Temperature dependence of secondary organic aerosol yield from the ozonolysis of β-pinene

C. Stenby, U. Pöschl, P. von Hessberg, M. Bilde, O. J. Nielsen, G. K. Moortgat
2006 Atmospheric Chemistry and Physics Discussions  
The temperature dependence of secondary organic aerosol (SOA) formation from ozonolysis of β-pinene was studied in a flow reactor at 263-303 K and 1007 hPa. The observed SOA yields were of similar magnitude as predicted by a two-product model based on detailed gas phase chemistry (Jenkin, 2004) , reaching maximum values of 5 0.22-0.39 at high particle mass concentrations. However, the measurement data exhibited significant deviations (up to 50%) from the predicted linear dependence on inverse
more » ... ndence on inverse temperature. When fitting the measurement data with a two-product model, we found that both the partitioning coefficients (K om,i ) and the stoichiometric yields (α i ) of the low-volatile and semi-volatile species vary with temperature. The results indicate 10 that not only the reaction product vapour pressures but also the relative contributions of different gas-phase or multiphase reaction channels are dependent on temperature. We suggest that the modelling of secondary organic aerosol formation in the atmosphere needs to take into account the effects of temperature on the pathways and kinetics of the involved chemical reactions as well as on the gas-particle partitioning of 15 the reaction products. 20 vegetation emit large amounts of biogenic volatile organic compounds (BVOCs) (500-1800 Tg C yr −1 ). Besides isoprene monoterpenes are the most abundant BVOCs, and with an emission rate of 10-50 Tg C yr −1 β-pinene is the second most important monoterpene (Wiedinmyer et al., 2004). Biogenic secondary organic aerosol (SOA) are formed from oxidation of BVOCs in the atmosphere by O 3 , OH and NO 3 radicals, Abstract Introduction Conclusions References Tables Figures Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion EGU particles. In current global atmospheric models the monoterpenes are usually assumed to account for most if not all SOA formation (Kanakidou et al., 2005) , and recent laboratory studies demonstrated the ability of SOA from monoterpenes to affect cloud properties and lifetime by acting as cloud condensation nuclei (Hartz et al., 2005; Van-Reken et al., 2005). Recently the temperature dependence of SOA formation from 5 ozonolysis has been modeled by Sheehan and Bowman (2001), and their parameterization has been incorporated into some advanced Global Atmospheric Models (Chung and Seinfeld, 2002; Tsigaridis and Kanakidou, 2003). Still these models appear to underestimate the organic aerosol particle mass in the free troposphere, which may be due to shortcomings in the characterization and representation of temperature depen-10 25 for wall loss of ozone. Abstract 25 10278 ACPD 6, Abstract ACPD 6, Abstract ACPD 6, Abstract ACPD 6, Abstract Chem. A, 105, 815-822, 2001. Abstract ACPD 6,
doi:10.5194/acpd-6-10275-2006 fatcat:y2cxzxl3erhihk6ct3ojcf5jqu