Front Range Ozone Early Action Compact Presentation to WESTAR Regional Ozone Conference Steven Arnold Air Pollution Control Division March 9th, 2004

Overview Denver’s Ozone Problem Sources The Early Action Compact Non-Attainment Boundary Control Actions

Ozone Summary

Ozone Status

Upslope Meteorology

Ozone averaging more than 80 ppb between 10,000 and 18,000 feet represents carry- over 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 177- NOAA Air Resources Laboratory

Back Trajectory Analysis-AQI 129- NOAA Air Resources Laboratory

Back Trajectory Analysis-AQI 101- NOAA Air Resources Laboratory

Topography (Denver Boulder Greeley CMSA Highlighted)

Denver Metro + Weld County VOC Emission Inventory

Denver Metro + Weld County NOx Emission Inventory

To avoid nonattainment, the Denver area entered into the Early Action Compact A multi-agency agreement 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

Joining the EAC ensures a nonattainment designation will be deferred for all counties 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 Early Action Compact

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 Overview of the EAC Schedule

If an area violates the standard, then EPA designates “nonattainment” A State Implementation Plan (SIP) is required SIP = control strategy plan with technical information Emission controls must be enforceable Conformity and more stringent source controls The Concept of Nonattainment

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 Potential Ozone Nonattainment Boundary

New Boundary May Include North Front Range Counties 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 Adams, Arapahoe, Boulder, Broomfield, Denver, Douglas, Elbert, Jefferson, Larimer, Morgan and Weld CDPHE responded to EPA proposal 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 NO x 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 Highlighted)

Ozone Modeling Area for EAC

Development of the Ozone Plan A plan has been drafted and proposed to the Air Quality Control Commission Description of the problem Accounting of all emission sources (“inventories”) Photochemical modeling to predict success by 2008

Controls on certain sources proposed Flash emissions from oil/gas sources 8.1 psi RVP gasoline 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 Enhanced I/M, federal measures, existing stationary sources rules Development of the Ozone Plan

Modeling these reductions shows improvement, but not enough All monitoring sites below 85 ppb in 2007 except the Rocky Flats site – 85.6 ppb “Weight of the evidence” used to show attainment 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 11 th ; Legislature then reviews Development of the Ozone Plan

What Next? 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