Potential of Tilia tomentosa to provide ecosystem services in terms of removing air pollutants

In contemporary debates on the problem of environmental pollution, particularly air pollution, opportunities for reducing and limiting emissions by identifying sources and implementing measures to reduce their harmful impact are increasingly sought-after. This requires the integration of additional methods for analysis and assessment of atmospheric air quality, which have a lower cost and allow a larger amount of data to be obtained. Such data may provide information not only about the levels of pollutants in the air, but also their impact on living organisms. Passive and active biomonitoring are now widely used as an alternative and complement to instrumental monitoring methods. Their advantages include lower cost and wider applicability in addition to the possibility of taking into account living organisms' responses to changes in their environment. The aim of this study is to carry out active phytomonitoring of air pollution in the city of Plovdiv (Bulgaria) using Tilia tomentosa saplings planted at four experimental sites with varying degrees of anthropogenic load in the spring of 2025. Field observations on the growth and physiology of the saplings were conducted monthly. Original results were obtained based on the dynamics of key processes such as photosynthesis and transpiration, the content of photosynthetic pigments and growth rates. The data analysis showed that significantly higher total chlorophyll and carotenoids content was found in the leaf samples from the two more strongly influenced sites, as well as a higher percentage of leaf injuries. The bioaccumulation rates of trees towards potentially toxic elements were also higher in these two plots. The results obtained can be applied for the sustainable management of an urban green system in order to enhance its potential to provide various ecosystem services such as air purification, improving the microclimate, noise suppression, aestheticization of the surrounding space and improving quality of life.