Atmospheric trace gas and aerosol particle concentration measurements in Eastern Lapland, Finland 1992–2001

Trace gases (SO2, NOx, O3) and aerosol particles alongside with meteorological parameters have been measured continuously since 1992 in a remote Arctic station in Värriö, Finnish Lapland. In this background region there are practically no local sources of pollution. The goal of this study was to investigate the transport of gaseous pollutants and aerosol particles to a remote area. The seasonal, diurnal and long-term behaviour of trace gases and aerosol particles is presented as well as their correlation with each other and with local wind direction. A slightly diminishing trend was observed for low summertime ozone (O3) concentrations from 1995 to 2001. No distinct long-term trends for other species were noted. The monthly-medium concentrations were highest for SO2 and NOx in the winter, for ozone in the spring and for aerosol particles in the summer. The cleanest air seemed to arrive with northwesterly local winds, whereas the most polluted air was associated with easterly local winds and occurred as short episodes.