Spatial variability in urban acid deposition, 1990: results from the Greater Manchester Acid Deposition Survey (GMADS) network in the UK

Abstract A small-scale intensive network of bulk collectors has been deployed around Greater Manchester, UK to investigate the spatial variability of acid deposition in the urban environment. The concentrations and bulk deposition rates of non-marine (nm) sulphate, nitrate, ammonium, hydrogen and calcium are reported. Episodic events of high pollution were found to occur; maximum concentrations were up to 22 times greater than the mean concentrations for these five major species. Calcium concentrations were inversely correlated to hydrogen concentrations. Acidity was generally lowest in the centre of Manchester where calcium concentrations were greatest. Calcium compounds in the urban atmosphere of Greater Manchester effectively buffer the acidity of precipitation.