Unfolding the effects of decontamination treatments on the structural and functional integrity of N95 respirators via numerical simulations

Abstract

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.

Structural and functional integrity of decontaminated N95 respirators: Experimental results

“…Further details of Geodict based analysis can be obtained from ref. [31]. In general, the porosity values of control and decontaminated samples obtained via CTAn and Geodict analyses are in good agreement.…”

Comparative Evaluation of Microorganism Disinfection Methods for N95 Respirators

“…Once the microorganisms were trapped in the fi lter, approximately 1% of the inoculated bacteria were recovered in the buff er solution, and the exact decontamination capacity of each method was unclear. However, other in-vitro studies have demonstrated that many methods tested in this study have effi cient decontamination capacity against viruses and bacteria, including M. tuberculosis [12,[17][18][19]. However, the microorganism trapping capacity of the N95 respirator is high and may not release the captured microorganisms from the fi bre fi ltration system.…”

Soft, strong, and breathable polylactic acid/polyethylene glycol microfibrous membranes with a fluffy alignment structure for skin contactor

“…These results indicate that in comparison with the traditional melt-blown microfibrous membranes with randomly distributed fibers, the microfibrous membranes with a fluffy alignment structure exhibit excellent and controllable air-penetration properties. 42…”