Since the end of the 1990s, the aerobiological network managed by the Regional Environmental Agency in Emilia-Romagna, Italy, started a systematic monitoring of different types of fungal spores, in particular Alternaria. This activity is of outstanding interest due to the various detrimental effects on human beings and on vegetation associated with Alternaria spores presence in the atmosphere. Daily concentration values of Alternaria spores are available from the Emilia-Romagna network in 10 stations. The availability of these data allows to set up a detailed analysis of the presence of Alternaria spores in different climatic and environmental settlements. The 19-year database of daily spore concentrations in most of the stations (1999–2017) can also support a preliminary analysis of climatic trends. A synthetic characterization of the main features associated with the presence and amount of Alternaria spores will be presented in this work. The period with the highest values of concentration in most of the measuring stations covers the warm season, with two main peaks of spore production in early and late summer. The most relevant trends for Alternaria season are mainly associated with an increase in the length of the period when spores are present. As for the amount of spores, signals are generally less evident, indicating a predominant decrease in the spore amount.