On the origin of SO₂ above northern Greece

Abstract

This paper describes the sources contributing to two seasonal peaks in columnar SO 2 amounts measured with a Brewer spectrophotometer at Thessaloniki, Northern Greece since 1982. The SO 2 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 SO 2 column. It is shown that more than 50% of the observed SO 2 column can be attributed to lignite‐burning sources in Bulgaria, Romania and former Yugoslavia, this percentage rising to 70% at periods with NE flow at 850 hPa. Winds from the NW‐N‐NE contribute around 60% to the observed mean SO 2 column during winter and 75% during the summer. When including all wind directions at 850 hPa, the Greek sources, including the lignite‐burning power plant complexes to the WSW of the city, contribute around 40% to the SO 2 column. These results are in qualitative agreement with independent observations from inversion of GOME measurements.