Gibson John, Farnood Ramin, Barbeau Benoit
Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON, M5S 3E5, Canada.
Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St, Toronto, ON, M5S 3E5, Canada.
Environ Sci Pollut Res Int. 2021 Nov;28(43):61853-61859. doi: 10.1007/s11356-021-16537-z. Epub 2021 Oct 1.
Surfaces can be contaminated by droplets produced through coughing or sneezing. In this exploratory work, the UV disinfection results of Bacillus subtilis spores in dried saliva droplets were fitted to a three-parameter kinetic model (R ≥ 0.97). This model has a disinfection rate constant for single organisms and a smaller one for aggregates found in droplets. The fraction of organisms found in aggregates (β) could account for the effects of different-sized droplets in the experimental work. Since a wide spectrum of droplet sizes can be produced, and some of the rate constants were uncertain, Monte Carlo simulation was used to estimate the UV inactivation performance in dried saliva droplets in a variety of conditions. Using conservative distribution for β, the model was applied to the UV disinfection of SARS-CoV-2 in dried saliva droplets. It was shown that a one-log reduction of SARS-CoV-2 was very likely (p>99.9%) and a two-log reduction was probable (p=75%) at a dose of 60 mJ/cm. Aggregates tend to be variable and limit the log reductions that can be achieved at high UV doses.
表面可能会被咳嗽或打喷嚏产生的飞沫污染。在这项探索性工作中，枯草芽孢杆菌孢子在干燥唾液飞沫中的紫外线消毒结果被拟合到一个三参数动力学模型（R≥0.97）。该模型对于单个生物体有一个消毒速率常数，对于飞沫中发现的聚集体有一个较小的速率常数。聚集体中发现的生物体比例（β）可以解释实验工作中不同大小飞沫的影响。由于可以产生广泛的飞沫尺寸范围，并且一些速率常数不确定，因此使用蒙特卡罗模拟来估计在各种条件下干燥唾液飞沫中的紫外线灭活性能。使用β的保守分布，该模型被应用于干燥唾液飞沫中SARS-CoV-2的紫外线消毒。结果表明，在剂量为60 mJ/cm²时，SARS-CoV-2很可能实现一个对数级的减少（p>99.9%），并且有可能实现两个对数级的减少（p=75%）。聚集体往往是可变的，并限制了在高紫外线剂量下可以实现的对数减少。
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