On the origin of SO2 above Northern Greece

This paper describes the sources contributing to two seasonal peaks in colu mnar SO2 amounts measured with a Brewer spectrophotometer at Thessaloniki, Northern Greece since 1982. The SO2 Brewer measurements combined with those at ground level, meteorological analysis and numerical simulations provide estimates on the contribution of local and remote sources to the SO2 colum n. It is shown that more than 50% of the observed SO2 column can be attribu ted to lignite-burning sources in Bulgaria, Romania and former Yugoslavia, this percentage rising to 70% at periods with NE now at 850 hPa Winds from the NW-N-NE contribute around 60% to the observed mean SO2 column during wi nter and 75% during the summer. When including all wind directions at 850 h Pa, the Greek sources, including the lignite-burning power plant complexes to the WSW of the city, contribute around 40% to the SO2 column. These resu lts are in qualitative agreement with independent observations from inversi on of GOME measurements.