AIR POLLUTION TOLERANCE INDEX OF ROAD AVENUE TREES IN URBAN ECOSYSTEM OF LAHORE CITY (PUNJAB), PAKISTAN

Abstract

Lahore is one of the most polluted cities in the world and the second most populated city of Pakistan. Now a days, it is facing tremendous increase in population, rapid urbanization, unplanned industrialization and ever-increasing number of vehicles on its roads. All these phenomena are cumulatively affecting not only the human health drastically but also the quality and quantity of the plants. There is limited number of air quality monitoring stations in this city, so the road side plants which are naturally biomonitors of air pollution, are investigated for their tolerance and sensitivity towards air pollutants. For the present study, 11 dominant tree species in landscape of Lahore city were selected to determine the Air Pollution Tolerance Index (APTI). APTI was calculated by measuring the parameters i.e., chlorophyll content (mg/g), ascorbic acid content (mg/g), relative water content (%) and pH. Air Pollution Tolerance Index (APTI) in descending orderof Mangifera indica L. (9.95 ± 0.55), Alstonia scholaris L. 
(9.65 ± 0.25), Dalbergia sissoo Roxb. (9.054 ± 0.35), Syzygium cumini (L.)Skeels (8.80 ± 0.60), Salix tetrasperma Roxb. (8.40 ± 1.20), Callistemon lanceolatus DC (8.30 ± 0.90), Terminalia arjuna Roxb. Ex Dc.) Wt. & Arn. (8.05 ± 1.22), Heterophragma adenophyllum Seem. Ex Benth & Hook.f. (7.10 ± 0.50), Bauhinia variegata L. (6.75 ± 1.15), Salix babylonica L. (6.75 ± 0.55) and Cassia fistula L. (5.90 ± 1.70), respectively showing their sensitivity towards air pollutants.