Transboundary ManMade Impacts at Class I Areas

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Transboundary Man-Made Impacts at Class I Areas

• Jim Boylan
• Georgia Department of Natural Resources
• VISTAS Joint Work Group MeetingRaleigh,
  NCSeptember 7, 2006

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GEOS-CHEM Simulations

• Harvard performed three GEOS-CHEM runs
• Run 1 Basecase with all emissions (MPE BCs)
• Run 2 Sensitivity with no U.S. anthropogenic
  emissions
• Run 3 Sensitivity with no global anthropogenic
  emissions (natural conditions)
• Transboundary Man-Made Impacts at Class I Areas
  calculated by (Conc. from Run 2) (Conc.
  from Run 3)
• Modeling performed for VISTAS and EPRI

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GEOS-CHEM Simulations

• VISTAS Runs (GEOS_4x5)
• 4 x 5 Grid Resolution
• 2002 Meteorology
• 2002 Biomass burning emissions inventory
• Original EPRI Runs
• 1 x 1 Grid Resolution
• 2001 Meteorology
• 2001 Biomass burning emissions inventory
• Revised EPRI Runs (GEOS_1x1)
• Canadian emissions reduced by 30
• New 1 x 1 grid definition better distinguishes
  U.S. and Canadian emissions

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Updated 1 x 1 GEOS-CHEM Grid
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CENRAP PSAT Modeling

• Environ performed CAMx PSAT simulation on the
  CONUS 36 km grid
• Canadian Emissions
• Mexican Emissions
• Boundary Conditions
• Transboundary Impacts (Man-Made Natural) at
  each Class I Areas calculated by summing impacts
• Canadian Impact Mexican Impact Boundary
  Conditions Impact
• More details in Ralphs ppt (next)

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VISTAS CMAQ Modeling

• UCR performed two annual CMAQ simulation on the
  CONUS 36 km grid
• Run 1 Basecase with all emissions
• 2018 OTW BaseF Emissions
• 36 km BCs from GEOS-CHEM to account for transport
  from outside North America
• Run 2 Sensitivity with clean BCs and Mexican
  and Canadian anthropogenic emissions removed.
• Assume all fires outside U.S. are natural
• Transboundary Man-Made Impacts at each Class I
  Areas calculated by (Conc. from Run 1)
  (Conc. from Run 2)

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CENRAP and VISTAS 36 km Grid
VISTAS 12 km Grid
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Mexico and Canada SO2 (July)
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Impact on Sulfate (July)
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Mexico and Canada NOx (Nov.)
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Impact on Nitrate (Nov.)
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Sulfate at MACA
-- Modeled 2018 Concentration (all emissions) --
Contribution from Mexico, Canada, and BCs
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Nitrate at MACA
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Organic Carbon at MACA
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Elem. Carbon at MACA
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Soils at MACA
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Coarse Mass at MACA
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Annual Average at MACA
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Ammonium Sulfate
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Ammonium Nitrate
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Organic Carbon Mass
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Elemental Carbon
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Dry Light Extinction (GEOS_1x1)
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Dry Light Extinction (PSAT)
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Dry Light Extinction (CMAQ)
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Dry Light Extinction (CMAQ)
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Nitrate at MACA
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MACA - January
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MACA - April
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MACA - October
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MACA - November
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MACA - December
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VISTAS Summary

• Sulfate (EPA default 0.23 mg/m3)
• Fairly consistent between models
• Ranges from 0.3 0.7 mg/m3
• Nitrate (EPA default 0.10 mg/m3)
• PSAT and CMAQ much higher than GEOS (10x)
• PSAT ranges from 0.05 0.3 mg/m3
• CMAQ ranges from 0.1 0.6 mg/m3
• Poor Model Performance ? over predictions
• Organic Carbon (EPA default 1.4 mg/m3)
• CMAQ, PSAT, and GEOS range from 0.05 0.15 mg/m3
  
• Many already be included in natural background
  value
• Elemental Carbon (EPA default 0.2 mg/m3)
• CMAQ and GEOS consistent (0.015 mg/m3)
• PSAT is about double (International Fires?)

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Add bext Impact to End Point
add 10 Mm-1
Option 1 Add International Transport (e.g., 10
Mm-1) to Natural Conditions and redraw Glide
Path ? not allowed by EPA
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Subtract bext Impact in 2018
subtract 10 Mm-1
2018 Projection (minus bext)
Option 2 Subtract International Transport (e.g.,
10 Mm-1) from 2018 projections
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Subtract bext Impact Each 10 Years
subtract 10 Mm-1
subtract 10 Mm-1
subtract 10 Mm-1
subtract 10 Mm-1
subtract 10 Mm-1
subtract 10 Mm-1
2018 Projection (minus bext)
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Comparison of Methods
2018 Projection (minus bext)
Nearly Identical Results between Option 1 and
Option 2
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Questions?