Model relevant attribution of biogenic SOA sources

Description

We conduct both a statistical decomposition analysis and bottom-up, linear combination modeling of simultaneous molecular composition and volatility measurements of biogenic secondary organic aerosol (SOA) from a series of controlled laboratory chamber studies and recent field campaigns such as the Biogenic Aerosol Effects on Clouds and Climate (BAECC) campaign. The Secondary Organic Aerosol Formation from Forest Emissions Experiment (SOAFFEE) chamber studies of isoprene and monoterpene derived SOA formed under a range of different chemical environments can be connected directly to molecular patterns observed in ambient SOA. From these spectral patterns, we can quantitatively apportion the sources of the SOA to different chemical processes and precursors such as monoterpene ozonolysis, reaction with the nitrate radical, isoprene photochemical oxidation, isoprene multiphase chemistry (e.g. IEPOX), and so on. Given that Earth System Models are incorporating various SOA formation schemes and precursors, these types of analyses provide direct guidance on the most important processes and precursors to incorporate in order to accurately simulate the sensitivity of natural aerosol sources to changes in atmospheric composition.