Numerical simulation of photochemical smog formation in Athens, Greece—A case study

High emission levels and the unfavourable topography are the main reasons for the alarming photochemical air pollution levels in Athens. An analysis of available air quality data proves that air pollution levels in Athens are largely affected by local wind circulation systems. The most frequent of these systems is dominated by the phenomenon of the sea breeze. Severe air pollution episodes occur, however, primarily under synoptic situations leading to stagnant conditions in the atmosphere over Athens. Photosmog formation in the Athens Basin is studied with the photochemical dispersion model MARS. The implicit solution algorithm incorporated in MARS is characterized by a variable time increment and a variable order. This solver allows avoiding unnecessary operator splitting by a coupled treatment of vertical diffusion and chemical kinetics. In this paper, MARS is used to analyse the situation on 25 May 1990, a day for which very high air pollution levels were reported in Athens. The simulation results elucidate the characteristics of a photosmog episode under stagnant conditions in Athens. In general, the model results reproduce satisfactorily the observed air pollution patterns.

[1]  Christos Zerefos,et al.  Assessment of the potential for photochemical air pollution in Athens : a comparison of emissions and air-pollutant levels in Athens with those in Los Angeles , 1992 .

[2]  N. Moussiopoulos,et al.  Numerical tests of a refined flux corrected transport advection scheme , 1995 .

[3]  Nicolas Moussiopoulos,et al.  Simulation of the wind field in Athens using refined boundary conditions , 1995 .

[4]  William R. Goodin,et al.  Numerical solution of the atmospheric diffusion equation for chemically reacting flows , 1982 .

[5]  G. Kallos,et al.  Modeling of photochemical pollution in Athens, Greece. Application of the RAMS-CALGRID modeling system , 1993 .

[6]  A New Technique for the Solution of Diffusion Equation Systems for Reacting Pollutants , 1987 .

[7]  Walter A. Lyons,et al.  Photochemical oxidant transport - Mesoscale lake breeze and synoptic-scale aspects , 1976 .

[8]  Ami Harten,et al.  On a large time-step high resolution scheme , 1986 .

[9]  Robert G. Lamb.  Note on the application of K-Theory to diffusion problems involving nonlinear chemical reactions , 1973 .

[10]  D. N. Asimakopoulos,et al.  AN EXPERIMENTAL STUDY OF THE HORIZONTAL AND VERTICAL DISTRIBUTION OF OZONE OVER ATHENS , 1987 .

[11]  P. Smolarkiewicz.  A Fully Multidimensional Positive Definite Advection Transport Algorithm with Small Implicit Diffusion , 1984 .

[12]  N. Moussiopoulos.  Photochemical air pollution in Athens , 1993 .

[13]  N. Moussiopoulos.  A numerical simulation of the sea-breeze in Athens , 1985 .

[14]  Paolo Zannetti,et al.  Computer Techniques in Environmental Studies , 1899 .

[15]  J. Bottenheim,et al.  Modelling study of a chemically reactive power plant plume , 1982 .

[16]  M. Petrakis,et al.  Characteristics of air pollution during the summer in Athens, Greece , 1985 .

[17]  G. Kallos,et al.  Synoptic and mesoscale weather conditions during air pollution episodes in Athens, Greece , 1993 .

[18]  Nicolas Moussiopoulos,et al.  Numerical simulation of the photochemical air pollution levels in Athens, Greece , 1988 .

[19]  Bang Quoc Ho,et al.  Urban Air Pollution , 1994 .

[20]  H. Güsten,et al.  Formation, Transport and Control of Photochemical Smog , 1986 .

[21]  N. Moussiopoulos.  Athenian photochemical smog: intercomparison of simulations (APSIS), background and objectives , 1993 .

[22]  D. Deligiorgi,et al.  Sea-breeze circulation and photochemical pollution in Athens, Greece , 1983 .

[23]  Zissis Samaras,et al.  Policy for reduction of traffic-related emissions in the greater Athens area , 1994 .

[24]  N. Moussiopoulos,et al.  Intercomparison of two models for the dispersion of chemically reacting pollutants , 1991 .