Water, Air and Soil Pollution: Focus

, Volume 1, Issue 5, pp 39–48

The Control of SO2 Dry Deposition on to Natural Surfaces by NH3 and its Effects on Regional Deposition

Authors

  • D. Fowler
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • M. A. Sutton
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • C. Flechard
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • J. N. Cape
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • R. Storeton-West
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • M. Coyle
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
  • R. I. Smith
    • Centre for Ecology and Hydrology (Edinburgh), Bush Estate
Article

DOI: 10.1023/A:1013161912231

Cite this article as:
Fowler, D., Sutton, M.A., Flechard, C. et al. Water, Air, & Soil Pollution: Focus (2001) 1: 39. doi:10.1023/A:1013161912231

Abstract

Two years of continuous measurements of SO2deposition fluxes to moorland vegetation are reported. The mean flux of 2.8 ng SO2 m-2 s-1 is regulated predominantly by surface resistance (r c) which, even for wet surfaces, was seldom smaller than 100 s m-1. The control of surface resistance is shown to be regulated by the ratio of NH3SO2 concentrations with an excess of NH3 generating the small surface resistances for SO2. A dynamic surface chemistry model is used to simulate the effects of NH3 on SO2 deposition flux and is able to capture responses to short-term changes in ambient concentrations of SO2, NH3 and meteorological conditions. The coupling between surface resistance and NH3/SO2 concentration ratios shows that the deposition velocity for SO2 is regulated by the regional pollution climate. Recent long-term SO2 flux measurements in a transect over Europe demonstrate the close link between NH3/SO2 concentrations and rc (SO2). The deposition velocity for SO2 is predicted to have increased with time since the 1970s and imply a 40% increase in v d at a site at which the annual mean ambient SO2 concentrations declined from 47 to 3 μg m-3 between 1973 and 1998.

canopy resistance deposition non-linearity SO2 velocity

Copyright information

© Kluwer Academic Publishers 2001