Air Pollution Mitigation Potential of Dominant Landscape Plants of an Urban Ecosystem (Lahore City) of Pakistan: An Air Pollution Tolerance Index (APTI) Assessment

Abstract

Lahore, the second largest city of Pakistan with higher population and large industrial zones, is under tremendous environmental stress of increasing air pollution. Roadside plants can mitigate increasing pollution rate by serving as a natural sink. This research work was designed to evaluate the role of roadside plantation in pollution mitigation in an urban ecosystem of Lahore. In this urban ecosystem, three busiest roadsides i.e., Zafar Ali Road, Canal Road and Jail Road with heavy traffic flow and commonness of plants were selected as sampling sites. Air Pollution Tolerance Index (APTI) of the selected plants was calculated through chlorophyll content (mg/g), ascorbic acid content (mg/g), relative water content (%) and pH. At control sites, ascorbic acid ranges from 3.11±0.21 (Cosmos sulphureus) to 1.18±0.08 (Tabarnaemontana divaricata) while at polluted sites, it was found to range from 2.95±0.09 (Cosmos sulphureus) to 1.03±0.08 (Tabarnaemontana divaricata). Chlorophyll content ranged from 37.00 ±1.11 (Ficus religiosa) to 5.28±1.22 (Hibiscus rosa sinensis) at control sites, while at polluted sites, it ranged from 29.09±1.15 (Ficus reliogiosa) to 5.56±0.95 (Tabarnaemontana divaricata). At control sites, relative water content ranged from 198.76 ±2.45 (Catharanthus roseus) to 10.02±1.95 (Tabarnaemontana divaricata) while at polluted sites, it was found to range from 192.40±2.11 (Catharanthus roseus) to 9.50 ±1.18 (Tabarnaemontana divaricata). At control sites pH value ranged from 6.69±0.21 (Catharanthus roseus) to 5.04 ± 0.45 (Alstonia scholaris). At polluted sites, it ranged from 6.69±0.21 (Catharanthus roseus) to 5.42±0.48 (Alstonia scholaris). At control sites, APTI value varies from 28.45±0.21 (Catharanthus roseus) to 2.59±0.11 (Tabarnaemontana divaricata).