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SUMMARY:Imaging organic aerosols - Dr Francis Pope\, Birmingham University
DTSTART:20160606T131500Z
DTEND:20160606T141500Z
UID:TALK65025@talks.cam.ac.uk
CONTACT:Paul Griffiths
DESCRIPTION:Organic aerosol particles play major roles in atmospheric chem
 istry\, climate\, and public health. Aerosol particle viscosity is importa
 nt since it can determine the ability of chemical species such as oxidants
 \, organics or water to diffuse into the particle bulk. Recent measurement
 s indicate that OA may be present in highly viscous states\, however\, dif
 fusion rates of small molecules such as water appear not to be limited by 
 these high viscosities.  In collaboration with Markus Kalberer (University
  of Cambridge) and Marina Kuimova (Imperial College London) a new techniqu
 e for measuring viscosity has been developed that allows for the imaging o
 f aerosol viscosity in micron sized aerosols through use of fluorescence l
 ifetime imaging of viscosity sensitive dyes.  This work has been conducted
  both on aerosols deposited on microscope coverslips and on particles that
  are levitated in their true aerosol phase through the use of a bespoke op
 tical trap developed at the Central Laser Facility at the Rutherford Lab i
 n Oxford.  The technique allows for the direct observation of kinetic barr
 iers caused by high viscosity and low diffusivity in aerosol particles.  I
 t can dynamically quantify and track viscosity changes during atmospherica
 lly relevant processes such oxidation and hygroscopic growth.  A range of 
 aerosol systems have been studied\, and will be discused\, including secon
 dary organic aerosol (SOA) and bioaerosols includuing pollen and fungal sp
 ores.  \n
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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