A method of quantifying the retention of PM2.5 and other atmospheric particulates by plant leaves.

Taking seven keynote tree species in urban afforestation of Chongqing as research objects, we established a new method for quantifying fine particulate matters (PM2.5, d≤2.5 μm) and other atmospheric particulates retained by tree leaves. The previously commonly used of method simply weighing filtrated membranes (SWFM) was modified by combining weighing several levels(10,2.5 μm)of filtrated membranes, and conversion of mathematical proportion relationship was also applied. With the modified method we do not need to directly collect and weigh the amount of PM2.5, and therefore may avoid the disadvantage of not completely collecting and accurately weighing PM10 or PM2.5 by SWFM, because by SWFM very tiny particulates among PM10 or PM2.5 might be lost in the filtration. The new method only demands simple equipments such as electronic balance and glassware that are easily found in ordinary laboratories, and also overcomes the limitations of using microscopes for observing, measuring and calculating the weight of retained particulates by leaves. The method is accurate, reliable and feasible after validating the accuracy and stability with soil samples filtered by a 120-mesh sieve. By using this modified method, PM2.5 and other atmospheric particulates retained by seven keynote tree species for urban afforestation in Chongqing were measured. Our study provides basic technological support for evaluating capacities of forests with different tree species and different structures to retain PM2.5 and other atmospheric particulates.