Upper Green River Basin WyomingWinter Ozone Study
WESTAR Oil and Gas ConferenceSeptember 12, 2007
Cara KeslarWyoming DEQ - Air Quality Division
Introduction
Background Ozone Monitoring
Field Study Design Field Study Results
Jonah 12:00 2/27/06
Background
Hourly Average Ozone Concentrations February 2005, Jonah
Study Periods
Slide compliments of NOAA
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: Not Likely Checked certifications Additional 3rd party audits Elevated concentrations at multiple monitors Winter 2006 put Chemiluminescent ozone monitor at Jonah
to check for VOC 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 High Elevation,
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 a special study Ambient and Meteorological Field Study Modeling Study Emission Inventories
Ozone Monitoring Field Study
Ozone Monitoring Field Study
2005 & 2006 meteorological evaluation – forecasting High pressure aloft Light surface winds Snow cover
Stable boundary layer UV reflectance
Gather online data from other sources Total columnar ozone GOES temperature profiles
Field Study - February and March 2007 Continuous Measurements Intensive Operating Periods (IOP)
Continuous Measurements
Continued and enhanced monitoring at Boulder, Jonah, and Daniel South
CastNet continued collecting ozone data
Airport operations Profiler Site Mesonet Meteorology
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 and Carbonyl concentrations
IOP Measurements
Tetheredsondes and VOC/Carbonyl at Boulder, Jonah and Daniel South
Rawin/ozonesondes at Airport
Mesonet Ozone Aircraft measurements
2007 Field Study Results
Jonah Station and surrounding area
3/17/07
Station
Mean 500 mb Wind Speeds
Feb-Mar 2005, 2006 Feb-Mar 2007
Substantially stronger upper level winds during 2007 field study
Mean Surface Temperatures
Feb-Mar 2005, 2006 Feb-Mar 2007Warmer temperatures during 2007 field study
Jonah 8-Hour O3
March
ppb
Consistently lower O3 in 2007
Maximum Ozone Concentration
0
20
40
60
80
100
120
140
Hourly Max 8-Hourly Max Hourly Max 8-Hourly Max
2005-2006 2007
Ozo
ne
(pp
b)
BoulderJonahDaniel
Aerial Measurements
17 March Morning Flight
Haystack Butte
NO titration and elevated PM under inversion
17 March Afternoon Flight
Boulder
- Low PM- Uniform O3 - No inversion
Rawinsonde/Ozonesonde
Morning AfternoonInversionO3 depletion
below inversion
No Inversion
72 ppb O3 layer
aloft
Ground-level Measurements
Hourly Ozone at Selected Sites
0 2 4 6 8 10 12 14 16 18 20 22H our(M ST)
0
10
20
30
40
50
60
Ozo
ne
(pp
b)
C ora
Jonah
S im psons G u lch
Ozone depletion due to NO titration
O3 at upwind location
UV Albedo
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
2/28 3/15 3/30 4/14 4/29
Albed
o
0
50
100
150
200
250
300
350
400
UV In
solat
ion (W
/m2)
AlbedoUV Insolation
2 March: Albedo = 0.81 (snow)
23 March: Albedo = 0.04 (bare ground)
Daily Avg.
07:00 – 19:00 MST
VOCs: Mean ConcentrationTotal Identified
010002000300040005000
Boulder Daniel Jonah
pp
bC
Paraffins
0
1000
2000
3000
Boulder Daniel Jonah
ppbC
Olefins
0
10
20
30
40
Boulder Daniel Jonah
ppbC
Median VOC Concentrations:Top Six
0
20
40
60
80
100
120
Ethan
e
Propa
ne
n-But
ane
i-But
ane
i-Pen
tane
n-Pen
tane
ppbV
BoulderDanielJonah
Median VOC Concentrations:Remainder of Top 21
0
1
2
3
4
5
6
7
8
Ethen
e
Met
hylcy
clohe
xane
2-M
ethy
lhexa
ne
Met
hyl te
rt bu
tyl e
ther
Cyclop
enta
ne
3-M
ethy
lhexa
ne
2-M
ethy
lhept
ane
2,2-
Dimet
hylbu
tane
n-Hex
ane
Toluen
e
Met
hylcy
clope
ntan
e
2-M
ethy
l-1he
xene
2-M
ethy
lpent
ane
n-Hep
tane
Benze
ne
ppbV
BoulderDanielJonah
Carbonyl Analysis12 Samples at Each Site
Not DetectedSometimes Detected
Detected in all or nearly all
samples2,5-Dimethylbenzaldehyde, Hexaldehyde, Isovaleraldehyde, m,o,p-Tolualdehyde, Propionaldehyde, Valeraldehyde,
Buteraldehyde (roughly half of all samples), Crotonaldehyde (2 samples)
Acetaldehyde, Acetone, Benzaldehyde, Formaldehyde
Formaldehyde
0
1
2
3
4
5
6
7
8
9
0400-0700 0900-1200 1400-1700
Time (MST)
ppbV
JonahBoulderDaniel
Max
Min
MeanTentative Conclusions:
•Several formaldehyde sources near Jonah (high early morning concentrations)
• Possibility of some midday photochemical production at Boulder
•Need more sampling!
Summary
Weather conditions associated with high ozone events in 2005-2006 did not occur during 2007 Warmer temperatures, lack of snow cover Morning surface inversions did not persist
Observed “background” O3 in 50 – 55 ppb range Increases in NOx and reduced O3 at Jonah
compared to 2005-2006 Need site downwind to observe results of O3 formation
Need more information on VOC/carbonyl
Lessons Learned
Difficult to forecast high O3 events Lack of reliability, and low humidities
limited usefulness of profilers Importance of local personnel to help with
troubleshooting equipment, downloading data and coordinating logistics
Recommendationsfor 2008 Field Study
Start operations by mid-January Maintain wind & temperature obs at 8 mesonet sites
(equipment has been purchased) Allow for potentially more IOPs by limiting cost of
each Reduce number of mesonet sites with O3 Eliminate tethersondes Focus on aircraft for horizontal and vertical distributions
of ozone, PM, temperature Simplify continuous upper air (SODAR or miniSODAR) Use leftover ozone/rawinsondes More VOC/carbonyl sampling
Questions
Cara KeslarField Study
Project Manager307-777-8684
Darla PotterActing Modeling Study
Project Manager307-777-7346
