The What, Where, When and Why of Wintertime Ozone Formation –

Results of the 2009 Wyoming Ozone Technical Forum

Robert A. Baxter, CCMDavid Bush T&B Systems, Inc.

Cara KeslarKen RairighJan Lydigsen Wyoming Department of Environmental Quality

2010 National Air Quality Conferences March 15 - 18, 2010

Overview

• An Ozone Forum in Wyoming?!?

• 2009 Technical Forum content– Day 1 – Meteorological and air quality measurements

and analysis

– Day 2 – Meteorological and air quality modeling

• Summary of recommendations

• Where to go from here

• Acknowledgements

An Ozone Forum in Wyoming?!?

CONVENTIONAL WISDOMOzone is considered to be produced photo-chemically at levels above health based standards only in Urban areas in the Summer

PROBLEMIn February-March 2005 hourly ozone concentrations greater than 120 ppb were recorded at monitoring stations in the Upper Green River Basin

Seen again in 2006, 2008, & 2009

Expected Here But Not Here!

Molenar

An Ozone Forum in Wyoming?!?

Monthly Max 8-Hour O3 January 2005 – March 2009

Stoeckenius

An Ozone Forum in Wyoming?!?2005 Elevated ozone recorded - Recognition of the problem

2006 Additional elevated ozone

– Initial workshop on potential causes and planning

– Multiple community forums and presentations

2007 Contracted first Upper Green River Wintertime Ozone Study – UGWOS 2007

– Lack of snow and no elevated ozone episodes

– Learned enough for planning future years

2008 UGWOS 2008

– Significant elevated ozone observed

– Documented spatial scale of problem and developed conceptual model

2009 UGWOS 2009

– Focused on additional chemistry

– Improved mesonet monitoring coverage and communications

The 2009 Ozone Technical Forum

• Held in Cheyenne during a snow storm on December 8 and 9

• Sponsored and coordinated by the Air Quality Division (AQD) of the Wyoming Department of Environmental Quality (WDEQ)

• Participants– Agencies (36)

– Industry (19)

– Academia (7)

– Private Consulting (28)

Ozone Technical Forum Content

• Two day intensive presentation and interaction – December 2009

• Day 1 – Meteorological and air quality measurements and analysis

• Day 2 – Meteorological and air quality modeling

Day 1

• Presentations from past and ongoing research– Air Chemistry– Meteorology– Air Toxics– Analysis

• Breakout into focused groups– Meteorology– Air Quality– Emissions

• Regrouping and summary

Air Chemistry

Montague

Jenkin & Clemitshaw, Atmos. Environ., 2000

Air Chemistry

Montague

UGWOS - Meteorology

Baxter

UGWOS - Meteorology

Baxter

UGWOS – Snow and UV Radiation

Stoeckenius

UGWOS – Snow and UV Radiation

Molenar

UGWOS – Spatial Monitoring

Bush

UGWOS – Spatial Monitoring

Bush

UGWOS – Precursors

Kirk

Breakout Discussion - Meteorology

1. What changes to the surface measurement network may be needed to provide a better representation of the surface winds for input in the wind field models?

2. What additional continuous upper air measurements are needed to properly characterize the spatial variability of the meteorology?

3. What is the size of network needed and how far outside the current study area should those measurements extend?

4. For any additional measurements that are needed, are they discrete and only needed during a short term intensive period, or should they be made continuously as part of a routine network?

Breakout Discussion – Air Quality

1. What additional precursor measurements are needed to fill in the measurement inventory for modeling?  What is the needed spatial and temporal distribution of these measurements?

2. Given the difference between surface and aloft emissions, What additional precursor measurements are needed spatially and temporally aloft?

3. Is the existing UGWOS spatial distribution of ozone measurements adequate? 

4. What additional vertical measurements of ozone may be needed?  How might these measurements be made on a routine basis (aircraft, tall tower, remote sensing, etc.)?

5. Are there any other chemical process that are taking place that could generate ozone that are not being addressed by the measurements being made?

Breakout Discussion - Emissions

1. Is our current level of understanding of emission activities adequate?  What can be done to improve our understanding?

2. Are there significant emission sources that may not be well understood? What is the difficulty in understanding such sources?

3. To what spatial extent around the study area is the inventory of sources needed?  What is the role of emissions from sources well outside of the current study region?

Day 2

• Presentations from past and ongoing modeling efforts– Conceptual model– Box Model– CALMET/CALGRID

• Panel discussions

Modeling & Analysis – History

Rairigh

Conceptual and Box Models

Stoeckenius

Conceptual and Box Model

Stoeckenius

Modeling & Analysis – CALMET

Reed

Modeling Panel Discussions

• Ozone Formation Chemistry• Meteorology• Transport / Dispersion Issues and

Boundary Condition Issues

Panel Discussion – Ozone Formation Chemistry

1. What are the optimum VOC/NOx ratios for winter ozone formation and how do they compare to observations and emission inventories?

2. Can indicator ratios and observation based methods be used to evaluate model performance, and what additional ambient monitoring data are needed?

3. If more refined atmospheric chemistry algorithms are recommended, which photochemical grid models (PGMs)/chemistry schemes are capable of replicating these reactions?

4. What adjustments might be considered regarding reaction rates and other temperature-dependent inputs to the models to realistically simulate winter ozone formation?

Panel Discussion – Meteorology

1. What are the pros and cons of existing prognostic and diagnostic meteorological models for replicating key meteorological conditions?

2. Do we need to be thinking about other considerations?

Panel Discussion – Transport / Dispersion & Boundary Conditions

1. What are the pros and cons of existing photochemical grid models (PGM) with regard to being able to simulate near-field dispersion processes and chemical interactions on a local-scale?

2. Are other investigations necessary to provide additional information regarding boundary conditions during high ozone events?

3. Is it necessary to use a very fine grid (e.g., < 1 km) or plume-in-grid treatments to adequately characterize transport/dispersion of local sources?

4. What grid extent is needed for a PGM to most effectively provide boundary conditions for winter-time ozone events in the UGRB?

Post Workshop Compilations

• Summaries for session moderators– Measurement and analysis– Modeling

• Questionnaires from attendees on the value of the workshop

• Ranking of importance to address specific research topics

Summary of Recommendations

• Emission Inventory - Improve Quantification– Formaldehyde– VOC Speciation– Mobile Sources

• Ambient Monitoring– Vertical Profile– Speciated VOCs, unknowns– PM Speciation– Background

• Meteorological Monitoring– Historical review of snow depth and meteorology– Vertical profile

• Ambient Air Model Development– Incorporate emission inventory recommendations from

the Tech Forum into the model– Evaluate CALGRID Model performance– Decision Point: Will this model work to predict ozone

formation in the UGRB?

Summary of Recommendations

Where to go from here

• AQD will issue decision document – Prioritize recommendations based on the ultimate goal of

making a working model • AQD will evaluate recommendations along with

available budget • Items that aren’t funded will be available for

industry to use as “supplemental environmental projects”

• Follow-up meeting in Fall 2010 to update the progress

Acknowledgements

• All included figures are from the Ozone Forum, referenced by presenter

• Presentations available at:http://deq.state.wy.us/aqd/Ozone%20Technical%20Forum.asp

Acknowledgements

Giving credit where credit is due . . .

Significant efforts have been expended by the Wyoming DEQ and its contractors in the planning and implementation of the UGWOS studies, collecting field data in an extremely challenging environment. Their efforts have resulted in a clear understanding of the unique processes behind the ozone production in this environment. In addition, third parties have acquired the data and published similar results, disseminating findings to the greater public.

Acknowledgements

• Air Resource Specialists

• Environ

• Environmental Analytical Service

• Intermountain Laboratories

• Meteorological Solutions

• Sonoma Technology

• T&B Systems

• UC Riverside

• University of Wyoming

• Wyoming DEQ

UGWOS Monitoring and Analysis

Acknowledgements

• Environ

• TRC

DEQ-contracted Modeling

Acknowledgements

• NOAA

• WRAP

• Argonne National Laboratory

• Houston Advanced Research Center

• California Institute of Technology

• Funding Sources: Jonah Interagency Office, Wyoming DEQ, Petroleum Association of Wyoming

Additional Participation

The What, Where, When and Why of Wintertime Ozone Formation –

Results of the 2009 Wyoming Ozone Technical Forum

Robert A. Baxter, CCMDavid Bush T&B Systems, Inc.

Cara KeslarKen RairighJan Lydigsen Wyoming Department of Environmental Quality

2010 National Air Quality Conferences March 15 - 18, 2010