E XCEPTIONAL E VENTS AND R EGION 9 AMTAC A PRIL 12,

T HE E XCEPTIONAL E VENTS R ULE & R9: *Data that was collected in accordance with all applicable requirements. 2 The Exceptional Events Rule (EER) is the only mechanism that allows S/L/Ts to exclude data* from regulatory decisions. R9 has > 45,000 exceptional event flags in AQS. o We have acted on a few, but there are many, many more. o Prioritizing those that affect immediate regulatory actions. o Flags associated with: Dry, dusty, windy areas (AZ, CA’s central valley) = PM 2.5, PM 10 flags Summer wildfires (CA, NV) = O 3, PM 2.5, PM 10 flags Volcanic activity (Hawaii) = SO 2, PM 2.5 flags Fireworks = PM 2.5 flags

T HE E XCEPTIONAL E VENTS R ULE & R9: 3 Currently takes many hours for S/Ls to produce, and for EPA to review and act on, one exceptional events package. EPA R9 and S/L/Ts are looking to guidance (rule change) to promote transparent and efficient implementation of the EER. National EER Workgroup has produced four products: o Overview memo o Q&A o Guidance on High Wind Dust Events o Website

G UIDANCE ON H IGH W IND D UST E VENTS Overview o R9/Workgroup product o Most applicable to dry, dusty areas in the West. o First comprehensive interpretation of the EER: broad principles apply to all exceptional events; many elements could be carried over to other event-specific guidance documents o Clarifies requirements, EER interpretation, provides step-by- step process for agencies to follow when developing packages, example analyses, package checklist, State/EPA submittal & review schedule. 4

G UIDANCE ON H IGH W IND D UST E VENTS Highlights o Addresses key litigation-risk issues: Definition of event = wind + dust, not just the wind itself Controls requirements and analyses o Provides streamlined process to satisfy “not reasonably controllable or preventable” criteria when wind speeds ≥ 25 mph* o Seeks progressive controls when events recur (e.g. optional High Wind Action Plan) o Provides general State/EPA submittal and review schedule 5 *25 mph = minimum wind speed needed to entrain particles from stabilized surfaces in the western US.

S TAKEHOLDER I NVOLVEMENT 6 Draft guidance is imminent; EPA will be soliciting stakeholder input o Janet McCabe will discuss at the April 25 th WESTAR meeting o EPA will also invite comment through NACAA o Very interested in receiving informal feedback during this time Near Term Draft Guidance for Stakeholder Review / Comment: 1. Overview Memo from Gina McCarthy to Regional Offices o Identifies concepts to be addressed through guidance o Describes administrative process for demonstration submittal 2. Frequently Asked Questions 3. High Winds Guidance Document 4. Website with example submissions at