Model assessment of air-pollution in Prague

Results of relatively simple gaussian dispersion model are presented. This model, developed in the beginning of this decade, is suitable mainly for determination of spatial distributions of annual mean concentrations of such kinds of air-pollution as sulphur dioxide (SO2), mixture of nitrogen oxides (NOx) or suspended particulate matter (SPM) from all types of emission sources located within the city - point sources, line sources and area sources. Model has been used in years 1994, 1996 and 1998 to assess the air-pollution distributions of the above mentioned kinds in the Prague area and the development of the air quality state. it contributed to the decision making process when possible impact of some changes in traffic system or in system of domestic heating, for example, has been investigated. In this contribution, behaviour of sulphur dioxide (SO2) and mixture of nitrogen oxides (NOx) ground concentration distributions are analyzed with respect to changing emission situation in Prague in recent years. Results show that SO2 ground concentration level decreases mainly due to changes in local heating methods and type of fuel used. Different trend can be seen in NOx ground concentrations thanks to rapid increase in the traffic density.