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) –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 –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

Transport 1-hr Standard 8-hr Standard Daytime Night-time Urban-to-Regional Regional-to-Continental

Chemistry 1-hr Standard 8-hr Standard Highly 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, NO y ) Research Focus: –Nocturnal meteorology and transport –Nocturnal chemistry –Export of pollution from Houston to E. Texas

Summary Meteorology –Conceptual model development –Testing model innovations during TexAQS II Transport –Regional modeling and source apportionment –Tetroon campaign to track regional air flow Chemistry –Chemical measurements on tower/aircraft –Expanded model chemical mechanism