Urban air pollution control: selection of trees for ecological monitoring using anticipated performance indices in a medium-size urban area in Southwest Nigeria

Abstract

The study assessed the biochemical parameters, sensitivity and tolerance levels to air pollution of the leaves of selected tree species along major roads in Ile-Ife in order to determine the tree species that will be most suitable in developing greenbelts along roadsides. The air pollution tolerance index (APTI) ranged from 8.5 to 13.9 for the entire tree species studied with Gmelina arborea, Polyalthia longifolia, Mangifera indica, Terminalia catappa and Tectona grandis having the highest during the wet season, and Polyalthia longifolia with the APTI in the dry season. Newbouldia laevis, Spondias mombin, Gliricidia sepium, Senna siamea, Psidium guajava and Anacardium occidentale, Albizia zygia were classified as tree species sensitive to air pollution during both dry and wet seasons. With reference to the API grading, Mangifera indica, Tectona grandis, Gmelina arborea with percentage grading of 62.5% were classified as 'good' greenbelt performers. Anacardium occidentale, Terminalia catappa, Spondias mombin, Newbouldia laevis, Senna siamea, Polyalthia longifolia with percentage grading of 56.25%, each, were classified as 'moderate' performers while Gliricidia sepium (50%), Psidium guajava (50%) and Albizia zygia (43.75%) were classified as 'poor' performers for bio-indicators of air pollution. The study concluded that Gmelina arborea, Tectona grandis and Mangifera indica were good biomonitors for greenbelt development.