More than two years after the battle against covid-19 began, aerating a room to disperse contaminated particles is still a "weapon" marginal against the virus, despite its importance beyond this pandemic.
"To reduce mortality and contain the pandemic, it would be necessary to reduce the level of contamination, which today the vaccine alone cannot do"notes the epidemiologist Antoine Flahault.
"A new phase is needed the improvement of indoor air quality"says the director of the Institute for Global Health at the Faculty of Medicine of the University of Geneva.
Sars-Cov-2 spreads mainly through the air. Clouds of particles escape when humans breathe, and even more so when they talk, shout or sing.
In a closed and poorly ventilated room, these particles can remain in the air for a long time, accumulate, move throughout the space and greatly increase the risk of infection.
Although it is accepted that covid transmission less than two meters It can be carried out by both droplets and suspended particles, there is no consensus on the importance of long-distance airborne transmission indoors.
According to researchers from the University of Bristol and the British Health Security Agency in the latest edition of the British Medical Journal, transmission over two meters is possible in different interiors.
However, his work based on 18 observational studies in several countries, it has some methodological limitations.
Improve indoor air quality
What is certain is that, if it is ventilated enough, the particles dissipate.
However, efforts to clean indoor air remain insufficient, according to specialists.
Ventilation is one of the "barrier gestures" recommended by the authorities. But, "in general, governments do not deal with this issue"observes Professor Flahault. Only a few countries, in Asia, America or Europe, announced plans in this regard.
In the United States, the Biden administration in March invited owners and managers of buildings, schools and other organizations to establish "strategies to improve indoor air quality in your buildings and reduce the spread of covid-19".
This plan, endowed with financing through the post-pandemic reactivation program, also affects public buildings.
are anticipated heating system testsventilation, air conditioning and the purchase of portable air filtration units, air filters and fans.
In Europe, the European Union did not establish binding standards to improve indoor air quality. Only Belgium announced a plan for places open to the public (cafes, restaurants, cinemas, gyms, etc).
The measures, voluntary until the end of 2024, will become mandatory after this date.
Beyond covid-19, the air battle could mark a new stage for public health, according to experts. This might exclude pathogens, but it would also reduce other transmissions, including contaminants.
"Such measures also would considerably mitigate the impact of other diseases"Stephen Griffin, associate professor of medicine at the University of Leeds, recently observed at the Science Media Center.
"Better ventilation also improves cognition by reducing carbon dioxide levels and, with filtration, can reduce the impact of pollen and allergies."he detailed.