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

Jonah Boulder Daniel South$

Date ppm Date ppm Date ppm

02/03/05 0.098 02/20/05 0.089 07/08/05 0.070

02/26/05 0.089 02/03/05 0.081 07/07/05 0.067

01/24/05 0.078 02/04/05 0.080 07/22/05 0.066

02/04/05 0.076 02/24/05 0.080 07/11/05 0.066

02/27/05 0.075 02/19/05 0.079 07/03/05 0.064

02/27/06 0.093* 04/21/06 0.081 02/25/06 0.083

02/25/06 0.081* 06/18/06 0.079 05/02/06 0.076

05/02/06 0.071 05/02/06 0.076 04/21/06 0.075

06/11/06 0.070 06/01/06 0.073 02/27/06 0.075

07/15/06 0.070 08/18/06 0.072 06/18/06 0.073* Less than 75% data completeness $ Began operation in July 2005

Theories on Causes

Monitoring error Stratospheric Intrusion Transport Locally Formed

Jonah 12:00 2/27/06

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

Theories on Causes (cont.)

Locally Formed: Most Likely Precursors emitted

in area Suspected tight

inversion Stagnant

conditions Sunny, snow cover

2005

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

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

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

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

2007 IOP Measurements

Temporary equipment to measure upper level winds, temp., relative humidity and ozone at Airport

Aircraft measurements of ozone, temp., VOCs

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

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 can’t 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, tempDetected inversions

x Five temporary surface sitesWind speed, wind direction and ozone

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2008 UGWOS IOP Measurements

Inversion layer measurement and columnar ozone measurement at airport:

8:00, 11:00, 13:00, 17:00 VOC/Carbon compounds sampling

Three hour integrated samples at Jonah, Boulder, Daniel: 4:00 – 7:00, 9:00 – 12:00, 14:00 – 17:00 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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Month/Day (MDD)

ppb

UGWOS Area Max

Thunder Basin

Campbell Co.

Centennial

Yellowstone

75 ppb

8-Hour Rolling Average O3Boulder, WY

February, 2008122

10495

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O3

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Compliments of Shell 2008

8-Hour Rolling Average O3Boulder, WYMarch, 2008

8081

90102

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O3

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7585

Compliments of Shell 2008

11 March @ 6:00 pm

12 March @ 4:00 pm

Elevated O3 below

inversion

Inversionat 100 m

Different wind directions above and

below inversion

O3

Temp

No Inversion, no elevated

O3

2008 Pinedale Airport Vertical Profiles

Raw data – subject to change32

Role of Mixing Heights

Elevated O3 when MH < 150 m agl Note mini-SODAR max range = 250 m agl

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SODAR Mixing Height

Daily Max 8-Hr Avg O3 at Boulder

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

Conditions Conducive to Ozone Formation

The Three S’s: Surface winds are light Snow cover is fairly complete Skies are clear to partly cloudy

And more S’s: Stable shallow surface layer with strong surface

inversion

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Monitored Ozone, 8-hour averageMonthly maximums: Upper Green and Yellowstone

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65

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105

115

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Jan-05 Jan-06 Jan-07 Dec-07

ppb

Boulder

Jonah

Daniel

Yellowstone

Upper Green Winter PeaksUpper Green Winter PeaksUpper Green Winter Peaks

2005 2006 2007 2008

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What’s being done to reduce emissions associated with oil and gas exploration and production?

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

BLM’s Jonah Infill Record of Decision enabled NOx reductions improvements to rig – natural gas engines

BLM’s Pinedale Anticline Record of Decision requires operators to drastically reduce NOx emissions

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Shell’s 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.

Well Completion Emission Controls

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Portable 4-Phase Completion Equipment

Ozone Precursor Sources that DEQ Controls

Gas production

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Well Separator

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Dehydrator & Pneumatic PumpControl Device

Uncontrolled Condensate & Produced Water Storage Tanks

200 bbl storage tanks

Multiple Well Facility

Dehy combustors

Tanks combustor

Dehy Contact Tower

Heater Stacks

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 (con’t.)

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:1:1 offsets for NOx and VOCs

For applications received after August 1, 2008:Offset of 1.5:1 for VOC and 1.1:1 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 operators60

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)

Site 2005 2006 2007 2005-2007 Average

2008 YTD value

Thunder Basin

0.063 0.072 0.072 0.069 0.074

Campbell County

0.063 0.065 0.072 0.067 0.050

Yellowstone

0.060 0.069 0.065 0.065 0.061

Boulder 0.079 0.072 0.067 0.072 0.101

Jonah 0.075 0.069 0.068 0.070 0.082

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 DEQ’s 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.

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