Assessment of Air Pollution Tolerance Index of Selected Plant Species Commonly Found along Roadsides in Pulau Pinang, Malaysia

This study focuses on the assessment of air pollution tolerance index (APTI) of two selected plant species commonly found along roadsides in Pulau Pinang, Malaysia. The plant species selected for the study were Bougainvillea sp. and Ficus sp. The plants were evaluated in terms of APTI by analyzing four different biochemical parameters leaf relative water content (RWC), ascorbic acid content (AA), total leaf chlorophyll (TCh) and pH of leaf extract. Based on APTI, Ficus sp. was found to be more tolerant compared to Bougainvillea sp. in all locations. Species with lower APTI value are considered sensitive species, which can be used as a biological indicator for further monitoring of air quality. Species with higher APTI value are tolerant species and thus, can be planted for pollution abatement in order to control and reduce environmental pollution.