The relationship between synoptic, mesoscale and microscale meteorological parameters during poor air quality events in Athens, Greece

This paper presents an analysis of some aspects of the ambient carbon monoxide (and some other pollutants) data from 1984–1993 recorded at 10 appropriately distributed locations in the Athens Basin. A major purpose of this study is to assess the influence of meteorological conditions on the concentrations of pollutants. Appropriate statistical methods have been applied which relate CO to wind speed and traffic patterns. In addition, an analysis of the meteorological conditions during days in which concentration levels exceed standards is given. The main characteristics of the results are: (i) The variation of CO, O3, NOx concentrations are strongly affected by traffic, wind speed and height of the inversion. (ii) It is difficult to define a firm urban rate of change for CO since it varies considerably from year to year, and it is not possible to unequivocally attribute the entire observed decrease to emission limitations and meteorological influences. An analysis of the seasonal, weekday and weekend diurnal variations is also presented. (iii) Surface ozone, NOx and other pollutant data at several urban and suburban stations in Athens with variable record lengths, all show a slight increasing trend.