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Hyo-Jick Choi is a biomedical engineer and assistant professor of Chemical and Materials Engineering at the University of Alberta

Consumers may be flocking to stores to buy surgical masks to guard against the coronavirus – clearing out store shelves across Canada – but is this really the best course of preventive action?

According to our research, the answer is no. What most people don’t realize is that current masks are limited when it comes to preventing transmission. In fact, if not used or discarded properly, surgical masks can actually increase the risk of virus transmission.

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Still, although they have their limitations, surgical masks and N95/N99 respirators are currently the best defence system we have for personal protection.

In order to be effective, however, they need to be used properly. As a result, it’s critical that the general public be educated on their proper use as well as their limitations. Otherwise, people could be unknowingly contributing to the spread of viruses such as the coronavirus and influenza.

The problem with surgical masks is that they only provide protection against large coronavirus-laden droplets, whereas much smaller virus-carrying droplets called aerosols can penetrate through masks. N95/N99 respirators are more effective at filtering small aerosols but lack the breathability of surgical masks, are more expensive and are not realistic for general public use.

The truth is, neither mask nor respirator is capable of killing a virus. Once contaminated, viruses can live on the surface of the filter for hours and up to a week, and are at risk of being spread to other surfaces when the masks are handled.

Given that people touch their face every four minutes on average, one of the biggest causes of infectious-disease transmission is our hands. Infectious droplets on the surface of a mask filter can quickly be transmitted to hands, as well as released into the environment.

Our prior experience with SARS, avian influenza, swine influenza and MERS strengthened the global belief that the next pandemic is inevitable, and to contain it, WHO recommends the use of respiratory protective measures as well as vaccine. In the absence of a vaccination – which can take more than six months to develop – people are greatly exposed to the risk of infection. The need for a simple yet efficient antiviral mask or respirator filter is considered key in preventing the spread of infectious diseases.

That’s why my team – funded by Mitacs, a national not-for-profit organization that fosters growth and innovation in Canada – set out to create a more effective solution, which is expected to be commercially available within the next 18 months.

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Working with Mitacs researcher Ilaria Rubino, we developed a salt coating that can be applied to surgical masks and respirators to effectively kill viruses. When liquid droplets of any size come in contact with the coating, the salt dissolves in the liquid and begins to evaporate. As salt crystalizes during the evaporation process, the crystals grow and sharpen, destroying the virus with their pointy edges.

Considering the shortage and high cost of respiratory devices during pandemic outbreaks, a virus-deactivating filter can be a critical component of a rapid response to the control and prevention of disease.

Until better solutions are in place to control the spread of viruses, it’s important to keep the following tips in mind when wearing a mask:

  • Surgical masks need to be replaced every few hours to remain effective, which means people should be replacing them after each use;
  • Be careful not to touch the mask itself when removing it or handling it; touch the ear loops or ties only;
  • Always wash your hands before and after handling a mask;
  • Never remove a mask and store it in a pocket or elsewhere before reusing it;
  • Check a mask for defects, holes or tears before use;
  • Ensure the mask fits as close to your skin as possible, with the white side facing inwards.

Maximizing public safety through proper use of masks is critical until next-generation technologies are introduced. At that time, I believe respiratory protection innovations will be able to contribute to national and global safety by filling the gaps in device performance, public health systems, supply-chain infrastructure and policies.

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