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 in 2003 and 2009 due to a breakdown of the data acquisition system and lack of man-power, respectively.
The measurements performed in 2009 led to annual average of 26.8 µg m-3 for PM10, well below the European annual limit value of 40 µg/m³ (the European directive 1999/30/EC for the year 2005 and onwards). In addition, the measurements performed in 2009 led to annual average of 19.0 µg m-3 for PM2.5, well below the future European annual limit value of 25 µg/m³ (European directive 2008/50/EC for the year 2015 and onwards). Carbonaceous species (organic matter plus elemental carbon) are the main constituents of PM2.5 (~57 %) followed by (NH4)2SO4 (24 %) and NH4NO3 (12 %). The data from 2009 confirmed the seasonal variations observed over the previous years, mainly driven by meteorology rather than by changes in emissions, as revealed by the lidar measurements. Aerosol physical and optical properties were also measured in 2009. The average particle number (from 10 nm to 10 µm) was about 7400 cm-3 and the mean geometric diameter was 70 nm. Their hygroscopic growth at 90% RH varies from <1.2 in December to 1.25 ¿ 1.35 (size dependent) in June. The mean (close to dry) aerosol single scattering albedo at ¿ = 550 nm was 0.76, and it 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 (about -0.9 µg m-3 yr-1), and from 2003 onwards also a slight decease in ozone concentrations too. The decreasing trends in oxidised and reduced nitrogen species are much less pronounced.JRC.DDG.H.2-Climate change and air qualit
