Evidence for Heterogeneous Reactions in the Atmosphere

  1. David R. Schryer
  1. George M. Hidy

Published Online: 21 MAR 2013

DOI: 10.1029/GM026p0204

Heterogeneous Atmospheric Chemistry

Heterogeneous Atmospheric Chemistry

How to Cite

Hidy, G. M. (1982) Evidence for Heterogeneous Reactions in the Atmosphere, in Heterogeneous Atmospheric Chemistry (ed D. R. Schryer), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM026p0204

Author Information

  1. Environmental Research & Technology, Inc., 2625 Townsgate Road, Suite 360, Westlake Village, California 91361

Publication History

  1. Published Online: 21 MAR 2013
  2. Published Print: 1 JAN 1982

ISBN Information

Print ISBN: 9780875900513

Online ISBN: 9781118663813



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Verification of heterogeneous reactions in the atmosphere through observations has remained a difficult, perhaps unachievable task because of the diversity and complexity of simultaneous chemical interactions which are suspected to occur. However, recent measurements combined with data analysis show promise for supplying both direct and indirect evidence of heterogeneous sulfur oxide and nitrogen oxide chemistry. Examples of useful methods are provided, which include (1) direct interpretation of observations in and near clouds and inference from thermodynamic properties, (2) inspection of combinations of aerometric data, (3) inference from statistical analysis, (4) comparison of observations with a validated air quality model, and (5) differences in particle size/composition distributions. An example involving thermodynamics is dry ammonium nitrate undergoing equilibrium transformation to the vapor phase, which is very sensitive to temperature. The other sample results presented suggest that heterogeneous oxidation of SO2 to sulfate may occur in the presence of suspended liquid water, particularly in winter, either through media buffered by absorbed ammonia or via suspended soot in droplets. No observational evidence has been found supporting metal-oxide- or ion-catalyzed reactions of sulfur dioxide or nitrogen oxides under atmospheric conditions.