Influence of leaf morphological characteristics on the dynamic changes of particulate matter retention and grain size distributions.

Plant leaves can retain atmospheric particulate matter (PM) and thus alleviate air pollution. Herein, four plant species (, , , and ) from the central part of Shanxi Province, China, were investigated to analyse the dynamic changes in their PM retention capacity and grain size over five periods. The relationship between leaf morphological characteristics (leaf size and leaf surface microstructure) and dynamic changes were discussed in PM retention, revealing the influence of leaf morphological characteristics on the amount of PM retention and its composition. The results showed that amount and grain sizes of the retained PM differed significantly among the various studied species; however, the trends in PM retention of different species in the time series were the same. The grain size distributions of PM from the four species displayed a bimodal distribution, in which the main peak distribution range was 5-60 μm and the secondary peak distribution range was 0.4-1 μm. Leaves of smaller sizes and those with rough surfaces had a high PM retention capacity. Leaves with deep grooves are conductive to retaining PM and PM, while leaves with hair are conductive to retaining PM. Therefore, the morphological characteristics of leaves should be considered when selecting the use of plant species to alleviate air pollution. Dynamics of PM retention capacity and grain size distributions of four plant species were analysed.Grain size distributions of PM retained on leaves had a bimodal distribution.Small leaves with grooves or hair are conductive to PM retention.Grooves are conductive to fine PM retention while hairs are conductive to coarse PM retention.