Background and aim: Air pollution has emerged as a serious global issues. Among anthropogenic sources, only mobile sources, i.e., vehicles contribute 70% of total air pollution as it emit higher amount of air pollutants into the ambient atmosphere, which create negative impact on air quality. To reduce such impact, environmentalists and policy makers have emphasized on the necessary of bio-monitoring of air pollution by using trees. Malda is famous for mango orchards which are abundant along NH-34 and SH-10. This district is home of 200 folk mango varieties of which Fazli, Aswina, Laxmanbhog, Langra, and Himsagar are predominant, hence these varieties have been selected for bio-monitoring.
Methods: The present study was conducted alongside national and state highways, i.e., NH-34 and SH-10 within Malda district from January- December, 2016. Then, 24 hours monitoring of NO2, SO2, and PM10 was carried out. All the leaves samples were collected in triplicate for estimation of the Total chlorophyll (Tchl), Ascorbic Acid (ASC), Relative Water (RWC) content, and Air Pollution Tolerance Index (APTI).
Results: The monthly average concentration of NO2 was highest (22.04 μg.m-3) during December and lowest (19.04 μg.m-3) during June 2016. SO2 concentration was maximum (4.38 μg.m-3) during October and minimum (2.00 μg.m-3) during June and August. 24 h monthly average concentration of PM10 was highest during January (124.43 μg.m-3) and surpassed the NAAQS (100 μg.m-3). The average ASC, Tchl content, and RWC was found to be maximum in Fazli. Leaf extract pH ranged from 4.93 ± 0.70 in Langra to 6.46 ± 0.33 in Himsagar. The APTI value of Fazli was found maximum (22.12 ± 0.26) and recognized as tolerant species.
Conclusion: As per the APTI value, Fazli is found to be a tolerant species, and Aswina, Laxmanbhog, Langar, and Himsagar are sensitive species.