SO2 oxidation products other than H2SO4 as a trigger of new particle formation. Part 2: Comparison of ambient and laboratory measurements, and atmospheric implications

Autor: Kari E. J. Lehtinen, S.-L. Sihto, Markku Kulmala, Frank Arnold, Tuukka Petäjä, T. Berndt, Ari Laaksonen, Santtu Mikkonen, Karine Sellegri, Y. Viisanen, F. Stratmann, M. Dal Maso, M. Hanke, P. Aalto, A. R. Ruuskanen, Robert Janson, J. Ucker, B. Umann, Ilona Riipinen, Colin D. O'Dowd
Rok vydání: 2008
Předmět:
Zdroj: Atmospheric Chemistry and Physics. 8:7255-7264
ISSN: 1680-7324
DOI: 10.5194/acp-8-7255-2008
Popis: Atmospheric new particle formation is generally thought to occur due to homogeneous or ion-induced nucleation of sulphuric acid. We compare ambient nucleation rates with laboratory data from nucleation experiments involving either sulphuric acid or oxidized SO2. Atmospheric nucleation occurs at H2SO4 concentrations 2–4 orders of magnitude lower than binary or ternary H2SO4 nucleation. In contrast, the atmospheric nucleation rates and H2SO4 concentrations are very well replicated in the SO2 oxidation experiments. We explain these features by the formation of free HSO5 radicals in pace with H2SO4 during the SO2 oxidation. We suggest that at temperatures above ~250 K these radicals produce nuclei of new aerosols much more efficiently than H2SO4. These nuclei are activated to further growth by H2SO4 and possibly other trace species. However, at lower temperatures the atmospheric relative acidity is high enough for the H2SO4–H2O nucleation to dominate.
Databáze: OpenAIRE