TELUS Spark Calgary's Science Centre

Mask Up

Science says mask up and here's why

Written by: Kayley Evans, TELUS Spark Manager of Business Development and Front of House, a B.A. Psychology, B.Sc. (Hon) Anthropology and M.A. Anthropology.

The information circulating around about COVID-19 (SARS-CoV-2) through memes, videos, social media, blogs, news sources and podcasts has been conflicting. Is COVID-19 deadly? Should we be worried? Is it blown out of proportion? Are masks even necessary? If you’re feeling confused, it is ok! It is so difficult to filter through everything, which is why we need science more than ever. In this “Here’s Why”, you’ll discover what the newest scientific evidence says about why wearing masks is one of the best ways we can stop the spread of this virus.

Q: Why has there been so much conflicting information out there about masks?

A: Since the discovery of SARS-CoV-2, there has been a mad dash by scientists to discover more about this virus, specifically how it is transmitted, how dangerous it is and what we can do to save more lives! Science is a process. New discoveries lead to new avenues of research. Although the coronavirus family is not new, this particular strain has never been found before in human populations. Put simply, we don’t know much about it. Thankfully, science is on the case and every day more peer-reviewed studies are published, evolving our understanding of what we need to do to protect others and ourselves.

In the beginning of the pandemic, some of the largest health organizations in the world stated that the public should not wear masks or facial coverings. These recommendations were based on the limited understanding of how SARS-CoV-2 is transmitted in the population, how widespread the virus was at the time and the fact that the world supply of masks needed to be reserved for frontline healthcare workers. As of June 2020 the World Health Organization and the Centre for Disease Control have both changed their recommendations and suggest that the public should combine masks with social distancing and frequent handwashing. These new guidelines were devised after careful review of new studies that show the ability of cloth masks to slow the spread of the disease1,2, which we will dive into below.

Q: How do cloth masks prevent the spread of COVID-19?

A: “Viruses are tiny! Surely a cloth mask can’t contain them!” Technically this is true, but in the case of COVID-19, the virus is trapped in large saliva droplets that only become tiny when they evaporate. As we breathe in the mask these droplets are trapped, which means that not nearly as many viral particles escape1,3,4. In fact, a recent study has shown that even if masks are 20-50% effective at containing viral particles it will still reduce the number of projected deaths and peak daily deaths from COVID-195. The key to these findings is that 80% of the population or more needs to wear masks for it to be effective. One way to encourage the use of face masks is for local policy makers to enact the mandatory use of face masks in public spaces, which we are starting to see happen all over the world6. Scientists have studied the effects of these mandatory orders and have found that it significantly decreases the daily growth rate of COVID cases4,7. At Spark, by requiring the use of face masks indoors we are hoping to keep our Science Centre as safe as possible for our employees and guests.

Q: Why should I wear a mask if people with symptoms are self-isolating?

A: You’re absolutely right that people who have symptoms should stay at home! However, this may not be enough to protect everyone from the spread of COVID-19. You’ve probably heard a lot of talk about people that are asymptomatic. This means that someone has the virus but they do not show any outward symptoms of the infection. Someone who is asymptomatic can still pass COVID-19 onto people through their respiratory droplets. Scientists are working around the clock and randomly testing people in an attempt to understand how many people may be infected and not know it. However, preliminary results suggest that about 18% of cases are asymptomatic8. On top of this, new evidence suggests that the virus is the most contagious on or before the onset of symptoms 9. Scientists call this the pre-symptomatic stage of the virus. All of this means that we cannot be 100% certain that those around us or ourselves aren’t accidentally transmitting the virus to others. It’s better to be safe and wear a mask to ensure we are all doing our part to prevent the spread.


  1. K. Conger, 2020. 5 Questions: Stanford Scientists on COVID-19 Mask Guidelines. Stanford Medicine News Center.

  2. N. Bai, 2020. Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus. Patient Care.

  3. N.H.L. Leung et al., 2020. Respiratory Virus Shedding in Exhaled Breath and Efficacy of Face Masks. Nature Medicine, 26.

  4. J. Howard et al., 2020. Face Masks Against COVID-19: An Evidence Review. Proceedings of the National Academy of Sciences, preprints.

  5. S.E. Eikenberry et al., 2020. To Mask or Not To Mask: Modeling the Potential for Face Mask Use By The General Public to Curtail the COVID-19 Pandemic. Infectious Disease Modelling, 5.

  6. A. Teslya et al., 2020. Impact of Self-Imposed Prevention Measures and Short-term Government-imposed Social Distancing On Mitigating and Delaying A COVID-19 Epidemic: A Modelling Study. PLOS Medicine.

  7. W. Lyu and G.L. Wehby, 2020. Community Use of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US. Health Affairs, ahead of print.

  8. J.A. Siordia Jr. 2020. Epidemiology and Clinical Features of COVID-19: A Review of Current Literature. Journal of Clinical Virology, 127.

  9. X. He et al. 2020. Temporal Dynamics in Viral Shedding and Transmissibility of COVID-19. Nature Medicine, 26.

How to properly wear a mask ft. Dr. Raj Bhardwaj

About Dr. Raj Bhardwaj

Dr. Raj Bhardwaj is a Family Physician and Urgent Care doctor working in downtown Calgary. He is also a Clinical Assistant Professor with the Department of Family Medicine at the Cumming School of Medicine at the University of Calgary.

He started in the Science Communication realm early, when he worked at the Edmonton Space & Science Centre in the 1990s, and he has refined his common-sense approach to explaining complex medical topics ever since.

Source: CBC Media Centre

Mask-Wearing Resources

"Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus" | Read Article >>

"Impact of self-imposed prevention measures and short-term government-imposed social distancing on mitigating and delaying a COVID-19 epidemic: A modelling study" | Read Article >>

"To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic" | Read Article >>

"Coronavirus disease (COVID-19) advice for the public: When and how to use masks" | Read Article >>

"5 Questions: Stanford scientists on COVID-19 mask guidelines" Read Article >>