1. Exceptional Events and Fire Matthew Lakin, Ph.D. Manager, Air Quality Analysis Office U.S. EPA, Region 9 Interagency Air and Smoke Council Meeting May 2, 2012 Disclaimer: Positions and views expressed here represent draft EPA guidance and/or staff recommendations and not final Agency policy

2. 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value calculations, NAAQS designation status, and State Implementation Plan development May 2, 2011 – EPA released draft guidance documents Overview note to reviewers Frequently asked questions (~30 pages) High Winds Guidance Document (~60 pages) Website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.htmhttp://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May-June, 2012 – EPA intends to release revised draft guidance documents May announce as a Notice of Availability soliciting further public comment 2

3. 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. 3

4. 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 4

5. 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 5

6. 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? 6

7. Questions? For further information on the Exceptional Events demonstrations or future guidance: Matthew Lakin Lakin.Matthew@epa.gov (415) 972-3851 Region 9 EE fire lead: Kate Hoag Hoag.Katherine@epa.gov (415) 972-3970 7 Region 9 Air Division fire lead: Don Hodge, Hodge.Don@epa.gov (415) 972-3240

8. Draft Guidance: High Wind EE Demonstrations 8 Step 1 Develop a Conceptual Model Step 2 Not Reasonably Controllable or Preventable Basic Controls Analysis (wind speed > threshold) Extensive Controls Analysis (wind speed < threshold) Step 4 Clear Causal Relationship Step 3 Historical Fluctuations Step 5 No Exceedance But For Event Human Event / Natural Event Affects Air Quality HW EE Guidance, Figure 2