Assessment between Platanus pollen and Pla a 1 allergen in two cities of North-western Iberian Peninsula

Platanus pollen is considered as a major cause of pollinosis in many southern European cities. This tree is commonly used in parks, avenues and gardens as ornamental species. The flowering period is short and abrupt between March and April, since this tree is characterized by having fast and explosive blooming process. This fact induces an important public health problem when Platanus bloom. The objective of the study is to evaluate the pollen and allergen concentration in two cities in the north-west of the Iberian Peninsula, Porto (Portugal) and Ourense (Spain), and analyse how weather parameters and environmental pollutants can affect the patterns of pollen and allergen airborne distribution. The pollen sampling was conducted, during 2018, using a Hirst volumetric sampler, and Pla a 1 aeroallergen was collected using a Burkard multivial cyclone sampler. The pollen counting was obtained following the Spanish Aerobiology Network methodology. Aeroallergens were quantified by ELISA method using a Pla a 1-specific antibody. Platanus pollen concentrations are seven times lower in the Porto atmosphere than in Ourense, but the Pla a 1 content is only 2 times higher in Ourense city. These differences can be explained by the influence of air pollutants in plants and meteorological factors. Platanus airborne pollen and Pla a 1 aeroallergen were correlated with some meteorological parameters, namely temperature, rainfall and relative humidity, and with atmospheric pollutants such as NO2 and O3. The results suggest the existence of different allergenic activities in the atmosphere of both cities.