The aim of the JRC-Ispra station for atmospheric research (45°49'N, 8°38'E) is to monitor atmospheric parameters (pollutant concentrations and fluxes, atmospheric particle chemical composition, number size distribution and optical properties) to contribute in assessing the impact of European policies on air pollution and climate change. The station has been operated continuously since November 1985, with a gap in gas phase data due to a severe breakdown of the data acquisition system in 2003 though.
The measurements performed in 2007 led to annual averages of ca. 32 µg m-3 O3, 0.8 µg m-3 SO2, 21 µg m-3 NO2 and 30 µg m-3 PM10. Carbonaceous species (organic matter plus elemental carbon) are the main constituents of PM2.5 (> 55 %) followed by NH4NO3 (20-30 %) and (NH4)2SO4 (10-20 %). The measurements confirmed the seasonal variations observed over the previous years, mainly driven by meteorology rather than by changes in emissions. Aerosol physical and optical properties were also measured in 2007. The average particle number (from 10 nm to 10 µm) was about 9200 cm-3 in 2007. The mean (close to dry) aerosol single scattering albedo (0.79) was low compared to the values generally observed in Europe, which means that the cooling effect of aerosols is reduced in our region compared to others.
Long-term trends (over 20 years) show consistent decreases in sulfur concentrations and deposition, PM mass concentration (-0.9 µg m-3 yr-1) and in extreme ozone value occurrence frequency. The decreasing trends in oxidised and reduced nitrogen species are much less pronounced. However, historical minimum in NO3-, NH4+, (and SO42-) wet deposition, as well as in O3 pollution indicators (AOT40 and SOMO35) were observed in 2007.JRC.H.2-Climate chang
