Evaluation of Urban Tree Species for Air Pollution Control: Integrating Air Pollution Tolerance Index (APTI), Anticipated Performance Index (API), and Socioeconomic Value in Ghana’s Central Region

Air pollution presents serious concerns to urbanized environments, necessitating the exploration of tree species capable of minimizing its affects. This study assessed the Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API) of four common tree species, Albizia lebbeck , Azadirachta indica , Khaya senegalensis , and Senna siamea along three major highways and a control road in the central region of Ghana. Physiological and biochemical parameters, including relative water content (RWC), leaf extract pH, ascorbic acid content, and total chlorophyll, were analyzed to calculate APTI, while API incorporated morphological and socioeconomic traits. One-way ANOVA and correlation matrices, were employed to evaluate variations across roads and relationships among some parameters. All the tree plants were classified as pollution-sensitive (APTI < 10), with Senna siamea showing relatively higher tolerance. Azadirachta indica exhibited significant resilience with consistent RWC and chlorophyll levels, earning the highest API score (81.25%) and an "Excellent" performance rating. In contrast, Albizia lebbeck showed significant reductions in chlorophyll and pH under polluted conditions, highlighting its potential as a bioindicator. These findings underscore the importance of integrating physiological, morphological, and socioeconomic criteria in urban tree selection. Azadirachta indica emerged as an ideal candidate for urban greenbelt development due to its adaptability and ecological benefits, while Albizia lebbeck and Senna siamea are valuable for bioindication of air pollution. This study provides a robust framework for sustainable urban greening and pollution mitigation in tropical regions. Further studies should include additional tree species and locations for a broader ecological perspective.