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Baton Rouge 8-hr Ozone Modeling Technical Review Meeting

Baton Rouge 8-hr Ozone Modeling Technical Review Meeting . Presentation to the LDEQ/AQSD & 8-hr Ozone SIP Coalition July 27, 2006. Today’s Presentation. Conceptual Model of 8-hr Ozone Episode Analysis Modeling System Modeling Domain Emission Inventory Development Area & Point Sources

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Baton Rouge 8-hr Ozone Modeling Technical Review Meeting

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  1. Baton Rouge 8-hr Ozone ModelingTechnical Review Meeting Presentation to the LDEQ/AQSD & 8-hr Ozone SIP Coalition July 27, 2006

  2. Today’s Presentation • Conceptual Model of 8-hr Ozone • Episode Analysis • Modeling System • Modeling Domain • Emission Inventory Development • Area & Point Sources • Motor Vehicles (on-road & off-road) • Biogenics & Fires

  3. Today’s Presentation • Initial/boundary conditions • Use of Probing Tools

  4. Conceptual Model • Baton Rouge is a Marginal 8-hr Ozone nonattainment area • Single 2003 exceedance DV: • LSU = 86 ppb • Four 2005 exceedance DVs: • LSU = 96 ppb • 2006 exceedances: • Will not attain standard by June 2007 as required

  5. Conceptual Model • Likely “bump-up” to Moderate area • Attainment date: June 2010 • Spatial distribution • Four key exceedance monitors • LSU, Baker, Carville, Port Allen • Aligned south-to-north along river • Other monitors mostly outside & south of Baton Rouge • Likely interaction between urban, industrial, and biogenic emissions

  6. Conceptual Model

  7. Conceptual Model • Temporal distribution • Diurnal: classic 12 – 4 PM peaks • Evidence of ozone cloud transport site to site • No obvious late AM ROFEs or THOEs • Possible early PM ROFEs or THOEs • Weekly: no clear-cut weekday/weekend dependencies – more analysis needed • Seasonal: trends toward late spring, early fall multi-day, multi-site episodes • In last few years, mid-summer episodes are typically 1-day, few sites

  8. Conceptual Model

  9. Conceptual Model • Weather requirements • Stagnation, light/variable winds under high pressure • Exceedances independent of wind direction • Clear skies • Temperatures do not need to be hot • Many exceedances in low 80’s F • Emissions-driven, not heat-driven • Few prolonged hot summer episodes • Excessive PBL venting or Gulf breeze? Recent interannual climate?

  10. Conceptual Model • Regional transport • Needs 2-3 day transport times • Recent summer episodes are too short • Some multi-day episodes are clearly caused by local stagnation, re-circulation • Some multi-day episodes establish consistent transport corridors from midwest, Ohio Valley, south-east U.S. • Choose episodes that represent mix of conditions • Season, meteorology, transport, WE/WD

  11. Episode Analyses • Screened 14 episodes from 2000-2004 • 2005 de-emphasized • Concern about availability of emissions data • Reduced to 6 candidates • Max exceedance monitor-days at 4 key monitors • Min number of modeling days • Different times of year • Recent episodes

  12. Episode Analyses • 6 candidates • May 19-30, 2003 (M, Sa, W, Th) • September 28-30, 2004 (W, Th) • April 12-30, 2003 (Su, M, F, Su, M, Tu) • October 4-6, 2003 (Sa, Su) • May 4-9, 2004 (Tu, W, Th, Sa) • August 11 – September 5, 2000 (F, Su, Th, F, Sa, Su, M, F, Sa, W, Th, F, Sa, Su)

  13. Episode Analyses • Comparison to CART analysis • Bin 10 (22%) • Bin 20 (24%) • Bin 25 (33%) • Bin 27 (10%) • Bin 35 (11%)

  14. Episode Analyses • Final 2-3 episodes need to be selected from 6 candidates • Input from advisory group • Consider schedule, resources, and pre-existing datasets • July 31 draft Protocol documents conceptual model for each of 6 episodes

  15. Episode Analyses

  16. Episode Analyses

  17. Episode Analyses

  18. Episode Analyses

  19. Episode Analyses

  20. Episode Analyses

  21. Modeling System • MM5 – Meteorological Model • Widely used to support regulatory modeling • EPS3 – Emissions Processor • LDEQ is familiar with EPS • CAMx – Air Quality Model • Widely used to support regulatory modeling in south-central U.S. • Full Chemistry PiG allows evaluation of HRVOC plumes

  22. Domain Configuration • Regional grid (36 km) based on TCEQ • Intermediate grid (12 km) captures transport from Midwest and Southeast • Local grid (4 km) along Gulf Coast, including Houston • Vertical grid based on St. Louis modeling

  23. Domain Configuration

  24. Domain Configuration

  25. Domain Configuration

  26. Emission Inventories • Start-point inventories: • 2002 CENRAP Base B • 2002 VISTAS Base G • 2002 MRPO Base K • TCEQ inventories and other datasets • Useful for August/September 2000 episode • Replace CENRAP data for Texas when available for other years?

  27. Emission Inventories • 2000-2005 LDEQ data, as available • Stationary point, area • On-road: VMT, MOBILE6 • Non-road: NONROAD

  28. Emission Inventories • Inventory projections • Specific modeling years (2000-2004, 2009) • Regional: based on RPOs, EPA, and TCEQ • Local: future year projections are challenging due to recent events • EGU and other large sources: • Use CEM as available for base case model performance evaluation • Use “typical” inventory rates for projected base and future years

  29. Emission Inventories • Biogenics from GloBEIS • All grids, episode-day specific • Driven by: • MM5 and/or temperature observations • Satellite PAR data • Land cover/biomass data (GIS, etc.) • Held constant into 2009 future year • Fires (wild, agricultural, prescribed) • As needed, as available

  30. Initial/Boundary Conditions • Only needed on 36-km grid • Use 2002 VISTAS model output fields • Derive monthly-average diurnally-varying IC/BCs for base case episodes • Use 2009 VISTAS model output fields • If available, as described above • Otherwise, use 2002 fields

  31. CAMx Probing Tools • Ozone Source Apportionment Technology (OSAT) • Determines source area/category contribution to ozone anywhere in the domain • Tracks NOx and VOC precursor emissions, ozone production/destruction, and initial/boundary conditions • Estimates ozone production uner NOx- or VOC limited conditions

  32. CAMx Probing Tools • OSAT • HOWEVER: it cannot quantify ozone response to NOx or VOC controls • Chemical allocation methodologies: • OSAT: standard approach • APCA: attributes ozone production to anthropogenic (controllable) sources only • GOAT: tracks ozone based on where it formed, not where precursors were emitted

  33. CAMx Probing Tools • PM Source Apportionment Technology (PSAT) • Parallel to OSAT operation • Tracks user-defined groups of species for sulfate, nitrate, ammonium, SOA, Mercury, and primary PM

  34. CAMx Probing Tools • Decoupled Direct Method (DDM) for sensitivity analysis • Calculates first-order concentration sensitivity to emissions, initial/boundary conditions • Allows estimates of effects of emission changes • Allows ranking of source region/ categories by their importance to ozone formation

  35. CAMx Probing Tools • DDM • Slower than OSAT, but: • Provides information for all species (not just ozone) • More flexible in selecting which parameters to track • Better estimate of small emission perturbation impacts (e.g., control measures) • Includes sensitivity from non-linear secondary effects

  36. CAMx Probing Tools • Process Analysis (PA) • Designed to provide in-depth analyses of all physical and chemical processes operating in model • Operates on user-defined species and any portion of the modeling grid • Appropriate for evaluating base case performance • Recent UNC enhancements

  37. CAMx Probing Tools • PA • Three components: • Integrated Process Rate (IPR): provides detailed process rate information for each physical process (emissions, advection, diffusion, chemistry, deposition) • Integrated Reaction Rate (IRR): provides detailed reaction rate information for all chemical reactions • Chemical Process Analysis (CPA): like IRR, but designed to be more user-friendly and accessible

  38. CAMx Probing Tools • Reactive Tracers (RTRAC) • Tracks multiple independent reactive gas and particle tracers • Tracers operate in parallel to the CAMx host model • Allows for several generations of products • Decay/production uses standard gas-phase mechanism photolysis and oxidants • Can output tracer decay rates to a separate Lagrangian model for “fenceline” dispersion calculations

  39. CAMx Probing Tools • RTRAC • Designed for primarily for air toxics • Assumes RTRAC species have minimal impact on photochemistry • Each tracer can be “tagged” for source apportionment • RTRAC works with IRON PIG • An optional “sampling grid” capability passively samples near-source sub-grid RTRAC surface concentrations within reactive PiG plumes

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