Treatment of Data Influenced by Exceptional Events

1
Treatment of Data Influenced by Exceptional Events

• Also known as the
• Exceptional Events Rule (EER)
• Bob Pallarino
• EPA Region 9

2
Background

• Certain NAAQS allow EPA to consider the effects
  of exceptional events in determining an areas
  attainment status.
• PM10 - 40 CFR 50, Appendix K, section 2.4
• PM2.5 - 40 CFR 50, Appendix N, section 1(b)
• Ozone - 40 CFR 50, Appendix I, section 1
• At this time, NO2, SO2, CO and lead data cannot
  be flagged as being affected by exceptional
  events.

3
Background

• In 2005 Congress amended Section 319 of the Clean
  Air Act and required EPA to promulgate a new rule
  that addressed the affects of exceptional events
  on ambient air quality data.
• 40 CFR 50.1(j) includes the definition of an
  exceptional event
• 40 CFR 50.14 includes the procedures and
  requirements necessary to document exceptional
  events
• 40 CFR 50.930 includes mitigation requirements

4
Background

• Section 319 of the CAA defines an event as an
  exceptional event if
• The event affects air quality
• The event is not reasonably controllable or
  preventable
• The event is caused by human activity that is
  unlikely to recur at a particular location or is
  a natural event
• The event is determined by EPA to be an
  exceptional event

5
Background

• Section 319 of the CAA specifically excludes the
  following as exceptional events
• Stagnation of air masses or meteorological
  inversions
• A meteorological event involving high
  temperatures or lack of precipitation or
• Air pollution relating to source noncompliance

6
Background

• EER proposed on March 10, 2006
• Final rule published March 22, 2007
• Effective date was May 21, 2007
• EER supersedes all previous policies on handling
  data influenced by natural or exceptional
  activities
• 1977 Guideline for the Interpretation of Air
  Quality Standards
• 1986 Guideline on the Identification and Use of
  Air Quality Data Affected by Exceptional Events
• 1996 Policy memo Areas Affected by PM10 Natural
  Events.

7
Exceptional Events Rule

• Three broad categories of Requirements that must
  be met
• Procedural Requirements
• Technical Requirements
• Mitigation Requirements

8
Exceptional Events RuleProcedural Requirements

• Data are flagged in EPAs AQS database.
• Public had an opportunity to review and comment
  on the states documentation.
• The documentation was submitted to EPA.
• EPA concurs with the states demonstration.
• Timelines in rule must be met

9
Exceptional Events RuleProcedural Requirements

• Flagging data in AQS
• Data must be flagged as it is submitted to AQS
  (50.14(c)(2)(i))
• Notification to EPA with an initial description
  and intent to request concurrence must be
  received by July 1 of the year following the year
  in which the exceedance occurred
  (50.14(c)(2)(iii))

10
Exceptional Events RuleProcedural Requirements

• Public Review (50.14(c)(3)(i))
• Final Documentation must be made available for
  public review and comment.
• Any comments received must be forwarded to EPA
  along with the States request for concurrence
• Regulatory language does not specify a minimum
  length of time for comment period, though
  preamble suggests 30 days.

11
Exceptional Events RuleProcedural Requirements

• Timelines
• Data is flagged with appropriate code as it is
  submitted to AQS (quarterly).
• By July 1 of year following the year in which
  event occurred, an initial description and
  notification of intent to request concurrence
  submitted to EPA.
• Full documentation submitted within 3 years of
  the quarter in which event occurred or 12 months
  before a regulatory decision by EPA.

12
Exceptional Events RuleTechnical Requirements

• Must show that the event satisfies the definition
  of an Exceptional Event (40 CFR 50.1(j))
• There is a clear causal connection between the
  exceedance and the claimed exceptional event.
• The event is associated with measured
  concentration in excess of normal historical
  fluctuations.
• There would have been no exceedances but for
  the event.

13
Exceptional Events RuleTechnical Requirements

• Must show that the event satisfies the definition
  of an Exceptional Event (40 CFR 50.1(j))
• The event affects air quality
• The event is not reasonably controllable or
  preventable
• The event is caused by human activity that is
  unlikely to recur at a particular location or is
  a natural event.

14
Exceptional Events RuleTechnical Requirements

• The event affects air quality
• This criterion can be met by establishing that
  the event is associated with a measured
  exceedance in excess of normal historical
  fluctuations and there is a causal connection
  between the event and the exceedance.

15
Exceptional Events RuleTechnical Requirements

• The event is not reasonably controllable or
  preventable
• This requirement is met by demonstrating that
  despite reasonable and appropriate measures in
  place, the event caused the exceedance.

16
Exceptional Events RuleTechnical Requirements

• The event is caused by human activity that is
  unlikely to recur at a particular location or is
  a natural event
• Structural Fires
• Industrial Accidents
• High Winds
• Volcanic Eruptions
• Earthquakes

17
Exceptional Events RuleTechnical Requirements

• There is a clear causal connection between the
  exceedance and the claimed exceptional event.
• Meteorological data
• News accounts
• For PM, speciation data
• Air quality modeling

18
Exceptional Events RuleTechnical Requirements

• The event is associated with measured
  concentration in excess of normal historical
  fluctuations.
• Data analysis comparing contemporary
  concentrations with the distribution of all
  measured data during the past several years.

19
Exceptional Events RuleTechnical Requirements

• There would have been no exceedances but for
  the event.
• Weight of evidence approach in evaluating but
  for analyses
• The less unusual a value is (see historical
  fluctuation analysis) the more thorough the but
  for analysis needs to be.

20
Exceptional Events RuleMitigation Requirements

• States must take appropriate and reasonable
  actions to protect public health from exceedances
  or violations of the NAAQS, including
• Public notification,
• Public education, and
• Implementation of measures.

21
Exceptional Events Rule

• More Information?
• Exceptional Events Rule (72 Federal Register,
  13560, March 22, 2007)
• Proposed Affirmation of PM10 attainment finding
  for the San Joaquin Valley (72 Federal Register,
  49046, August 27, 2007)
• Final Affirmation of PM10 attainment finding for
  the San Joaquin Valley (73 Federal Register
  14687, March 19, 2008)
• Bob Pallarino, EPA Region 9, [phone],
  pallarino.bob_at_epa.gov