AN EXPERIMENTAL STUDY OF THE HORIZONTAL AND VERTICAL DISTRIBUTION OF OZONE OVER ATHENS

Abstract In this study, we present measurements of ozone (O 3 ) concentrations both on the surface and aloft, taken at sites appropriately located to give information about the effect of the local flows, such as the sea breeze circulation, on the air quality of Athens. Profiles of O 3 and other meteorological parameters of the atmospheric boundary layer were obtained at a location in the center of Athens. Surface measurements of O 3 were conducted in a number of other locations which included the shoreline and an island. The measurements confirmed well known models for the effect of sea breeze on photochemical pollutants and the diurnal variation of O 3 in the evolving atmospheric boundary layer and showed that pollutants released in the evening and early morning hours are advected offshore where they generate O 3 which in turn is advected back to the city by the sea breeze. They also showed that Athens pollutants are found in considerable concentrations in Aegina and outside the main basin to the north. The results of this study demonstrate the need to take into account advection patterns in any attempt to formulate pollution abatement strategies for sites with strong local circulations such as the Athens basin.