Current knowledge of the role of air and the smallest particles in SARS-CoV-2 transmission requires special attention. Current leadership and public health information is gradually shifting the focus to the airborne transmission route, which is primarily associated with the breathing and conversations of asymptomatic people. Providing guidelines for adequate protection against the inhalation of airborne particles with the virus will be essential to contain the spread of COVID-19. This is evidenced by a study in Risk Analysis.
This study provides several lines of evidence for transmitting particles of the virus in the air, as well as recommendations for further research and public health communication.
To date, the main transmission methods of concern have been field transmission (coughing and sneezing) and transmission of the virus from hand to face from infected surfaces. More attention should be paid to inhaling small particles that can remain in the air and can be transported over short and long distances.
Reports of asymptomatic people infecting other COVID-19s show that activities such as normal breathing, talking, etc., contain small drops and particles that can be transported, as healthy people do not seem to cough and Do not sneeze on a regular basis.
Because the aerosol particles produced by speaking and breathing are so small, they are held in the air for a relatively long period of time before gravity pulls them to the ground. This allows them to travel long distances.
A 2006 SARS-CoV-1 study showed that particles with a diameter of 1-3 microns remained suspended in the air almost indefinitely, particles 10 microns in size held for 17 minutes, and 20 microns took 4 minutes to fall to the floor. A recent laboratory study showed that the virus can remain viable and infectious in these particles for several hours (it remained viable for the entire three-hour study duration) and on the surface for up to several days.
The study offers the following recommendations to solve the problem of a similar airborne transmission method of COVID-19:
- All data must be collected to study the concentration, survival time, and transport distances for SARS-CoV-2 in aerosol form at various temperatures and humidity levels.
- Further, investigate air concentrations and the role of aerosol doses in various parts of the respiratory tract in the progression and severity of the disease.
- Investigate the potential for aerosol contamination of buildings, rooms, and surfaces to provide a basis for decontamination protocols.
- Examine and record data to determine the role that human activity plays in potentially generating aerosols capable of transmitting SARS-CoV-2 in both enclosed and open spaces.
- Further study appropriate measures to limit the inhalation of small aerosols (<5 μm) inside buildings, rooms, and surfaces where aerosols can move and settle.