Efficacy of Tree Leaves as Bioindicator to Assess Air Pollution Based on Using Composite Proxy Measure

Abstract

Air pollution has become a major issue in cities due to urbanization, population growth, industrial development, and increasing number of vehicles. The study used Gmelina arborea tree leaves as a bioindicator to determine the Air Pollution Tolerance Index (APTI) as a simple and effective compositional index of environmental health in three cities in the Caraga Region, Philippines. To calculate the APTI, four biochemical parameters of tree leaves were calculated: relative water content, total chlorophyll content, leaf-extract pH, and ascorbic acid content. In terms of the APTI category, results showed that all G. arborea species collected in all sample sites are classified as sensitive to air pollution, with the sample collected in Bayugan City being the most sensitive, with an APTI value of 7.66, and the samples collected in Butuan and Cabadbaran City being the least sensitive, with APTI values of 9.54 and 9.11, respectively. A Kruskal-Wallis test revealed a significant difference between the APTI values of G. arborea trees in the three sampling areas in the Caraga region. Based on the APTI computed values of the tree leaves determined in all sites, it is concluded that G. arborea species can be used as a bioindicator of air pollution, classified as sensitive.

Keywords

• apti, bioindicator, leaf extract ph, total chlorophyll content, air pollution