Can Surgical Masks Be Reused by Steam Cooking?

A recent pandemic in Hong Kong saw citizens facing a choice of either no mask or reusing masks after some form of DIY sterilization. A legislator suggested steam cooking as a method. This article evaluates this claim and explores the complex issue around reusing surgical masks.

Simple Answer

Yes, if done very carefully, but with significant limitations. Surgical masks are not designed for repeated use and their effectiveness in protecting against the virus is questionable. However, using multiple masks or a good respirator may be a more effective solution when in crowded places.

Understanding the Mask

Surgical Mask: Typically designed for single-use and to provide basic protection against airborne particles and droplets. N95 Mask: Blocking at least 95% of particles larger than 0.3 microns, N95 masks are more effective but also designed for single use due to the potential for degradation of protective properties.

The primary reason surgical masks cannot be reused is due to the accumulation of contaminants, fluid absorption, and mechanical damage over time, all of which compromise the mask's effectiveness.

The Coronavirus Targeted

The SARS-CoV-2 virus is spherical with a diameter of approximately 60–140 nm. It has a protective shell, the envelope, and internal genetic material (RNA) that it uses to attach to and enter human cells.

Transmission Modes of the Virus

Respiratory Droplets: Droplets produced when an infected person coughs or sneezes can be as small as 5μm and can be filtered by high-efficiency masks like N95s. Contaminated Surfaces: These can be ingested through hand-to-face contact and may survive for hours, especially in moist environments.

To effectively address the virus, one needs to deactivate it by targeting its Spike Protein which is crucial for attachment to human cells, or using heat to denature the proteins constituting the virus.

Steam Cooking for Reuse

While steam cooking may seem like a viable alternative, it is not a recommended method. The key factors to consider are the quality of steam, the duration, and the precise temperature. Even if steam cooking could theoretically sterilize the mask, the biofilm on the mask surface and fluid absorption could still affect the mask's ability to filter droplets.

Do Not Microwave Your Mask

Microwaving masks is not only unsafe due to the presence of metal parts, but also ineffective. Microwaves do not evenly distribute heat, and the small size and lack of water content in masks make them unsuitable for microwaving.

A Rare Case of Mask Reusability

A remarkable example of mask reuse involves a woman who cared for a COVID-19 patient and her mother, remaining uninfected. She wore two layers of masks (an inner N95 and an outer surgical mask) and changed them every 4.5 hours. Additionally, she wore goggles, diligently disinfected herself, and maintained strict hygiene practices.

Conclusion

The reuse of surgical masks is a complex issue, with significant limitations. While steam cooking may seem like a method to sterilize masks, it is not recommended. Instead, using multiple masks, a N95 respirator, or prioritizing social distancing and hygiene practices may be more effective in protecting oneself during a pandemic.