PNNL

Abstract

Molecular functional groups such as organosulfates (CHOS) and organonitrates (CHNO) are important tracers for field observations of secondary organic aerosols (SOA). While CHOS and CHNO species are prevalent in the atmosphere, there is a lack of knowledge regarding daily and day-and night-time variations in these species in urban atmosphere. Meteorological factors such as wind speed/direction, relative humidity and temperature can influence the formation of CHOS/CHNO. To comprehend these trends, we utilized multi-modal chemical imaging and advanced high resolution mass spectrometry techniques to acquire particle speciation and molecular features (MFs) associated with day and night sampling periods. Additional remote sensing measurements were analyzed to investigate the association between cloud structure and formation of CHOS/CHNO. Back trajectory analysis revealed oceanic influence of southern wind airmass in later June sampling periods with organic fraction