Yue Chen, Li Guang-de, Xi Ben-Ye, Cao Zhi-Guo
Ministry of Education Key Laboratory of Silviculture and Conservation, Beijing Forestry University, Beijing 100083, China.
Faculty of Agriculture Forestry & Medicine, the Open University of China, Beijing 100039, China.
Huan Jing Ke Xue. 2021 Jan 8;42(1):114-126. doi: 10.13227/j.hjkx.202006054.
The objective of this study was to explore the differences of five methods for evaluating the PM retention capacity of leaves based on the same experimental materials and leaf area measurement method and to summarize the advantages and disadvantages of each method. In this study, four tree species (, , , and ), which are common in Beijing and have greatly different leaf characteristics, were selected as the research objects. The mass subtraction method (MS), the membrane filter method (MF), the aerosol regenerator method(AR), the scanning electron method (SEM), and the elution weighing method coupled with a particle size analysis based on ultrasonic cleaning (ultrasonic-EWPA) were used to evaluate the PM retention capabilities and characteristics of the leaves of the four tree species. The total time needed and the total cost were measured simultaneously during the evaluation process. The results showed that although the values of PM retention efficiency obtained by different methods were quite different, the ranks of the efficiency of four tree species obtained by different methods were the same or partially the same. Additionally, the results obtained by the methods with the same or similar principles were more overlapped (AR and SEM had the most overlapped results). In addition, 89% of the species ranks of the same index obtained by each method were > > > , and the remaining 11% were > > > . Among the five methods, ultrasonic-EWPA was the one with the largest number of indexes and the highest cost, and MS was the one with the least number of indexes and the lowest cost. The one that needed most time was MF, while the one that needed the least time was AR. ultrasonic-EWPA and SEM are high input and high output methods. That is to say, although they needed more time and cost, they can prove more information; however, MS was opposite, which resulted in less information but lower time and cost needed. So, it is suitable for roughly evaluating the total PM retention capacities of trees; MF had a medium amount of information, low cost, but required too much time, which needs to be weighed and balanced before selecting this method. The AR method had strict requirements for equipment and parameters and should be used with caution. The results of this study can provide a comprehensive and detailed scientific basis for researchers to choose specific methods in the future.
本研究的目的是基于相同的实验材料和叶面积测量方法，探究五种评估叶片颗粒物滞留能力的方法之间的差异，并总结每种方法的优缺点。在本研究中，选取了在北京常见且叶片特征差异较大的四种树种（、、、）作为研究对象。采用质量减法（MS）、膜过滤法（MF）、气溶胶再生器法（AR）、扫描电子法（SEM）以及基于超声清洗的粒度分析洗脱称重法（超声-EWPA）来评估这四种树种叶片的颗粒物滞留能力和特征。在评估过程中同时测量所需的总时间和总成本。结果表明，尽管不同方法获得的颗粒物滞留效率值差异很大，但不同方法得到的四种树种的效率排名相同或部分相同。此外，原理相同或相似的方法得到的结果重叠度更高（AR和SEM的结果重叠度最高）。另外，各方法得到的同一指标的树种排名中，89%为>>>，其余11%为>>>。在这五种方法中，超声-EWPA的指标数量最多、成本最高，MS的指标数量最少、成本最低。所需时间最长的是MF，所需时间最短的是AR。超声-EWPA和SEM是高投入高产出的方法。也就是说，虽然它们需要更多的时间和成本，但能证明更多信息；然而，MS则相反，得到的信息较少，但所需时间和成本较低。所以，它适合粗略评估树木的总颗粒物滞留能力；MF的信息量中等、成本低，但所需时间过长，在选择该方法前需要权衡利弊。AR方法对设备和参数要求严格，应谨慎使用。本研究结果可为研究人员今后选择具体方法提供全面详细的科学依据。
