RESUMEN
Pollen concentrations in the atmosphere of Istanbul, a city located between two continents, has been monitored for 1 year as part of a larger research program. The sampling sites were located in two different continents: the Asian part (AS) and the European part (EP). The sampling was performed in AS and EP of the city by using Hirst type volumetric method, and pollen grains of 58 and 62 taxa were identified in the two parts, respectively. The pollen spectrum reflected the floristic diversity of the region. The main pollen producers at the sites were characterized by some allergenic pollen and were identified as Cupressaceae/Taxaceae, Urticaceae, Pistacia sp., Quercus sp., Platanus sp., Fraxinus sp., and Xanthium sp. These pollen types contributed to the total pollen sum with a percentage of more than 80% at both monitoring sites. The highest amount of pollen grains was recorded in April. The greatest number of species was recorded in May, when 42 types (AS) and 44 types (EP) were present.