叶片大气颗粒物滞纳能力评估方法的定量对比

为探究基于相同实验材料和叶面积测定方法的前提下，5种评估叶片滞尘能力方法的差异，并在此基础上归纳总结各方法的优缺点，本研究以北京市常见、叶片特征区别较大的4个城市绿化树种油松（Pinus tabuliformis）、侧柏（Platycladus orientalis）、银杏（Ginkgo biloba）和一球悬铃木（Platanus occidentalis）为研究对象，采集叶样后，分别用质量差减法（MS）、滤膜法（MF）、气溶胶再发生器法（AR）、电镜扫描法（SEM）和基于超声清洗的洗脱称量粒度分析法（ultrasonic-EWPA）对4个树种叶片的PM滞纳能力及特征进行评估.评估的同时测定每种方法评估所需总时间，并计算其所需总成本.结果表明，虽然不同方法得到的叶面滞尘效率数值的差异巨大，但得到的叶面滞尘效率的树种排序存在重合部分，其中，评估原理相同或类似的方法得到的结果重合部分更多（最多的为AR和SEM）.各方法得到的针对同一指标的相同树种排序中，有89%的排序为侧柏 > 油松 > 一球悬铃木 > 银杏，其余排序为一球悬铃木 > 银杏 > 侧柏 > 油松.5种方法中，得到指标数量最多、成本最高的均为ultrasonic-EWPA，得到指标数量最少、成本最低的均为MS；耗时最长的为MF，最短的为AR.ultrasonic-EWPA和SEM是高投入高产出型方法，即虽然需要较多的实验耗时及成本，但能得到更丰富的评估信息；MS则属于低投入低产出型，得到的信息量较少，适用于只需粗略评估树木总滞尘能力的情况；MF所得信息量中等，成本较低，但耗时过长，使用前需进行权衡；AR对设备和参数的要求严格，需谨慎使用.本研究结果可为今后研究人员选择用于评估植物滞尘能力的具体方法提供全面详实的科学依据.

Quantitative Comparison of Methods to Assess the Airborne Particulate Matter Retention Capacity of Leaves

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 (Pinus tabuliformis, Platycladus orientalis, Ginkgo biloba, and Platanus occidentalis), 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 P. orientalis > P. tabuliformis > P. occidentalis > G. biloba, and the remaining 11% were P. occidentalis > G. biloba > P. orientalis > P. tabuliformis. 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.