Reactions of acetone oxide stabilized Criegee intermediate with SO2, NO2, H2O and O3

International audienceAtmospheric aerosol particles represent a critical component of the atmosphere, impacting global climate, regionalair pollution, and human health. The formation of new atmospheric particles and their subsequent growth to largersizes are the key processes for understanding of the aerosol effects. Sulphuric acid, H2SO4, has been identified toplay the major role in formation of new atmospheric particles and in subsequent particle growth. Until recently thereaction of OH with SO2 has been considered as the only important source of H2SO4 in the atmosphere. However,recently it has been suggested that the oxidation of SO2 by Criegee biradicals can be a significant additionalatmospheric source of H2SO4 comparable with the reaction of SO2 with OH.Here we present some results about the reactions of the acetone oxide stabilized Criegee intermediate, (CH3)2=OO,produced in the reaction of 2,3-dimethyl-butene (TME) with O3.The formation of the H2SO4 in the reaction of acetone oxide with SO2 was investigated in the speciallyconstructed atmospheric pressure laminar flow reactor. The Criegee intermediate was generated by ozonolysisof TME. The H2SO4, generated by addition of SO2, was directly monitored with Chemical Ionization MassSpectrometer (SAMU, LPC2E). Relative rates of reactions of acetone oxide with SO2, NO2, H2O and ozone weredetermined from the dependencies of the H2SO4 yield at different concentrations of the reactants.Atmospheric applications of the obtained results are discussed in relation to the importance of this additionalH2SO4 formation pathway compared to the reaction of OH with SO2