November 06, 2003

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Houston Area Ozone Air Quality
Overview of Tools , Techniques , Communications
and Improvements to Better Understand Ozone
November 06, 2003 Doug Deason ExxonMobil
Chemical Engineering and Manufacturing Support
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Agenda items
PROPRIETARY

• Tools/techniques being used to analyze
  exceedances and VOC data
• Use of back trajectory analysis
• New / improved tools for meteorology measurement
• Ozone Action Days Forecast Warning systems
• Modeling to simulate ozone spikes
• Improvements to Emission Reporting
• New Regulations in the works?
• Industry TCEQ cooperation including specific
  projects
• Upcoming relevant Technical Seminars in TX

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Tools/techniques being used

• Measurements and Methods
• Extensive monitoring locations
• Monitors with ozone , NOx speciated VOC
• Map follows
• Owned by City of Houston , TCEQ , and Houston
  Regional Monitoring (HRM)
• SSM Emission Event Reporting analysis
• On the web reporting of SSM Emission Events
  since early 2003
• Episode Specific Data
• TCEQ Monitoring Operations Group for selected
  episodes
• HRM publishes summary information for all ozone
  exceedances
• Special analyses by TCEQ Industry for selected
  exceedances
• Examples follow

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(No Transcript)
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Ozone Action Days Forecast System

• Ozone Forecast - Ozone Conducive Meteorology
  triggers
• Accuracy 1994-2002 is 83.
• Key forecast criteria include
• Wind speed between 10a.m.-4p.m. lt7 mph
• Temperature above 74 degrees F
• Satellite pictures indicate low cloud cover
• Day before estimate of incoming regional ozone
• TCEQ Monitoring Operations Owns

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Ozone Warning System

• Ozone Warning
• Initiated in 2000 to issue warnings to the public
  based on measured levels of ozone
• Initial warning system specifically targets high
  ozone levels in the Houston-Galveston-Brazoria,
  Dallas-Fort Worth, and San Antonio areas
• Measured high 1 hour ozone triggers
• Orange 125 ppb ozone
• Red 165 ppb ozone
• Purple 205 ppb ozone
• TCEQ Tools are non-proprietary and data is
  available from National Weather Service others
• TCEQ Monitoring Operations Owns

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Ozone Episode Followup

• HRM Members receive compilation of data for each
  ozone exceedance episode
• Tabulation of key data for each monitor that
  exceeded
• Summary data (Example attached)
• Back trajectory plots
• NOAA Satellite Image NOAA NWS Forecast of
  Fronts , Pressure, and Weather
• Exploring improving shared analysis tools to
  better automate data visualization and facilitate
  analysis.
• Exploring improved to do specific event analysis

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Ozone Episode Followup

• TCEQ Monitoring Operations posts data for
  selected Ozone Episodes
• Ozone Maximum One-Hour Clock Averages
• Ozone Maximum One-Hour Running Averages
• Ozone Maximum Eight-Hour Running Averages
• Ozone Graph of Five-Minute Data for the Day
• Ozone Graph of Peaks
• Ozone Graph of Net Ozone Production
• Ozone Animation
• Plume Animation
• Plume Animation - Regional
• Satellite Image Houston - True Color
• Satellite Image Texas - True Color
• Satellite Animation - GOES12

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Modeling to simulate ozone spikes

• Urban Airshed Model
• Grid size and coarseness of emissions
  representation inhibit ability to replicate ozone
  spikes
• Cant generate enough ozone
• Box Model
• Lack of all dynamic physical processes produces
  too much ozone in a static box
• Developmental work underway at Univ. of Texas
  Univ. of North Carolina is attempting to
  iteratively couple these two models to better
  simulate ozone spikes

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Industry TCEQ cooperation
PROPRIETARY

• Specific Projects
• 2001-Emission Inventory Verification project
• Is the annual inventory submission being done
  well with existing tools?
• Voluntary Episodic Release Reduction Initiative
• Integrated Science Committee
• Jointly identify key research projects to fund
• Emission Inventory
• HRVOC Inventory Source Analysis (to determine
  source focus)
• Emission Point Type Classification Improvement
• For 2000 Episode Modeling
• For improving future annual submissions
• Shared monitoring (HRM results provided to TCEQ)

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Improvements to Emission Reporting

• Annual data reported and used for modeling with
  supplemental special inventory for modeling
  episode
• Areas for improvement include
• More speciation of VOCs
• Better classification of Emission Point Types to
  correspond to regulated equipment types
• Improved monitoring for major sources of HRVOC
  emissions
• Major HRVOC Emission Sources in the Houston area
  are
• Fugitives 48 Routine 17 SSM Emission Events
• Flares 30 Routine 73 SSM Emission Events
• Cooling Towers 7 routine 10 SSM and Emission
  Events
• Polymer Vents 8 routine 0 SSM and Emission
  Events

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New Regulations in the works?

• Lowered HRVOC Reportable Quantities to 100 in
  9/2001
• Improving Monitoring for Flares Cooling Towers
  by YE05
• Flare Metering Composition Analysis in place
• Continuous cooling tower leak detection/speciation
  
• Improving Fugitives Monitoring 1H2004
• Adds new components to periodic Method 21
  monitoring
• Mid Course Review 1-hour SIP Update - 2004
• Will address Account Cap Emission Limits for
  HRVOC
• Sources include Flares , Vents , Cooling Towers
• New Emission Limits become Effective in 2006
• HGA SIP Revision in 2004

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Choosing a Focus

• Significant data and analysis has lead Houston to
  Focus on specific substances , emission sources
  , and types of emissions
• Analysis of 2000 TEXAQS Data
• Led to understanding of significance of HRVOC
• Emission Inventory Analysis to identify key
  sources
• Led to focus on fugitives , flares , cooling
  towers , and vents
• Understanding of Emission Rate Variability
• Led to focus on understanding reducing
  emissions from SSM Emission Events

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TEXAQS Texas Air Quality Study2000

• A 20 million one month air quality sampling
  study was done in August and Sept. 2000
• Some of the slides that follow hilight some of
  the preliminary science observations, findings,
  learnings, and questions
• These data and learnings were unavailable for the
  Dec. 2000 SIP
• Data processing and learning are ongoing

TEXAQS
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TxAQS Preliminary Results

• Ozone appears to be produced more efficiently by
  ship channel emissions than from urban area
  emissions
• Ship Channel yield more than twice the urban
  yield
• 12 - 15 molecules of ozone produced per molecule
  of NOx
• Highest yield the investigators have seen so far
• The rate of ozone formation from industrial
  emissions in the HG area is faster than observed
  in other areas of the US
• Production rates 50 to 100 ppb /hour observed at
  both surface monitors and aircraft measurements

Ozone yield
Reactivity
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Focus on Highly Reactive VOC Control

• Focus on key compounds and emission type
• Ethylene, propylene, and butadiene have high
  reactivity and very high yield
• Houston has a unique high density of industrial
  sources of these compounds
• Houston has many episodic releases of these high
  reactivity and high yield compounds

Ozone Forming Potential - Incremental Ozone Yield
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Can Upset Releases Be Significant?

• A few key points
• Short term releases of very Highly Reactive /
  High Yield VOC can result in rapid and high
  levels of ozone formation (THOEs) over a very
  localized area (which can be carried by air
  elsewhere).
• Large releases of less reactive or lower yield
  VOCs can additively increase typical ozone
• In the Houston area , both types occur

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Are Upset Releases Significant?
TEXAQS
Upset or other episodic emissions may have caused
or contributed to ozone NAAQS exceedances on
perhaps 6 to 10, of 21 spike exceedance days in
2000
Reflects short term concentration elevation
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Conclusion

• Keys to Houston progress include
• TCEQ and Industrial collaboration to identify
  potential problems and develop solutions.
• New science was a key eye-opener (TEXAQS)
• Willingness to question what we thought we knew
• Open communications
• Trust building over time
• Focused objectives (cant work on everything at
  once)

TEXAQS