Harvard University School of Engineering and Applied Sciences  Environmental Sciences and
Engineering (ESE) Program		 Atmospheric Sciences Seminar
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Current Projects
 
  • Phase Transitions of
       Atmospheric Particles

     - Crystallization of SNAP
        Particles
     - 1×3TDMA
     - Atmospheric Nanoparticles
     - Modeling Aerosol Phase
        Transitions and Radiative
        Effects

  • Dissolution and
       Precipitation of Minerals
       in Aquatic Environments
     
  • Chemical Oxidation
       Reactions and Hydrophobic
       -to-Hydrophilic Aging of OAs

     - Aerodyne AMS analysis
     - CCN properties of OAs

  • Origins of Life:
       Mineral Surface Photo-
       Electrochemistry


    • Harvard Environmental Chamber

    AMAZE-08


    Closed Projects

      - Crystallization of Sulfate and
       Nitrate Coatings on
       Tropospheric Mineral Particles
     
      - Tropospheric Mineral
       Particles as Ice Nuclei
     
      - Building Structures at
       the Nanoscale


     

     

    CCN properties of organic aerosol particles

    A Droplet Measurement Technologies cloud condensation nuclei counter is used alongside the AMS in our flow tube studies, which allows us to track changes in cloud condensation nuclei (CCN) properties of aging organic atmospheric particles while simultaneously studying the changes in aerosol chemistry. The study of CCN properties is a key research focus because the indirect effect of atmospheric particles on radiative forcing and the hydrological cycle contributes significantly to uncertainties in current climate model predictions.

    Typical activation curves are shown below: (a) ammonium sulfate particles at 0.3% and 1% supersaturation, (b) homogeneously generated oleic acid particles, at varying levels of ozone exposure and a supersaturation value of about 0.6%.

    CCN data

     

    People Involved

    Publications

    1. J.S. Shilling, S.M. King, M. Mochida, D. Worsnop, and S.T. Martin, "Mass Spectral Evidence that Small Changes in Composition Caused by Oxidative Aging Processes Alter Aerosol CCN Properties," Journal of Physical Chemistry A, 2007, 111, 3358-3368. PDF File. Supporting Information.

     
     



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    Environmental Chemistry Group