On the origin of SO₂ above northern Greece

Abstract

Abstract. This paper describes the sources contributing to two seasonal peaks in colunmar 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 column. It is shown that more than 50% of the observed SO2 column can be attributed to ligniteburning 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 SO2 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 SO2 colurn. These results are in qualitative agreement with independent observations from inversion of GOME measurements.

Aerosol sources and their contribution to the chemical composition of aerosols in the Eastern Mediterranean Sea during summertime

“…Central Europe is identified as by far the most important emitting region for both SO 2 and nss-SO 4 measured in Crete. The Central Europe source strength of S compounds calculated here is in agreement with previous findings of Zerefos et al (2000) who reported that 70% of SO 2 measured North of Greece (Thessaloniki) originates in Bulgaria and surrounding countries. Important sources were observed from Hungaria, Romania and Bulgaria, which is in agreement with SO 2 emission data for 1999 provided by UNECE/EMEP.…”

“…Another explanation could be that numerous power plants in Central Europe S-containing lignite as fossil fuel inject SO 2 at up to several hundred meters altitude, even reaching the lower free troposphere. Evidence for this theory has recently been gathered in the form of SO 2 maxima frequently observed at the top of the PBL over northern Greece (Zerefos et al, 2000 and references herein; P. Formenti, personal communication). This phenomenon is likely to result in higher long-range transport of this compound.…”

“…Mihalopoulos et al (1997) showed that the highest levels of sulfate and nitrate measured on Crete originated from longrange transport of air masses coming from west and northcentral Europe. Zerefos et al (2000) assessed the role of long-range transport of air pollutants above Greece and estimated that 70% of the total SO 2 column above the northern Greece during NE flow could originate from lignite combustions in Central Europe. During the PAUR II campaign (Crete Island, May 1999), significant correlations were observed between ammonium sulfate mass, aerosol scattering coefficient and aerosol single-scattering albedo (ω 0 ), indicating the key role of ammonium sulfate in determining the radiative forcing of the Eastern Mediterranean area .…”

SO2 in Beirut: air quality implication and effects of local emissions and long-range transport

“…Another hypothesis relayed on a possible contribution of the thermal power station to the global concentration of SO 2 in Beirut. (Lelieveld et al 2002;Luria et al 1996;Sciare et al 2003;Zerefos et al 2000). Since the lifetime of SO 2 varies from a few days to weeks (Wayne 2000), the HYSPLIT model was used to establish the 48-h backward trajectories of air masses ending in Beirut for the whole period of the measurements.…”

Nine years of UV aerosol optical depth measurements at Thessaloniki, Greece

“…Apart from local pollution, aerosols that originate from biomass burning, anthropogenic aerosols from the highly populated urban centres and industrial areas of Central and Eastern Europe and maritime aerosols, converge over this area (Formenti et al, 2002;Balis et al, 2003). For the lower troposphere over the Mediterranean, particularly during summer, European pollution is mainly responsible for the reduction of air quality, whereas in the free troposphere pollution is largely determined by trans-boundary and possibly intercontinental transport (Zerefos et al, 2000;Lelieveld et al, 2002;Balis et al, 2003Balis et al, , 2004.…”