We need a paradigm shift

For decades we have been subject to very precise and restrictive regulations on the physical, chemical and bacteriological parameters of tap water , or on hygiene and food storage . On the quality of the air in buildings , however, the law intervenes little or nothing.

Still, we are talking about a crucial issue for our health. We learned this the hard way in this long year and a half of the coronavirus pandemic , a pathogen that is transmitted by breathing. 

An article published by the prestigious scientific journal Science hinges on this assumption . A real call, signed by 39 scientists, for a paradigm shift in the way we consider and deal with the transmission of respiratory infections . 

Air quality in buildings and Covid-19

By now we know well that Covid-19 is transmitted in the air . But exactly how? 

According to the American Centers for Disease Control and Prevention , in the first place there is the so-called aerosol , that is, those very small particles that are emitted by an infected person and remain suspended in the air for several hours. Then come the droplets , ie the coarser particles that can reach the mucous membranes of another person following a sneeze; being heavier, they fall to the ground more quickly. The third way is to touch the nose, eyes or mouth with the hands on which the virus has deposited (hence the prescription to wash them often and carefully). 

An in-depth study published by Scienza in rete invites us to take into consideration precisely the first point, the aerosol. The canonical meter of distance , in fact, keeps us reasonably safe from droplets. The smaller droplets, however, are more insidious, because they remain in the air and even manage to move.

Hence the need – indeed, the urgency – to ventilate closed environments and, more generally, to ensure better air quality in buildings.

How to improve indoor air quality

“There were no standards for clean water until the nineteenth century. People accepted that the water could be contaminated, or that they could get sick by drinking water. So there was a paradigm shift ”, explains Lidia Morawska , first author of the article in Nature, interviewed by Vox . “The reasoning is the same: we must not accept getting sick from respiratory viruses. We should do something to avoid it ”. 

“The existing standards for indoor air quality are aimed at guaranteeing the thermal and olfactory well -being of the occupants and limiting exposure to chemical compounds such as benzene, carbon monoxide, formaldehyde”, reiterates the article on Scienza in Rete A third must be added to these two main objectives: to limit the risk of infection by pathogens .

There are already some useful technologies, it would be enough to adopt them on a large scale. The most basic? A display showing CO2 concentrations in the air . If it exceeds a certain limit, it means that the ventilation is insufficient. 

Once the technologies are installed, the right parameters must be established . Some purely quantitative values ​​can be established a priori based on the size of the building and the number of people per square meter.

Inside a library  where people sit at their station in silence, however, the risk of contagion is very different from that of a gym , where they struggle on the treadmill. It therefore becomes necessary to study flexible ventilation systems , linked to the activities carried out within that specific building.

Is it complex? Certainly. But, experts point out, it is indispensable if we want to ” protect ourselves from unnecessary suffering and economic losses “.