Development of a Method to Estimate Particulate Matter Adsorbed on the Leaf Surface

Particle pollution is a growing health and environmental concern for many countries nowadays. This study aimed to assess the effect of different leaf types in PM removal by plants and to establish a method to measure PM deposited on plant leaves. Twelve plant species with varying leaf types were tested for their ability to remove dust in 1 m-3chamber for 6 h. To measure the amount of PM deposited on leaves before and after dust treatment, three plant species were tested. Before dust treatment, leaves were wiped with wet towel then 400cm-2 of leaves per plant was sampled for PM measurement. The plants were further exposed to PM for 6h. Sample leaves were washed with distilled water, then the water used in washing was vacuum-filtered using three filter papers to separate particles of different sizes (10-<100㎛, 2.5-<10㎛, and 0.2-<2.5㎛). Filter papers were dried then weighed. Overall, PM2.5 was 10% and 8% lower while PM10 was 11% and 8% lower with plants in the chamber compared to an empty one at 2 and 4h, respectively. Based on leaf type, there is not much difference in PM2.5 removal among the plants while needle-leaved plants have the highest PM10 removal. As for determining the amount of PM deposited on leaves, wiping of leaves with wet towel was apparently not so effective in removing particles on the leaves especially of Clusia. Scindapsus leaves had the highest deposition of the smallest and the largest PM per 400 cm-2 leaf area. Since diplants have the potential to reduce PM from the atmosphere, a reliable way to measure the amount of PM adsorbed on plant leaf surfaces is necessary.