Fig. 8
Samples of Euonymus japonicus leaves before (a) and after (b). (a) leaves before cleaning, and (b) leaves after cleaning. T1: outer sidewalk area (slightly polluted area of atmospheric particulate matter), T2: area between the relief road and the sidewalk (moderately polluted area of atmospheric particulate matter), T3: area in the middle of the main road (heavy pollution area of atmospheric particulate matter). Plant identification by Prof. Chengyang Xu from Beijing Forestry University (identification information refers to Flora of China)