1. Exceptional Events Rule
NESCAUM MAC Meeting
April 24-25, 2007
Alison Simcox, US EPA - New England

2. New Exceptional Events Rule
Proposed March 10, 2006 (71 FR 12592)
Final Rule
Signed March 14, 2007
Published March 22 (72 FR 13560)
Effective May 21, 2007

3. Background
1977 First EPA policies on AQ data affected by exceptional or natural events (EEs)
1986 EPA published "Guideline on the Id and Use of AQ Data Affected by EEs" - guidance for flagging data
1990 CAA amendments considered areas influenced by natural sources of air pollution - Section 188(f) of Part D, Subpart IV
1996 EPA published "Areas Affected by PM-10 Natural Events“ - guidance for data affected by natural events (wildfire, volcanic/ seismic activities, high wind)
1998 EPA published "The Interim AQ Policy On Wildland and Prescribed Fires“ – guidance on data affected by fires set for resource benefits
2005 Congress promulgated SAFE-TEA-LU, requiring EPA to propose/ finalize EE rule

4. Statutory Definition of Exceptional Event
Section 319: “Exceptional event” is an event that:
Affects air quality;
Is not reasonably controllable or preventable;
Is an event caused by human activity that is unlikely to recur at a particular location or is a natural event (e.g., unplanned fires or destructive storms); and
Is determined by the Administrator to be an exceptional event.

5. Key Requirements of amended Section 319
Exceptional event must be demonstrated by reliable and accurate data.
State must show “clear causal relationship” between NAAQS exceedances and event.
Must be a public-review process related to an “exceptional event” determination.
Rule must set criteria/procedures for States to petition EPA to exclude data affected by exceptional events.

6. Applicability of Rule
Will apply to all pollutants for which NAAQS provides discretion to discount or exclude data
PM and Ozone
Other pollutants will be considered as NAAQS for these are reviewed

7. Provisions of Rule Provide public notification of event
Provide public education concerning event
Implement reasonable & appropriate measures to protect public health related to event
Above requirements not linked to EPA’s approval/disapproval of State’s request to have data excluded under rule
States not required to submit documentation to EPA of mitigation actions taken

8. When Can Data Be Excluded?
Data flagged by State as an EE
when there is “sufficient demonstration” that event occurred, and
Event has affected AQ so as to cause exceedance or violation of a NAAQS
A daily value only eligible for exclusion if State can show that exceedance of NAAQS would not have occurred “but for” influence of EE

9. Documentation of EEs: Weight-of-Evidence approach
Approach similar to historical treatment of EEs
After flagging data in AQS, States expected to develop support doc thru consultation with EPA Region
For high concs (e.g.,>95 percentile), lesser amount of doc needed to show event affected AQ.
(For ex., newspaper acct or satellite images (e.g., upwind wildfire, volcanic eruption) with daily/seasonal average ambient concs)
For lesser concs (e.g.,<75 percentile), stronger evidence needed to justify exclusion of data.
(For ex., event in city where there are many sources and complex meteorology and topography)

13. Documentation of EEs: What to Include:
Minimum: demonstrate that event occurred and that emissions transported in direction of monitor(s)
Size of area affected by transported emissions
Relationship in time between event, transport, and recorded concentrations
Pollutant species-specific info supporting causal relationship between event and concentrations

14. Examples of Supporting Information for EE Demonstrations
Id of event and transport to monitor(s)
Docs from land owners/managers, satellite imagery of fire, smoke and smoke plume transport or trajectory calculations
Id of spatial pattern of affected area
Use of satellite or surface-measurement data
Info about temporal patterns (time/duration)
Observed concentration spikes at multiple locations with time delay in downwind direction

15. EE Demonstrations (cont.)
Id of chemical composition
Provide routine speciation data, monitoring networks, or lab analysis of archived PM filters
For ex., more organic or crustal material than typical of other high-conc events
(e.g., id natural fires vs industrial sources, or crustal material from transported smoke)
Natural Events
High wind speeds relative to typical levels for season of year

16. Time Lines for Flagging Data & Submitting Demos
States must report to EPA all flagged data affected by exceptional event before July 1st of year following event
States must submit full demos to EPA on exceptional events within 3 years following event to support annual average determinations….but demos must be submitted no later than 12 months before any NA decisions for an area
States must submit full doc on EEs annually, and by July 1st, for exceedances of the short-term NAAQS
Where there are “special regulatory circumstances”, States may be required to submit flags and documentation related to EEs on expedited schedule

17. Special Provision to allow States to flag data for CY 2004-2006
For States which may have not flagged data impacted by EEs because the daily value was below the current NAAQS, EPA is permitting States to flag and submit an initial description of the event to EPA before October 1, A State may request an extension up to but no later than December 1, 2007.

18. Fireworks
State wishing to flag AQ data influenced by fireworks emissions must:
Show that use of fireworks is integral to traditional national, ethnic, or other cultural events
Show that the event affected AQ
Submit doc showing a clear causal connection between emissions from fireworks event and measurement at monitor

19. Fireworks (cont)
EPA encourages States to take precautions to minimize exposure to fireworks emissions
Use lower-emitting fireworks
Locate displays downwind of populated areas
States strongly encouraged to institute educational programs that alert the public to health effects associated with exposure to emissions from fireworks displays.

20. Prescribed Burning PB data that may be flagged as “exceptional event”
Where PB needed to protect natural ecosystem (e.g., reducing brush, fallen trees, other fuel loading)
State must certify that it has adopted and is implementing Smoke Management Program (SMP), and that SM plan in place at time of event, or State must ensure that burner employed SM practices
PB data not determined to be “exceptional event”
Addressed under EPA’s "Interim Air Quality Policy on Wildland and Prescribed Fire“
Interim policy provides guidance on actions burners must take to protect AQ during prescribed burns. Also provides process for States to exclude PB data
EPA will work with other federal agencies/stakeholders to revise interim policy within next 16 months

21. Agricultural Burning Not addressed under exceptional events rule, but…
EPA may address this issue in late 2007 during revision of “Interim Air Quality Policy on Wildland and Prescribed Fire”

22. For More Information… Final rule:
EPA New England contact:
Alison Simcox (617)
EPA OAQPS contact:
Larry Wallace (919)