Assessment And Characterization Of Dust Particles From Tree Leaves As An Indicator Of Air Pollution In Urban Local Bodies : A Case Study On Barrackpore Sub-Division, West Bengal

摘要

Urban growth in terms of population and areal expansion, changing scenario of landscape, conversion of non-built-up land to impervious land has been an increasing trend in worldwide. The gradual increase of concrete roads, cementation of imperviousness in urban extent, rapid growth of motor vehicles, domestic and industrial emissions are becoming a serious issue for the environment which degrade the urban health quality. To access the level of air pollution in urban areas, environmental monitoring is needed. Environmental monitoring can be done by active and passive processes. Active monitoring is having several limitations, so passive monitoring is being given much importance to monitor air pollution in recent days. The dust deposited over the roadside tree leaves are one of the indicators of environmental air pollution. In the present study tree leaves (Polyalthia longifolia) with dust from 4 selected sample sites were taken considering the urban characteristics, traffic junctions and industrial areas of Barrackpore subdivisions of West Bengal, India to characterize and analyze the size distribution, presence of different elements in the dust which are responsible for air pollution in the atmosphere. Scanning electron microscope (SEM) analysis was used to detect the size distribution of dust particles and SEM attached to an energy dispersive x-ray spectrometer (SEM-EDX) was used to analyze the elemental distribution of the dust. Elemental analysis has displayed the presence of elements, like Mg, Al, Si, Cl, K, Ca, S, C, Fe, Zn, Pb and Ti in the collected samples that indicates the air pollution concentration in the different urban unit. The mineral composition in the elements was observed by x-ray diffraction analysis (XRD). The phase identification from XRD has identified quartz, potassium, magnetite, carbon, feldspar, scrutinyite, cristobalite, silicon, oxide, etc., are present in the samples. The size variation and frequency of the particulates have also been categorized in each sample site. The results show that below 2.5 mm particles are dominants everywhere that indicate the air quality is poor.