Ozone in Winter in the Upper Green River Basin

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Ozone in Winter in the Upper Green River Basin

• Greater Yellowstone Area Clean Air Partnership
  Meeting
• October 15, 2008

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Jonah/Pinedale 2005
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Sublette County Wells
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Sublette Co. Gas Production 1980-2007
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How Ozone is Formed

• Formed through a complex series of reactions
  between nitrogen oxides and volatile organic
  compounds driven by sunlight.
• Generally thought to occur under sunny, high
  temperature situations (i.e., summer months in
  urban areas)

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Changes to 8-hr Ozone National Ambient Air
Quality Standard

• Previous Standard 3-year average of the 4th
  highest daily 8-hour averaged ozone concentration
  0.08 ppm
• Standard Revised in May 2008 3-year average of
  the 4th highest daily 8-hour averaged ozone
  concentration 0.075 ppm
• The primary (health-based) and secondary
  (welfare-based) standard were set at the same
  value

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History of Air Monitoring in the Upper Green
River Basin

• Began ozone monitoring in 2005
• Standard was 0.08 (0.084)
• Found elevated levels
• 4th high 8-hour 0.080 on February 24th
• (Yellowstone monitor that day was 0.049)
• Confirmed that monitor was functioning properly
• Recurred in 2006
• 4th high 8-hour 0.075 on February 27th
• (Yellowstone monitor that day was 0.056)

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2005 2006 Top 5 8-hour ozone concentrations
Less than 75 data completeness Began
operation in July 2005
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Theories on Causes

• Monitoring error
• Stratospheric Intrusion
• Transport
• Locally Formed

Jonah 1200 2/27/06
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Theories on Causes - conclusions

• Monitoring error Not Likely
• Checked certifications
• Additional 3rd party audits
• Elevated concentrations at multiple monitors
• Winter 2006 put Chemiluminescent ozone monitor at
  Jonah to check for interference and found none
• Stratospheric Intrusion Not Likely
• Tight inversion and stagnant conditions for
  several days
• Transport Slight Possibility
• Other areas had not reported high wintertime
  conditions

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Theories on Causes (cont.)
2005

• Locally Formed Most Likely
• Precursors emitted in area
• Suspected tight inversion
• Stagnant conditions
• Sunny, snow cover

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Ozone and Wind Speeds, Jonah, WY, Feb 1-4, 2005
Slide compliments of NOAA
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AQD Response to Ozone Events

• Concerns about elevated concentrations
• Potential for NAAQS violation
• Health effects on local public
• More development planned in SW Wyoming
• Requested proposals for an Ambient and
  Meteorological Field Study

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AQD Initiated an Intensive Field Study in Jan.
2007

• Study Objectives
• Determine meteorological conditions
• Identify causes of high ozone
• Identify ozone distribution
• Identify role of ozone precursors
• Develop tools to model ozone formation

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2007 Ozone Monitoring Field Study
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2007 Continuous Measurements

• Continued monitoring at Boulder, Jonah, and
  Daniel South
• CastNet continued collecting ozone data
• Wind speed with height at airport
• Seven temporary stations to measure wind speed,
  wind direction and ozone

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2007 Intensive Operating Periods (IOPs)

• Operational forecasts
• Elevated ozone events likely
• Trigger Intensive Operating Periods (IOPs)
• IOP Measurement Objectives
• Determine structure of atmosphere during high
  ozone events
• How shallow is the inversion?
• What does the vertical ozone profile look like?
• What differences exist between Jonah, Boulder,
  Daniel?
• Determine spatial variability of ozone
  concentrations around Upper Green River Basin
• Determine VOC concentrations

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2007 IOP Measurements

• Temporary equipment to measure upper level winds,
  temp., relative humidity and ozone at Airport
• Aircraft measurements of ozone, temp., VOCs

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Summary 2007 vs. 2005-2006 Weather Patterns

• Weather conditions associated with high ozone
  events in 2005-2006 did not occur during 2007
• Lack of snow cover in 2007
• Stronger upper level winds in study area in 2007
• Stronger surface winds in 2007
• Morning surface inversions did not persist

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Meteorology

• Why important?
• Ozone a secondary pollutant
• Ultraviolet light (sunshine)
• Temperature inversion

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Ozone Sunlight

• UV energy from the sun is required to produce
  ozone
• Historically, scientists believed ozone cant be
  formed in low temperatures or areas with low sun
  angles (i.e., winter)
• Study measured UV energy
• Result when ground is highly reflective, UV
  energy is doubled

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Ozone Sunlight
Albedo 0.81 (snow)
Albedo 0.04 (bare ground)
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Preliminary conclusions

• In the winter
• Temperature inversion
• Still air
• Snow cover
• Sunshine
• Ozone precursors present in UGRB
• Produce elevated ozone

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2008 Field Study Objectives

• Develop a more complete characterization of
  winter ozone events in the Upper Green River
  Basin
• Provide data for
• Development of a conceptual model of ozone
  formation
• More accurate numerical simulations of high ozone
  events

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2008 Study Approach

• Study design based on 2005 2006 high ozone
  event data
• Identify meteorological and air quality modeling
  data requirements
• Identify data needed to evaluate initial theories
• Develop episode forecasting protocol
• Use field study website to post daily forecasts
  and raw data
• Conduct measurements mid-January March 2008
• Continuous Measurements to supplement existing
  network
• Intensive Operating Periods (IOPs)

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2008 UGWOS Continuous Sampling

• Routine data collection at existing sites
  (Boulder, Jonah, Daniel South, Pinedale-CASTNET)
• Airport operations
• Surface ozone
• Surface winds
• Sodar Site
• Upper level winds, temp
• Detected inversions
• Five temporary surface sites
• Wind speed, wind direction and ozone

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2008 UGWOS IOP Measurements

• Inversion layer measurement and columnar ozone
  measurement at airport
• 800, 1100, 1300, 1700
• VOC/Carbon compounds sampling
• Three hour integrated samples at Jonah, Boulder,
  Daniel 400 700, 900 1200, 1400 1700
  MST
• Aircraft grab samples
• Aircraft
• Morning and afternoon flights
• Ozone, PM2.5, Temperature, Pressure

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Wyoming Daily Max 8-Hr O3 2008 UGWOS Study
Period
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85
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Compliments of Shell 2008
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75
85
Compliments of Shell 2008
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2008 Pinedale Airport Vertical Profiles
11 March _at_ 600 pm
12 March _at_ 400 pm
Temp
O3
No Inversion, no elevated O3
Different wind directions above and below
inversion
Inversion at 100 m
Elevated O3 below inversion
Raw data subject to change
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Role of Mixing Heights
SODAR Mixing Height
Daily Max 8-Hr Avg O3 at Boulder

• Elevated O3 when MH lt 150 m agl
• Note mini-SODAR max range 250 m agl

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Photos from Boulder Visibility Camera

• Feb. 19, 2008

• Feb. 19, 2007

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Typical characteristics of high ozone episodes

• Extensive snow cover, light winds, clear to
  partly cloudy skies
• Strong, surface based inversion
• Precursors trapped in very shallow layer (less
  than about 150 m)
• High morning NOx and VOC
• Limited horizontal mixing results in strong
  spatial gradients
• Morning NW to afternoon SE wind reversal
• Most common at Jonah also seen at other sites
• Highest ozone nearly always found at Boulder
  lowest at Daniel and Cora in 2008

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Conditions Conducive to Ozone Formation

• The Three Ss
• Surface winds are light
• Snow cover is fairly complete
• Skies are clear to partly cloudy
• And more Ss
• Stable shallow surface layer with strong surface
  inversion

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Whats being done to reduce emissions associated
with oil and gas exploration and production?
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Ozone Precursor Sources

• Drill rigs
• Venting and Flaring from Well completion
  activities
• Gas production
• Vehicles

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Emission controls Rig Engines

• State has no authority to regulate non-road
  sources
• BLMs Jonah Infill Record of Decision enabled NOx
  reductions improvements to rig natural gas
  engines
• BLMs Pinedale Anticline Record of Decision
  requires operators to drastically reduce NOx
  emissions

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Shells Nabors 784 Drill Rig
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Insulated Urea storage tank used w/SCR to control
NOx emissions from the diesel generators.
Urea Tank
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Cat 3512 (1500 HP each) Diesel Generator Stacks
w/SCR Note Typically all 3 generators operate
only during the drilling of the first 2,500 feet
of each well with 2 generators operating for the
rest of the drilling.
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Well Completion Emission Controls
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Portable 4-Phase Completion Equipment
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Ozone Precursor Sources that DEQ Controls

• Gas production

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Well Separator
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Dehydrator Pneumatic PumpControl Device
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Uncontrolled Condensate Produced Water Storage
Tanks
200 bbl storage tanks
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Multiple Well Facility
Dehy combustors
Tanks combustor
Dehy Contact Tower
Heater Stacks
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Immediate Response to the Ozone Challenge

• Preliminary conclusion is that VOC controls
  should be the primary focus
• Control existing uncontrolled sources by Jan 2009
• Increase inspections to look at all fields in
  Sublette County
• Voluntary reduction of VOC producing activities
  during times when met. conditions appear
  conducive to ozone formation

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Additional Responses

• Improve precursor emission inventories
• Revise oil gas best available control
  technology (BACT) requirements
• Interim offsets permitting policy

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Permitting New Sources

• AQD can no longer conclude that increases in NOx
  and/or VOC in Sublette County can be justified
• Interim permitting policy was implemented on July
  21, 2008
• All applications will require a demonstration
  that the proposed facility will not prevent
  attainment or maintenance of an air quality
  standard

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Interim Policy (cont.)

• Offset must be in Sublette County
• Offset must be enforceable, or approved by AQD
• Reductions must occur after 4/1/08
• Offset Ratios
• For applications currently under AQD review
• 11 offsets for NOx and VOCs
• For applications received after August 1, 2008
• Offset of 1.51 for VOC and 1.11 for NOx
• Currently are approximately 80 applications where
  offsets are being discussed with AQD

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Upcoming Monitoring

• Continued operation of continuous monitors
• Move the Jonah monitor
• Adding a monitor in Pinedale operating in
  November
• Special winter monitoring in 2009
• AQD will conduct forecasting for winter of 2009
  to inform public and operators

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Additional work

• Further VOC analysis
• Develop a full scale ambient ozone model
• Modeling is necessary to predict improvements
  from emission reduction activities

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AQD Monitoring Site 4th high 8-hour ozone values
(ppm)

• These sites have 3 complete years of data for
  2005-2007

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Ozone Non-attainment Implementation Timeline

• March 12, 2008 Final Rule signed
• May 27, 2008 Final Rule took effect
• March 12, 2009 State designation package (for
  attainment/non-attainment areas) due to EPA
• March 2010 EPA makes final designations on
  attainment/non-attainment areas
• 2013 Non-attainment SIPs due

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What will non-attainment mean

• Requests for new permits will be subject to new
  requirements, which include offsets and Lowest
  Achievable Emission Rate control requirements
  for large sources currently, DEQ applies Best
  Available Control Technology (BACT) to new
  equipment.
• NOx and VOC Controls for existing sources.
• Conformity determinations on all federal
  actions places additional constraints on
  federal agencies to conform with DEQs
  nonattainment strategy.
• There could be requirements imposed on
  non-industrial sources as example is an
  inspection and maintenance program for all
  mobile sources in the area.
• DEQ will need to devise requirements that will be
  effective and make sense for the Upper Green.
  These may look like what other states have done
  or be entirely different. Ultimately emission
  reduction requirements must demonstrate success
  both through modeled attainment and acceptable
  actual ozone levels at the monitors.