Handling it right

ISHRAE shares a complete guide on how to operate air conditioning and ventilation systems to control spread of coronavirus disease (COVID-19) in workspaces

- ISHRAE

The COVID-19 pandemic has engulfed the world and India is no exception. The COVID-19 virus belongs to the Corona family to which SARS and MERS also belong. As the COVID-19 virus is still not fully understood, the behavior of SARS and MERS is considered as a reference to the extent they do not contradict the present observations. The COVID-19 virus affects the respiratory track and starts with symptoms similar to the common flu. Given that the virus is a mutated strain, there is no vaccine available to fight against this contagion.

COVID-19 Transmission Routes

The size of a coronavirus particle is in the range of 80-160 nanometers. It is transferred via infected microscopic airborne particles and contaminated aerosol droplets. Droplets and small particles of a broad spectrum of diameters get generated during the course of coughing and sneezing and, to a lesser extent, even by talking and breathing. Most large cough droplets fall on nearby surfaces and objects – such as desks and tables, where they remain active for hours and even 2-3 days. The difficult part is that the infected carrier is asymptomatic in the incubation period varying from 7 to 15 days.

Small particles (less than 5 microns) released during cough stay airborne for hours and can be transported over long distances. Small droplet nuclei or residue are formed from droplets (usually within milliseconds) in the air, which shrink in size due to the process of evaporation and desiccation in low humidity.

It is known that most of the infectious particles ranging from 0.65 to 3.3μm in the cough-generated aerosols were immediately respirable. There is also no reported data or studies to rule out the possibility of the airborne-particle route. One indication for this: Coronavirus SARS-CoV-2 has been isolated from swabs taken from exhaust vents in rooms occupied by infected patients.