Watch how the common electric cooker sanitizes N95 masks for reuse
S. Himmelstein | August 07, 2020Sporadic shortages of personal protective equipment (PPE) have plagued medical professionals and consumers alike during the COVID-19 pandemic. Proper disinfection permits reuse of PPE, particularly the N95 respirator masks viewed as the gold standard for shielding the user against airborne droplets and particles. An efficient sanitization solution likely available in many kitchens has been demonstrated by University of Illinois researchers: dry heating of these masks in an electric cooker
Dry heating for 50 minutes at 100° C in an electric cooker was shown to decontaminate N95 respirators while maintaining their required filtration and fit properties. Masks inoculated with four different viruses, including the coronavirus, were effectively decontaminated via thermal inactivation mechanisms.
The initial particle filtration efficiency of a new mask exceeds 99%. The treated respirators maintained their filtration capacity of more than 95% and kept their fit after 20 cycles of decontamination in the electric cooker. The pressure drop across the mask was also not significantly affected by the decontamination process.
The research published in Environmental Science & Technology Letters indicates that this electric cooker application could enable safe reuse of limited supplies of the respirators, which are originally intended to be one-time-use items.
Dry heating for 50 minutes in an electric cooker decontaminated N95 respirators while maintaining their required filtration and fit properties. Source: Chamteut Oh et al.
The video says the walls of the cooker are at 170C. The masks are are at 100C. Do I set my cooker to 170C or 100C?
In reply to #1
From the linked article:
The temperature of the pot surface rapidly increased to 170 °C within 5 min and then dipped to remain between 120 and 150 °C inside the pot….On the basis of the results, dry heat (100 °C, 5% relative humidity, 50 min) is an appropriate decontamination technology for N95 respirator reuse.
In reply to #2
So, what temperature do I set my roaster oven? If I get too high, I ruin the masks. If I get too low, I don't kill the virus.
In reply to #3
The recommended setting appears to be 100 C (212 F). For additional clarification, you might want to contact the lead researcher at the University of Illinois, Thanh H. Nguyen
In reply to #4
OK. Thanks. I will.
While the video indicates that sterilization can be achieved within a " common electric cooker " , that same level of sterilization may not be achieved once the masks are removed unless absolute laboratory conditions are maintained in the external environment. By placing the masks upon an untreated surface, i.e. a table or desk or exposing the masks to untreated air, recontamintion will again take place. While this method may work within a controlled environment, less than desirable results will be obtained outside of such and in the environment of a common kitchen may produce a product that is more or less contaminated than before it went into the cooker