Department of Textile and Fibre Engineering, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, India.
Department of Materials Science and Engineering, Clemson University, 161 Sirrine Hall, Clemson, SC, 29634, USA.
Sci Rep. 2022 Mar 9;12(1):4191. doi: 10.1038/s41598-022-08150-y.
Filtering facepiece respirators (FFRs) provide effective protection against diseases spread through airborne infectious droplets and particles. The widespread use of FFRs during the COVID-19 pandemic has not only led to supply shortages, but the disposal of single-use facemasks also threatens the environment with a new kind of plastic pollution. While limited reuse of filtering facepiece respirators has been permitted as a crisis capacity strategy, there are currently no standard test methods available for decontamination before their repeated use. The decontamination of respirators can compromise the structural and functional integrity by reducing the filtration efficiency and breathability. Digital segmentation of X-ray microcomputed tomography (microCT) scans of the meltblown nonwoven layers of a specific N95 respirator model (Venus-4400) after treatment with one and five cycles of liquid hydrogen peroxide, ultraviolet radiation, moist heat, and aqueous soap solution enabled us to perform filtration simulations of decontaminated respirators. The computed filtration efficiencies for 0.3 µm particles agreed well with experimental measurements, and the distribution of particle penetration depths was correlated with the structural changes resulting from decontamination. The combination of X-ray microCT imaging with numerical simulations thus provides a strategy for quantitative evaluation of the effectiveness of decontamination treatments for a specific respirator model.
过滤式面罩（FFR）能有效预防经空气传播的传染性飞沫和颗粒引发的疾病。在 COVID-19 大流行期间，FFR 的广泛使用不仅导致供应短缺，而且一次性口罩的处置也对环境造成了一种新的塑料污染。虽然有限的重复使用过滤式面罩作为应对危机的能力策略被允许，但在重复使用之前，其消毒的标准测试方法目前尚未确定。通过减少过滤效率和透气性，口罩的消毒可能会破坏结构和功能的完整性。对特定 N95 口罩模型（维纳斯-4400）的熔喷无纺层的 X 射线微计算机断层扫描（microCT）扫描进行数字分割，这些熔喷无纺层在经过一次和五次液体过氧化氢、紫外线辐射、湿热和水性肥皂溶液处理后，我们能够对消毒后的口罩进行过滤模拟。对于 0.3µm 颗粒的计算过滤效率与实验测量结果吻合良好，并且颗粒穿透深度的分布与消毒引起的结构变化相关。因此，X 射线 microCT 成像与数值模拟相结合为评估特定口罩模型的消毒处理效果提供了一种策略。
