Roadside Plants as Bio-indicators of Urban Air Pollution

Abstract

This paper describes air pollution tolerance among roadside plants exposed to varying degrees of vehicular pollutants. Evaluation of air pollution tolerance index (APTI) of 10 selected wild plant species was carried out to assess their response to ambient levels of air pollutants along the busy roadways of Ahemadnagar Four parameters namely total chlorophyll, ascorbic acid, pH of leaf extract and relative water content were determined and computed together to signify air pollution tolerance index (APTI) of plants. The observed significant reduction in total chlorophyll, ascorbic acid and relative water content showed inverse relationship with traffic density. Similarly, pH of leaf extract followed an exponential decrease with increase in traffic density and drifted towards acidic range. Comparison of APTI values from control to polluted sites revealed maximum reduction in Bougainvillea spectabilis while least change was noted in Peltophorum pterocarpum. Among the plants studied maximum net per cent reduction of APTI over control was seen in Bougainvillea spectabilis and Ageratum conyzoides and are considered to be sensitive species. While Peltophorum pterocarpum and Portulaca oleraceae are tolerant species since they have shown least per cent reduction in APTI.