Evaluation of Air Pollution Tolerance Index (APTI) as a tool to monitor pollution and green belt development: A review

Air pollution is a global phenomenon arising out of the unsustainable, unplanned and rapid develop-ment. The quality of air is deteriorating day by day because of rising concentrations of various gases in the atmos-phere. Presently, no such system has been developed ever that completely eliminates air pollutants, but nature has created many systems to deal with the harmful results of different anthropogenic activities up to a certain limit. Some plants can survive well with higher pollutant concentrations and act as pollution scavenger. Green plants act as a sink and filter to minimize air pollution by absorption, adsorption, detoxification, accumulation and/or metabolization without sustaining serious decline in growth, thus improving air quality by providing oxygen to the atmosphere. The plants which can withstand higher pollutant concentrations can serve as tolerant species and may be suggested to act as pollution scavengers. In the present study the air pollution tolerance index of some plants has been reviewed which are widely distributed throughout India and may prove helpful for the abatement of elevated air pollution levels such as Mangifera indica, Azardirachta indica, Saraca indica, Ficus religiosa, Ficus benghalensis, Shorea robusta and Bougainvillea spp. The wild indigenous species are superior performers in air pollution reduction as compared to the cultivated non indigenous species. The screening out of tolerant plant species from the sensitive ones can provide a database which may help landscapers to design green belts around industries and National Highways.