Air pollution mitigation and suspended particulate matter retention potential of selected plant species across seasonal variation in the urban area.

Air pollution is a pressing environmental concern in urban areas, especially in densely populated cities like Delhi, India. However, plant species can effectively capture airborne suspended pollutants. Given this, the present study aimed to investigate the seasonal variations (pre- and post-monsoon) in the pollution-mitigating potential, biochemical characteristics, and suspended particulate matter (SPM) capturing capacities of select plant species in Delhi. Also, using biochemical parameters, plant morphology, and socioeconomic factors, the study computed tolerance indices such as the Air Pollution Tolerance Index (APTI) and Anticipated Performance Index (API). Ficus religiosa L. exhibited the highest APTI value of 11.94, while Polyalthia longifolia (Sonn.) Thwaites displayed the lowest 7.99 APTI value during the pre-monsoon. Ficus benghalensis L. showed the maximum SPM adhesion on the leaves, with a deposition of 1305.46 µg/cm2, whereas F. religiosa exhibited the lowest SPM deposition of 56.62 µg/cm2. Moreover, the statistical analysis indicated a positive correlation between ascorbic acid and chlorophyll content (R2 > 0.6) with APTI. Also, F. religiosa demonstrated a significant Pearson's correlation (P < 0.05) between chlorophyll content and SPM deposition during the pre-monsoon. The study highlighted the dynamic nature of plant-based air pollution mitigation. It offered valuable insights into the potential of green infrastructure as a sustainable solution for addressing air quality concerns in urban environments. The results emphasized the significance of selecting adequate plant species and considering seasonal variations in developing urban greening strategies to combat air pollution.

Assessment of metals and metalloids agglutinated to airborne suspended particulate matter in selected plant species during the pre-and post-monsoon in the urban area.

The elemental accumulation has emerged as a major environmental concern due to various anthropogenic sources such as vehicles, road dust, and industrial activities, contributing to the agglutination of elements to airborne Suspended Particulate Matter (SPM). SPM-bound elements accumulate on plant surfaces impact air quality and human health due to their noxiousness. Therefore, plants' ability to capture and mitigate air pollutants plays a crucial role in urban areas. This study aimed to investigate the levels and distribution of twenty-six elements, comprised of heavy metals (Cd, Pb, Cr, Cu Zn, Co, Ni, Fe, Mn, Ag, Mo, V, Ga, and Bi), light metals (B, As, Te, and Se), and metalloids (Al, Li, Sr, K, Mg, Na, Ca, and Ba) accumulated on the surface and inside the leaves of dominant plant species during the pre-and post-monsoon at six categorized (commercial, traffic-prone, residential, educational, greenbelt and industrial areas) locations in Delhi, India. In addition, the Metal Accumulation Index (MAI) was determined, and the statistical analysis was conducted using two-way ANOVA, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis (HCA). In the pre-and post-monsoon, two-way ANOVA revealed significant differences (P < 0.05) in metal concentrations. During the pre-monsoon plants exhibited the highest metal accumulation (∼21%) at the Anand Vihar (commercial) in Delhi, with the maximum average concentrations of Cr (118.25 mg/kg), Cu (204.38 mg/kg), Zn (293.27 mg/kg), and Fe (2721.17 mg/kg). Ficus benghalensis L exhibited the maximum 213.73 MAI at the Anand Vihar in the pre-monsoon. Ni and Cr indicated the highest correlation (P < 0.05, r = 0.82) in the PCA test. HCA test revealed similarity (∼87.7%) at ITO (traffic-prone) and Okhla Phase-2 (industrial) in F. religiosa regarding metal concentration patterns. Findings highlighted seasonal elemental pollutants uptake dynamics of plant species and explored species-specific metal accumulation, revealing potential implications of metal-tolerant plants for urban greenbelt.