Kinetics

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Black Carbon and Organic Carbon Aerosol Mass and
Optical Properties Comparability and Causes of
Uncertainties
Suzanne Paulson Brian Barkey Sheldon
Friedlander Kuo-Nan Liou Antonio
Miguel Departments of Atmospheric Oceanic
Sciences, Chemical Engineering, and Institute of
the Environment, UCLA
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EC OC in Ambient Particles
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Transmission electron micrographs of ambient
aerosols collected near ground level at UCLA by
T. Barone and S.K. Friedlander .
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Many Questions Remain
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• Refractive indices of EC and OC aerosols are
  uncertain.
• Impact of (non-spherical) shape on aerosol
  scattering.
• Impact of mixing state on optical properties of
  EC and OC aerosols.
• Impact of mixing state and oxidizers on evolved
  gas analyzers of EC/OC mass.
• The link between filter-based measurements of EC
  OC mass and optical properties.

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Goals of this Project
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• 1.  Develop an instrument to measure aerosol
  angular scattering and polarization.

Polar Nephelometer
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• 2. Extract refractive indices from the angular
  scattering data for OC and BC aerosols, including
  OC-coated black carbon.

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• 3. Experimentally verify/reconcile theoretical
  expectations for the scattering properties of
  non-spherical aerosols.

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Goals of this Project
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• 4. Investigate the underlying factors that
  control differences in EC and OC mass and optical
  property data from instruments that are in wide
  use.
• EC/OC mixing state.
• Oxidizing seed.

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Chamber
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Instrumentation Filter-Based
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Instrumentation in-situ Optical
 
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Instrumentation Physical Chemical
Characterization
 
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Goals of this Project
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• 4.2. Quantify instrument/method specific
  responses for the several aerosol types, and
  differences between methods.
• Focus on fresh photochemically aged diesel, two
  stroke gasoline, secondary organic aerosol,
  with without inorganic and oxidizing seed.
  Internal and external mixtures of these types
  will be investigated.

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Experiments

• Planned for the basic set of runs.
• C Conditional on results of initial experiments.

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Goals of this Project
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• 4.3 The additivity of instrument responses to
  aerosol components and for external mixtures will
  be assessed.
• 4.4 The evolution of the fractal structure of
  ultrafine diesel particles as they are
  incorporated into the accumulation mode will be
  investigated.
• 4.5 Establish the relationship between common
  off-line measurements of EC and OC mass and
  optical absorption, and in situ properties of
  scattering and absorption.

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Evolved Gas Analyzer Data
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PM2.5 from Riverside, CA in late summer. Analyzed
with a Sunset Labs NIOSH EGA. The solid line
indicates the evolved carbon signal. PC is
material that has been assigned as charred polar
OC it does not volatilize and only leaves the
filter under oxidizing conditions.