Roadside Vegetation Research Paper

The term vegetation means total plant cover, roadside vegetation includes the plants that grow near the roadside. Vegetation can be an effective sink for airborne particulates which adheres to surface of leaves (Fowler et al., 1989). In urban areas, urban forest ecosystem plays a significant role in the adsorption of airborne particulates, thus, purifying air and also creating a positive visual and health impact (Wei-Kang et al., 2015).
In Urban areas, roadside vegetation is fruitful in overcoming air pollution produced by vehicular activity as trees are good absorbents of air pollutants. Besides reducing air pollution, roadside vegetation is aesthetically important. It also controls road run off and increase biodiversity in the area (Cavanagh,
Mostly, the studies were carried out in developed countries about particulate matter concentration in roadside plants. Very limited studies have been carried out in developing countries about particulate matter concentration in roadside vegetation (Tanushree et al., 2011).
Particulates adsorb on the surface of vegetation temporarily and can later be washed off from the leaves with rain and deposited in soil/ground, where natural processes decompose the organic components of PM, while the inorganic components are accumulated in soil and the soil solution (Dzierżanowski et al., 2011). Surface interactions play an important role for longer retention of particles on the leaves surface. For instance, if leaf surface is wet or sticky then particles stay on surface for longer period of time (Cavanagh,
Ottelé et al., 2009). Leaves of some species possess specific morphological features that may enhance air filtration process by capturing more particles, such as, trichomes and structure of epicuticular wax layer (Bakker et al., 1999). Species with trichomes, wide and rough leaf surfaces and thicker epicuticular wax layer are considered more effective accumulators of PM (Li et al., 2015). The epicuticular wax layer, its thickness and composition are important factors for PM accumulation, because some particles penetrate inside it and are deposited there (Kaupp et al., 2000). Particulate matters are captured by twigs and bark and remain there for long time period because of their surface characteristics. Mainly, leaves act as constant absorbers for particulate matters as they are more exposed part of the plant (Samal and Santra, 2002). Trees capture more particulate matter as compared to shrubs and herbs. The structure of tree crowns leads to turbulent air movements, which increase PM deposition on leaves (Fowler et al., 1989). Trees, with their large total leaf area, are considered the most effective type of vegetation for this purpose (McDonald et al.,