Dry aerosol particle deposition on indoor surfaces: Review of direct measurement techniques

Localizing and measuring aerosol deposition is essential to improve our knowledge regarding contaminants and their transfer mechanisms, the cleanliness of people's environments and, consequently, our health. However, examining aerosol deposition is challenging, as it is based on several different mechanisms linked to aerosols, surfaces and air flow properties. Many techniques exist to measure aerosol deposition, but only a few techniques directly measure aerosol deposition without modifying the deposition itself. In this article, we review and describe the existing measurement techniques, which directly measure a deposition flux of aerosol particles on indoor surfaces. They are classified according to whether they measure a mass or a number surface deposition concentration. Among mass concentration measurement techniques, a few are the most commonly used in the literature and are well-known, whereas micro-sensors have been recently developed and these continue to be improved upon in laboratory experiments. Experimenters need to know more about the theoretical and technical aspects involved in order to build and implement these micro-sensors. Micro-sensors generally feature the ability to carry out in situ and close to real-time measurement. Number concentration measurement techniques are mainly based on optical systems. Commercial devices apart, these techniques are adaptable, and their configurations depend on experimental constraints. They also require some theoretical consideration depending on which kind of aerosol deposition is observed. On the other hand, commercial devices are turnkey solutions and are developed for specific purposes, such as cleanroom deposition measurement, in order to provide user-friendly devices and facilitate attaining repeatability in the measurement protocol. Copyright (c) 2021 American Association for Aerosol Research