on that day, lightning-started wildfires were burning in southern Oregon. ODEQ submitted to the EPA exceptional event documentation on March 21, 2012, for this and several other flagged exceedances that occurred in September 2009 at the Klamath Falls site and other sites in Southern Oregon. This document covers only the September 25, 2009, Klamath Falls exceedance because ofits potential impact on air quality decisions for the Klamath Falls PM25 nonattainment area and does not indicate the EPA's views on concurrence or non concurrence ofthe other flagged exceedances. The EPA's Exceptional Event Evaluation The EPA evaluated whether the documentation provided by ODEQ for the flagged exceedance ofthe 24-hour PM2

_ 5NAAQS on September 25, 2009, in Klamath Falls, Oregon, demonstrated that the requirements ofthe Exceptional Events Rule were met.

I 72 FR 13560. 2 Note that the level ordocumentation may vary by the type orevent and can be guided in part by the relative magnitude ofthe ohserved concentrations. To ohtain concurrence. the EPA must determine that the demonstration is complete and provides a reasonahle technical demonstration. 72 FR 13573 (March 22, 2007).The table below summarizes the requirements ofthe Exceptional Events Rule and describes how ODEQ met each requirement. All references to page numbers, tables and figures relate to the March 21, 2012, documentation.



### Procedural Requirements: EPA's Evaluation ofli'Jagged Exceedances:

• The data are flagged in ODEQ flagged the September 25, 2009, 24-hour PM25

EPA's AQS database. value as a wildfire exceptional event in EPA's AQS 40 CFR 50.14(c)(2)(i) database prior to the July 1, 20I0, deadline. and (iii)

• The public had an ODEQ provided a 30 day public comment period on the

opportunity to review documentation for the September 25, 2009, claimed and comment on exceptional event exceeedance. (See cover letter from demonstration Anthony Barnack emailed to EPA on September 19, justifying data 2011.) ODEQ received comments from one exclusion. 40 CFR commenter, who supported exceptional event 50.14(c)(3)(i) and (iv) concurrence.

• Demonstration EPA received demonstration documentation from justifying data ODEQ on March 21, 2012, well before the deadline of exclusion submitted not later than 3 years following the end ofthe calendar timely to EPA. 40 quarter in which the flagged concentration was recorded CFR 50.14(c)(3)(i) (in this case, September 30, 2012).



### Technical Criteria: 

## • The event satisfies ODEQ provided FRM and continuous nephelometer the criteria in 40 PM2.5data (Table 1on page 2 and Figure 18 on page 18) CFR 50.1

### U) (i.e., as evidence that the event affected air quality at the affects air quality, is Klamath Falls Peterson School site on September 25, not reasonably 2009. controllable or preventable, is an ODEQ provided a news article dated September 25, event caused by 2009, (pages 27-28), a website link to the interagency human activity that Incident Information System (page 1) that attributed the is unlikely to recur at wildfires in southern Oregon in mid-September to a a particular location lightning storm on September 12 and 13, 2009, and a or a natural event, website link to the National Interagency Coordination and is determined by Center Incident Management Situation Reports that EPA to be an described the difficulty in containing the fires, providing exceptional event). evidence that the September 25, 2009, event was not 40CFR reasonably controllable or preventable and that it was a

250.14(c)(3)(iii)(A) natural event.



## • There is a clear ODEQ provided satellite images of smoke (page 14), causal connection model back trajectories (page 15), weather maps (page between the 16), and continuous PM25data from the Peterson School exceedance and the site (page 20), to establish airflow movement from the claimed exceptional location ofthe wildfires to the air at breathing level in event. 40 CFR Klamath Falls and provide evidence that the wildfires 50.14(c)(3)(iii)(B) affected air quality at the Klamath Falls Peterson School site on September 25, 2009. ODEQ also provided a map showing the location and size ofwildfires (pages I and 13), locations ofother monitors impacted by smoke during that period (page I), and graphically displayed historical levels ofPM2.5in the Klamath Fall area during September from 2000 to 2008 (Figure 6 on page 8). DEQ also evaluated the possibility ofotherburning contributing to the exceedance and found no evidence ofsignificant controlled burns or agricultural burning on September 25, 2009, as discussed below for the "but for'' requirement. Based on the suite ofevidence provided, including satellite images, back trajectories, maps, PM2 .5data, meteorological data, and no evidence ofother significant sources ofburning, we conclude that there is a clear causal connection between the exceedance and the September 25, 2009,event. 

# • The event is To show PM25concentrations during the 2009 fire associated with season were in excess ofnormal historical fluctuations, measured including background, ODEQ plotted data in Figure 6 concentrations in (page 8 ofODEQ's documentation) to show that in excess ofnormal previous Septembers from 2000-2008, 24-hour PM25 historical levels were below 20 [!g/m3

, except for a few days in fluctuations September 2002, when many fires were burning in including Oregon. Based on the presented data indicating that past background. 40 CFR Septemberbackground levels, in the absence of 50.14 (c)(3)(iii)(C) unwanted wildfires, are normally below 20 [!g/m3

, which is well below the 24-hour PM2 5NAAQS, we conclude that the exceedance concentration of65.2**~tg/m on**  September 25, 2009, is in excess ofnormal historical fluctuations including background.



### 3• There would have been no excecdances "but for'' the event. 40CFR 50.14(c)(3)(iii)(D)

Conclusion To show there would have been no excccdanccs "but for" the event, ODEQ plotted data in Figure 6 (page 8) and Figure 10 (page 12) to show that in previous Septembers from 2000-2008 (except for a few days in September 2002, when many fires were burning in Oregon), 24-hour PM2.5 levels at the Peterson School site were below 20 [!g/m3

. ODEQ also investigated whether there were any controlled burns near Klamath Falls on orjust before September 25, 2009, and found none of any significant magnitude were recorded by any ofthe agencies that track controlled burns (page 28-30). We have no information that agricultural burning occurred on orjust prior to September 25, 2009 (sec email from ODEQ to EPA dated May 23, 2012), and given other evidence connecting the wildfire to the excccdance, we have no reason to believe that agricultural burning was a contributing factor. Based on information about other burning in the area and the presented data indicating that air quality levels in September, in the absence of unwanted wildfires, arc normally well below the 24- hour PM2.5NAAQS, we conclude that but for the wildfires at the time ofthe September 25, 2009, cxceedance, there would have been no exceedance of the 24-hour PM2.5NAAQS at the Klamath Falls Peterson School site.

In light ofthe documentation submitted by ODEQ on March 21, 2012, EPA concurs on the PM2.5 level of62.5 [!g/m3 flagged as an exceptional event for September 25, 2009. Accordingly, we are placing a concurrence indicator in the EPA's AQS database for September 25, 2009. While the information and analyses presented in ODEQ's submittal documents do not represent the entire suite ofpossible evidence for exceptional event packages, and additional or alternate evidence may be necessary to make an exceptional event determination for other wildtire or other types ofevents, in this particular instance the EPA finds that the weight ofevidence is sufficient for concurrence on the tlagging ofthe data for the Klamath Falls monitor on September 25, 2012. Note that the EPA's decisions on exceptional event exclusions are not considered final agency action until they are acted upon as part ofa final regulatory action, such as in an action concluding that the affected data may be excluded from use in a designation or determination ofattainment, which is subject to public notice and comment.



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