Modelling of PM2.5 episodes in four cities of northwestern Greece

A two-years period of measurements of particulate matter (aerodynamic diameter less than 2.5 mu m; PM2.5) concentrations have been used in order to model seasonal concentrations at the main cities of West Macedonia region, namely Kozani, Florina, Kastoria, and Grevena. This study represents an interesting approach for areas close to lignite-mining operations and lignite-fired power stations that result in major particulate pollution (flyash and fugitive dust). The problem is more complicated for urban areas due to additional contributions from urban pollution sources. For the period of sampling, a number of selected days with relatively high mean daily PM2.5 concentration have been modeled, in order to assess the dominant meteorological conditions in the four cities of the area. The Air Pollution Model (TAPM) has been employed in order to deal with the specified periods by the approximation of particles' trajectories and wind fields. The model predicted influence from stack emission only in the cities of Kozani and Grevena, for the respective experimental periods. The analysis has indicated that a system of meteorological conditions and topographic complexity modulate the transferable particulate pollution of the area examined. However, it remained to be a qualitative approximation, due to the absence of detailed emission inventories in the area.