Exploring a Pollution Event
Glenn Gehring, Technology Specialist III
Tribal Air Monitoring Support (TAMS) Center
Institute for Tribal Environmental Professionals (ITEP)
Northern Arizona University
541-612-0899
glenn.gehring@nau.edu
http://www4.nau.edu/itep
http://www4.nau.edu/tams
What Do These Data Mean?
Vertical
manifold
Toxics Flow
Controller
Tubing for
NOy
Gas Analyzer Rack
NOy
Continuous
Particulate
Sensor Unit
Data Logger
Calibrator
316 Stainless
Steel 1/8 inch
tubing connects
regulator to
calibrator
NOx
SO2
Continuous
Particulate
Monitor
Control
Units
Zero Air
Generator
Ozone
CGA
660?
Fitting
must
match
bottle
EPA Protocol Gas
Two big factors related to pollutant dispersion:
Ventilation Index (horizontal movement)
Stability (vertical mixing)
Mixing Height & Wind = Ventilation Index
Mixing
Height
Wind
NOAA ARL Stability Forecast
Zi - Boundary layer depth
(meters above model terrain)
10xKz - Vertical mixing
coefficient times 10 (m2/s2)
A – Extremely Unstable
B – Moderately Unstable
C – Slightly Unstable
D – Neutral
E – Slightly Stable
F – Moderately Stable
G – Extremely Stable
Includes an indication
of upward push
Ozone and PM-2.5 Readily Transport long
distances and React in the Atmosphere
Ozone is the Product of a Reaction Initiated
by Light (Photochemical Reaction) in the
Atmosphere; Ozone “Precursors,” such as
NOx and VOCs are Emitted From Sources
Very important chemical reactions related to ozone:
Ozone Diurnal (daily) Patterns
Quapaw Site on July 22, 2004 – Site’s highest 8-hr Ozone
93 ppb as an 8-hour
average
What were other 8-Hour ozone
concentrations on July 22, 2004?
I selected ozone for
one state at a time
and merged the
resulting data in a
spreadsheet.
Since these data have
spatial references for each
monitoring site (lat, long) I
can easily put this data into
GIS software. Then I can use
gradients to make higher
concentrations appear as
larger circles on the map.
Area 8-hr Ozone on July 22, 2004
Saint Louis
Kansas
City
Quapaw Site
Oklahoma
City
Tulsa
Little Rock
Memphis
I can also use GIS extensions to help illustrate.
8-hr Ozone on July 22, 2004 with Prediction Contours
(ESRI Geostatistical Analyst)
Quapaw Site
I can use Air Data or other
resources to get point
source emissions data, map
it and make the size of the
circles proportional to
emissions. I can also use
NOAA’s Air Resources
Laboratory’s HYSPLIT
software to perform
backward trajectories from
monitoring sites on the day
of concern.
July 22, 2004, 24-hour Backward Trajectories
(NOAA Air Resource Laboratory HYSPLIT Model)
proportional NOx point source emissions – 2002 EI
Quapaw Site
Now I have some suspect areas that may have
contributed to the problem (something near the
three coal-fired power plants). I can use ARL’s
HYSPLIT software to run forward dispersions
from the power plants to see where the model
indicates their emissions were when I had the
high concentration. In this example I set the
model to average concentrations from 100 m to
ground level and set it for a 48-hour release
beginning 48-hours prior to the high
concentration at the Quapaw site.
Oologah Power Plant 48-hr dispersion
(NOAA Air Resource Laboratory HYSPLIT Model)
Quapaw
Site
GRDA Power Plant 48-hr dispersion
(NOAA Air Resource Laboratory HYSPLIT Model)
Quapaw
Site
Muskogee Power Plant 48-hr dispersion
(NOAA Air Resource Laboratory HYSPLIT Model)
Quapaw
Site
Combined 48-hr dispersion
(NOAA Air Resource Laboratory HYSPLIT Model)
Quapaw
Site
Forward Trajectory from 3 Coal-Fired Power Plants on July 22, 2004
(endpoints that are less than 10 meters AGL)
Forward Trajectory from 3 Coal-Fired Power Plants on July 22, 2004
(endpoints that are less than 20 meters AGL)
NE Oklahoma Coal-Fired
Power Plant NOx Emissions
Most Relevant Winds for Ozone
WIND ROSE PLOT
Station #13968 - TULSA/INT'L ARPT, OK
Tulsa Ozone Season Wind Rose,
Lines Indicate the Direction the Wind Came FROM,
and Colors Indicate Wind Speed
Source: EPA AirData (1999 EI)
NORTH
(1984-1992, March 1 to October 31, from 8 AM to 6 PM)
25%
N
What if you
live here?
20%
15%
10%
5%
E
W
WEST
EAST
S
MODELER
2003 Ozone Monitoring Locations (Red Dots)
SOUTH
DATE
COMPANY NAME
26.5% of Oklahoma facility NOx emissions are from Muskogee, Mayes and Rogers Counties (1999)
Wind Speed (m/s)
> 11.06
1/20/2004
DISPLAY
UNIT
COMMENTS
22.9% of Oklahoma facility NOx emissions are from three NE Oklahoma coal-fired power plants (1999)
Wind Speed
m/s
AVG. WIND SPEED
CALM WINDS
5.20 m/s
3.17%
1.80 - 3.34
ORIENTATION
PLOT YEAR-DATE-TIME
0.51 - 1.80
Direction
(blowing from)
1984 1985 1987 1988 1989 1990
1992 1991 Mar 1 - Oct 31
8 AM - 6 PM
8.49 - 11.06
5.40 - 8.49
3.34 - 5.40
PROJECT/PLOT NO.
GIS for Air Quality Course