Accumulation of Particulate Matter, Heavy Metals, and Air Pollution Tolerance Index of 10 Species of Urban Forest Plants

Rapid industrialization and economic development have exacerbated air pollution. Among air pollutants, particulate matter (PM) has notable harmful effects on humans. Additional measures are necessary to reduce PM content in the air, as it does not dissolve naturally. Plant leaves, which accumulate PM, can serve as biological filters. Urban forests positively impact the health of city dwellers by acting as natural filters to reduce PM content and improve air quality. This study aimed to examine the leaves of 10 different woody plants from urban forests for biomonitoring purposes and evaluate their effectiveness for urban greening through the estimation of accumulated PM and the air pollution tolerance index (APTI). These species exhibited varying PM accumulation levels and APTI. The APTI was highest in Acer triflorum and lowest in Prunus serotina. The accumulation of surface PM10 (sPM10) was highest in Juniperus chinensis and lowest in P. serotina. The accumulation of sPM2.5 was highest in Acer triflorum and lowest in Magnolia denudata. The in-wax PM10 (wPM10) and wPM2.5 accumulations were highest in Abies holophylla and lowest in M. denudata. In addition to PM, the plants analysed in this study accumulated heavy metals (HMs), with the average concentrations measured in the following descending order Mn > Sr > Zn > Rb > Cu > Cr > Pb. Among them, Mn, Zn, and Sr constituted a large proportion, whereas Pb was detected only in some plants. These results suggest the potential of the studied plants to enhance sustainability and their reactivity to pollutants, which could be exploited to improve plant-based purification technologies as biofilters.