Are Aerosols Prime Driver of COVID Spread?

It may be difficult to remember a time before wearing masks became our new normal. More than six months into life with Covid-19, we have been conditioned to see masks and social distancing as our best defense. Study after study has found the combination to be one of the most effective ways to flatten the curve. 

The main argument for these measures is that they protect us from droplets: particles in larger liquid form that tend to fall to the ground quickly. Viruses are spread whenever people cough, breathe, talk or sneeze, and if the particles are heavy enough to fall, it makes sense that masks and social distancing are sufficient protection. 

But every particle is different in size. Many are far too small to measure and not heavy enough to fall right away. These are classified as aerosols, and they can stay in the air much longer and spread further away than droplets can.

In July 2020, a coalition of 239 scientists successfully petitioned the World Health Organization (WHO) to include airborne transmission information in its Covid-19 guidelines. However, the Centers for Disease Control (CDC) has gone back and forth on the subject, adding similar guidelines in September, only to retract them soon after. Given the lack of cohesive guidance, it’s unsurprising that most states have reopened schools, restaurants and gyms, all of which are primed for airborne transmission. In many of these, masks are only required while entering and leaving.

Experts around the world are urging much more caution and focus on the spread of Covid-19 through aerosols. 

One study found that aerosols can easily travel the length of a large room before hitting the floor. Another found that SARS-coV-2, the disease that causes Covid-19, can survive in the air for hours. Furthermore, evidence suggests that large droplets can evaporate and transform into aerosols, and more aerosols than droplets are produced by talking, coughing and sneezing. Research found that loud talking can produce anywhere from a few dozen to a few hundred droplets, and most of those were aerosols.

A choir rehearsal in Washington state was classified as a “super-spreader” event after one infected participant produced 52 new cases. The infected person was standing in front of most others, indicating his or her droplets would have trouble reaching others’ eyes, ears and mouths. One of the new cases was standing more than 40 feet behind the infected person.  

The choir room had poor ventilation, a key factor that experts say significantly affects airborne transmission chances. 

While hundreds of conflicting studies make it difficult to know for sure just how big a role airborne transmission plays in the spread of Covid-19, the letter from the 239 scientists recommended the following to minimize the effects of aerosols:

  • Provide sufficient and effective ventilation (supply clean outdoor air, minimize recirculating air) particularly in public buildings, workplace environments, hospitals, and aged care homes
  • Make sure all public buildings, particularly hospitals, offices and retirement homes, are well-ventilated
  • Add extra ventilation with proper exhaust systems, air filtration and germicidal UV lighting
  • Be sure not to overcrowd any space, particularly public transportation

We hope that all of you are staying safe and have a low key Thanksgiving knowing that you are protecting your loved ones.

If you or your loved ones have been seriously injured, please contact any of the experienced attorneys at Murray & Murray today.