Aerosols are readily transported on airstreams through building sanitary plumbing and sewer systems, and those containing microbial pathogens (known as bioaerosols) are recognized as contributors to infection spread within buildings. When a defect occurs in the sanitary plumbing system that affects the system integrity, a cross-transmission route is created that can enable the emission of bioaerosols from the system into the building. These emission occurrences are characterized as short-burst events (typically <1 min in duration) which make them difficult to detect and predict. The characterization of these emission events is the focus of this research. Two methods were used to characterize bioaerosol emission events in a full-scale test rig: (a) an Aerodynamic Particle Sizer (APS) for particle size distribution and concentrations; and (b) a slit-to-agar sampler to enumerate the ingress of a viable tracer microorganism (Pseudomonas putida). The APS data confirmed that most particles (>99.5%) were <5 μm and were therefore considered aerosols. Particles generated within the sanitary plumbing system as a result of a toilet flush leads to emissions into the building during system defect conditions with an equivalence of someone talking loudly for over 6 and a half minutes. There were no particles detected of a size >11 μm anywhere in the system. Particle count was influenced by toilet flush volume, but it was not possible to determine if there was any direct influence from airflow rate since both particle and biological data showed no correlation with upward airflow rates and velocities. Typical emissions resulting from a 6 L toilet flush were in the range of 280–400 particles per second at a concentration of typically 9–12 number per cm³ and a total particle count in the region of 3000 to 4000 particles, whereas the peak emissions from a 1.2 L toilet flush were 60–80 particles per second at a concentration of 2.4–3 number per cm³ and a total particle count in the region of 886 to 1045 particles. The reduction in particles is in direct proportion to the reduction in toilet flush volume. The slit-to-agar sampler was able to provide viable time course CFU data and confirmed the origin of the particles to be the tracer microorganism flushed into the system. The time course data also have characteristics consistent with the unsteady nature of a toilet flush.

中文翻译：

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来自有缺陷的卫生管道系统的气溶胶和生物气溶胶颗粒大小和动力学

气溶胶很容易通过建筑卫生管道和下水道系统在气流中运输，而那些含有微生物病原体的（称为生物气溶胶）被认为是感染在建筑物内传播的促成因素。当卫生管道系统中出现影响系统完整性的缺陷时，会创建一条交叉传输路径，使生物气溶胶从系统排放到建筑物中。这些排放事件的特征是短爆发事件（通常持续时间 <1 分钟），这使得它们难以检测和预测。这些排放事件的表征是本研究的重点。使用两种方法来表征全尺寸试验台中的生物气溶胶排放事件： (a) 空气动力学粒度仪 (APS) 用于粒度分布和浓度；恶臭假单胞菌）。APS 数据证实，大多数颗粒 (>99.5%) 小于 5 μm，因此被视为气溶胶。由于冲水马桶而在卫生管道系统内产生的颗粒会导致在系统故障情况下排放到建筑物中，相当于有人大声说话超过 6 分半钟。在系统的任何地方都没有检测到大于 11 μm 的颗粒。颗粒数受马桶冲水量的影响，但无法确定是否受到气流速率的直接影响，因为颗粒和生物数据均显示与向上气流速率和速度没有相关性。6 升马桶冲水产生的典型排放范围为每秒 280-400 个颗粒，浓度通常为每厘米 9-12 个³和 3000 至 4000 个颗粒的总颗粒数，而 1.2 升马桶冲水的峰值排放量为每秒 60-80 个颗粒，浓度为每厘米³ 2.4-3^个，总颗粒数在886 到 1045 个粒子的区域。颗粒物的减少与马桶冲水量的减少成正比。狭缝到琼脂取样器能够提供可行的时间过程 CFU 数据，并确认颗粒的来源是冲入系统的示踪微生物。时间进程数据还具有与马桶冲水的不稳定特性一致的特征。