Pollen calendars and regional gradients as information tools in the Extremadura pollen monitoring network (SW Spain)

Pollen allergies are one of the most important problems among respiratory diseases in today's society. The creation and development of aerobiological information tools are useful to provide information to patients and doctors. In this work, we analysed the pollen spectrum of Extremadura to generate pollen calendars for Badajoz, Caceres, Don Benito, Plasencia and Zafra. Additionally, we analysed regional pollen gradients and plotted the main pollen season (MPS) characteristics (start date, peak date, end date and duration) in each city. In Extremadura, 35-40 different types of pollen are frequently identified, the most abundant of which (in decreasing order) belong toQuercus, Poaceae,Olea, Cupressaceae,Platanus,PlantagoandPinus. The dates when the highest accumulation of pollen occurs in the air are from mid-April to the end of May in Badajoz and Caceres; from mid-March to early June for Don Benito; from mid-April to early June for Plasencia; and from mid-April to 10 June for Zafra. Moreover, it could be confirmed that in the Extremadura region, the start date and the peak date occur earlier in the cities in the south of the region and that the duration of the pollen season is longer in these cities. The differences observed among cities may be due to the varieties of urban species and their management (pruning and irrigation), the influence of peri-urban landscapes, medium- and long-distance pollen transport and climate. The representation and geolocation of pollen calendars obtained using geographic gradients provide information in a simple, fast and visual way and can be of great interest to allergic patients and health professionals.