Hybrid decontamination method for facial respirators using ultraviolet germicidal irradiation and microwave generated steam / Thirumaaran Gopalan

Thirumaaran , Gopalan (2024) Hybrid decontamination method for facial respirators using ultraviolet germicidal irradiation and microwave generated steam / Thirumaaran Gopalan. Masters thesis, Universiti Malaya.

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Abstract

The unprecedented Covid-19 pandemic caused by SARS-CoV-2 has caused a significant escalation in global demand for Personal Protective Equipment (PPE). PPE especially face masks acts as primary respiratory protection against this lethal virus. The worldwide shortage of masks issues due to ever-expanding demand poses a serious threat to health workers worldwide who battling this pandemic on the frontlines. Decontaminating face masks for reuse purposes could be a rewarding solution to mitigate the issue. Ultraviolet Germicidal Irradiation (UVGI), Aerosolized Hydrogen Peroxide (aHP), and Microwave-Generated Steam (MGS) are among the investigated decontamination methods that exhibit astounding virucidal results while preserving the integrity and performance of the treated mask. This research aims to investigate the decontamination efficiency of the hybrid decontamination system (UVGI + aHP) and (UVGI + MGS) on an N95 respirator contaminated with Feline Coronavirus (FCoV). A mask sterilizing machine prototype equipped with UVGI and aHP decontamination system was designed and developed. Virus viability tests were conducted to measure the efficiency of the selected decontamination treatments. In these tests, N95 respirators inoculated with viable FCoV were treated with selected three decontamination systems in a single and hybrid treatment design by applying varying exposure times. UVGI achieved a log reduction of at least 3 at a lower treatment time compared to MGS and aHP. MGS exhibits higher efficiency in achieving 4 log reduction compared to the other two single treatments. Results exhibit that the tested rapid treatment time of aHP was not effective against the virus. In addition, hybrid decontamination of (UVGI + MGS) achieved at least 4 log reduction in microbial load faster than single treatments of MGS and UVGI. The results indicated that the hybrid decontamination procedure is effective in achieving higher log reduction values.

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