Exceptional Events and Fire

Matthew Lakin, Ph.D.Manager, Air Quality Analysis Office

U.S. EPA, Region 9

Interagency Air and Smoke Council MeetingMay 2, 2012

Disclaimer: Positions and views expressed here represent draft EPA guidance and/or staff recommendations and not final Agency policy

Background

• 2007 Exceptional Events (EE) Rule• Provides mechanism by which air quality data can be excluded from

regulatory decisions and actions • Affects design value calculations, NAAQS designation status, and State

Implementation Plan development

• May 2, 2011 – EPA released draft guidance documents• Overview note to reviewers• Frequently asked questions (~30 pages)• High Winds Guidance Document (~60 pages)• Website http://www.epa.gov/ttn/analysis/exevents.htm

• May-June, 2012 – EPA intends to release revised draft guidance documents • May announce as a Notice of Availability soliciting further public comment

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Exceptional Events (EE) Rule Elements

Under 40 CFR 50.14 (c)(3)(iii), the State demonstration to justify data exclusion must provide evidence that:

A. The event satisfies the criteria set forth in 40 CFR 50.1(j) for the definition of an exceptional event, which are that the event: • affects air quality; • is not reasonably controllable or preventable, and• is an event caused by human activity that is unlikely to recur at a

particular location or a natural event;

B. There is a clear causal relationship between the measurement under consideration and the event that is claimed to have affected the air quality in the area;

C. The event is associated with a measured concentration in excess of normal historical fluctuations, including background; and

D. There would have been no exceedance or violation but for the event.

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Fire Policy and EE

EPA’s Fire Policy would ideally address definition of the event:

• Clarify “Human Activity Unlikely to Recur”

• Clarify “Not Reasonably Controllable or Preventable”; The EE Rule Preamble gives the following examples:

• Build up of fuel

• Ecosystem depends on fire

• Control of pest or disease outbreaks

• Mechanical removal not feasible

• Clarify Smoke Management Practices (SMP) and BSMP as ways to safeguard public health

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Technical Considerations for EE Demonstrations

Critical elements:

• Conceptual Model: a narrative description of how the event unfolded and resulted in the exceedance(s); should tie the various rule criteria together into a cohesive explanation of the event

• Clear Causal Relationship: Analyses and descriptions showing relationship between concentration measurement and the wildfire event that is claimed to have affected the air quality

• Examples: back trajectories, satellite imagery, chemical tracers

• No Exceedance “But for” the Event: Analyses (quantitative and qualitative) showing that the NAAQS would not have been exceeded if there were no wildfire

• Examples: historical comparisons (met analysis), linear regression, photochemical modeling

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How Can FLMs Help the Districts?

• Open communication: talk with districts before, during, and after a fire

• Technical analysis:• Active tracking of fires: identify which information to keep• Broadscale analysis at NPS (and district?) monitors:

• Linear regression• Blue Sky modeling

• Temporary monitoring (e.g. E-BAMs)• Other ideas?

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Questions?

• For further information on the Exceptional Events demonstrations or future guidance:

Matthew LakinLakin.Matthew@epa.gov(415) 972-3851

• Region 9 EE fire lead:

Kate HoagHoag.Katherine@epa.gov(415) 972-3970

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• Region 9 Air Division fire lead:

Don Hodge, Hodge.Don@epa.gov(415) 972-3240

Draft Guidance: High Wind EE Demonstrations

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Step 1Develop a

Conceptual Model

Step 2 Not Reasonably Controllable or

Preventable

Basic Controls Analysis (wind

speed > threshold)

Extensive Controls

Analysis (wind speed <

threshold)

Step 4Clear Causal Relationship

Step 3Historical

Fluctuations

Step 5No Exceedance But For Event

Human Event / Natural Event

Affects Air Quality

HW EE Guidance, Figure 2