Atmospheric transport and wet depositions of acidifying substances in northwestern Russia

Data on measuring chemical composition of the atmospheric precipitation sampled at the national network of monitoring transboundary transport of pollutants over the period from the late 1970s to 2007 are generalized. The area of investigation covers northwestern European Russia. It is shown that the errors of the principal pollutants (sulfur and nitrogen compounds) measurements are, on average, within 6%. The precipitation character over the measurement period changed from subacid (4 < pH < 5) to neutral (5 < pH < 6). The sulfur deposition intensity in the region decreases over the last decades on a permanent basis. An opposite tendency is observed for the nitrogen deposition. Annually means both of sulfur and nitrogen depositions are close to the critical loads adopted. The trajectory analysis of the air mass transport leading to a conclusion that main emission sources of pollutants must be located in the Central European countries. It is supposed that the conditions of the 1999 Gothenburg Protocol on abating acidifying substance emissions into the atmosphere are not observed, at least for nitrogen.