Seasonal Variations in Air Pollution Tolerance Index (APTI) of Selected Avenue Tree Species in Bhubaneswar, Odisha

The study examines spatial and seasonal variations in the air pollution tolerance index (APTI) of four tree species (Ficus religiosa, Polyalthia longifolia, Syzygium cumini, and Lagerstroemia speciosa) across three sites (industrial, traffic, and natural forest area) in Bhubaneswar city of Odisha. Significant variations in leaf biochemical parameters (leaf pH, ascorbic acid, total chlorophyll, and relative water content) were observed among species, depending on site conditions and seasons. The calculated APTI value (using four biochemical parameters) inferred P. longifolia as tolerant (33.97), F. religiosa moderately tolerant (22.07 to 25.46) towards air pollution. Conversely, S. cumini and L. speciosa showed lower APTI value, indicating their sensitivity to the polluted environment. Irrespective of species, pollution tolerance was higher in the rainy season than in the winter and summer seasons. Pearson's correlation study revealed that leaf relative water content and ascorbic acid enhance the tree's defence against pollution-induced oxidative stress. Study suggest P. longifolia and F. religiosa are best for urban afforestation, avenue plantation, and air pollution control management in Bhubaneswar.