Even more important than masks and gloves in coronavirus fight is proper ventilation
An enormous experiment is now complete, carried out all around us. It was not a prospective, randomized, double-blind study. Its results are nonetheless conclusive. A great many COVID-19-infected Americans engaged in grocery shopping, and spreading virions, before knowing they were infected. They left COVID in the air and on surfaces: plastic wrapped meat, cereal boxes and vegetables and fruit. Close behind were millions of Americans who purchased these groceries, placed them on the kitchen counter, and consumed them. Simultaneously, COVID cases declined, wherever lockdown measures were followed. Reportedly COVID remains infective on surfaces for 1-3 days. The experiment conclusively establishes that if possible, such transmission is relatively minor.
COVID transmission? Recall the large New Jersey family celebrating together, the choir group practicing together, and the many nursing homes. COVID is spread in the air. Yes, droplets containing virions are forcibly expelled by sneezing and coughing and smaller ones even by speaking. These droplets fall to surfaces. Virions in smaller droplets that do not fall are also expelled by breathing, with gentle, restful breathing expelling fewer virions than heavy breathing as in shouting, singing or after exercise.
Imagine a person seated at a desk. He lights a cigarette, takes a puff, exhaling gently through his nostrils. A small cloud of smoke wafts around his head. Seated across the desk, you likely would not be able to smell the smoke immediately. Within 30-60 seconds, you would. Imagine instead that you entered the room after he had finished the cigarette. You would smell it immediately at a distance. Undetectable, COVID virions can spread in the same manner. Were the two of you outdoors, a hint of a breeze from you to him would protect you.
No two infected people shed virions at the same rate, and the number of virions necessary to infect you is large. The minimum infective dose which varies among pathogens is typically in the hundreds to thousands. Becoming infected is dependent on how many virions are being added to the room, how big the room is and how long you are collecting them.
Typical masks, useful for larger droplets, neither filter the wearer’s breath nor fit tightly. Gloves are not helpful if the infected person touches their outside while putting them on, or the potential victim touches the outside taking them off. But then, this is about surfaces.
Ventilation: Free the air of virions! Every closed space needs to have windows or doors open at opposite ends of the space to permit flow-through. Where necessary, fans should be placed at the downwind opening, blowing outward, to assist in establishing this flow-through. In barber shops, bars, small offices, restaurants, grocery stores and larger spaces; in cars, buses, trains, subways and somehow in airplanes. And hospitals! Yes, there is mixing in all these scenarios, but it is better than people being confined together in a closed, stagnant space. The whole business of becoming infected is a numbers game!
This story was originally published August 1, 2020 at 8:00 AM with the headline "Even more important than masks and gloves in coronavirus fight is proper ventilation."