Inadequate Indoor Air Ventilation Creates Significant COVID-19 Risk
The US Centers for Disease Control and Prevention (CDC) announced a new science brief on May 7, 2021, to reflect current knowledge about the SARS-CoV-2 beta coronavirus transmission.
The CDC stated 'the principal mode by which people are infected with SARS-CoV-2 is through exposure to respiratory fluids carrying infectious virus, and less from surfaces.'
Furthermore, virus exposure occurs in three principal ways: (1) inhalation of very fine respiratory droplets and aerosol particles, (2) deposition of respiratory droplets and particles on exposed mucous membranes in the mouth, nose, or eye by direct splashes and sprays, and (3) touching mucous membranes with hands that have been soiled either directly by virus-containing respiratory fluids or indirectly by touching surfaces with the virus on them.
People release respiratory fluids during quiet breathing, speaking, singing, exercise, coughing, sneezing in the form of droplets. These droplets carry SARS-CoV-2 and transmit infection.
Specifically, the largest droplets settle out of the air rapidly, within seconds to minutes. And the smallest, very fine droplets and aerosol particles can remain suspended in the air for minutes to hours.
The CDC says to avoid 'enclosed spaces with inadequate air ventilation and prolonged virus exposure of more than 15 minutes.'