Knowledge of seasonal and diurnal fluctuations of allergenic and phytopathogenic fungal spores in the air and the determination of the influence of weather and environmental parameters on spore concentrations are of great practical use in control of both human and animal health as well as plant diseases. The aim of this study was to evaluate the dynamics of the occurrence of Alternaria spores in the air at three sites located in different geographical regions of Poland. The study was done from 15 April to 30 September in 2010–2011 in Rzeszów (Carpathian Foothills, south-east Poland), Lublin (Lublin Upland, central east), and Poznań (central west); the distance between the experimental sites ranged from 138 to 441 km. To assess the concentration of Alternaria spores, the volumetric method was used. In both years, the highest concentration of spores was observed in Poznań and the lowest in Rzeszów. In 2010 the annual total, monthly total and maximum spore concentration were higher than in 2011 at all monitoring sites. The greatest concentration of Alternaria spores was recorded in August, followed by July. High spore concentrations were also noted at the beginning of September. The differences in daily concentrations, average concentrations and cumulative numbers of spores were statistically significant. The reasons for this can be related not only to weather parameters, which is often raised in the literature, but also to the type of landscape. Landscape and geo-botanical conditions of Great Poland and Carpathian Foothills greatly differ. In both years, the highest number of Alternaria spores was found in Poznań – the city with the highest urbanization factor and the capital of the region with large-scale farming, connected with the intensification of agricultural practices.