Baton Rouge 8-hr Ozone Modeling Technical Review Meeting

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Baton Rouge 8-hr Ozone ModelingTechnical Review
Meeting

• Presentation to the
• LDEQ/AQSD
• 8-hr Ozone SIP Coalition
• July 27, 2006

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Todays 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

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Todays Presentation

• Initial/boundary conditions
• Use of Probing Tools

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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

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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

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Conceptual Model
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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

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Conceptual Model
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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 80s F
• Emissions-driven, not heat-driven
• Few prolonged hot summer episodes
• Excessive PBL venting or Gulf breeze? Recent
  interannual climate?

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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

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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

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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)

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Episode Analyses

• Comparison to CART analysis
• Bin 10 (22)
• Bin 20 (24)
• Bin 25 (33)
• Bin 27 (10)
• Bin 35 (11)

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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

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Episode Analyses
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Episode Analyses
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Episode Analyses
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Episode Analyses
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Episode Analyses
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Episode Analyses
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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

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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

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Domain Configuration
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Domain Configuration
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Domain Configuration
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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?

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Emission Inventories

• 2000-2005 LDEQ data, as available
• Stationary point, area
• On-road VMT, MOBILE6
• Non-road NONROAD

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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