Air pollution is a significant contributor of urbanization and traffic-related activities, especially via greater deposition of particulate matter and physiological stresses associated with urban vegetation. This paper examines the effects of urbanization on the leaves of Tilia × europaea through the combination of physical, biochemical and physiological parameters to determine the effect of air pollution in the leaves. Samples of leaves were taken in traffic sites and control sites in Debrecen, Hungary and subjected to analysis of deposition of dust and photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), relative water content (RWC), ascorbic acid levels, leaf extract pH and Air Pollution Tolerance Index (APTI). Findings showed that spatial differences existed in all the parameters measured, which were a result of urban environmental conditions. Although there were no significant differences in the dust deposition between the sites, the Tilia leaves had a high potential to trap the particulate matter in both conditions. There was a great variation in the chlorophyll a concentration with a significant higher concentration in the traffic exposed areas indicating adaptive or compensatory mechanisms of environmental stress. Conversely, chlorophyll b and total chlorophyll were more in control areas, which shows that pigments could be undergoing degradation because of the presence of pollution. There were no statistically significant changes in other parameters, such as carotenoids, RWC, pH, and ascorbic acid, but there were trends that indicated physiological adaptation to urban stressors. The APTI values were quite site-specific, which proves the sensitivity of the given integrated index when it comes to identifying the level of pollution tolerance. Altogether, the results indicate that Tilia × europaea can be considered an effective bioindicator species of urban air pollution. The research shows that a combination of several leaf-based parameters offers an overall evaluation of the plant responses to environmental stress and can be used to employ APTI in city ecological surveillance. These findings also enhance comprehension of the adaptation mechanisms of plants in polluted environments, and have practical implications on urban green space planning and air quality management.