Influence of non-ideality on aerosol growth

S. Compernolle, K. Ceulemans, J.-F. Müller
2008 Atmospheric Chemistry and Physics Discussions  
Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their vapor pressure and activity coefficient. The activity coefficient is a nonideality effect and is a complex function of SOA composition. In a previous publica-15 et al. leads to significantly higher SOA yields (by up to a factor 1.6) compared to the ideal case and to other parameterizations. Water uptake is model
more » ... ptake is model dependent, in the order: ideal>UNIFAC-Raatikainen >UNIFAC-Peng>UNIFAC-Hansen≈UNIFAC-Magnussen≈UNIFAC-Ming. In the absence of salt dissolution, phase splitting from pure SOA is unlikely. Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc 25 the sake of simplicity, a lack of activity coefficient data for some compounds, and the small expected variation in activity coefficient compared to variation in vapor pressure, at least when the SOA constituents are of similar nature. Several different UNIFAC parameterizations (Fredenslund et al., Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 15 with c p,i , c g,i the mole quantity of species i per volume of air in aerosol phase and gas phase respectively, and c om the mole quantity SOA per volume of air. Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion ing of organic molecules, and therefore to a lower SOA yield. The water uptake is model dependent, in the order: ideal>UNIFAC-Raatikainen>UNIFAC-Peng>UNIFAC-Hansen≈UNIFAC-Magnussen≈UNIFAC-Ming. As opposed to UNIFAC-Hansen, both UNIFAC-Raatikainen and UNIFAC-Peng were fit to multifunctional molecules (diacids and hydroxy-acids) of atmospheric interest, and can be expected to produce more reli- 8, 2008
doi:10.5194/acpd-8-17061-2008 fatcat:2gbqdncn7rdsfbv7zgmiig4gry