Application of the FAPPS system based on the CALPUFF model in short-term air pollution forecasting in Krakow and Lesser Poland

: The aim of the study is to present the FAPPS (Forecasting of Air Pollution Propagation System) based on the CALPUFF puff dispersion model, used for short-term air quality forecasting in Krakow and Lesser Poland. The article presents two methods of operational air quality forecasting in Krakow. The quality of forecasts was assessed on the basis of PM 10 concentrations measured at eight air quality monitoring stations in 2019 in Krakow. Apart from the standard quantitative forecast, a qualitative forecast was presented, specifying the percentage shares of the city area with PM 10 concentrations in six concentration classes. For both methods, it was shown how the adjustment of the emissions in the FAPPS system to changes in emissions related to the systemic elimination of coal furnaces in Krakow influenced the quality of forecasts. For standard forecasts, after the emission change on June 7, 2019, the average RMSE value decreased from 23.9 μg/m 3 to 14.9 μg/m 3 , the average FB value changed from -0.200 to -0.063, and the share of correct forecasts increased from 0.74 to 0.91. For qualitative forecasts, for the entire year 2019 and separately for the periods from January to March and October to December, Hit Rate values of 5.43, 2.18 and 3.48 were obtained, the False Alarm Ratios were 0.28, 0.24 and 0,26, and the Probability of Detection values were 0.66, 0.75, and 0.74. The presented results show that the FAPPS system is a useful tool for modelling air pollution in urbanized and industrialized areas with complex terrain.