Individual aerosol particles from an urban background site in Mainz (Germany), a traffic hotspot site in Essen (Germany), the free troposphere in the Swiss Alps (high altitude research station Jungfraujoch), a rural background/marine site on Cyprus (Cyprus Atmospheric Observatory) and a rural background site in the forested area of Odenwald (Germany) were characterised with two different scanning electron microscopy techniques, operator controlled (opSEM) and computer controlled (ccSEM). For all samples, about 500 particles were investigated by opSEM, and between 1103 and 6940 particles by ccSEM. Large systematic differences (in some cases a factor up to ~ 20) in the abundance of the various particle groups are observed in the results of the two techniques. These differences are dependent on particle type and size. With ccSEM, information on the mixing state of particles (e.g., presence of heterogeneous inclusions, surface coatings or gradients in chemical composition) cannot be obtained, and particle groups which are recognised by their complex morphology (e.g., soot and fly ash particles) are classified into other particle groups. In addition, highly volatile particles (i.e., particles which evaporate under electron bombardment within seconds) will be overlooked by ccSEM. If these limitations of ccSEM are not considered, normalising the particle group abundances to 100% (a popular practise in many publications) may lead to drastic misinterpretation of the real aerosol composition. OpSEM is indispensable when detailed information of particle composition is required, although it suffers from a much higher expenditure of time. In conclusion, both techniques might be used for single particle characterisation as long as drawbacks of each are considered.

来自美因茨（德国）的城市背景站点，德国埃森（Essen）的交通热点站点，瑞士阿尔卑斯山的自由对流层（高空研究站少女峰（Jungfraujoch）），塞浦路斯的农村背景/海洋站点（塞浦路斯大气）中的单个气溶胶颗粒使用两种不同的扫描电子显微镜技术（操作员控制（opSEM）和计算机控制（ccSEM））对Odenwald（德国）森林地区的天文台和乡村背景进行了表征。对于所有样品，通过opSEM研究了大约500个颗粒，而通过ccSEM研究了1103和6940之间的颗粒。在两种技术的结果中，观察到各种粒子组的丰度存在较大的系统差异（在某些情况下，系数高达20左右）。这些差异取决于粒子的类型和大小。有了ccSEM，无法获得有关颗粒混合状态的信息（例如，存在异质夹杂物，表面涂层或化学成分梯度），并且通过其复杂形态识别的颗粒组（例如，烟灰和粉煤灰颗粒）被分类为其他颗粒。粒子群。此外，ccSEM将忽略高挥发性颗粒（即在几秒钟内在电子轰击下蒸发的颗粒）。如果不考虑ccSEM的这些局限性，则将粒子组的丰度标准化为100％（许多出版物中的流行做法）可能会导致对真实气溶胶成分的严重误解。当需要详细的颗粒组成信息时，OpSEM是必不可少的，尽管它要花费更多的时间。综上所述，