Assessment of air quality benefits of vegetation in an urban-industrial region of India by integrating air monitoring with i-Tree Eco model

In the last few years, urban trees have emerged as an effective nature-based solution to mitigate increasing air pollutant levels due to urbanization and industrialization. This study aims to assess the synergistic effect of urban trees on improving air quality by combining real-time PM_2.5 monitoring with the i-Tree Eco model. The monitoring was conducted during rush hours with high traffic volume and during non-rush hours, in both the tree alley and a non-tree road section within the industrial areas of the north-west region of the National Capital Territory of Delhi, India. The i-Tree Eco model was run using the diameter at breast height values of tree species present in the study area, and the PM_2.5 reduction ability of the trees was quantified. The results from both approaches indicated that urban trees can significantly reduce the traffic-fed PM_2.5 concentrations. Therefore, it is suggested that tree plantations be integrated into air pollution management strategies in urbanized regions with high traffic volumes. Although this study explores the initial link between trees and air quality in Delhi, further research incorporating local wind speed and direction measurements would provide a more comprehensive understanding of how trees influence air quality in any highly polluted urban setting.