title: Reaction between CH3O2 and BrO radicals: a new source of upper troposphere lower stratosphere hydroxyl radicals.
abstract: Over the last two decades it has emerged that measured hydroxyl radical levels in the upper troposphere are often underestimated by models, leading to the assertion that there are missing sources. Here we report laboratory studies of the kinetics and products of the reaction between CH3O2 and BrO radicals that shows that this could be an important new source of hydroxyl radicals:BrO + CH3O2 → products (1). The temperature dependent value in Arrhenius form of k(T) is k1 = (2.42–0.72+1.02) × 10–14 exp[(1617 ± 94)/T] cm3 molecule–1 s–1. In addition, CH2OO and HOBr are believed to be the major products. Global model results suggest that the decomposition of H2COO to form OH could lead to an enhancement in OH of up to 20% in mid-latitudes in the upper troposphere and in the lower stratosphere enhancements in OH of 2–9% are inferred from model integrations. In addition, reaction 1 aids conversion of BrO to HOBr and slows polar ozone loss in the lower stratosphere.
authors.affiliation: †School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
authors.forename: Dudley E
authors.initials: DE
authors.lastname: Shallcross
authors.affiliation: ‡School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Kimberley E
authors.initials: KE
authors.lastname: Leather
authors.affiliation: ‡School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Asan
authors.initials: A
authors.lastname: Bacak
authors.affiliation: †School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
authors.forename: Ping
authors.initials: P
authors.lastname: Xiao
authors.affiliation: §School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.|∥Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Edmond P F
authors.initials: EP
authors.lastname: Lee
authors.affiliation: ∥Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Maggie
authors.initials: M
authors.lastname: Ng
authors.affiliation: ∥Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Daniel K W
authors.initials: DK
authors.lastname: Mok
authors.affiliation: §School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, U.K.
authors.forename: John M
authors.initials: JM
authors.lastname: Dyke
authors.affiliation: ⊥School of Earth and Environment, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Ryan
authors.initials: R
authors.lastname: Hossaini
authors.affiliation: ⊥School of Earth and Environment, University of Leeds, Leeds LS2 9JT, U.K.
authors.forename: Martyn P
authors.initials: MP
authors.lastname: Chipperfield
authors.affiliation: †School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
authors.forename: M Anwar H
authors.initials: MA
authors.lastname: Khan
authors.affiliation: ‡School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, U.K.
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Percival
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D017605:Bromine Compounds / Q000737:chemistry*; D003198:Computer Simulation; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D016018:Least-Squares Analysis; D016014:Linear Models; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry*; D008956:Models, Chemical; D010545:Peroxides / Q000737:chemistry*; D013696:Temperature
chemical_list: D017605:Bromine Compounds; D010545:Peroxides; D017665:Hydroxyl Radical; D008697:Methane