How effective has been the reduction of SO2 emissions on the effect of acid rain on ecosystems?

The paper attempts to assess the effectiveness of the reduction of SO, emis sions over recent years for protection of ecosystems in both Europe and eas tern USA by analysis of temporal changes in the acidifying potential (AP) o f wet deposition defined as [SO42-]-([Ca2+]+ [Mg2+). Spatial and temporal p atterns of acidifying potential were studied. The main result is that there is no statistical evidence for a trend towards improvement in the acidifyi ng potential, because there have been declines in Ca precipitation. This su ggests that the reduction of SO, emissions has not been effective as an aba tement strategy. (C) 2001 Elsevier Science B.V. All rights reserved.