Atmospheric net particle accumulation on 96 plant species with contrasting morphological and anatomical leaf characteristics in a common garden experiment

Abstract

Urban green spaces function as biological filters in reducing atmospheric particles. Yet there is a profound requisite to identify the most effective plant species by their leaf traits that can enhance particle capture and improve ambient air quality. In this study, we investigated leaves of 96 perennial urban plant species consisting of 43 deciduous broadleaf trees, 32 deciduous broadleaf shrubs, 14 deciduous and evergreen needle/scale-like, 5 evergreen broadleaves, and 2 climber species for their differences in net particle accumulation. Leaf saturation isothermal remanent magnetization (SIRM), a proxy for traffic and industry induced particle accumulation, along with morphological and anatomical leaf traits were analyzed in a common garden experiment in June and September 2016. Leaf SIRM varied significantly between plant species. The most effective net particle accumulating plant species with a median value of 23.0 μA were Buddleja davidii, Viburnum opulus, Carpinus betulus, Quercus ilex, Viburnum lantana, Rosa rugosa, Sorbus aria, Aesculus hippocastanum, Pseudotsuga menziesii, Acer campestre. The least effective net particle accumulating plant species with a median value of 10.4 μA were Populus alba, Alnus glutinosa, Larix kaempferi, Larix decidua, Plantanus x acerilifolia, Acer pseudoplatanus, Robinia pseudoacacia, Quercus palustris, Rosa canina, Liquidambar styraciflua. The “variable importance” in net particle accumulation for the investigated plant species was achieved using ®randomForest. The presence of leaf trichomes and specific leaf area were identified as important leaf traits for categorization of the selected plant species in low, medium, and high net particle accumulators. The extensive analysis of plant species at leaf-level with distinct micro-morphology contributes to a better understanding of plant species behavior in net particle capture and their contribution in reducing atmospheric particulate matter. Furthermore, this study has practical implications for policymakers in making informed choices when planning urban green infrastructures. Lastly, our study can become a basis to validate atmospheric deposition model using species-specific information.