Strong seasonal effects and long-term weather-related factors drive the temporal variability of airborne pollen in the atmosphere of San Miguel de Tucumán, Argentina

Abstract Knowledge about variations in allergenic pollen in the atmosphere is essential for human health programmes. This study aims to evaluate the influence of climatic variability on the arboreal pollen (AP) load, considering the annual, seasonal and intra-diurnal variability during ten years. We obtain data using a volumetric Burkard spore trap in San Miguel de Tucumán city. The seasonal behaviour of AP showed a short and intense flowering period from August to October. However, annual pollen concentrations varied considerably with 2008 and 2012 the years with the lowest and highest pollen contributions, respectively. The qualitative composition of the AP was represented mainly by Broussonetia papyrifera, Morus, Celtis, Alnus, Platanus, Fraxinus, Myrtaceae, Juglans and Salix. During the ten years of continuous sampling, there was little variation in the pollen concentration per hour. The lowest and highest contribution occurred at 2 p.m., and 2 a.m., respectively. There was a strong seasonal effect on AP concentration. Air temperature positively affected AP concentrations, while air humidity negatively affected AP concentrations. Overall, the shape and intensity of the seasonal AP pattern in this region appears to be driven by long-term phenological dynamics.