Scientific Theme: Advanced Modeling and Observing Systems

Complementary Research: Faculty Fellows Research
Photoprocessing of Organic Acids in the Earth's Atmosphere
Veronica Vaida
Funding: NSF
The Vaida group studies sunlight initiated chemistry of significance to climate. In the Earth‘s
atmosphere, rapid oxidation of biogenic and anthropogenic emissions produces organic
(acids, alcohols) and inorganic (HNO3, H2SO4) hydrophilic compounds which are key
ingredients in aerosol formation and subsequent cloud nucleation which significantly
influence climate. Solar photons perform effective photo-reduction of atmospheric targets.
The Vaida group studies sunlight-initiated chemical reactions proceeding in the ground
electronic state by excitation of a vibrational overtone state by visible red light in aqueous
environments. This chemistry affects aerosol processing and nucleation.
Aerosols are globally distributed suspensions of small particles in air and known to influence climate through
reflection of solar radiation and nucleating clouds. Organics partition to the water-air interface and have a profound
effect on climate and chemistry in the atmosphere. Organics emitted from sources such as biomass burning create a
coating on the sea surface and on aerosols.
Accomplishments
The stability, partitioning, oxidative processing, and permeability of these organic films have been investigated in
the Vaida lab. The results of these studies are used to explain recent field results, which show that the surfaces of
collected aerosols are dominated by long-chain fatty acids.
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