Commentary

A geeky scientific paper on airborne COVID-19 and the biggest B.C. scandal of the year

Why aren't health authorities and the provincial government doing more to prevent the spread of the virus?

by Charlie Smith on May 13th, 2022 at 7:26 AM
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      Over the past couple of weeks, I've been extremely busy dealing with everything from arts and DOXA film-fest coverage to the Broadway Plan to various administrative issues related to the Georgia Straight.

      I regret that I haven't set aside sufficient time to address the top provincial scandal over the past year.

      So what is this scandal, you might ask.

      It's the B.C. government's ongoing refusal to implement policies to stem the spread of COVID-19.

      This is notwithstanding continued high hospitalizations and a growing number of deaths.

      That's to say nothing of the neurological and cardiovascular complications that will inevitably ensue from untrammelled transmission of the virus.

      I was recently reminded of the inaction by the province and B.C. health authorities as I read a thought-provoking paper published in Environmental Science & Technology in January.

      The abstract was tweeted by one of the authors, University of Colorado Boulder atmospheric-chemistry expert Jose-Luis Jimenez.

      "Some infectious diseases, including COVID-19, can undergo airborne transmission," the abstract states. "This may happen at close proximity, but as time indoors increases, infections can occur in shared room air despite distancing."

      Keep in mind that health authorities are putting patients with COVID-19 in the same hospital rooms as those without the disease. But I digress.

      Here's what I found fascinating about this scientific paper: it examined key factors that influence airborne disease transmission indoors.

      They include the rate of aerosol generation, breathing flow rate, masking and its quality, ventilation and aerosol-removal rates, and the number of occupants and duration of exposure.

      Not only did this paper consider the infectious nature of airborne COVID-19, it also contrasted that with transmission of measles, influenza, and tuberculosis.

      "Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at higher risk parameter values," the researchers note. "Because both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission."

      It goes on to describe the SARS-C0V-2 virus, which causes COVID-19, as a "pathogen of initially moderate infectivity (more recently increased by some variants such as Delta or Omicron)".

      The paper cites scientific literature on outbreaks of COVID-19 in choir rehearsals, religious services, buses, workshop rooms, restaurants, and gyms. In all of these situations in B.C., there's no requirement for anyone to wear masks.

      "There are a few documented cases of longer-distance transmissions of SARS-CoV-2 in buildings," the paper states. "However, cases of longer-distance transmission are harder to detect as they require contact tracing teams to have sufficient data to connect cases together and rule out infection elsewhere."

      The researchers used a "box model" to estimate viral aerosol concentrations indoors.

      That included taking into account the "concentration of infectious quanta in the air in the enclosed space". They write that this implicitly includes the efficiency of aerosol particles in the lungs of a person susceptible to the disease. 

      Their equation also considered particles' efficiency in causing infection, the capacity of an infected person to emit virus particles, and the penetration efficiency of virus-carrying particles through masks. In addition, this equation took into account the volume of the space, the removal capabilities of air-cleaning devices, and the infectivity decay rate of the virus, among other factors.

      Then they combined that with a Wells-Riley infection model to determine the relative risk of transmission in different situations when sharing the same air in a room.

      Deeper in their paper, the researchers state that temperature, relative humidity, particle size, and geometry and airflow in a space are also significant factors in determining the risk.

      "Respiratory particle sizes in the range of 1-5 μm [microns] are thought to play a role in aerosol transmission of COVID-19, because of a combination of high emission rates by activities such as talking and low deposition rates," they state.

      Keep in mind that these are smaller than what's considered to be "droplets", which were defined in a Science article as than 100 microns in size.

      In their closing discussion, the researchers show that "mitigation measures to limit shared-room airborne transmission are needed in most indoor spaces whenever COVID-19 is spreading in a community".

      It's worth repeating: "most indoor spaces" require mitigation to limit shared-room airborne transmission.

      "Among effective measures are reducing vocalization, avoiding intense physical activities, shortening the duration of occupancy, reducing the number of occupants, wearing high-quality well-fitting masks, increasing ventilation, improving ventilation effectiveness, and applying additional virus removal measures (such as HEPA filtration and UVGI disinfection)," they state.

      Here in B.C., there is no mandatory provincial indoor mask mandate.

      At times, B.C. health authorities have even discouraged visitors to hospitals from wearing higher-quality masks.

      An inescapable conclusion...

      Earlier this week, the provincial health officer, Dr. Bonnie Henry, said on the CBC Early Edition that she hopes to never have to reinstate provincial mandates in response to COVID-19.

      This came in the same week that the B.C. Centre for Disease Control reported another 59 deaths involving people testing positive for COVID-19 between April 24 and 30.

      However, B.C.'s fatality figures have come under considerable criticism online from veteran reporter Salim Jiwa.

      The official number of B.C. fatalities of people with COVID-19 has topped 3,000 since the pandemic began.

      A recent paper published in the Lancet suggested that the actual number might be more than twice as high, based on the total of unexplained deaths in the province.

      Regardless of how many people are dying from COVID-19, there's one inescapable conclusion that can be drawn from the paper in Environmental Science & Technology.

      The people in charge of our health system—at the health authority and provincial levels—don't appear to be interested in instituting a multipronged approach to prevent the spread of COVID-19 through the air.

      If they did, they would be recommending high-quality masks like N95s or C99s. They would be urging school boards to encourage HEPA filters in classrooms. They would be holding public briefings to discuss the latest findings by aerosol scientists. And they would be launching ad campaigns to educate the population about airborne transmission so ordinary folks who don't read medical journals could take proper steps to prevent the spread the next time they hold a dinner party.

      That, my friends, is why I feel that this is the top provincial scandal over the past year. It breaks my heart. I'm sure that it also breaks the hearts of many of my readers.

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