Avenue plantations in Delhi and their efficacy in mitigating air pollution

ABSTRACT

To develop effective vegetation strips for filtering out point source air pollutants, several characteristics of vegetation strips and concentrations of 6 air pollutants (PM₁₀, PM_2.5, SO₂, NO_X, ozone, benzene) at five sites in Delhi were studied. Four air pollutants were within the prescribed limits; whereas the concentration of PM₁₀ (80.27−710 μg/m³) was 3-4 times while PM_2.5 (27.34−327.11 μg/m³) was 2-3 times higher than the standard limits notified by the Ministry of Environment, Forest and Climate Change, Government of India in 2009. Anand Vihar (AV) was the most polluted site whereas the Mandir Marg (MM) the least polluted. Species composition of the vegetation strips and their abundance, canopy type, and size of the leaf determined the efficacy as a filter for air pollutants. The abundance of broadleaved species such as Ficus religiosa, Alstonia scholaris and Polyalthia longifolia showed negative, statistically significant (p < 0.01) relationships with all the air pollutants analysed suggesting an abundance of broadleaved trees are effective in the filtration of air pollutants. The abundance of microphyllous trees such as Prosopis juliflora were the least effective filters. Ficus religiosa was the most effective tree species with respect to filtering air pollutants and particulate matter.

KEYWORDS:

• Air pollutants
• filters
• urban trees
• vegetation strips

Acknowledgments

We are thankful to the Principal of Shivaji College, Dr. Shashi Nijhawan for providing the research facility. We also acknowledge Delhi Pollution Control Committee (DPCC), Govt. of NCT Delhi. The contribution of Bhawna, Monika, Shubham, Anshu, Mallika, and Manish for field data collection is also acknowledged. We are grateful to the reviewer for their constructive suggestions and corrections made on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are thankful for University of Delhi for providing the grant (SHC 307) under Innovation project scheme.

Notes on contributors

Vijay Kumar

Vijay Kumar has a PhD in Botany from the University of Delhi and is currently teaching as an assistant professor in Botany at Shivaji College (University of Delhi). He has been working on the vegetation development on the fly ash dykes/dumps and also in the development of vegetation filter strips to control air pollution. He has an expertise in Restoration Ecology and Bioremediation.

Virat Jolli

Virat Jolli has a PhD in Environmental Studies from the University of Delhi and is currently teaching as an assistant professor in Environmental Studies at Shivaji College (University of Delhi). His specialisation is in Biodiversity Conservation and Environmental Impact Assessment.

Cherukuri Raghvendra Babu

Cherukuri Raghvendra Babu has a D.Phil. in Botany from Calcutta University and is Professor Emeritus at the Centre for Environmental Management of Degraded Ecosystems (University of Delhi). He has been working for more than three decades in the areas of Environment and Ecology. His expertise is in the conservation of biodiversity and the ecological restoration of degraded ecosystems.