Coronavirus eye-opener: If not used properly, surgical masks and respirators can actually promote the spread of viruses, says leading Canadian researcher

Edmonton, Alberta— In the wake of reports that major retailers are selling out of basic surgical masks amid growing concern of coronavirus spread, a leading University of Alberta researcher — whose Mitacs-funded research intern is leading the charge to develop a universal preventive filter capable of killing viruses — confirms that current masks are limited when it comes to preventing transmission and, if not used properly, can actually increase the risk of transmission.

“Surgical masks and respirators are currently the best defence system we have for personal protection, but the general public needs to be educated on their proper use and their limitations,” said Hyo-Jick Choi, Biomedical Engineer and Assistant Professor, Chemical and Materials Engineering at the University of Alberta. “Otherwise, people could be unknowingly contributing to the spread of viruses like coronavirus and influenza,” he said.

The problem with surgical masks is that they only provide protection against large virus-laden droplets, whereas respiratory viruses such as coronavirus are also spread through much smaller droplets called aerosols. 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.

According to Choi, neither mask nor respirator is capable of killing a virus, meaning once contaminated, viruses can live on the surface of the filter from hours up to a week and are at risk of being spread to other surfaces when the masks are handled.

New and improved masks preparing for launch

Choi’s team — funded by Mitacs, a national not-for-profit organization that fosters growth and innovation in Canada, with a key role played by Mitacs researcher Ilaria Rubino — has developed a salt coating that can be applied to surgical masks and respirators to effectively kill viruses. When liquid droplets of any size come into contact with the coating, the salt dissolves in the liquid and begins to evaporate. As salt crystallizes during the evaporation process, the crystals grow and sharpen, destroying the virus with their pointy edges.

“We’ve tested our system on three different influenza viruses and have shown that the virus on the surface of a coated contaminated mask is inactive within five minutes and completely destroyed within 30 minutes,” Choi said. Based on these results, the technology is now in the process of being commercialized, and Choi expects it to be widely available within 12 to 18 months.

Mitacs researcher Rubino, a PhD student in the Department of Chemical and Materials Engineering at the University of Alberta, has been the main group member to work on the salt-coated masks project since 2015, investigating their protective action. “It’s remarkable to have the opportunity to positively affect the health and wellbeing of so many people through engineering,” Rubino said. “Our technology will contribute to global health by improving infection prevention of pandemic and epidemic diseases.”

In the meantime, Choi is urging members of the public who are using surgical masks and respirators to keep these important tips in mind:

  • Surgical masks need to be replaced every few hours to remain effective, which means you should replace it 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.

About Mitacs:

In 2003 with the SARS outbreak, several Mitacs-affiliated mathematician researchers quickly united as a team. The outcome of their research was an equation quantifying the necessary quarantine period for SARS. They shared their research outcomes at the MITACS, PIMS and Health Canada meeting on SARS and made recommendations for Canadian public health policy. The new quarantine policy undoubtedly saved many lives in Canada. Today, Mitacs works to drive innovation, with partners studying infectious diseases among a myriad of other challenges.

Celebrating 20 years of connecting research with industry to solve challenges, Mitacs is a not-for-profit organization that fosters growth and innovation in Canada. Working with more than 100 post-secondary institutions, thousands of companies, and both federal and provincial governments, Mitacs builds partnerships that support innovation in Canada. Mitacs receives funding from the Government of Canada, the Government of Alberta, and every other province. For more information on Mitacs, visit