Several studies warn that the virus may linger in closed environments for a long time and some technological projects, including a Spanish one, have decided to try and face the challenge of being able to detect it in the air.
THE start of the de-escalation phase makes us face issues that have been confusing since the beginning of the coronavirus pandemic. When we go back to commercial or leisure venues more than one person will wonder if social distancing or reduced capacity is sufficient enough to avoid contagion.
How long does the virus remain in the air in these closed environments? It is difficult to give an unequivocal answer, because it probably depends on many factors, but some scientists have not given up on trying to figure this out.
Since day one we have known that the virus does not only travel through air, but can be transported in the form of small drops that are expelled by infected people through their speech, breathing, coughs and, of course, the sneezing.
“The particles that we emit have a very wide range of sizes, the largest weighing more and depositing earlier, but the smallest remain in the air and can be transported over longer distances,” explains María Cruz Minguillón in a Teknautas report created by the Institute for Environmental Diagnosis and Water Studies (IDAEA, CSIC centre located in Barcelona) on this complex issue.
The virus is about 100 nanometres in size (a nanometre is a millionth of a millimetre) and the droplets in which it travels can be thousands of times larger but this is so small that it is invisible to the naked eye.
After a sneeze, the heaviest virus droplets fall quickly to a distance of between one and two metres, but other more lighter droplets remain suspended and go as far as eight metres, according to the New England Journal of Medicine.
Some studies have already looked specifically at the spread of SARS-CoV-2. One of them, published in ‘Emerging Infectious Diseases,’ a journal for the Centres of Disease Control and Prevention (CDC), measured the virus in the air of a hospital in Wuhan (China), finding a higher concentration in ICUs than in other rooms.
The most striking thing about this work was that the researchers even came to detect the pathogen four metres away from the patients. However, other research published in ‘JAMA’ only found the virus in rooms in some cases, but an added factor to them were air exhaust fans.
In Spain, the Carlos III Health Institute has announced that it is funding the AIRCovid19 project (Air Innovation & Research for Covid19) led by Antonio Alcamí, researcher at the Severo Ochoa Centre for Molecular Biology (CBMSO-CSIC).
The project, in which the La Paz and Severo Ochoa hospitals, the National Centre for Microbiology, IMDEA Nanoscience and ISGlobal of Barcelona participate, seeks to detect SARS-CoV2 in the air in different areas of hospitals and health centres in a fast and efficient manner.