Fine scale air quality modeling using dispersion and CMAQ modeling approaches: An example application in Wilmington, DE

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Fine scale air quality modeling using dispersion
and CMAQ modeling approaches An example
application in Wilmington, DE

• Jason Ching
• NOAA/ARL/ASMD
• RTP, NC
• Ching.jason_at_epa.gov

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Collaborators

• Mohammed A Majeed
• Delaware Department of Natural Resources and
  Environmental Conservation
• New Castle, DE
• Vlad Isakov
• Atmospheric Sciences Modeling Division, NOAA
  RTP, NC
• Andrey Khlystov
• Duke University,
• Durham, NC

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Outline of Presentation

• Background and Rationale of investigation
• Conceptual Hybrid modeling approach
• Description and role of EDATAS database to fine
  scale air toxic modeling
• Future Plans

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Example of regional and local model results
Hybrid approach (CMAQ with local scale modeling)
4 km CMAQ only
CMAQ and Hybrid results for Philadelphia study
reflecting enhanced details to CMAQ from
incorporating local scale modeling with the
hybrid approach
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• Hybrid approach provides a means for introducing
  fine scale concentration detail to regional scale
  model simulations
• This approach needs to be evaluated
• A collaboration of opportunity!
• Field study monitoring program, EDATAS, Enhanced
  Delaware Air Toxics Assessment Study focus on
  Wilmington, DE
• Concurrent investigations to characterize fine
  scale fields of air toxics and PM
• Continue investigations toward advancing the
  development of advanced air quality modeling
  tools for air toxics and other applications.

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• A rich database of air toxics measurements to
  provide
• Better understanding of the micro-level air
  quality impacts of emission sources.
• (2) Enhanced spatial resolution of the ambient
  toxics dataset throughout city and variability at
  spatial scales of order 100m by mobile
  measurements
• (3) Means to evaluate our hybrid approach

Measurements of Ozone, HCHO, Cr(VI), fine
particles
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Grids for concentration distribution at
neighborhood scales
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Neighborhood scale variability of
formaldehyde(summer 2005)

• The X-axis shows the concentration of HCHO in
  ?mol/m3
• The Y-axis shows the number of observations.

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COMMENTS on EDATAS

• The EDATAS database of toxics (including HCHO and
  Cr(VI) measurements using mobile van transects
  provide a unique, albeit limited bases for
  characterizing air toxics at neighborhood scales.
• Future efforts will focus on utilizing such data
  for evaluating and assessing advanced air toxics
  modeling such as hybrid modeling approaches.
  

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Fine scale model investigations for Wilmington, DE

• Modeling is the only tool that provides a link
  between sources and ambient concentrations
• Modeling at fine scales need evaluation. EDATAS
  will be used for this purpose.
• Model ready detailed emission inventory has been
  prepared, including road-linked emissions data.
• Air toxics version of CMAQ to be run in nested
  mode to 1 km grid size
• Local scale modeling (using AERMOD) applied to
  local emission sources, thus providing sub grid
  information to CMAQ at 4 km or greater
• Preliminary results follow Example simulation is
  for a July, 2001 average.

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Example Regional to fine scale using Nested grid
CMAQ (benzene)
Aurban Burban Crural
A B
C
(A) 12 km
(B) 4 km
(C) 1 km
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Example of Time Series for HCHO CMAQ (12km)
95th percentile from the 12x12 distribution
(based on 1 km grid CMAQ results Grid cell A
Urban (see previous slide)
0 2 4 6 8
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HCHO Concentration (ppb)
Jul 1 4 8 12 16
20 24 28 Aug 1
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Example of local contributions of HCHO using
AERMOD. Information to be used with CMAQ as
needed for the hybrid approach
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Next steps

• Implement the hybrid approach by incorporating
  local scale with CMAQ modeling
• Evaluate and assess both such outputs with EDATAS
  database (of mobile measurements)
• Perform additional CMAQ modeling at 1 km grid
  size to investigate fine scale resolution of
  combined regional and local scale contributions
  to investigate the characteristics of SGV and
  corresponding distribution functions as a
  complement to CMAQ at grids sizes of 4 and 12 km.
  
• Explore and examine the merits of applications
  that utilize (a) hybrid modeling approach as well
  as (b) an enhanced CMAQ system that is
  complemented with SGV distributions. e.g.,
• Performing exposure analyses, health risk
  assessments
• Performing grid model evaluation
• Weight of Evidence RRF/DV(CF) analyses for SIPS

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The End Thank you for your attention

• Disclaimer The research presented here was
  performed under the Memorandum of Understanding
  between the U.S. Environmental Protection Agency
  (EPA) and the U.S. Department of Commerce's
  National Oceanic and Atmospheric Administration
  (NOAA) and under agreement number DW13921548.
  This work constitutes a contribution to the NOAA
  Air Quality Program. Although it has been
  reviewed by EPA and NOAA and approved for
  publication, it does not necessarily reflect
  their policies or views.