Variations and trends of Betula pollen seasons in Moscow (Russia) in relation to meteorological parameters

This study investigates possible links of meteorological data and the start date, end date, duration, date of peak, peak value and Seasonal Pollen Index (SPI) of birch pollen seasons recorded in Moscow, Russia, during 1993–2015. Pollen data were collected by a volumetric spore trap. Correlation analysis was used to study relationships between various parameters of pollen seasons. Simple linear regression analysis was conducted to investigate trends over time; multiple stepwise regression analysis was used to describe SPI fluctuations as a function of seasonal or monthly climatic parameters. Air temperatures increased significantly during the study period, but no effect on the timing of the birch pollen season was found. Only the severity of the season showed significant changes that can be considered as a consequence of global warming. Rainfall in May and June of the year preceding flowering, total rainfall in the 40-day pre-season period and average temperature during the pollination were shown to be the most important parameters affecting birch pollen concentrations.