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### Draft Guidance to Implement Requirements for the Treatment of Air Quality Monitoring Data Influenced by Exceptional Events

This summary document and its attachments 1 clarify key provisions of the 2007 Exceptional Events Rule (EER) to respond to questions and issues that have arisen since the rule was promulgated. The draft guidance in this document and the attachments, al ong with examples of approved demonstrations on the EPA’s website 2 , are provided to help ensure that the EPA’s final guidance provides an efficient and effective process to make determ inations regarding air quality data affected by events. The EPA notes that we released a previous version of these draft guidance documents to state, local, and tribal agencies, and to ot her parties as requested in May of 2011. The EPA incorporated some of the comm enters’ feedback into these revised draft guidance documents. An accounting of the pr eliminary comment and response process is documented in the docketed response to comments document. 3 The EPA notes that these draft guidance documents and the exceptio nal events website present examples to illustrate specific points. The example analyses and level of rigor are not necessari ly required for all

demonstrations. Please direct comments on these draft guidance documents to Docket ID No. EPA-HQ-OAR-2011-0887 by the comment deadline indicated in the Federal Register Notice of Availability. For guidance-related questions, please contact Beth W. Palma at 919-541-5432.

These draft guidance materials identify the four independent criteria on which exclusion of event-affected data depends, describe the ad ministrative process and associated timing for submittal and review of demonstrations, provide answers to frequently asked questions, and provide previously reviewed demonstrations a nd best practice compone nts. The EPA recognizes the challenges that air agencies 4 face in preparing exceptional event demonstration packages. The EPA also recognizes the limited resources of the air agencies that prepare and submit exceptional event demonstration packages and of the EPA regional offices that review these demonstration packages. One of the EPA’ s goals in developing exceptional event implementation guidance is to establ ish clear expectations to enable affected agencies to better manage resources as they prepare the docum entation required under the EER. The EPA expects submitters to prepare and submit the appropriate level of supporting documentation, which will vary on a case-by-case basis using the wei ght-of-evidence approach. The EPA expects the resources required to prepare (and review) packages to decrease as we continue to identify ways to streamline the process and c ontinue to build our database of example demonstrations and analyses. In addition, the EPA acknowledges that certain extrem e exceptional event cases may require more limited demonstration packages. Th is necessary case-by-case approach, however, makes the development of general guid ance with bright lines difficult.

1 Attachment 1, “Draft Exceptional Events Rule Frequently Asked Questions” (the draft Q&A document), Attachment 2, “Draft Guidance on the Preparation of Demonstrations in Support of Requests to Exclude Ambient Air Quality Data Affected by High Winds under the Ex ceptional Events Rule” (the draft High Winds Guidance document), and Attachment 3, “Request for Comments on the Draft Guidance Documents on the Implementation of the Exceptional Events Rule” (the Request for Comments document).

2 Additional information and examples of exceptional event submissions and best practice components can be found at the EPA’s Exceptional Events website located at http://www.epa.gov/ttn/analysis/exevents.htm.

3 Response to Comment document entitled, “Responses to Significant First-Round Comments on the Draft Guidance Documents on the Implementation of the Exceptional Events Rule.”

4 References to “air agencies” are meant to include state, local, and tribal air agencies responsible for implementing

the EER.Draft for Public Notice and Comment

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Page 2 of 10 This draft guidance overview document and its attachments are based on the following principles:

1. Air agencies should not be held accountable for exceedances due to events that were beyond their control at th e time of the event.

2. It is desirable to implement reasonabl e controls to prot ect public health. 5

3. Clear expectations will enable the EPA and othe r air agencies to better manage resources related to the exceptional events process.

Exceptional Event Rule Provisions

On March 22, 2007, the EPA promulgated the “Tr eatment of Data Influenced by Exceptional Events; Final Rule” (72 FR at 13560) pursuant to the 2005 amendment of Clean Air Act (CAA) Section 319. This rule, known as the Exceptional Events Rule, superseded the EPA’s previous natural events guidance and thos e sections of the interim fire policy document that address exceptional events. 6 The EER created a regulatory proce ss codified at 40 CFR parts 50 and 51 (50.1, 50.14 and 51.930). These regulatory sections contain definitions, procedural requirements, requirements for air agency demonstrations, and criteria for EPA approval for the exclusion of air quality data from regulat ory decisions under the EER.

The definition of an exceptional event at 40 CFR §50.1(j) repeats the CAA definition which provides that an exceptiona l event is one that affects air qualit y, is not reasonably controllable or preventable, and is caused by human activity that is unlikely to recu r at a particular location or a natural event. Additional requirements in 40 CFR §50.14(a)(2) and (b)(1) identify that an air agency must demonstrate “a clear causal rela tionship between the measured exceedance or

violation of such standard and the event” and that “an exceptional event caused a specific air pollution concentration in excess of one or more national ambient air quality standards.” The rule further requires at 40 CFR §50.14(c)(3)(iv) that the demonstration to justify data exclusion shall provide evidence that the event is associated w ith a measured concentration in excess of normal historical fluctuations, including background, an d evidence that there would have been no

exceedance or violation but for the event.

5 With respect to exceptional events, Section 319 of the Clean Air Act states the following guiding principles (among others); (i) the principle that protection of public health is the highest priority

*** (iv) the principle that each State must take necessary measures to safeguar d public health regardless of the source of the air pollution

6 Previous guidance and policy documents that either implied or documented the need for identifying data affected

by an exceptional event include: i) “Guideline for Interpretation of Air Quality Standards, ” U.S. EPA, OAQPS No. 1.2-00 8, Revised February 1977. ii) “Guideline On the Identification and Use of Air Quality Data Affected by Exceptional Events” (the Exceptional Events Policy), U.S. EP A, OAQPS, July 1986. iii) “Areas Affected by PM10 Natural Events” (the PM 10 Natural Events Policy), memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, to the EPA regional offices, May 30, 1996. iv) “The Interim Air Quality Policy on Wildland and Prescribed Fires” (the Interim Fire Policy), memorandum from Richard D. Wilson, Acting Assistant Administrator for Air and Radiation, to the EPA regional administrators, May 15, 1998. v) “Guideline on Data Handling Conventions for the PM NAAQS,” U.S. EPA, OAQPS, EPA-454/R-98-017,

December 1998.Draft for Public Notice and Comment

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Page 3 of 10 Treatment of Technical Criteria for Ex clusion of Data Affected by Events

When considered together, the EER provisions summarized above identify the following six elements that air agencies must address when requesting that the EPA exclude event-related concentrations from regulatory determinations:

 the event affected air quality

 the event was not reasonably controllable or preventable

 the event was caused by human activ ity that is unlikely to recur at a particular location, or

was a natural event

 there exists a clear causal relationship between the speci fic event and the monitored

concentration

 the event is associated with a measured c oncentration in excess of normal historical fluctuations including background

 there would have been no exceedance or violation but for the event

In reviewing exceptional events demonstra tion packages, the EPA has found that the following EER elements, along with historical fluctuations, play a significant ro le in the air agencies’ supporting do cumentation:

1. not reasonably controllab le or preventable

2. if the event was caused by human activity, that human activity is unlikely to recur at a particular location 7

3. clear causal relationship between specific event and monitore d concentration

4. no exceedance or violation but for the event 8

As described in the draft guidance documents, the EPA’s technical revi ew of a demonstration package would therefore focus on these elements. While the EER requires and the EPA expects complete demonstration packages to contain na rrative and evidence supporting all six elements, the EPA’s position is that these four elements re present distinct facts that air agencies must

demonstrate for the EPA to concur on an event claim. 9 Note that if an event is natural, then the

second element is not considered in a demonstration review. In the case of an event that is initiated by a natural process, such as a volca no or high wind dust event, the event would be

considered a natural event if sources are entirely na tural or contributing anthropogenic sources are reasonably controlled. 10 This concept is explained in more detail in Attachment 2, the draft High Winds Guidance document.

7 The remaining part of this criterion, “or a natural event” is intentionally omitted here.

8 Criteria 1, 3, and 4 on this list, along with historical fluctuations, are considered “independent elements” in the draft High Winds Guidance document.

9 While the “historical fluctuations element” is considered an independent element, it also plays an important role in the “clear causal relationship” and “no exceedance bu t for” demonstrations. The EPA will review agency submissions using a weight-of-evidence approach. The st ate’s role in satisfying this element is to provide appropriate analyses and statistics comp aring the event-affected concentration to normal historical fluctuations and conclude that the provided data show that the event was in excess of normal historical fluctuations. The EPA will review the information provided by the air agency. “Normal historical fluctuations” will generally be defined by those days without events for the previous years. The EP A acknowledges that natural events can recur and still be eligible for exclusion under the EER; therefore, events do no t necessarily have to be rare to satisfy this element. However, in most cases, the EPA expects that failure of th e “historical fluctuations” el ement indicates likely failure

for “clear causal relationshi p” and/or “no exceedance but for” as well.

10 Human activity would be considered to have played little or no direct causal role in causing the entrainment of the dust by high wind if contributing anthropogenic sources of dust are reasonably controlled, and thus the event wouldDraft for Public Notice and Comment

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Page 4 of 10 The EPA recognizes the inherent links between all six elements and expects that some sections of a demonstration package (e.g., affects ai r quality, natural event) may repeat or refer to

other sections of the demonstr ation package (e.g., clear causal relationship, but for). Further, each potential event can have varied and differing characteristics, and thus would usually require a case-specific demonstration and evaluation. Therefore, the EPA w ould use a “weight-ofevidence” approach in evaluating each elemen t within an exceptional event demonstration package.

In the draft guidance documents, the requi rement that the event was not reasonably controllable or preventable, which is part of the definition of an exceptional event in both the Clean Air Act and the EER, would mean that if a set of control measures could reasonably have been in place for contributing sources at the time of the event, then they must have been in place for the event to qualify as an exceptional event under the EER. This EER requirement applies to all events but is more complicated for high wind dust events because the event typically includes both natural and anthropogenic sour ces of dust. In contrast, an event such as a lightning-induced wildfire does not include an anthropogenic cont ribution to the event. Among other factors to consider, reasonableness would need to be judged in light of the technical information available to the air agency at the time the event occurr ed. The EPA would expect for nonattainment areas to already have the technical in formation needed to reasonably control anthropogenic sources in their jurisdiction. It would be important that each demonstration package address the question of

reasonable controls. As with the other elem ents, whether an event was not reasonably controllable or preventable would be evaluated on a case-by-case basis. In general, reasonable controls would not include any control on emissi ons-generating activity outside of the state or

tribal boundaries of the state (or tribal lands) within which the concentration at issue was

monitored.

Timing of EER Demonstration Package Submittal and Review

The EPA understands that the initial identificatio n of data affected by exceptional events and the subsequent preparation, submittal, and revi ew of demonstration packages is a resource intensive process. Delays in processing and making decisions on submitted packages create regulatory uncertainty and potentially increase the workload for both the submitting agency and the EPA. In addition, the backlog of pending acti ons makes retrieval of data to support new submittals potentially more difficult. Further, air agencies and the EPA often face timelines by which they must make regulatory decisions that can be affected by the inclusion or exclusion of

event-affected data.

The EPA will work with air agencies as they prepare complete demonstration packages that meet the requirements of the EER. In an effort to streamline this id entification, preparation, submittal, and review process, the EPA has developed the following draft guidelines.

be considered a natural event. If anthropogenic sources co ntributed significantly to a measured concentration (or if emissions from anthropogenic sources alone would have resulted in an exceedance or violation of the NAAQS) and these same emissions from anthropogenic sources are affect ed by an event and are reasonably controllable but did not have those reasonable controls applied at the time of th e event, then the event would not be considered a natural

event.Draft for Public Notice and Comment

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Page 5 of 10 1. Identification of data affected by exceptional events in AQS – The EPA is aware that air agencies routinely review their air qual ity monitoring data, which may result in the

identification of certain da ta being affected by an ex ceptional event. Although air agencies may flag any data in AQS that they wish to flag, the EPA encourages air agencies to flag only data that might have a regulatory consequence and for which an approvable demonstration is likely. 11 Should air agencies wish to flag values for informational purposes, the EPA prefers that they use the AQS flags intended for this

purpose.

2a. Air agency submittal of letter of intent to submit a package (optional) – To promote early communication, the EPA suggests that air agencies provide a letter of intent to submit a demonstration package for flagged data in AQS as soon as possible, if possible within 12 months from the event occurrence, af ter the agency identifies the event(s) as being significant. 12 This initial notification can assist both the air agency and the EPA in the planning and prioritization process.

2b. Air agency notification of intent to submit a package (optional) - Air agencies choosing not to submit a letter of intent are still encouraged to contact their EPA regional office more informally to alert it of the forthcoming demonstration submittal.

3. EPA response to air agency letter of intent – The EPA anticipates responding to the air agency’s letter of intent within 60 days of receipt. The EPA response will provide the regional office’s best assessment of the prior ity that can be given to the submission once received and any case-specific advice the EPA may have to offer for the preparation of

the demonstration.

4. Air agency submittal of exception al event demonstration packages 13 – Air agencies should prepare a technical demonstration packag e, taking into account the information in the EPA’s guidance documents, which shows th at a particular ai r quality monitored value(s) is influenced by an exceptiona l event. The EPA acknowledges that certain extreme exceptional event cases may lessen the technical burden associated with demonstration packages. Air agencies that be lieve their demonstration packages are tied to near-term regulatory actions should s ubmit their demonstration packages well in advance of the regulatory deadline. Air agen cies should also iden tify the relationship between the exceptional event-related flagged data and the anticipated regulatory action

11 States should place flags and an initial event descrip tion in AQS in accordance w ith the AQS data submission schedules (i.e., within 90 days of the end of the previous quarter) but not later than July 1 st of the calendar year following the event in which the flagged measurement occu rred. Note that for data certification purposes, it is recommended to flag data prior to su bmittal of data certification (May 1 st ).

12 The Letter of Intent is an optional step and the EPA reco gnizes that states may need additional time to prepare and submit demonstration packages particularly where the basis of the exclusion is violating an annual standard or a 3- year design value. Similarly, a state could consider submitting an annual letter of intent if annual submittal makes sense for resource planning or for histor ically seasonal events. If a state deci des to submit a letter of intent, the EPA recommends that it be submitted as expeditiously as possibl e after the state identifies the event or events as having significance.

13 The EER allows states to submit packages up to 3 ye ars following the end of the calendar quarter in which the event occurred, or 12 months prior to the date that a regulatory decision must be made by the EPA.Draft for Public Notice and Comment

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Page 6 of 10 in the cover letter that accompanies their initial submittal package to the reviewing EPA regional office.

5. EPA prioritization of subm itted demonstration packages – The EPA will generally give priority to exceptional event determina tions that may affect near-term regulatory decisions, such as SIP submittal actions, National Ambient Air Quality Standards (NAAQS) designations, and cl ean data findings.

6. EPA review of prioritized demonstration packages – The EPA generally intends to conduct its initial review of a submitted excep tional event demonstr ation package within 120 days of receipt. Following this initial re view, the EPA will gene rally send a letter to the submitting agency that includes a completeness determination and/or a request for additional information, a date by which th e supplemental information should be submitted (if applicable), and an indicator of the timing of the EPA’s final review. The EPA encourages air agencies to provide supplemental information if needed and requested by the EPA. The EPA anticipates a 60-day response time for states to provide additional requested information. 14 The EPA intends to make a decision regarding event concurrence within 18 months of submittal of a complete package, or sooner if required by a near-term regulatory action. Determina tions on Exceptional Ev ent demonstrations do not constitute final agency action until they are relied upon in a regulatory decision such as a finding of attainment or nona ttainment which will be conducted through noticeand-comment rulemaking procedures.

Exceptional Events Rule Frequently As ked Questions Document (Attachment 1)

The “Draft Exceptional Events Rule Frequently Asked Questions” document (the draft Q&A document) provides draft responses to questi ons that have arisen since the EER was promulgated. The questions are grouped into six broad areas. The EPA encourages those involved in flagging data and pr eparing demonstration packages to review the draft questions and answers, and to provide input regarding th eir usefulness and appropr iateness and regarding additional questions which need answers. The follo wing bullets identify key points of interest in the draft Q&A document:

 Natural events, such as volcanic eruptions, do not have to be infrequent to qualify as exceptional events under the EER. Frequent even ts with natural triggers that have a contribution from anthropogenic activities that are reasonably controlle d could be eligible “exceptional” events, provided the events meet the demonstration requirements for the

technical criteria.

 The EER does not prohibit air agencies from flagging individual concentration values below the level of the NAAQS. However, in gene ral, only such data that contribute to a violation of the NAAQS are excludable. Qu estions 29-31 of the draft Q&A document describe the few, limited situations in which concentration values below the level of the NAAQS contribute to violations of the NAAQS.

14 The EPA recognizes that states may need more than 60 days to prepare and submit some types of supplemental information. The EPA is willing to work with agencies on supplemental timeframes; however, the mandatory timing of EPA actions may limit the response time the EPA allows.Draft for Public Notice and Comment

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Page 7 of 10  An event that an air agency has concluded is associated with a measured concentration

“in excess of normal historical fluctuations” will be reviewed using a weight-of-evidence approach. The comparison of the measured concentration to normal historical concentrations will also influence how much information is needed to successfully meet other technical elements. For example, when the observed concentration is high compared to historical concentrations, the EPA may require less additional evidence to demonstrate the “but for” finding. The dr aft Q&A document provides recommendations for showing how the observed concentration co mpares to the distri bution of historical

concentrations.

 Question 6 in the draft Q&A document desc ribes types of evidence that could be submitted as part of a demonstration showi ng that an ozone exceedance would not have

occurred but for the effect of a fire event. In particular, statistical or photochemical dispersion model predictions of the ozone conc entration that would have occurred in the

absence of the fire would be a relevant t ype of evidence, provid ed the demonstration package is transparent about the technical basis for the model and its uncertainties. Also, as noted below, the EPA intends to develop a separate draft guidance document for firerelated events.

 Not every natural or infrequent anthropogeni c event that affects air quality is a true "exceptional event" under the definition of that term in the Exceptional Event Rule. Ambient data affected by an event that does not meet the "but fo r" criterion cannot be excluded under the authority of the Exceptional Events Rule even if in all other respects the event meets the definition of an exceptional event. The Exceptional Events Rule does not address data handling associ ated with events that are not considered “exceptional” under the EER, and does not provide the EPA w ith authority to exclude such data. Yet,

the event-related concentration could stil l impact design values. An air agency incorporating the event-related concentrati on in a design value used for a prospective attainment demonstration might seem to need more emission reductions to attain the NAAQS by its attainment deadline than is actually the case. The EPA plans to more formally address this topic on a pollutant/NAAQS basis, the first of which will be ozone guidance in the preamble of a soon-to-be- proposed rulemaking on SIP requirements for areas designated nonattainment for the 2008 ozone NAAQS. Until the planned guidance for a pollutant and NAAQS of interest is i ssued, air agencies shoul d consult with their EPA regional office if they face this situa tion. EPA further discusses this issue in Question 13 in the draft Q&A document.

 To remove any possible confusion, the passages of the preamble that were declared to be a legal nullity by the court that reviewed the EER are specifically identified in Question 20 in the draft Q&A document. 15 While air agencies cannot re ly solely on these passages as the EPA guidance on interpretation of th e EER, this draft guidance overview document

and its attachments are consis tent with those sections.

15 See NRDC v. EPA, No. 07-1151 (D.C. Cir. 3/20/09).Draft for Public Notice and Comment

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Page 8 of 10  The EPA identifies in Question 28a of the Q&A document currently existing mechanisms that air agencies can use at various points in the exceptional events process to resolve disagreements regarding non-concurrence on submittal packages.

High Winds Guidance Document (Attachment 2)

The attached “Draft Guidance on the Preparati on of Demonstrations in Support of Requests to Exclude Ambient Air Quality Data Affect ed by High Winds under the Exceptional Events Rule” (the High Winds Guidance document) when finalized will be a resource for air agencies when flagging data and preparing demonstrations packages for high wind dust events that have

affected PM 10 and PM 2.5 concentrations. The draft document applies the provisions of the EER and the general guidance conveyed in this dr aft guidance overview docum ent and in the draft Q&A document to the particular situation of a high wind dust event. While the document is specific to high wind dust events, it outlines how the EPA intends to implement the preparation and review process for exceptional events and, ther efore, may have relevance for other types of exceptional events. The following are some of th e highlights of the draf t High Winds Guidance

document:

 In nonattainment areas, a reference point fo r considering what constitutes reasonable control of wind-blown dust during high wind even ts would be the set of measures that are identified as RACM or BACM in the approve d SIPs of other areas with similar windblown dust conditions, depending on area classification. USDA best management practices designed to effectively reduce fug itive dust air emissions and prevent loss of soil during high winds could also be considered if applicable to the dust source. Also,

RACM or BACM measures in an area’s own approved SIP should be considered part of

the reasonable set of controls. The assessmen t of whether an event was not reasonably controllable will be made on a case-by-cas e basis considering all the facts.

 Reasonable controls generall y would not need to be implemented for wind-blown dust from undisturbed natural landscapes or previo usly disturbed landscap es that are being

allowed to return to natural conditions.

 For purposes of qualifying for the exclusion of data affected by wind events with sustained wind speeds above 25 miles per hour (o r above another threshold determined to be appropriate for a particular area), the de monstration of reasonable controls applied to disturbed landscapes and other anthropogenic sources of dust could be less rigorous because: (1) the contribution from natural undis turbed lands is likely to be high and, (2) at such high wind speeds many available cont rols would have been ineffective in significantly reducing wind-generated dust emissions.

 In response to commenter feedback, the EPA has developed and added the optional prospective controls analysis as a means of documenting existing controls and reaching up-front agreement as to what constitutes “reasonable” controls. In the prospective controls analysis, the air agency would provide information on attainme nt status, identify natural and anthropogenic windblown dust source s and emissions, provide the status of SIP submittals (if applicable), and identif y the wind speed up to which the collective windblown dust controls are expected to be effective. Air agencies would submit theirDraft for Public Notice and Comment

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Page 9 of 10 prospective controls analysis in advance of an agency submittal and the EPA review of any specific demonstration submittal, with a le tter of intent, or with their demonstration package submittal. The EPA review and approval of controls and an appropriate high wind threshold would also typically be e ffective for a minimum of three years.

 If the EPA has approved a SIP containing wind- blown dust controls within the past three years, then the submitting air agency has the option of using their current, implemented SIP-approved controls and specifying a high wi nd threshold to which the controls are expected to be effective to constitute the set of controls that would have been reasonable to implement.

 The EPA would further encourage air agencies to work with the EPA regional offices to develop High Wind Action Plans, which need no t be incorporated into the SIP, as a way to develop a mutual underst anding of what additional controls are reasonable to implement in light of foreseeable high wind conditions. Similar to a Natural Events

Action Plan 16 , the optional High Wind Action Plan is a mechanism to implement necessary controls on newly-iden tified sources needing reasonable controls such that the EPA could consider future high wind events not reasonably controllab le or preventable.

Requests for Comments (Attachment 3)

As part of the public comment process, the EPA is soliciting feedback on a series of questions that address the following topics:

 specific, broadly applicable, streamlining mechanisms

 available web-based information, links, tools, or methodologies

 available sources of wind data and their applicability in informing local high wind

thresholds

 additional feedback and tools to convert 1-5 minute wind speed data to hourly averages

 the anticipated use and functionality of the prospective controls an alysis and the high wind action plan

 technical analyses that can be used to dem onstrate that the wind exceeded an identified high wind threshold and that the exceedan ce was caused by emissions that were not reasonably controllable

 the utility and functionality of “Inf ormational Only” (“I”) flags in AQS

 characterizing “extreme” events

On-line Availability of Exceptional Even t Packages and Best Practice Components

To assist air agencies in d eciding what type and how much evidence/technical analysis to

include in their demonstra tion packages, the EPA has developed a public website at http://www.epa.gov/ttn/analysis/exevents.htm that contains EPA-approved demonstration

16 On May 30, 1996, Mary D. Nichols, Assistant Administrator for Air and Radiation issued a memorandum to EPA regional offices entitled, “Areas Affected by PM 10 Natural Events.” The policy, known as the PM 10 Natural Events Policy, or simply the Natural Events Policy, set fort h procedures for protecting public health through the development of a Natural Events Ac tion Plan (NEAP), which implements Best Available Control Measures (BACM) for human-generated particulate emissions in areas that could violate the PM 10 NAAQS due to natural events. Promulgation of the Exceptional Events Rule superseded the Natural Events Policy.Draft for Public Notice and Comment

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Page 10 of 10 packages and links to best-pr actice components. The EPA devel oped this website to provide examples to illustrate specific points; the example analyses and level of rigor are not necessarily required for all demonstrations. The website will c ontinue to evolve as agencies submit and the EPA reviews additional demonstration packages.

Draft Guidance Documents Still under Development

The EPA intends to develop a separate draft guidance document addressing the preparation of demonstrations to support wildfire-related event claims, in cluding events that may have

affected ozone concentrations. We also intend to develop a draft documen t that when finalized would replace the Interim Fire Policy and w ould contain additional guidance on basic smoke management practices for prescribed fires. The EPA has not established a schedule for developing these documents. We expect to provi de opportunities for stakeholder input on these

draft documents.

Conclusion

The EPA intends to follow the draft guidance provided in this overview document and its attachments during the public comment period a nd document finalization process, because we believe it is consistent with the Exceptional Ev ents Rule and the guidan ce already provided in the preamble to the rule. Although the EPA hopes to formalize the concepts in these guidance documents by issuing final guidance, the EPA has not excluded the possibility of issuing rule revisions. The EPA is deferring a decision on whet her to revise the Exceptional Events Rule.

The EPA’s Office of Air Quality Planning and Standards and the EPA regional offices are

available for assistance and c onsultation. Interested parties may direct comments on this guidance to Docket ID No. EPA-HQ-OAR-2011-0887 . For guidance-relate d questions, please

contact Beth W. Palma at 919-541-5432.

Attachments:

1. Draft Exceptional Events Rule Frequently Asked Questions

2. Draft Guidance on the Preparation of Demonstr ations in Support of Requests to Exclude Ambient Air Quality Data Affected by Hi gh Winds under the Exceptional Events Rule

3. Request for Comments on the Draft Guid ance Documents on the Implementation of the Exceptional Events Rule