Intercomparison of the CALMET/CALPUFF Modeling System for Selected Horizontal Grid Resolutions at a Local Scale: A Case Study of the MSWI Plant in Krakow, Poland

Increase in grid resolution in atmospheric non-steady-state dispersion models induces a more faithful reflection of the area surface, and thus contributes to more detailed and diversified calculation results but also significantly prolongs the calculation time. This paper presents the influence of horizontal grid resolution in the CALMET/CALPUFF modeling system on the results of air quality impact assessment in a local scale carried out for the Municipal Solid Waste Incineration (MSWI) Plant in Krakow using the maximum permissible emission of NOx. Subject to comparative analysis were four grids of the following resolutions: 100, 250, 500 and 1000 m. A direct intercomparison of air concentrations was made for 676 discrete receptors with the use of statistical indicators. On the basis of the calculations and analyses, it has been stated that, depending on the regular grid spacing, some differences in calculated concentrations can occur affecting the results of the air quality impact assessment. The highest concentrations in all computational receptors present in the given case were obtained for 100 m grid spacing. When compared to a grid of 100 m, the relatively smallest discrepancies were obtained for a grid of 250 m, with an already significantly shortened calculation time.