Lori Bocchino Wyoming DEQ October 22, 2008 Upper Green Winter Ozone

Presentation Overview Background Field Study Overview Model Development What’s next 2 Warbonnet 20 Feb 2008

Background Oil & Gas activity growth Historical ozone levels Unique features of SW WY ozone episodes 3

Local Anthropogenic Sources:

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AQD Monitoring Site 4 th high 8-hour ozone values (ppm) 7 Site Average 2008 YTD value Yellowstone Boulder Jonah These sites have 3 complete years of data for

Unique Features of SW WY Ozone Episodes 8 Winter events Low sun angle Cold temperatures Rural location Low Population No PSD major industrial sources All Minor source oil & gas, compression Limited mobile source activity?

Initial Theories Monitoring error, possible interferences Stratospheric Intrusion Transport Locally Formed 9 Jonah 12:00 2/27/06 O3 conc. = 103 ppb

Upper Green Winter Ozone Study Field Study Overview 10

Field Study Objectives 11 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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Study Approach 13 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 Conduct measurements February - March 2007 and mid-January – March 2008 Continuous Measurements to supplement existing network Intensive Operating Periods (IOPs)

UGWOS Continuous Sampling Routine data collection at existing sites (Boulder, Jonah, Daniel South, Pinedale-CASTNET) Airport operations FRM O3 analyzer Winds Profiler Site (RWP) Sfc winds, temp RWP/RASS/SODAR (2007) Mini-SODAR (2008) x Mesonet x Winds and ozone (Speedway, Big Piney and Mesa operated in 2007) 14

UGWOS IOP Measurements 15 Rawinsonde/ozonesonde at airport: 8:00, 11:00, 13:00, 17:00 VOC/Carbonyl 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 O3 (KI), PM2.5 (DustTrak) Temperature, Pressure

Forecasting for IOPs 16 Used NWS models GFS and NAM High Pressure Axis Approaching or Over Western Wyoming Low Wind Speeds Aloft and at Surface Warmer Temperatures Aloft Colder Surface Temperatures Strengthening Inversion Significant Snowpack

February IOPs 17

March IOPs 18

Upper Green Winter Field Study Results 19

What is the background ozone concentration? 20 Operational definition of background: What are ozone concentrations at CASTNet? What are concentrations outside of study area during events? What are concentrations inside study area when favorable conditions are not present? 55 ppb

2007 Field Study Opportunities for Elevated Ozone Meteorology did not set up as in 2005 and 2006 Few opportunities for elevated levels Saw episodes on 8-hour concentrations in low-to- mid 60 ppb Called one IOP March

Notable events during 2007 Lack of snow cover, local surface heating produced high temps during days resulted in deep mixing. Mornings were calm but winds in afternoon were too strong to run tethered balloons and aircraft. Collected data regarding UV radiation and reflection Tracked microscale wind flow around the Basin Analyzed VOC samples taken during IOPs Big red balloons were too tempting for neighbors looking for target practice in off-season. 22

SW Wyoming Daily Max 8-Hr O 3 : 2008 UGWOS Study Period 23

24 Snow Cover From: NOAA National Operational Hydrologic Remote Sensing Center Snow Depth (IOP #1) Snow Depth

Photos from Boulder Visibility Camera 25 Feb. 19, 2008 Feb. 19, 2007

Vertical Profiles and Mixing Heights Inversions inhibit mixing 26

Role of Mixing Heights Elevated O3 when MH < 150 m agl Note mini-SODAR max range = 250 m agl 27 SODAR Mixing Height Daily Max 8-Hr Avg O3 at Boulder

Ozone 18 – 21 February Boulder 122 ppb on 21 Feb

February 18, 2008 Prevailing, strong winds from the NW Well-mixed atmosphere Regionally uniform ozone concentrations, with 8-hour averages from network sites less than 60 ppb 29

February 18, 2008 PM Regionally low “baseline” ozone concentration of about 55 ppb 30

February 19, 2008 High pressure over area Stable surface layer Significantly higher ozone concentrations reported by some network sites, including an 8-hour average of 80 at Jonah Rapid development of high concentrations relative to clean conditions on February 18 31

February 19, 2008 After initial NW winds in early morning, winds become regionally light and variable 32

February 19, 2008 AM 33 Airport profile shows strong surface inversion Similar surface inversion of 10º to 15ºC were uniquely present during the mornings of all high ozone days

February 19, 2008 PM Profile shows surface inversion with low wind speeds, restricting mixing Higher ozone concentrations developing near surface 34

February 19, 2008 PM High ozone concentrations in Jonah area High concentrations well into foothills 35

February 20, 2008 Continued high pressure, stable conditions Ozone concentrations again develop over course of day O3 > 75 ppb 8-hour avg. at Boulder, Daniel, Warbonnet, and Simpsons Gulch 36

February 20, 2008 Continued mostly light and variable winds Note afternoon winds in Jonah/Warbonnet area somewhat stronger and from the SE 37

Surface Winds, 20 Feb :009:00 12:0015:00 Times are MST

February 20, 2008 AM Higher morning concentrations than previous days No definitive areas of significant ozone carryover Higher concentration over the New Fork river may be more a function of time (late in the flight) 39

February 20, 2008 PM Vertical profiles show continued inversion, limited mixing, and “baseline” conditions above inversion 40 Balloon Sounding at Pinedale Airport (Wenz Field) Aircraft Spiral Flight Pattern Sounding over Boulder

February 20, 2008 PM Surface network misses high values W-SW of The Mesa O3 peaks south of Jonah mid- afternoon consistent with NW morning winds switching to SE O3 peaks NW of Jonah in late afternoon consistent with SE afternoon winds Full spatial extent of high readings in southern portion of study area not well defined 41

February 21, 2008 Continued high pressure, stable conditions Ozone concentrations again develop over course of day 8-Hour avg O3 > 75 ppb at all sites except Daniel and Cora 8-hour average of 122 ppb recorded at Boulder – the highest for the year 42

February 21, 2008 Continued mostly light and variable winds Note afternoon winds at Warbonnet more southerly than previous days 43

February 21, 2008 AM Again, no obvious ozone carryover from previous day, but ozone concentrations above “baseline” 44

February 21, 2008 PM Vertical profiles show continued inversion, limited mixing, and “baseline” conditions above inversion 45 Balloon Sounding at Pinedale Airport (Wenz Field) Aircraft Spiral Flight Pattern Sounding over Boulder

February 21, 2008 PM Peak concentrations at Boulder consistent with a Jonah source and southerly winds High readings also noted in southern portion of study area – extent not well defined Readings consistent with surface network data 46

March 11, 2008 PM Highest readings recorded by aircraft during study, though beyond surface network coverage Readings consistent with network-reported data (O3 > 75 ppb at Boulder, Jonah, Airport, and Haystack Butte, with Simpsons Gulch also high) 47

Summary of key finding from IOPs 48 Periods of high ozone characterized by stable conditions, surface inversion, low surface mixing height, and low surface winds Polluted conditions can develop very quickly – within 24 hours of clean conditions High ozone can occur anywhere in the study area; depending on meteorology Southern extent of high O3 values not well characterized by these data

UV Radiation – UGWOS Data quality issues with UV readings (out > in) Loss of snow-reflected UV in mid-March

March 23, 2008 Flight Though not conclusive, higher concentrations appear to correlate with areas of greater snow cover 50

Upper Green Winter Ozone Study Ozone Precursors 51

Ozone Precursors 52 NOx = NO + NO2 CO Non-Methane organic compounds NMHC Alkanes, alkenes, aromatics, etc. Carbonyls Formaldehyde Acetaldehyde Crotonaldehyde Others

NOx Typical high ozone day at Jonah High morning NO → strong local source Low afternoon NOx → photochemical processing O3 peak at 14:00 coincides with wind shift 53

CO 54 Analyzed from 3-hr integrated canisters Clean continental background ~ 250 ppb CO > 250 ppb indicates influence of combustion sources Highest values at Jonah

Sample proportions of compounds indicate some kind of oil/gas handling source and they make up roughly 95% of the sample a-pinene, b-pinene, and d-limonene make up less than 1% of these samples => If biogenic sources such as vegetation were a major contributor, these compounds would be expected to make up a larger percentage of each sample 2006 VOC Canister Data 55

NMHC target compounds MDLs from 0.3 to 0.6 ppbV

Species Abundance: Boulder MIR weighting indicates relative reactivity for typical summer urban conditions; reactivities in SW WY may be very different Toluene, xylenes significant contributors to reactivity Aldehydes very reactive but concentrations are low Boulder data; includes all species found in at least 75% of all samples

Species Abundance: Jonah Note log scale Many more species > MDL compared to Boulder Overall results similar to Boulder w.r.t. importance of toluene and xylenes Jonah data; includes all species found in at least 75% of all samples

Upper Green Winter Ozone Study Model Development 59

Conditions Conducive to Ozone Formation 60 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

Typical characteristics of high ozone episodes 61 Strong, surface based inversion: pollutants 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 (only within the inversion layer) This flow pattern serves to recirculate ozone and ozone precursors within the study area, thereby enhancing ozone production Large changes in ozone concentrations aloft over small distances Rapid ozone formation/photochemical reactions

Typical characteristics of high ozone episodes 62 High VOC/NOx ratios in field data (2007 and 2008) VOC/NOx ratios (mass basis) 7:1 to 192:1 (2007) Albedo as f(snow cover) correlates well with high O3 measurements Once high ozone concentrations have formed, ozone levels remain elevated even with increasing cloud cover ahead of an approaching storm system Concentrations did not retreat to near background conditions until brisk (usually west or northwesterly) winds arrived and scoured out the surface inversion

Conceptual Description Simple (Box) models to evaluate O 3 formation: Mixing height, atmospheric chemistry, solar radiation (albedo) as f(snow cover), reactivity of VOCs Trapping inversions on high O 3 days appear to be causing precursor pollutants (NOx, VOC) to build up Evaluate whether the box model(s) are properly replicating key O 3 formation processes UGWOS field study data to be analyzed to support the development of the conceptual model Current box model results look promising 63

Identify relationships between NOx and VOC mixing ratios, met conditions, & resulting O 3 concentrations Develop a reasonable working hypothesis of the factors involved in the observed high O 3 events Can models reproduce monitored NOx, VOC and O 3 concentrations in the UGRB? Conceptual Description 64

Drill rigs, which have come off the northern end of the Pinedale Anticline (winter drilling stipulations) operating much closer to Jonah and Boulder monitors These rigs now closer to Jonah production and Jonah drilling activities, clustered together in areas at lower elevations, which experience strong radiation inversion conditions than would exist at higher elevations (operating on the Anticline) 800 feet drop in elev. => Anticline to Warbonnet Winter Drill Rigs Clustered 65

Diesel soot particles in the presence of fresh NO and NO 2 emissions may serve as a catalyst for surface-based reactions, fostering heterogeneous reactions The presence of diesel soot can be evaluated by looking at PM 2.5 monitors and aircraft data to see if elevated levels of diesel soot were measured in conjunction with high values of ozone Need speciated PM2.5 measurements to better define sources contributing to PM2.5 concentrations Diesel Soot and Ozone 66

Aircraft Data – Feb 20 th (Afternoon) 67

Model Selection When choosing the most appropriate model the principal issues to consider are: Complexity of dispersion Terrain Meteorology effects Scales of motion In choosing the most appropriate model it is very important to understand the model's limitations and apply it only to the situations that match its capabilities 68

Several months or longer away from potentially having tools (models) to develop verifiable control strategies for winter ozone formation and local ozone transport Can’t afford a lot of time experimenting with models that don’t cut the mustard Currently, there are no photochemical models specifically designed and tested to simulate localized wintertime ozone formation in a rural mountainous environment Have multiple years of field data available to develop and test models Model Selection 69

Model Selection Particle Models Pollutant releases represented by a stream of particles Transport by modeled winds; diffuse randomly Computationally expensive, but may be best type to represent pollutant concentrations close to source Puff Models Pollutant releases represented by a series of puffs of material Transported by modeled winds; each puff represents a discrete amount of pollution, whose volume increases due to turbulent mixing Much less computationally expensive than particle models Grid Models Pollutant distributions represented by concentrations on a (regular)3-D grid Computationally demanding Regional-scale air shed analyses and urban ozone studies; SIP planning Difficulties arise when scale of pollutant release smaller than grid point spacing Sub-grid scale concentration gradients 70

Near-Field Modeling If near-field plume-receptor interactions largely contributing to current ozone issues in JPDA, this is somewhat fortunate Have many years of expertise in science of near-field modeling, much data to “tune” model; several available near-field models to consider Near-field dispersion processes and AQ issues easier to model against observations; far-field AQ issues more difficult and costly to analyze 3030

What’s Next? 72 Awaiting final field study report Obtaining funding for 2009 field study “Conceptual model” development Currently underway Use routine data and data from UGWOS Photochemical modeling Target February – March 2008 episodes Use UGWOS data and detailed emission inventories Ozone forecasting training UW study Nonattainment? Rulemaking? Permit policy changes?

Possible Objectives for 2009 Field Study 73 Evaluate conditions south and southwest of Sublette Co. Southern extent of elevated O3/PM levels not well known Influence of industrial sources and other oil & gas fields in SW Wyoming not well understood Collect additional data on ozone precursors Focus on Boulder or new site downwind of Jonah Nitrogen species: NOy, possibly others SO2, CO Consider continuous TNMHC with reduced canister sampling Enhance temporary continuous winter season monitoring Add temperature, pressure sensors to mesonet stations Add cellular modems for near real-time data reporting Enhanced aircraft instrumentation NO2 photolysis, NOx, NOy, SO2, CO, HCHO, winds

Questions? 74