Air pollution tolerance index (APTI) and expected performance index (EPI) of trees in sambalpur town of India

Abstract

Poor disposal of waste and release of pollutants to the environment through urbanization, industrialization and anthropogenic activities have been a serious threat to human health. Therefore, there is a need to evaluate the pollution status of towns through the identification of bio-monitor and bio-indicator trees. Keeping this in view, a work was undertaken to study the Air Pollution Tolerance Index (APTI) and Expected Performance Index (EPI) of trees in Sambalpur town, located in Western flanks of Eastern India during three seasons (monsoon, post-monsoon and pre-monsoon) in 2015–16. The measurements of different biochemical parameters (ascorbic acid: di-chlorophenol indophenol method of Keller and Schwager (Eur J For Pathol 7:338–350, 1977); leaf extract pH: electrometric method of Liu and Ding 2008; relative water content: oven dry method of Prajapati and Tripathi (2008) and total chlorophyll: acetone extraction method of Arnon (Plant Physiol 24:1–15, 1949), and socio-economic characters (plant habit, canopy structure, and type of plant, laminar structure and economic value as per Moore and Chapman (Methods in plant ecology, Blackwell Scientific Publications, Oxford, 1986) and Noor et al. (Environ Geochem Health 1–15, 2014) of selected 21 trees were carried out from five polluted or experimental sites (i.e. Remed, Ainthapali, Dhankauda, Dhanupali and Durgapali) and a non-polluted or control site (i.e. Sambalpur University campus) based on commonness of tree species to all the sites and close proximity to the roads. A total of 45 samples (3 trees of each species × 5 leaves from each tree x three replicates per treatment) for every species in each site were analysed as per above standard protocol and methodology. The APTI of the trees in the control site ranged from 8.99 (Butea monosperma) to 31.63 (Peltophorum pterocarpum), while that in the experimental sites it was ranged from 10.47 (Tamarindus indica) to18.04 (Mimusops elengi). In most cases of trees (67.71%), the APTI values were higher in experimental sites than the selected trees in control site, indicating thereby that the species having higher APTI values had a greater tolerance against air pollution. The categories of various trees, classified on the basis of overall APTI, revealed that in the control site 66.67, 19.05 and 14.28% of the total trees were in the intermediately tolerant (IT), moderately tolerant (MT) and tolerant (T) categories respectively; whereas in the experimental sites, 42.86, 23.81, 19.05 and 14.28% of the species were in the intermediately tolerant (IT), moderately tolerant (MT), tolerant (T) and sensitive (S) categories respectively. Finally, based on the EPI scores, the trees found to be fit for plantations are Ficus religiosa, Madhuca indica, Azadirachta indica, Artocarpus heterophyllus, Mangifera indica, Ficus benghalensis and Syzygium cumini, owing to their placement in Best or Excellent category (81–100%). On the other hand, species like Ziziphus jujuba, Tamarindus indica and Thevetia peruviana can be used as good bio-indicators due to their low EPI scores (31–50%). This work will be highly useful in formulating the management strategy against rising air pollution issues of the developing urban areas.