AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
The Role of Chemical Aging Reactions and the Production of Extremely Low Volatility Organic Compounds on Ultrafine Particle Concentrations over Europe
David Patoulias, Christos Fountoukis, Jan Julin, Ilona Riipinen, SPYROS PANDIS, Carnegie Mellon University
Abstract Number: 195 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract In this work, we continue the development of a three-dimensional chemical transport model, PMCAMx-UF, focusing on the simulation of the ultrafine particle size distribution and composition. The Volatility Basis Set (VBS) approach is used for the simulation of organic aerosol. PMCAMx-UF is applied to Europe to quantify the contribution of organic vapors to total number concentrations and fresh particles’ growth. PMCAMx-UF uses the new version of the Dynamic Model for Aerosol Nucleation and the Two-Moment Aerosol Sectional algorithm to track both aerosol number and mass concentration using a sectional approach. We evaluate the model predictions for the European domain against field observations collected in the PEGASOS campaigns during June of 2012 and May-June of 2013. The measurements include both ground stations across Europe and airborne measurements from a Zeppelin airship. Sensitivity tests highlight the importance of chemical aging reactions, the production of extremely low volatility organic compounds (ELVOCs) and the evaporation of primary organic emissions for the ultrafine particle number concentrations. PMCAMx-UF reproduces reasonably well the N10 (number concentration of particles larger than 10 nm) hourly observations both aloft (over the Po Valley in Italy) as well as at the ground level. The ground level concentrations of N100 are well predicted (fractional error of 55% and fractional bias equal to -20%) while there is tendency to overestimate N10 by approximately 40%. The chemical aging reactions and the production of ELVOCs result in increases of the N100 concentration mainly in central and northern Europe by 100-200% while increasing slightly by 10-30% the N10 concentration over central Europe.