title: Regional and global impacts of Criegee intermediates on atmospheric sulphuric acid concentrations and first steps of aerosol formation.
abstract: Carbonyl oxides ("Criegee intermediates"), formed in the ozonolysis of alkenes, are key species in tropospheric oxidation of organic molecules and their decomposition provides a non-photolytic source of OH in the atmosphere (Johnson and Marston, Chem. Soc. Rev., 2008, 37, 699, Harrison et al, Sci, Total Environ., 2006, 360, 5, Gäb et al., Nature, 1985, 316, 535, ref. 1-3). Recently it was shown that small Criegee intermediates, C.I.'s, react far more rapidly with SO2 than typically represented in tropospheric models, (Welz, Science, 2012, 335, 204, ref. 4) which suggested that carbonyl oxides could have a substantial influence on the atmospheric oxidation of SO2. Oxidation of 502 is the main atmospheric source of sulphuric acid (H2SO4), which is a critical contributor to aerosol formation, although questions remain about the fundamental nucleation mechanism (Sipilä et al., Science, 2010, 327, 1243, Metzger et al., Proc. Natl. Acad. Sci. U. S. A., 2010 107, 6646, Kirkby et al., Nature, 2011, 476, 429, ref. 5-7). Non-absorbing atmospheric aerosols, by scattering incoming solar radiation and acting as cloud condensation nuclei, have a cooling effect on climate (Intergovernmental Panel on Climate Change (IPCC), Climate Change 2007: The Physical Science Basis, Cambridge University Press, 2007, ref. 8). Here we explore the effect of the Criegees on atmospheric chemistry, and demonstrate that ozonolysis of alkenes via the reaction of Criegee intermediates potentially has a large impact on atmospheric sulphuric acid concentrations and consequently the first steps in aerosol production. Reactions of Criegee intermediates with SO2 will compete with and in places dominate over the reaction of OH with SO2 (the only other known gas-phase source of H2SO4) in many areas of the Earth's surface. In the case that the products of Criegee intermediate reactions predominantly result in H2SO4 formation, modelled particle nucleation rates can be substantially increased by the improved experimentally obtained estimates of the rate coefficients of Criegee intermediate reactions. Using both regional and global scale modelling, we show that this enhancement is likely to be highly variable spatially with local hot-spots in e.g. urban outflows. This conclusion is however contingent on a number of remaining uncertainties in Criegee intermediate chemistry.
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK. c.percival@manchester.ac.uk
authors.forename: Carl J
authors.initials: CJ
authors.lastname: Percival
authors.affiliation: Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS9055, Livermore, California 94551, USA.
authors.forename: Oliver
authors.initials: O
authors.lastname: Welz
authors.affiliation: Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS9055, Livermore, California 94551, USA.
authors.forename: Arkke J
authors.initials: AJ
authors.lastname: Eskola
authors.affiliation: Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS9055, Livermore, California 94551, USA.
authors.forename: John D
authors.initials: JD
authors.lastname: Savee
authors.affiliation: Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS9055, Livermore, California 94551, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Osborn
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK.
authors.forename: David O
authors.initials: DO
authors.lastname: Topping
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK.
authors.forename: Douglas
authors.initials: D
authors.lastname: Lowe
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Utembe
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK.
authors.forename: Asan
authors.initials: A
authors.lastname: Bacak
authors.affiliation: The Centre for Atmospheric Science, The School of Earth, Atmospheric and Environmental Science, The University of Manchester, Simon Building, Brunswick Street, Manchester M13 9PL, UK.
authors.forename: Gordon
authors.initials: G
authors.lastname: McFiggans
authors.affiliation: Biogeochemistry Research Centre, School of Chemistry, The University of Bristol, Cantock's Close BS8 1TS, UK.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Cooke
authors.affiliation: Biogeochemistry Research Centre, School of Chemistry, The University of Bristol, Cantock's Close BS8 1TS, UK.
authors.forename: Ping
authors.initials: P
authors.lastname: Xiao
authors.affiliation: Biogeochemistry Research Centre, School of Chemistry, The University of Bristol, Cantock's Close BS8 1TS, UK.
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Archibald
authors.affiliation: Biogeochemistry Research Centre, School of Chemistry, The University of Bristol, Cantock's Close BS8 1TS, UK.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Jenkin
authors.affiliation: rdscientific, Newbury, Berkshire, UK.
authors.forename: Richard G
authors.initials: RG
authors.lastname: Derwent
authors.affiliation: Department of Applied Environmental Science, University of Stockholm, Stockholm, Sweden.
authors.forename: Ilona
authors.initials: I
authors.lastname: Riipinen
authors.affiliation: Department of Applied Environmental Science, University of Stockholm, Stockholm, Sweden.
authors.forename: Daniel W K
authors.initials: DW
authors.lastname: Mok
authors.affiliation: Department of Applied Environmental Science, University of Stockholm, Stockholm, Sweden.
authors.forename: Edmond P F
authors.initials: EP
authors.lastname: Lee
authors.affiliation: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, UK.
authors.forename: John M
authors.initials: JM
authors.lastname: Dyke
authors.affiliation: Combustion Research Facility, Sandia National Laboratories, 7011 East Ave., MS9055, Livermore, California 94551, USA.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Taatjes
authors.affiliation: Biogeochemistry Research Centre, School of Chemistry, The University of Bristol, Cantock's Close BS8 1TS, UK.
authors.forename: Dudley E
authors.initials: DE
authors.lastname: Shallcross
mesh_terms: D000336:Aerosols; D001272:Atmosphere; D010084:Oxidation-Reduction; D013464:Sulfuric Acids / Q000032:analysis*
chemical_list: D000336:Aerosols; D013464:Sulfuric Acids; C033158:sulfuric acid