Regional Modeling for Stationary Source Control Strategy Evaluation

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Regional Modeling for Stationary Source Control
Strategy Evaluation

• WESTAR Conference on
• BART Guidelines and Trading
• September 1, 2005
• Tom Moore - mooret_at_cira.colostate.edu

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Presentation Topics

• Purpose is to gather input on regional modeling
  approach analysis steps
• Review selected materials from Evaluation of the
  CALPUFF Chemistry Algorithms, AWMA Annual
  Meeting, June 21-25, 2005, Ralph Morris, S. Lau
  B. Koo, ENVIRON International Corporation
• Suggest process and timing for preparation and
  completion of Regional Modeling Protocol by the
  WRAP Regional Modeling Center

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Challenges in Evaluating source-by-source BART as
a Control Strategy

• Just one control strategy option, addressing just
  one approach to regional haze, required for
  analysis in isolation of other measures
• Reasonable progress toward RHR goal of natural
  conditions by 2064 will need to consist of many
  control strategies for different visibility
  precursors (e.g., ozone, PM, FP, etc.)
• Natural visibility conditions, especially the
  effect of natural fire emissions, major component
  even for Worst 20 days
• Need to design evaluation of BART as a
  complement, a part of an integrated point source
  emission reduction program

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Regional Modeling Analysis

• When 2018 base case modeling analysis is
  completed in late 2005
• Shows how much reasonable progress is being made
  from federal mobile source programs and
  point/area rules on the books
• Then begin to evaluate WRAP region Point Source
  Control Scenarios
• RMC 2005-06 workplan task to address BART
• Can provide met data as needed by regulatory
  agencies
• Compile/coordinate results from individual agency
  analyses
• Develop regional modeling protocol to support
  evaluation of point source control strategy
  options

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Planning Emissions and Modeling Analysesfor the
Dont CAIR region

• First need to think through questions that need
  to be answered
• Need information about agencies plans
• Need to compile sufficiently complete information
  and/or agreement from regulatory agencies using
  source-specific BART analysis approach
• About estimates of emissions reductions
• About results from CALPUFF modeling
• Need information by very early 2006
• Agencies selecting reasonable progress option
  allows RMC to apply regional model to BART and
  other point sources

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Issues to be analyzed with modeling

• Class I Area AQ and AQRV Issues
• PSD Pollutants (PM10, SO2, NO2)
• Visibility
• Acid (S and N) Deposition
• Visibility is frequently the most limiting Class
  I Area AQ/AQRV issue in NSR/PSD permitting and is
  the issue associated with Regional Haze Rule
  (RHR) BART requirements
• Visibility impairment for such sources is
  primarily associated with secondary sulfate (SO4)
  and nitrate (NO3) fine particulate matter (PM2.5)

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Technical Assessment Options

• 3 Options
• Individual source assessment
• Cumulative assessment of all BART-eligible
  sources
• Assessment based on model plants

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EPAs Analysis Options

• Individual Source Assessment (source-by-source
  analysis)
• Use CALPUFF or other EPA approved model
• Compare to natural background
• Cause impact of 1.0 deciview or more
• Contribute 0.5 deciview (State may set lower
  threshold)
• Cumulative - Consider all eligible sources to be
  subject, based on an analysis of an areas
  contribution to visibility impairment -- or
  demonstrate that no sources are subject, based on
  cumulative modeling.
• Develop model plants to exempt sources with
  common characteristics
• BART Guidelines provide example model runs

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Using CALPUFF?

• Sulfur and nitrogen emissions from most sources
  will primarily be in the form of SO2 and NOX
• The SO2 and NOX emissions are converted to
  sulfate (SO4) and nitrate (NO3) in CALPUFF
• CALPUFF SO4 and NO3 estimates drive the
  visibility assessment
• Therefore the CALPUFF SO4 and NO3 chemical
  formation algorithms are critically important to
  the NSR/PSD and RHR BART process

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Using CALPUFF?

• EPA 2001 draft Guidance for Demonstrating
  Attainment of the Air Quality Goals for PM2.5 and
  Regional Haze
• States should use a regional scale photochemical
  grid model to estimate the effects if a control
  strategy on secondary components of PM. Changes
  in primary components may be estimated using a
  numerical grid model (with no chemistry), a
  Lagrangian model, or in some cases a receptor
  model (EPA, 2001, pg. 169)
• CALPUFF is a Lagrangian puff model that EPA FP
  modeling explicitly states should not be used for
  SO4 and NO3 impacts

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Using CALPUFF?

• Lack of temperature effects and 50F minimum
  temperature used in development will overstate
  sulfate and nitrate formation under cold
  conditions
• Enhanced photochemistry, radicals and sulfate and
  nitrate formation rates occurs on hot summer days
• MESOPUFF-II transformation rates developed using
  temperatures of 86, 68 and 50F
• Therefore, inappropriate for use below 50 F
• MEOSPUFF-II will overstate SO4 and NO3 formation
  results as temperatures below 50F (10C)

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Using CALPUFF?

• Previously evaluated CALPUFF MESOPUFF-II and
  RIVAD SO4 and NO3 formation rates against latest
  state-of-science chemistry modules developed by
  Carnegie Mellon University (CMU)
• Reported on at AWMA Specialty Conference on Air
  Quality Model Guidelines in Mystic, CT October
  2003
• SO4 and NO3 formation chemistry out of date and
  inaccurate
• Developed in 1983 Overly Simplistic Neglects
  Major Variables and Processes
• CALPUFF should not be used for SO4 and NO3
• Supported by EPA AQ guideline and FP Guidance
• Supported by chemical modeling community
• Likely overestimation bias for large NOx/SO2
  sources

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Can you evaluate CALPUFF Chemistry using
Real-World Data?

• Extensive PM measurement networks across US that
  measure real-world SO4 and NO3
• IMPROVE, CASTNet, STN, SEARCH
• CALPUFF typically applied to one or small group
  of sources inconsistent with measurements that
  are due to all sources
• Running CALPUFF with all sources become
  computationally prohibitive or must perform
  extensive source combination

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Evaluation of Single Source Impacts
Reduce SO2 and NOx emissions by 20 and 10 TPD,
respectively Compare maximum 24-hr visibility,
SO4 and NO3 impacts in rings around
source Compare CMAQ-LISBON w/ MESOPUFF-II and
RIVAD CALPUFF chemistry with CMAQ V4.4
9 source locations GA NY, OH, IL, TX, ND, WY,
AZ and OR
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Visibility comparisons (Mm-1) for January 2002
and 9 sources
large over-prediction using CALPUFF chemistry
algorithms compared to CMAQ chemistry gt 100 gt
1000
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Visibility comparisons (Mm-1) for July 2002 and 9
sources
CALPUFF chemistry algorithms generally smaller
compared to CMAQ chemistry gt 100 gt 1000
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Conclusions Evaluation of CALPUFF Chemistry

• SO4 and NO3 formation chemistry out of date and
  inaccurate
• Developed in 1983 Overly Simplistic
• Neglects Major Variables and Processes
• Greatly overstates SO4 and NO3 in winter
  resulting in overestimating visibility impacts by
  100 to 1000 in many cases
• Understates SO4 in summer, overstates NO3
• CALPUFF Nitrate (NO3) particularly inaccurate,
  overstated and unreliable

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Potential process for Regional Modeling Protocol

• Compile 2018 BART source likely emissions
  reductions data 9-12/05
• Compile source-specific BART modeling data
  9-12/05
• Same time - prepare master spreadsheet of
  individual BART sources
• Emissions (projected 2018 base case and PTE)
• Expected emissions reductions beyond current
  controls
• Other supporting data
• Run zero-out simulations of NH3 and VOC at BART
  sources using tagged emissions in regional model
  late 2005
• When spreadsheet complete as possible, compile
  regional BART emissions reductions EIs and
  tag those emissions in model to estimate change
  from applying BART
• Conduct other regional analyses of SO2 Annex
  (expansion), other alternative programs, etc.

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Comments/questions/next steps?