Front Range Ozone
Early Action Compact
Presentation to WESTAR
Regional Ozone Conference
Steven Arnold
Air Pollution Control Division
March 9th, 2004
Overview
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Denver’s Ozone Problem
Sources
The Early Action Compact
Non-Attainment Boundary
Control Actions
Ozone Summary
Site Name
Welby
Highland
S. Boulder Creek
Carriage
Chatfield Res.
USAF Academy
Arvada
Welch
Rocky Flats North
NREL
Fort Collins
Greeley
Rocky Mtn. N.P.
Weld County Tower
2000
2001
2002
2003
2000-2002 2001-2003
8-hr. O3
4th Max.
Value
(ppm)
8-hr. O3
4th Max.
Value
(ppm)
8-hr. O3
4th Max.
Value
(ppm)
8-hr. O3
4th Max.
Value
(ppm)
3-yr. Avg.
4th Max.
Value
(ppm)
3-yr. Avg.
4th Max.
Value
(ppm)
0.062
0.076
0.072
0.071
0.080
0.072
0.076
0.068
0.081
0.083
0.070
0.069
0.078
---
0.064
0.077
0.071
0.072
0.077
0.07
0.074
0.064
0.082
0.081
0.067
0.074
0.070
---
0.068
0.076
0.078
0.073
0.083
0.072
0.073
0.069
0.088
0.081
0.072
0.066
0.091
0.082
0.085
0.095
0.077
0.083
0.077
0.091
0.095
0.075
(Shut dow n)
(Shut dow n)
0.087
(0.080)
0.087
(0.083)
0.065
0.076
0.074
0.072
0.080
0.071
0.074
0.067
0.084
0.082
0.070
--0.078
(0.080)
0.066
0.081
0.077
0.077
0.085
0.073
0.077
0.070
0.087
0.085
0.071
--0.081
(0.082)
Ozone Status
2004
Site Na me
W elby
Highland
S. Boulder Creek
Carriage
Chatfield Res.
USAF Academy
Arvada
W elch
Rocky Flats North
NREL
Fort Collins
Greeley
W eld County Tower
Rocky Mtn. NP
3-yr. Avg.
4th Ma x .
Va lue
(ppm)
Highe st
Allow a ble
4th Ma x .
(ppm)
0.066
0.081
0.077
0.076
0.085
0.073
0.076
0.070
0.087
0.085
0.071
--(0.080)
0.120
0.087
0.094
0.096
0.076
0.105
0.098
0.108
0.075
0.078
0.107
--(0.094)
0.081
0.080
Upslope Meteorology
Ozone averaging more
than 80 ppb between
10,000 and 18,000
feet represents carryover from the previous
day and/or transport.
This ozone would have
been available for
mixing throughout the
mixed layer during the
late afternoon,
contributing to the
ozone burden at the
surface.
Back Trajectory Analysis- AQI
177NOAA Air Resources Laboratory
Back Trajectory Analysis-AQI
129NOAA Air Resources Laboratory
Back Trajectory Analysis-AQI
101NOAA Air Resources Laboratory
Topography (Denver Boulder Greeley CMSA Highlighted)
Denver Metro + Weld County VOC
Emission Inventory
Denver EAC-2002 Hydrocarbon Emissions for the Denver Area + Weld County
(Total HC=511 tpd)
Mobile Sources (evaporative)
14 %
Point Sources
12 %
Denver EAC-2007 Hydrocarbon Emissions for the Denver Area + Weld County
(Total HC= 475 tpd)
Mobile Sources (exhaust)
15 %
Point Sources-Flash
26 %
Non-Road (evaporative)
2%
Mobile Sources (evaporative)
14 %
Point Sources
12 %
Mobile Sources (exhaust)
10 %
Non-Road (evaporative)
1%
Non-Road (exhaust)
12 %
Area Sources
19 %
Point Sources-Flash
31 %
Non-Road (exhaust)
10 %
Area Sources
22 %
Denver Metro + Weld County NOx
Emission Inventory
Denver EAC-2002 Nitrogen Oxides (NOx) Emissions for the Denver Area + Weld County
(Total NOx= 363 tpd)
Point Sources
29 %
Denver EAC-2007 Nitrogen Oxides (NOx) Emissions for the Denver Area + Weld County
(Total NOx= 324 tpd)
Mobile Sources (exhaust)
40 %
Mobile Sources (exhaust)
33 %
Point Sources
33 %
Area Sources
7%
Non-Road (exhaust)
24 %
Area Sources
9%
Non-Road (exhaust)
25 %
Early Action Compact
To avoid nonattainment, the Denver area entered into
the Early Action Compact
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A multi-agency agreement
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RAQC, CDOT, AQCC, EPA, DRCOG, CDPHE, and Elbert, Larimer,
Morgan and Weld Counties
Controls implemented faster than traditional process
Requires complex modeling
Requires implementing controls by 12/31/05
Success must be shown by 12/31/07 – attainment
Early Action Compact
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Joining the EAC ensures a nonattainment
designation will be deferred for all counties
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Control over control measures
No transportation or general conformity
No nonattainment NSR permitting requirements
No RACT for all stationary sources
No “nonattainment” stigma
Basically, an “insurance policy” from nonattainment
Failure to meet any of the EAC deadlines triggers
automatic activation of nonattainment
Overview of the EAC Schedule
3/11 - AQCC public hearing
3-5/04 - Legislative review of AQCC adopted SIP
4/15/04 - EPA finalizes designation (deferred) and
boundaries
12/31/04 - Plan due to EPA
The Concept of Nonattainment
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If an area violates the standard, then EPA
designates “nonattainment”
A State Implementation Plan (SIP) is
required
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SIP = control strategy plan with technical
information
Emission controls must be enforceable
Conformity and more stringent source controls
Potential Ozone
Nonattainment Boundary
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EPA guidance recommends a minimum
nonattainment boundary as the
Denver/Boulder/Greeley CMSA
Also, the CAA requires the area to include
“…the area that can be shown to cause or
contribute to nonattainment…”
Review of sources, modeling, topography,
and meteorology are considered in
determining the boundaries
New Boundary May Include
North Front Range Counties
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Sources in many counties may “cause or
contribute” to violations
Weld County and RMNP monitors are perilously
close to recording violations
EPA recommends 11 counties as the 8-hour ozone
nonattainment area
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Adams, Arapahoe, Boulder, Broomfield, Denver,
Douglas, Elbert, Jefferson, Larimer, Morgan and Weld
CDPHE responded to EPA proposal
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Shave off northern Larimer and Weld Counties, all of
Elbert County, and eastern Morgan, Weld, Adams, and
Arapahoe Counties from boundary
Proposed 8-hour Ozone
Nonattainment Area
Eastern Colorado VOC Sources (Denver Boulder Greeley CMSA Highlighted)
Eastern Colorado NOx Sources (Denver Boulder Greeley CMSA Highlighted)
Oil/Gas Activities
(from Colorado Oil and Gas Conservation Commission)
Purple:
Permits
Green/Red: All
Oil/Gas Wells
Eastern Colorado Oil and Gas (Denver Boulder Greeley CMSA Highl
Ozone Modeling Area for EAC
Modeling Domain for the Denver Ozone EAC
12-km Grid
4-km Grid
1.3 -km Grid
N
200
0
200 Miles
W
E
S
Development of the
Ozone Plan
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A plan has been drafted and proposed to the
Air Quality Control Commission
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Description of the problem
Accounting of all emission sources (“inventories”)
Photochemical modeling to predict success by
2008
Development of the
Ozone Plan
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Controls on certain sources proposed
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Flash emissions from oil/gas sources
8.1 psi RVP gasoline
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EPA may set RVP at 7.8 psi
Uncontrolled industrial engines
Natural gas processing plants
Dehydrators at oil/gas operations
Current controls remain in place
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Enhanced I/M, federal measures, existing stationary
sources rules
Development of the
Ozone Plan
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Modeling these reductions shows improvement, but
not enough
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“Weight of the evidence” used to show attainment
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All monitoring sites below 85 ppb in 2007 except the
Rocky Flats site – 85.6 ppb
Used if modeled concentrations less than 90 ppb
Corroborative analysis of modeling results/uncertainties,
emissions trends, anomalous meteorology, levels of
control
Attainment presumed based on the proposed plan
AQCC hearing March 11th; Legislature then reviews
What Next?
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Monitoring this summer will provide
new perspectives
Modeling will continue to be refined
Legislative session and AQCC Actions
are only Round 1
EPA actions and actions of 22 parties
and other interests are all unknowns