Modelling Highly Oxygenated organic Molecule formation from monoterpenes at different temperatures and nitrogen oxides concentrations

Description

Field and laboratory experiments have identified large and rapid formation of Highly Oxygenated organic Molecules (HOMs) from monoterpenes. We have used the aerosol dynamics model ADCHAM, and the recently developed Peroxy Radical Autoxidation Mechanism (PRAM) to simulate peroxy radical (RO2) autoxidation and formation of HOM and Secondary Organic Aerosols (SOA). We show that PRAM are able to capture the observed mass spectrums and trends in individual HOM species during a wide range of experimental conditions and chambers environments in the Jülich Plant Atmosphere Chamber (JPAC), the AURA chamber at Aarhus University, the COALA chamber at University of Helsinki and the CLOUD chamber at CERN. The complex and non-linear dependence of HOM formation caused by NO, NO2 and NO3 was investigated by simulating experiments with variable nitrogen oxides concentrations in CLOUD and COALA. We evaluate possible reaction pathways leading to HOM organonitrates via monoterpene + NO3, RO2 + NO and RO2 + NO2 reactions. We also constrain the volatility of individual HOM species by investigating the observed drop in the HOM(g) concentration during ammonium sulfate seed particle additions in the COALA chamber. Finally, we implemented PRAM into the chemistry transport model ADCHEM and evaluated the modelled HOM concentrations and SOA mass formation against observations at the SMEARII field station in Finland.

Period	2019 Aug 29
Event title	European Aerosol Conference 2019
Event type	Conference
Location	Gothenburg, SwedenShow on map