Exhalation of infectious micrometer-sized particles has been strongly implicated in respiratory infection spread. An important fundamental question is then the fate of infectious exhaled particles in indoor spaces, i.e., whether they will remain suspended in an aerosol until ventilation leads to their clearance or whether they will deposit, and if so, on what surfaces in an indoor space. We investigated the interplay between deposition and ventilation using model experiments with a breathing simulator manikin in an office environment. The breathing simulator utilized physiologically correct exhalation and inhalation breathing waveforms as well as an anatomically correct manikin. The simulator output fluorescein-doped particles with a volume distribution spanning the 1–3 μm range. The office environment was a 344 m³ room equipped with desks. Four different test conditions were created by changing the simulator location and via different air change rates and MERV ratings of filters in the HVAC system. We found that the rate of ventilation exceeds the rate of deposition on all surfaces (quantified by Stanton numbers, which were below unity) with several important exceptions: (1) surfaces close to (within 2 m of) the simulator; and (2) non-passive surface exteriors (return grilles and diffusers). A detectable decrease in Stanton number with distance suggests that the room environment cannot be approximated as truly well-mixed. The finding of enhanced deposition on non-passive surfaces at all distances from the room highlights that infectious particles may preferentially deposit on such surfaces in indoor spaces. Finally, while our results highlight particular surfaces with enhanced deposition, our results confirm the importance of ventilation in a room as a means to reduce infectious aerosol particle concentrations, as in large part the clearance for particles appears to occur by ventilation.

呼出传染性微米级颗粒与呼吸道感染传播密切相关。一个重要的基本问题是室内空间中传染性呼出颗粒的命运，即它们是否会保持悬浮在气溶胶中直到通风导致它们清除，或者它们是否会沉积，如果是，则在室内空间的哪些表面上。我们在办公室环境中使用呼吸模拟器人体模型进行模型实验，研究了沉积和通风之间的相互作用。呼吸模拟器利用生理上正确的呼气和吸入呼吸波形以及解剖学上正确的人体模型。模拟器输出荧光素掺杂粒子，其体积分布跨越 1–3 μm 范围。办公环境为 344 m ³房间配有书桌。通过改变模拟器位置以及 HVAC 系统中过滤器的不同换气率和 MERV 等级，创建了四种不同的测试条件。我们发现通风速率超过了所有表面的沉积速率（由低于 1 的斯坦顿数量化），但有几个重要的例外：（1）靠近模拟器（2 m 内）的表面；(2) 非被动表面外观（回风格栅和扩散器）。斯坦顿数随距离的可检测减少表明房间环境不能被近似为真正混合良好。在距房间所有距离的非被动表面上沉积增强的发现突出表明，传染性颗粒可能优先沉积在室内空间的此类表面上。最后，