DIFFERENCES ON THE IMPACTS AND ORIGINS OF POLLEN IN FOUR MAJOR SWEDISH CITIES BETWEEN 2014 AND 2019

Abstract: Allergies are widespread in the world and coming from various sources, one of the causes being airborne allergens and especially, pollen. The negative impact of pollen is enhanced by pollution and climate change which are some of the biggest issue humankind is facing today. Pollen can be transported easily through the atmospheric pathway and air currents over thousands of kilometers, making the study and forecast of air currents very useful to predict high pollen episodes. In Sweden, already up to 24% of the population are affected by allergic rhinitis and this number is likely to increase. In this study I focused on four of the major Swedish cities: Gothenburg, Malmö, Stockholm and Umeå. I chose to compare the cities between them and between two years of high pollen counts, 2014 and 2019. I first studied the differences on the impact of pollen on allergy sufferers. I studied and tested the correlation between the pollen counts, the prescription rate and number of patients per 1000 inhabitants of antihistaminic drugs, between the two years and in the four cities. In a second part, I studied the backward trajectories of air currents, linked to pollen counts, to establish both a potential maximum area of coverage from the pollen traps, and, the potential origins of pollen in the Swedish cities during high pollen count days. The results were interesting, despite a strong correlation between the pollen count and the patients/prescription rate data, I found the later one being up to 31% higher in 2019 than 2014, while, the pollen count was lower in 2019. For the second part of the study, the pollen trap range could not be established, however a list of countries and regions being the most likely origin of pollens has been established for each city. Overall and across the four cities, Sweden, Norway, Finland, Denmark, Germany, Poland, Belarus, Estonia, Latvia and Lithuania are the most likely origins of pollens for the years 2014 and 2019. These data are allowing a more targeted surveillance of these areas, in an attempt to better forecast the high pollen periods and, ease the pollen allergy sufferer’s burden.