This study assessed the air pollution tolerance index (APTI) of four plants around the Seplat Gas Flow Station in Sapele, Delta State. Fresh leaves of the plants were collected, weighed, dried and extracts were made. Standardized procedures for determining APTI were adopted. The physio-biochemical characteristics of the four plant species ranged from; pH 4.57–5.36, chlorophyll content 0.17-0.45 mg/g, RWC 41.0%–80.0%, ascorbic acid: 0.91 – 1.58 mg/g, while APTI varied from 5.75 – 6.99. The result revealed that the APTI of all four plants fall into the sensitive category and the order of increasing sensitivity was Megathyrsus maximus > Pennisetum purpureum > Ficus exasperate > Axonopus compressus.