Transformation of organic aerosol in Sacramento during CARES

 

Authors

Ryan Moffet — Sonoma Technology Inc.
Xiao-Ying Yu — Pacific Northwest National Laboratory
Jerome D Fast — Pacific Northwest National Laboratory
Rahul Zaveri — Pacific Northwest National Laboratory
Alexander Laskin — Purdue University
Mary Gilles — Lawrence Berkeley National Laboratory

Category

Field Campaigns

Description

Fixed-site microscopy sampling during the Carbonaceous Aerosols and Radiative Effects Study (CARES) field campaign allowed for the observation of chemical changes within individual organic particles throughout a period of photochemical aerosol formation and buildup. To observe changes in the chemical composition of the particles with a 10–30 nm spatial resolution, a combination of scanning transmission x-ray microscopy/near-edge x-ray absorption fine structure spectroscopy (STXM/NEXAFS) and computer-controlled scanning electron microscopy/energy dispersive X-ray spectroscopy (CCSEM/EDX) was used. SEM observations showed the characteristics of organic aerosol, sea salt, dust, and primary biogenic particles. STXM/NEXAFS measurements were used to show an increase in organic mass on individual particles in addition to changes in the detailed microstructure in internally mixed inorganic/organic particles.