Topics and Issue for Further Discussion by the Natural
Events Workgroup
First Cut
July 29, 2004
1. Guiding Principles for the Natural Events Policy (see page 3 of the NEP).
Do we all agree that these continue to be the guiding principles?
2. What should a revised Natural Events Policy (NEP) cover?
 Pollutants
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PM10, PM2.5
Add PMcoarse? O3?
Types of Events
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Volcanic and seismic activities, wildland fires, high winds
Must high winds be described as “unusually high winds”?
Add “drought impacts”?
Address “[Fourth of July] Fireworks”?
Is the NEP consistent with the PM10 limited maintenance plan option and associated design
values?
3. What is required to document a natural event?
NEP: Establishment of a clear and causal relationship between the measured exceedance and the
natural event
 Are there required items for documentation? (See Lydia’s response 2.)
 Is “a clear causal relationship between the measured exceedance and the natural event” the
appropriate standard for documentation?
 Is there flexibility for handling complex situations (e.g., low winds at a monitor that is impacted
by dust lofted by high winds away, even far away, from the monitor)?
 Is the windblown dust natural event requirement that souces are in compliance with BACM “at
the time if the high wind event” an issue?
 Can states flag data below the level of the standard? What documentation is required?
 How do we assure state documentation is adequate?
4. What is the timeframe for documenting a natural event?
NEP: Documentation within 180 days of the exceedance
 Is there a need for different timeframes for exceedances of the 24-hour (or short-term) standard v.
exceedances of the annual standard?
 How does the timeframe relate to other Clean Air Act requirements (e.g., Part 58 annual data
certification)?
 What should EPA’s response be if a NEAP is not submitted within the timeframe?
5. What are state and EPA role and responsibilities for natural events documentation?
 How can the policy provide for state flexibility in documentation and at the same time achieve
consistency in EPA’s implementation of the policy?
 What are the specific roles of the state and EPA?
6. When is a Natural Events Action Plan (NEAP) needed (or not needed)?
NEP: At a minimum, within 18 months of the date when natural events cause a NAAQS to be
violated.
 Is there a need for different timeframes for violations of the 24-hour (or short-term) standard v.
violations of the annual standard?
 Must the NEAP be adopted as a SIP revision? (See the top of page 8 and middle of page 9 of the
NEP.)
 What should EPA’s response be if a NEAP is not submitted within the timeframe?
7. How complex does a NEAP have to be to serve its purposes?
 What should be the focus of a NEAP? How detailed does a NEAP have to be?
 What must be covered by BACM? “Contributing anthropogenic sources of dust” (p. 5)? “Any
sources of soil that have been disturbed by anthropogenic activities” (p. 6)? “Contributing
sources” (p. 6)?
 How general can a NEAP be and still be useful?
 For example, can a state develop a windblown dust NEAP that could be applied to multiple
areas of the state?
 Are there ways other than the covered area that NEAPs can be general?
 What does submission to EPA “for review and comment” mean (or imply)?
 State and EPA role and responsibilities
 How can the policy provide for state flexibility in NEAP development and at the same time
achieve consistency in EPA’s implementation of the policy?
 Definition of specific roles