THE SEASONAL AND DIURNAL-VARIATION OF SULFUR-DIOXIDE IN GREATER ATHENS AREA, GREECE

Hourly sulphur dioxide concentrations obtained by the Athens air pollu tion monitoring system for a eight-year period started in 1989 were an alysed. The analysis showed a strong seasonal variation, with maximum during the cold period of the year and a minimum during the warm perio d. The diurnal variation of sulphur dioxide concentrations for the win ter season, has a double peak structure. The morning peak is observed between 08:00 and 12:00 LST and the night peak from 20:00 until 23:00 LST. During summer period the dominant peak is observed between 09:00 - 11:00 LST. Maximum sulphur dioxide concentrations are observed at ce ntral-city residential stations (downtown Athens and Piraeus) during t he cold period of the year, while at stations located in industrial ar eas the seasonal variation has a very small amplitude. Auto-correlatio n technique is applied to the sulphur dioxide concentrations for winte r and summer seasons, for all stations. It is found that in all statio ns exhibit a well defined oscillatory behaviour because of their diurn al peaks in both seasons.