Upper Green River Basin WyomingWinter Ozone StudyWESTAR Oil and Gas ConferenceSeptember 12, 2007

Cara KeslarWyoming DEQ - Air Quality Division

IntroductionBackgroundOzone Monitoring Field Study DesignField Study ResultsJonah 12:00 2/27/06

Background

Hourly Average Ozone Concentrations February 2005, JonahStudy PeriodsSlide compliments of NOAA

2005 & 2006 Top 5 8-hour ozone concentrations* Less than 75% data completeness $ Began operation in July 2005

Theories on CausesMonitoring error: Not Likely Checked certificationsAdditional 3rd party auditsElevated concentrations at multiple monitorsWinter 2006 put Chemiluminescent ozone monitor at Jonah to check for VOC interference and found noneStratospheric Intrusion: Not LikelyTight inversion and stagnant conditions for several daysTransport: Slight PossibilityOther areas had not reported high wintertime conditions

Theories on Causes (cont.)Locally Formed: Most LikelyPrecursors emitted in areaSuspected tight inversionStagnant conditionsHigh Elevation, sunny, snow cover2005

AQD Response to Ozone EventsConcerns about elevated concentrationsPotential for NAAQS violationHealth effects on local publicMore development planned in SW WyomingRequested proposals for a special study Ambient and Meteorological Field StudyModeling StudyEmission Inventories

Ozone Monitoring Field Study

Ozone Monitoring Field Study2005 & 2006 meteorological evaluation forecastingHigh pressure aloftLight surface winds Snow cover Stable boundary layerUV reflectanceGather online data from other sourcesTotal columnar ozoneGOES temperature profilesField Study - February and March 2007Continuous MeasurementsIntensive Operating Periods (IOP)

Continuous MeasurementsContinued and enhanced monitoring at Boulder, Jonah, and Daniel SouthCastNet continued collecting ozone dataAirport operationsProfiler SiteMesonet Meteorology

Intensive Operating Periods (IOPs)Operational forecastsElevated ozone events likelyTrigger Intensive Operating Periods (IOPs)IOP Measurement ObjectivesDetermine 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 BasinDetermine VOC and Carbonyl concentrations

Tetheredsondes and VOC/Carbonyl at Boulder, Jonah and Daniel SouthRawin/ozonesondes at AirportMesonet OzoneAircraft measurementsIOP Measurements

2007 Field Study ResultsJonah Station and surrounding area3/17/07Station

Mean 500 mb Wind SpeedsFeb-Mar 2005, 2006Feb-Mar 2007Substantially stronger upper level winds during 2007 field study

Mean Surface TemperaturesFeb-Mar 2005, 2006Feb-Mar 2007Warmer temperatures during 2007 field study

Jonah 8-Hour O3MarchppbConsistently lower O3 in 2007

Jonah O3 and NOxFebruary 8-Hour O302040608010012013579111315171921232527ppb200520062007March 8-Hour O301020304050607080135791113151719212325272931ppb200520062007February 8-Hour NOx02040608010012014016018013579111315171921232527ppb200520062007March 8-Hour NOx020406080100120140160135791113151719212325272931ppb200520062007

Maximum Ozone Concentration

Aerial Measurements

17 March Morning FlightHaystack ButteNO titration and elevated PM under inversion

17 March Afternoon FlightBoulder

- Low PM- Uniform O3- No inversion

Rawinsonde/OzonesondeMorningAfternoonInversionO3 depletion below inversionNo Inversion72 ppb O3 layer aloft

Ground-level Measurements

Hourly Ozone at Selected SitesOzone depletion due to NO titrationO3 at upwind location

UV Albedo2 March: Albedo = 0.81 (snow)23 March: Albedo = 0.04 (bare ground)Daily Avg.07:00 19:00 MST

VOCs: Mean Concentration

Median VOC Concentrations:Top Six

Median VOC Concentrations:Remainder of Top 21

Carbonyl Analysis12 Samples at Each Site

Formaldehyde01234567890400-07000900-12001400-1700Time (MST)ppbVJonahBoulderDanielMaxMinMeanTentative Conclusions:Several formaldehyde sources near Jonah (high early morning concentrations) Possibility of some midday photochemical production at BoulderNeed more sampling!

SummaryWeather conditions associated with high ozone events in 2005-2006 did not occur during 2007Warmer temperatures, lack of snow coverMorning surface inversions did not persistObserved background O3 in 50 55 ppb rangeIncreases in NOx and reduced O3 at Jonah compared to 2005-2006Need site downwind to observe results of O3 formationNeed more information on VOC/carbonyl

Lessons LearnedDifficult to forecast high O3 eventsLack of reliability, and low humidities limited usefulness of profilersImportance of local personnel to help with troubleshooting equipment, downloading data and coordinating logistics

Recommendationsfor 2008 Field StudyStart operations by mid-JanuaryMaintain wind & temperature obs at 8 mesonet sites (equipment has been purchased)Allow for potentially more IOPs by limiting cost of eachReduce number of mesonet sites with O3 Eliminate tethersondesFocus on aircraft for horizontal and vertical distributions of ozone, PM, temperatureSimplify continuous upper air (SODAR or miniSODAR)Use leftover ozone/rawinsondesMore VOC/carbonyl sampling

QuestionsCara KeslarField Study Project Manager307-777-8684Darla PotterActing Modeling Study Project Manager307-777-7346

No snowSeveral sources close to station Balloon shows wind is blowingSignificantly stronger upper level winds during 2007 field studySignificantly warmer temperatures during 2007 field study than in previous two yearsOzone depletion below inversionLooked at correlations between mesonet sites. Maixumum were close but found differences diurnal patterns.Differences are seen in nighttime titration. Typically upwind hovered around 55ppb

On days with fresh snow cover, 80% of UV is reflected. This information can be used in modeling for winter ozone to make sure model is treating snow cover properlyHigher concentrations at Jonah b/c of site location. Generally speaking paraffins less reactive than olefins.Typical natural gas. Higher values at Jonah are expected b/c of placement.Why is there no ethene found at Jonah? Need to speak with lab. Need more sampling.When weather patterns dont cooperate, difficult to call intersive sampling when you dont have all the conditions necessary.About 250,000 left. Need to cut back 2008 study.