Mineral dust photochemistry induces nucleation events in the presence of SO2

Yoan Dupart, Stephanie M. King, Bettina Nekat, Andreas Nowak, Alfred Wiedensohler, Hartmut Herrmann, Gregory David, Benjamin Thomas, Alain Miffre, Patrick Rairoux, Barbara D'Anna, Christian George

Research output: Contribution to journalArticlepeer-review

111 Scopus citations


Large quantities of mineral dust particles are frequently ejected into the atmosphere through the action of wind. The surface of dust particles acts as a sink for many gases, such as sulfur dioxide. It is well known that under most conditions, sulfur dioxide reacts on dust particle surfaces, leading to the production of sulfate ions. In this report, for specific atmospheric conditions, we provide evidence for an alternate pathway in which a series of reactions under solar UV light produces first gaseous sulfuric acid as an intermediate product before surface-bound sulfate. Metal oxides present in mineral dust act as atmospheric photocatalysts promoting the formation of gaseous OH radicals, which initiate the conversion of SO2 to H2SO4 in the vicinity of dust particles. Under low dust conditions, this process may lead to nucleation events in the atmosphere. The laboratory findings are supported by recent field observations near Beijing, China, and Lyon, France.

Original languageEnglish (US)
Pages (from-to)20842-20847
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number51
StatePublished - Dec 18 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • Atmospheric optics
  • OH production
  • Photocatalysis
  • SO nucleation


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