标题：Trends in the bulk deposition and atmospheric concentration of air pollutants in the Finnish Integrated Monitoring catchment Pallas during 1992–2012
摘要：The air and precipitation chemistry of 15 components was monitored within the Pallas Integrated Monitoring catchment during 1992–2012. A continuous time series of 21 years was available for the bulk deposition of acidifying compounds and base cations, whereas for the atmospheric concentration of sulphur and nitrogen compounds and ozone, the measurements covered 14–21 years. In this paper, an updated analysis of trends in these time series is presented and discussed in relation to the development in European emissions. The most notable result, a significant increase in NO3 bulk deposition since 1997, could serve as a general warning of the threats of excessive nutrient inputs to the vulnerable arctic ecosystems. There were no major changes in ozone concentrations between 1992–2012. The annually averaged source areas of gaseous SO2 and NO2 detected at Pallas were estimated using air parcel back trajectories.
