chemistry of wildfire emissions : a kinetic study of the gas-phase 1 reactions of furans with the NO 3 radical 2

NO3 chemistry of wildfire emissions: a kinetic study of the gas-phase 1 reactions of furans with the NO3 radical 2 Mike J. Newland, Yangang Ren, Max R. McGillen, Lisa Michelat, Véronique Daële, Abdelwahid Mellouki 3 ICARE-CNRS, 1 C Av. de la Recherche Scientifique, 45071 Orléans Cedex 2, France 4 5 Correspondence to: Mike J. Newland (mike.newland@cnrs-orleans.fr; mellouki@cnrs-orleans.fr) 6 7 8 Abstract. Furans are emitted to the atmosphere during biomass burning from the pyrolysis of cellulose. They are one of the 9 major contributing VOC classes to OH and NO3 reactivity in biomass burning plumes. The major removal process of furans 10 from the atmosphere at night is reaction with the nitrate radical, NO3. Here we report a series of relative rate experiments in the 11 7300 L indoor simulation chamber at CNRS-ICARE, Orléans, using a number of different reference compounds to determine 12 NO3 reaction rate coefficients for four furans, two furanones, and pyrrole. In the case of the two furanones, this is the first time 13 that NO3 rate coefficients have been reported. The recommended values (cm molecule s) are: furan (1.50±0.23) ́10, 214 methylfuran (2.37±0.55) ́10, 2,5-dimethylfuran (1.10±0.33) ́10, furan-2-aldehyde (9.28±2.3) ́10, 5-methyl-2(3H)15 furanone (3.00±0.45) ́10, 2(5H)-furanone <1.4 ́10, and pyrrole (7.35±2.06) ́10. The furan-2-aldehyde + NO3 reaction 16 rate is found to be an order of magnitude lower than previously reported. We also recommend a faster rate for the a17 terpinene+NO3 reaction ((2.70±0.81) ́10 cms). These experiments show that for furan, alkyl substituted furans, 5-methyl18 2(3H)-furanone, and pyrrole, reaction with NO3 will be the dominant removal process at night, and may also contribute during 19 the day. For 2(5H)-furanone, reaction with NO3 is not an important atmospheric sink. 20