Effects of species-specific leaf characteristics and reduced water availability on fine particle capture efficiency of trees

Trees can improve air quality by capturing particles in their foliage. We determined the particle capture efficiencies of coniferous Pinus sylvestris and three broadleaved species: Betula pendula, Betula pubescens and Tilia vulgaris in a wind tunnel using NaCl particles. The importance of leaf surface structure, physiology and moderate soil drought on the particle capture efficiencies of the trees were determined. The results confirm earlier findings of more efficient particle capture by conifers compared to broadleaved plants. The particle capture efficiency of P. sylvestris (0.21%) was significantly higher than those of B. pubescens, T. vulgaris and B. pendula (0.083%, 0.047%, 0.043%, respectively). The small leaf size of P. sylvestris was the major characteristic that increased particle capture. Among the broadleaved species, low leaf wettability, low stomatal density and leaf hairiness increased particle capture. Moderate soil drought tended to increase particle capture efficiency of P. sylvestris. •Coniferous Scots pine was the most efficient particle collector.•Decreasing single leaf size increases particle deposition of the total leaf area.•Hairiness of the leaf increases particle deposition. Trees can improve air quality by removing PM2.5 pollutants carried on the wind at a velocity of 3 m s−1, the efficiency of which depends on species leaf characteristics and physical factors.