Ozone Regulation under the Clean Air Act

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Ozone Regulation under the Clean Air Act

• Darcy J. Anderson
• AZ Dept. of Environmental Quality

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Presentation Outline

• 8-Hour Ozone Standard Background / Timeline
• 8-Hour Ozone Standard Designation Process
• Arizona Designation Process Examples
• Potential Impacts of 8-Hour Ozone Designations
  on Tribes
• Next Steps in 8-Hour Ozone Process

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NAAQS for Ozone

• 1-hr standard 0.12 ppm (parts per million)
• 8-hr standard 0.08 ppm

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The 8-Hr Rolling Average

• Average of 8 consecutive hours
• EPA ozone standard requires that 4th highest 8-hr
  average be 0.084ppm
• Actual standard is 0.080ppm, but anything 0.084
  is truncated to 0.080
• Small-group activity on this today at 145

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8-Hour Ozone Standard Background / Timeline

• July 1997 EPA issued revised 8-hour health-based
  standard for ozone.
• Studies show that long-term, low exposure to
  ozone as harmful to human health as short-term,
  high exposure.
• New standard more protective for longer exposure

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8-Hour Ozone Standard Background / Timeline

• 2000 EPA issues guidance documents
• February 2001
• U.S. Supreme Court upheld 8-hour ozone standard
• Directed EPA to develop implementation approach

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Comparison of Ozone Standards
Standard Level Averaging Time Form (attainment test)
One-Hour 0.12 ppm 1 hour Three exceedances at a monitor allowed in a three year period fourth exceedance is a violation
Eight-Hour 0.08 ppm 8 hours Three-year average of the annual fourth highest 8-hour concentration, calculated for each monitor
Because of rounding convention, 0.085 ppm
considered level of violation
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8-Hour Ozone Standard - Designation Process

• November 2002 lawsuit settlement
• EPA environmental groups agree on schedule for
  EPA to promulgate 8-hour ozone designations

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8-Hour Ozone Standard - Designation Process
(cont.)

• February 27, 2003 EPA memorandum on 8-hour ozone
  designations
• Extended deadline for states to submit
  recommendations for designating areas
• New deadline July 15, 2003

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8-Hour Ozone Standard - Designation Process
(cont.)

• June 2003 EPA proposes rule for implementing
  8-hour NAAQS
• Final rule for implementing 8-hour NAAQS expected
  early 2004

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8-Hour Ozone Standard - Designation Process
(cont.)

• July 15, 2003 State recommendations for area
  designations submitted to EPA
• Tribes could also submit recommendations by this
  date
• Options
• Attainment / unclassifiable
• Nonattainment

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8-Hour Ozone Standard - Designation Process(cont.)

• July 2003 Governors recommendation for AZ
  submitted to EPA
• Recommended all areas of state attainment /
  unclassifiable for 8-hour standard except Phoenix
  metro area
• No state jurisdiction / recommendation for Indian
  reservations
• Some Arizona tribes submitted their
  recommendations

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Arizona Designation Process Examples

• Monitoring data exceedances, violations
• Location of emission sources
• Meteorology, geography, and jurisdictional
  boundaries
• Population
• Traffic and commuting patterns

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Potential Impacts of 8-Hour Ozone Designations on
Tribes

• Boundary / background / transport
• Tribes can provide valuable ozone data for urban
  nonattainment areas
• Tribes can conduct additional ozone and NOx
  monitoring to assist with model verification
• Public information / outreach (API)
• Ozone mapping AIRNOW

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Next Steps in 8-Hour Ozone Process

• February 6, 2004 Revised nonattainment area
  recommendations due to EPA
• EPA looking at 2003 ozone monitoring data to
  determine effect on recommended area designations
• Designations and classifications published in FR
  by April 30, 2004

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Next Steps Ozone Implementation Plan

• June 2, 2003 EPA proposed rule to implement
  8-hour NAAQS
• Option 1 All areas under Subpart 2
• Option 2 Separate areas based on whether they
  meet the 1-hour standard
• Regulate areas meeting the 1-hour standard under
  Subpart 1
• Regulate areas exceeding the 1-hour standard
  under Subpart 2
• Subpart 1 - more flexible, minimal mandated
  controls
• Subpart 2 - proscriptive (attainment dates based
  on classification marginal, moderate, serious,
  etc

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Next Steps Ozone Implementation Plan (cont.)

• Anticipate implementation of new standard for
  Phoenix area either under subpart 1 or marginal
  under subpart 2
• Subpart 1 option - Attainment demonstration due
  2007 attainment required 2009
• Subpart 2 option Attainment required 2007
• New control measures may be necessary to meet
  proposed attainment date

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Next Steps in 8-Hour OzoneProcess NOx Waiver

• What is a NOx waiver?
• Draft rule proposes NOx waiver under CAA Section
  182(f) apply to any area designated nonattainment
  for 8-hour standard
• Requires new analysis to obtain waiver under
  8-hour guidance

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NOx Waiver (cont.)

• NSR RACT requirements for major stationary VOC
  sources also apply to major NOx sources
• Unless NOx waiver provision implemented

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For More Detail

• Refer to full text outline in manual
• Outline follows PowerPoint slide pages