The development of loads of cations, anions, Cd and Pb in precipitation and of atmospheric concentrations of N-components, in Switzerland from 1988 to 2003

This study presents the results of the analyses of Cd, Pb, cations and anions present in precipitation and dust at a pre-alpine and a suburban site in Switzerland in the period from 1988 to 2003. The aim of these measurements was to monitor the success of measures taken to diminish pollutant emissions. No change was found for Ca2+, K+, Na+ and Mg2+ loads - in line with expectations, as no reducing measures had been taken. Statistically significant and largely decreasing values (50-90%) were found for Cl- and Cd (linked to the fitting of filters in incineration plants), Pb (unleaded petrol), SO42-(diminishing the use of mineral oil with high S content), and the proton (lower HCl and SO2 emissions). A smaller decrease (up to 30%) or none was registered for oxidised nitrogen components (fitting cars with catalytic converters, but an increase in numbers of cars and trucks). No significant change was found for NH3 as farming techniques had undergone no major changes. The long-term measurements show that the measures taken to reduce emissions were successful. A shorter monitoring period would have been misleading owing to data variability and temporary incidents e.g. amount of precipitation.