Α Review of Surface and Lower Troposphere Ozone Concentration Characteristics Around the Urban Area of Athens, the Aegean Sea and at the Central and Eastern Mediterranean

Abstract

During the last 20 years, systematic studies of the variability of ozoneconcentrations by analyzing surface ozone measurements at peripheralAthens stations and at rural sites at Central Greece, the Aegean Sea andthe Central and Eastern Mediterranean have been carried out. Also,ozone, humidity and carbon monoxide summertime vertical profilescollected over some Aegean and Eastern Mediterranean airports within theMOZAIC project have been analyzed. Special focus was given to the studyof atmospheric circulation in the European/N. African sector by usingcomposite synoptic meteorological maps during high and low summer ozoneepisodes. It comes out that for the examined area in the lowertroposphere and in the boundary layer the role of the synoptic weatherconditions and the associated large-scale transport of air masses seemto be more important for the ozone variability than the local orregional short-term ozone photochemical production. The highest ozoneconcentrations are associated with large scale tropospheric subsidenceof ozone rich air masses under prevailing anticyclonic conditions (N.Africa) while the lowest ozone concentrations are associated with lowpressure prevailing conditions (N. Europe) inducing a strong westerlyflow of Atlantic air masses poor in ozone and rich in humidity to theMediterranean basin.