Stressful environmental conditions have a profound influence on the formation of plant generative organs. Parameters characterizing the pollen are susceptible to large fluctuations over the years and are closely related to climatic conditions during the formation of pollen grains. This article presents the results of birch pollen investigations (Betula pendula Roth.). Examined trees grow in urban ecosystems on areas with different anthropogenic load. The complex of factors exogenous and endogenous nature, that characterizes the formation of male sterility in birch have been considered. The results on the impact of main climatic factors (temperature and humidity), and the effects of pollutants on the production of sterile pollen grains are presented in detail. The optimal parameters of temperature and humidity for the formation of minimum amount of pollen, characterized by male sterility have been revealed. The dependence of carbon monoxide atmospheric concentration and the level of pollen sterility is shown. The proposed by the author model allows predicting the level of birch sterile pollen (Betula pendula Roth.) in terms of Barnaul, depending on weather conditions, the level and content of pollutants in the atmosphere.