Weather Makes a Difference: 8-hour
Ozone Trends for 1997-2007
State and Local Information for EPA Region 7
Kansas
Missouri
Nebraska
Composite trend for available sites in these states:
EPA Region 07 (selected sites)
80
70 -
JD
Gl
Q.
0
c:
n 60
O
S)50
ca
% 40
<
c 30
o
w
I20
~-8rrrr8r~
. O.
1—• - -
o .
#
o
o
*•
— Adjusted for Weather
Unadjusted for Weather
1998
2000
2002
Year
2004
2006
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Air Quality Planning and Standards
April 2008
-------
Kansas
Ozone
On average, ozone adjusted for weather conditions declined 11 percent between 1997 and
2007. These improvements in ozone are in response to both state and regional reductions
in NOx and VOC emissions. The level of ozone improvement varies from site to site.
Trends for 1997-2007 for urban areas with complete ozone and meteorology data are
presented below. Ozone season (May 1 - September 30) averages of daily maximum 8-
hour ozone were adjusted to remove the influence of year-to-year variability in weather
conditions. The dotted line shows the trend in observed values at monitoring sites, while
the solid line illustrates the underlying ozone trend after removing the effects of weather.
The solid line serves as a more accurate ozone trend for assessing changes in emissions.
Typical weather conditions are determined by averaging conditions (e.g., temperature,
humidity, etc.) for the time period presented. The information provided is useful for
reviewing the weather influence for a particular ozone season. The solid line represents
ozone levels anticipated under typical weather conditions.
Seasonal Average 8-hour Ozone Trends
Wichita, KS 8-hr Ozone Trends
.Q
CL
Cl
(d 80
c
o
N
O
a) 60
CJ>
CO
-------
Kansas City, KS 8-hr Ozone Trends
n
Cl
Cl
0 80
c
o
N
O
9160
CO
0
5 40
CO
c
o
u)
CO
0)
00
.#¦-
0"
¦ o- *
, o
o..
20
—* Adjusted for Weather
Unadjusted for Weather
©'
•o..
— '
1998
2000
2002
Year
2004
2006
-------
Missouri
Ozone
In St Louis ozone adjusted for weather conditions declined 14 percent between 1997 and
2007. This improvement in ozone is in response to both state and regional reductions in
NOx and VOC emissions.
Trends for 1997-2007 for a site with complete ozone and meteorology data are presented
below. Ozone season (May 1 - September 30) averages of daily maximum 8-hour ozone
were adjusted to remove the influence of year-to-year variability in weather conditions.
The dotted line shows the trend in observed values at monitoring sites, while the solid
line illustrates the underlying ozone trend after removing the effects of weather. The
solid line serves as a more accurate ozone trend for assessing changes in emissions.
Typical weather conditions are determined by averaging conditions (e.g., temperature,
humidity, etc.) for the time period presented. The information provided is useful for
reviewing the weather influence for a particular ozone season. The solid line represents
ozone levels anticipated under typical weather conditions.
Seasonal Average 8-hour Ozone Trends
St Louis, MO 8-hr Ozone Trends
J2
Q_
CL
0 80
c
o
N
O
a) 60
D)
CO
L.
(D
- 40
CO
c
o
w
A3
on
|00 zu
• —
o*'
&
,°-
Adjusted for Weather
Unadjusted for Weather
1998
2000
2002
Year
2004
2006
Nebraska
-------
Ozone
In Omaha, NE, ozone adjusted for weather conditions declined 12 percent between 1997
and 2007. This improvement in ozone is in response to both state and regional reductions
in NOx and VOC emissions.
Trends for 1997-2007 for a site with complete ozone and meteorology data are presented
below. Ozone season (May 1 - September 30) averages of daily maximum 8-hour ozone
were adjusted to remove the influence of year-to-year variability in weather conditions.
The dotted line shows the trend in observed values at monitoring sites, while the solid
line illustrates the underlying ozone trend after removing the effects of weather. The
solid line serves as a more accurate ozone trend for assessing changes in emissions
Typical weather conditions are determined by averaging conditions (e.g., temperature,
humidity, etc.) for the time period presented. The information provided is useful for
reviewing the weather influence for a particular ozone season. The solid line represents
ozone levels anticipated under typical weather conditions.
Seasonal Average 8-hour Ozone Trends
Omaha-Council Bluff, NE 8-hr Ozone Trends
Seasoral Average Ozone (ppb)
80 ~
60 -
40 -
Adjusted for Weather
Unadjusted for Weather
1998 2000 2002 2004 2006
Year
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