Abstract
Approximately 100 high-volume filter samples collected in the Tees area during june to October 1967 have been analysed for some 20 inorganic components. Ammonium and sulphate ions were major components af all the samples analysed comprising 65 per cent of the total soluble ion content and were present in proportions close to that of ammonium sulphate. The visibility recorded at one of the stations showed good correlation with sulphate and ammonium ion concentration less good with smoke and virtually no correlation with sodium ion.