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Modeling Compliance with the 8-Hour Standard. Jay Olaguer Houston Advanced Research Center 10/06/04. Texas Environmental Research Consortium. TERC is a consortium of stakeholders: Local government agencies (City of Houston, HGB and DFW counties) Environmentalists (ED, GHASP) - PowerPoint PPT Presentation
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Texas Environmental Research Consortium
• TERC is a consortium of stakeholders:– Local government agencies (City of Houston, HGB
and DFW counties)– Environmentalists (ED, GHASP)– Business and Industry (GHP, Dallas C of C).
• TERC’s mission:– Fund research to improve ozone science and air
modeling in East Texas– $5 million from TX Legislature for 2004-2005– Collaboration with TCEQ in identifying research
Basic Problem
• How to model attainment of 8-hr standard?
• Transport yields background up to 80 ppb
• Current AQ models used for SIPs are barely sufficient for 1-hr, let alone 8-hr
• Selection of appropriate episode(s) not straightforward (Full ozone season?)
• Need much more observational data to evaluate model performance
Meteorology
1-hr Standard 8-hr Standard
Boundary Layer Free Troposphere
(0-3 km) (3-16 km)
Horizontal Flow Vertical Motion
Chemistry
1-hr Standard 8-hr StandardHighly Reactive Moderately Reactive VOCs (e.g., ethylene) VOCs (e.g., n-butane)Rapid Ozone Long-Lived Products Formation (e.g., PAN, acetone)
8-Hr Conceptual Model
• Explain high background ozone in E. TX
• Explain local 8-hour exceedances in: HGBPA, DFW, NE TX EAC areas.
• Information sources: surface monitors, previous conceptual models, trajectory analyses, forecast modeling (NCAR)
• Statistical and physical model analysis to get a mental picture of causal mechanism
Transport from Out-of-State
• Examine transport impact of out-of-state sources on E. Texas regions
• Apportion source region/type contributions for various meteorological episodes:– Aug 1999 DFW episode– Sep 1999 Austin/San Antonio episode– Aug/Sep 2000 HGB episode
• Sensitivity to height of air column in model
Best Practice for Modeling 8-Hr Ozone in Context of TexAQS II
• Real-time trajectory and grid modeling for forecasting/adaptive observation planning
• Testing of modeling innovations: – Observational data assimilation – Expanded chemical mechanism– Source attribution methods
• Development of regional model for 8-hour SIP applications
Summer 2005 Tetroon Campaign
• Constant altitude balloons to track air flow
• Tower and/or chase aircraft chemical measurements (ozone, VOCs, NOy)
• Research Focus:– Nocturnal meteorology and transport– Nocturnal chemistry– Export of pollution from Houston to E. Texas