Rainfall acidity in northern Britain.

The acidity of rain has attracted considerable international interest during the past decade. An area of enhanced rainfall acidity with its focus in the Low Countries of north-west Europe was identified by the European air chemistry study1 for the period 1955–68, and widespread concern arose as a result of observations that fish populations were decreasing in areas of Scandinavia subject to acid rain2. We report here measurements of acidity and related anion concentrations in rain collected at 16 sites in northern Britain during the period 1978–80. Estimates are provided of annual deposition of acidity in rain, the proportion of this acidity attributable to sulphuric and nitric acids, and an example of the influence of local concentrations of pollutant gases on rainfall acidity in cities.