Document Archives Modeling & Emissions Inventories

VOC/NOx Sensitivity Analysis

Posted Under: Modeling, Modeling, Ozone, Reports


In 2017, Ramboll Environ performed sensitivity analyses to estimate the effects that VOC and/or NOx emission reductions have on 2023 ozone design values in the Denver Metro/North Front Range nonattainment area.  A summary of this analysis was presented at the RAQC’s Modeling Forum on November 2, 2017, which can be found here.  An analysis tool was also developed as part of this effort, which allows users to view projected ozone design values for each monitoring site based on various levels of NOx and VOC reductions.

VOC/NOx Sensitivity Analysis Tool

2017 Ozone Modeling Forum

Posted Under: Modeling, Modeling, Modeling Forum, Ozone (8-Hour Standard), Stakeholder Meetings


Nov. 2nd, 2017
1:00 – 4:30PM


Modeling Sensitives Overview – Ralph Morris

Local Source 2017 Ozone Source Apportionment Modeling (2011 Modeling Database) – Ralph Morris, Ramboll Environ

Contributions of International Emissions (2011 Modeling Platform) – Ralph Morris

2023 Ozone Projections and VOC/NOx Emissions Sensitivity Modeling – Ralph Morris

Front Range Air Pollution and Photochemistry Experiment (FRAPPÉ) and DISCOVER-AQ 2014 Regional Source Impact Analysis – Frank Flocke & Gabriele Pfister, NCAR

Comparison of Ozone Nonattainment Area Oil and Gas Inventories with Monitored Ambient VOC Precursors – Dale Wells, APCD

Discussion and Next Steps – RAQC Staff

2017 Source Apportionment Modeling Report Available

Posted Under: Modeling, Modeling, News Room - News, Ozone, Reports


As part of future ozone planning for the Denver Metro/North Front Range (DM/NFR) nonattainment area, the Regional Air Quality Council (RAQC) and Air Pollution Control Division (APCD) recently completed a report on ozone source apportionment modeling for the 2017 emissions year using the 2011 modeling database developed for the Moderate Area Ozone State Implementation Plan (SIP).  The report detailing this modeling effort is now available on the RAQC website (Denver/North Front Range Local Source 2017 Source Apportionment Modeling Using a 2011 Modeling Database).

In addition to the report, modeling results have been loaded into a Source Apportionment Visualization Tool (SA Vis Tool) that can be accessed through the Intermountain West Data Warehouse (IWDW).  Through this tool, users can isolate individuals monitors to see the source contributions on individual days and averaged over multiple days.

Beyond this modeling effort, the RAQC and APCD are also in the process of conducting sensitivity modeling that includes evaluation of:

  • 2023 future year modeling based on on-the-books reductions
  • Impact of both intrastate emissions controls outside Colorado and contributions of international emissions
  • Impact of broad Nitrogen Oxides (NOx) and/or Volatile Organic Compound (VOC) reductions at monitors in the DM/NFR nonattainment area

Upon completion of these sensitivity runs, the RAQC and APCD will be hosting a modeling forum to present results and discuss how the analyses play into future ozone planning efforts.

Please feel free to contact Amanda Brimmer, RAQC,  with any questions or comments.

Photochemical Dispersion Modeling Update

Posted Under: General Air Quality, Modeling, Ozone (8-Hour Standard), Presentations

Presented to the Regional Air Quality Council, April 8, 2016

Photochemical Dispersion Modeling Update, Ken Lloyd,RAQC and Dennis McNally, Alpine Geophysics