Abstract

Advances in instrumentation have enabled researchers to understand aerosol processes at microscopic levels. Besides the development of instruments, other aspects like its calibration, interpretation of data, long term accuracy are pivotal. The Electrical Low-Pressure Impactor (ELPI) is one such advanced and relatively recent instrument that is used to measure the number and charge size distribution of aerosol particles. The charger toggles automatically for the set-time enabling the software to estimate “size segregated charge per particle” in measurement mode. The current levels become stable only after the transition time of 2–4 s when the charger toggling takes place. The accuracy in the estimation of “charge per particle” depends on the correctness of the omission of the transitory values. In this study, the role of transition time on the software predicted charge per particle was probed quantitatively. This was done for 1% (w/v) NaCl and 1% (w/v) Na₂CO₃ particles respectively generated via the nebulization process. ELPI + software (ELPI + VI version 2.0) was found to over-predict the charge per particle by a factor of 0.2–4.8. The transitory time used in the software seem to be insufficient and therefore quantitative results of this work will be helpful while performing data analysis.

摘要

仪器的进步使研究人员能够在微观水平上了解气溶胶过程。除了仪器的发展，其他方面，如校准、数据解释、长期准确性也很关键。电动低压撞击器 (ELPI) 是一种先进且相对较新的仪器，用于测量气溶胶颗粒的数量和电荷大小分布。充电器在设定时间自动切换，使软件能够在测量模式下估计“每个粒子的大小分离电荷”。只有在充电器切换发生 2-4 秒的过渡时间后，电流水平才会稳定。“每个粒子的电荷”估计的准确性取决于忽略暂态值的正确性。在这项研究中，定量探讨了跃迁时间对软件预测的每个粒子电荷的作用。这是针对 1% (w/v) NaCl 和 1% (w/v) Na雾化过程分别产生_2个CO _3颗粒。发现 ELPI + 软件（ELPI + VI 2.0 版）将每个粒子的电荷高估了 0.2-4.8 倍。软件中使用的过渡时间似乎不足，因此这项工作的定量结果将有助于进行数据分析。