Six-foot social distancing rule misses bigger risks, MIT

People overlook covid aerosols which is the main source of indoor contamination

When it comes to being indoors, the six feet rule of social distancing misses the bigger point of how coronavirus spreads, according to two Massachusetts Institute of Technology experts.

While staying six feet apart can help prevent the spread of large droplets of saliva or mucus that carry coronavirus and other germs, that distance does nothing to protect people from tiny airborne particles of virus called aerosols, MIT engineer Martin Bazant and mathematician John Bush write in a report published Tuesday in the Proceedings of the National Academy of Sciences.

Coronavirus is an airborne virus and even the US Centers for Disease Control and Prevention has said an overreliance on cleaning surfaces may lead people to neglect the bigger danger -- breathing in contaminated air.

Bazant and Bush worked out a complex formula for calculating how quickly someone might be expected to be exposed to virus in various closed rooms. The calculation takes into account air circulation, the rate of replacement of potentially contaminated air with clean air, and factors in known instances of spread -- for instance a choir rehearsal in Skagit Valley, Washington, in which 53 people became infected.

"To minimize risk of infection, one should avoid spending extended periods in highly populated areas. One is safer in rooms with large volume and high ventilation rates," they wrote.

"One is at greater risk in rooms where people are exerting themselves in such a way as to increase their respiration rate and pathogen output, for example, by exercising, singing, or shouting," they added.
"Likewise, masks worn by both infected and susceptible persons will reduce the risk of transmission."
They applied their guideline to a theoretical classroom designed to hold 19 students and a teacher and calculated how quickly the air could be fully exchanged with open windows and with an adequate HVAC system.

"For normal occupancy and without masks, the safe time after an infected individual enters the classroom is 1.2 hours for natural ventilation and 7.2 hours with mechanical ventilation," they wrote. That's with kids sitting quietly.

"Extended periods of physical activity, collective speech, or singing would lower the time limit by an order of magnitude," Bush and Bazant added.
"Our analysis sounds the alarm for elderly homes and long-term care facilities, which account for a large fraction of COVID-19 hospitalizations and deaths," they wrote.
"In nursing homes in New York City, the law requires a maximum occupancy of three and recommends a minimum area of 80 square feet per person."Under such conditions, keeping people six feet apart protects them for only three minutes, they calculated. It fails after 17 minutes if an infected person comes into the room briefly.
"With mechanical ventilation in steady-state, three occupants could safely remain in the room for no more than 18 minutes," they wrote.
"This example provides insight into the devastating toll of the COVID-19 pandemic on the elderly," they wrote. "Furthermore, it underscores the need to minimize the sharing of indoor space, maintain adequate, once-through ventilation, and encourage the use of face masks."

Tags : #Aerosol #SocialDistancing #MIT #CovidResearchLatest #HVACSystem #MechaicalVentilation

About the Author

Team Medicircle

Related Stories

Loading Please wait...

Trending Now

Dr. Rohan Palshetkar shares his invaluable insights about the Maternal Mortality Rate causes and improvements in India April 29, 2021
It is important to adopt a non-judgmental attitude towards any teenage girl seeking contraceptive advise suggests Dr. Teena Trivedi, Obstetrician and GynecologistApril 16, 2021
80% of the diseases are psychosomatic which means they have roots in the mind and this is where homeopathy steps in - It resolves physical ailments by finding the cause in the mind – Dr. Sanket Dhuri, Consultant Homeopath April 14, 2021
A futuristic Vision of a Healthcare Entrepreneur: Shyatto Raha, CEO, and Founder of MyHealthcareApril 12, 2021
Saher Mehdi, Founder and Chief Scientist at wellOwise talks about aspects making healthcare more equitable and reachableApril 10, 2021
Wide variety of therapies to address autism in children explained by Dr. Shilpa Jasubhai, Clinical PsychologistApril 09, 2021
Allopathic and Homeopathic medicines should not be taken together says Dr. Sunil Mehra, Homeopath ConsultantApril 08, 2021
The charm of homeopathic medicine is that it can be taken with conventional medicines – Dr. Shruthi Shridhar, Consulting Homeopath April 08, 2021
Dissociative Identity Disorder and associated concepts explained by Dr. Vinod Kumar, Psychiatrist and Head of Mpower - The Centre (Bangalore) April 07, 2021
Dissociative Identity Disorder explained by Dr. Shilpa Jasubhai, Clinical PsychologistApril 05, 2021
Sehat Ki Baat, Karishma Ke Saath- Episode 6 Healthy Diet For Boosting Metabolism Which Can Help Thyroid Patients April 03, 2021
Significant Pointers on Kidney Health by Dr. Santosh Waigankar, Consultant Urooncologist and Robotic Surgeon at Kokilaben Dhirubhai Ambani HospitalApril 01, 2021
Dr. Vaishal Kenia, Ophthalmologist Talks About the Different Possibilities Available for the Treatment of Glaucoma Depending Upon Their Type and SeverityMarch 30, 2021
No Definitive Role of Diet in Treatment of Lymphedema but Intake of Calories, Salt and Long Chain Fatty Acids should be controlled says Dr. Ramani CVMarch 30, 2021
Dr. Kiran Chandra Patro, Senior Nephrologist Talks About Dialysis as the Temporary Process and Not a Permanent Cure for the Patients of Renal DysfunctionMarch 30, 2021
Two out of three new chronic kidney disease patients are found to have diabetes or hypertension informs Dr. Sreeharsha HarinathaMarch 30, 2021
Glaucoma Treatment: Medications or Surgery? A valuable piece of advice from Dr. Pranay Kapdia, Chairman and Medical Director of Kapadia Eye CareMarch 25, 2021
Dr. Shraddha Satav, Consultant Ophthalmologist Recommends that Everybody After 40, Should Go for the Complete Eye Checkup at Regular IntervalMarch 25, 2021
Childhood Obesity is not a Disease but a Condition which can be very well ManagedMarch 19, 2021
World Sleep Day - 19 th March 2021- Know More About Healthy Sleep As Per The Guidelines by The World Sleep Society March 19, 2021