Structure-activity relationship for the gas-phase reactions of NO3 radical with organic compounds: Update and extension to aldehydes

In this work is presented an extension and an update of a recently published structure-activity relationship (SAR) for the prediction of rate constants for gas-phase reactions of VOCs with NO3 radicals (See previous version in Kerdouci et al., 2011). Such predictive tools are very useful to describe the reactivity of organic compounds in atmospheric models. This SAR is constructed on the group-additivity method and is based on a wide kinetic database for 185 organic compounds. In addition to alkanes, alkenes and saturated and unsaturated oxygenated species already included in the first version of this SAR, this extended version comprises now aldehydes and unsaturated aldehydes. Indeed, since then, new kinetic studies have been performed for alkenals which allow the parameterization of this class of compounds. In addition, since new rate constants have been measured for unsaturated ethers, the parameterization of this family of compounds has been completed. Finally, this new version of the SAR shows very good predictive capabilities with more than 90% of the experimental rate coefficients being reproduced within a factor of two.