Against covid and the upcoming pandemics, it is time to reconsider the minimum safety requirements for indoor air, the vector of many pathogens.Would you ingest water or food knowing they have been contaminated with a life-threatening pathogen? Why, then, do we accept to breathe the air of closed places where the covid coronavirus, the flu virus or other infectious agents could circulate – and maybe all together?
Today humanity spends most of its time indoors, yet there are no rigid air control standards similar to those historically conquered for the water we drink or the food we consume. All this must change , to reduce the transmission of known viruses and prevent the next pandemics: this is the appeal that 40 scientists from 14 different countries entrust to a study published in Science .
A HOLE TO FILL. In the last two centuries, investments and legislative interventions have been made to improve food safety, water quality and sanitation, with the aim of protecting public health. It is thanks to these measures that some diseases have completely disappeared from industrialized countries. However, the same cannot be said for the quality of the air in enclosed spaces: even if it is now evident that many diseases, from covid to flu, to measles, are transmitted by air, we tend to consider this eventuality as “a risk unavoidable”.
We do not lack the means and knowledge, and the expense to adapt the buildings would be minimal compared to the economic damage not only of the pandemic but also, to stay in less catastrophic situations, of the days of work lost due, for example, to the flu. seasonal. Why then is there no action?
A CHANGE OF PACE. According to the international team led by Lidia Morawska, who heads the International Laboratory for Air Quality and Health of the Queensland University of Technology (Australia), a paradigm shift similar to that which, in 1800, led to the reorganization of water networks and sanitation systems in large cities. We must aim for international ventilation standards that can limit the spread of pathogens, while “today, most of these rules – outside specialized health care or research facilities – only control the spread of odors, CO2 levels, temperature and humidity, ”explains Morawska.
ScienceIt is difficult to contract the covid from surfaces
THE ENGINEERING ASPECT. Buildings of the future should be designed with the possible spread of new respiratory viruses and the prevention of known infections in mind. The new generation ventilation systems should be controllable on demand , based on the crowding of the premises, the type of activity that takes place there and its breathing rhythm (a gym has different needs than a theater). They should also do this in an energy-efficient way to limit environmental impact, and provide monitors or other systems to inform the occupants of the room about the air conditions in the room they are about to share with others.
THE RIGHT TO BREATHE “HEALTHY” AIR. It is not a question of comparing new public spaces to biosecurity laboratories , but of providing conditions for acceptable and low-risk air standards, in a future that we want to imagine without masks. Since the air in public spaces is shared, it is a question of starting to consider it as a public good and protecting it as such. Perhaps starting with the approval of standards for indoor air quality to be compulsorily adopted in all countries, a bit like – or should happen – with the guidelines for outdoor air quality, referring to pollution. atmospheric.
ERRORS OF EVALUATION. According to the scientists, the superficiality with which the risk of airborne transmission of the covid was initially treated is the result of a historical prejudice. In the mid-1850s it was believed that cholera spread through miasmas (i.e. the mephitic smells of Victorian London), before the English physician John Snow became convinced, by mapping the neighborhoods where cholera was most prevalent, that the reason was l contaminated water. In 1847 the Hungarian doctor Ignaz Semmelweis discovered that disinfecting hands with chlorine before helping women to give birth greatly reduced postpartum infections and maternal mortality.. Thus gradually began to spread the belief that water and hands (and not air, nor odors!) Were vectors of diseases.
PROGRESS WITH RESERVATIONS. At the beginning of the 1900s, the American public health expert Charles Chapin, asserted that most respiratory diseases were transmitted and contracted or through the close proximity of infected respiratory droplets, i.e. the thicker and heavier droplets exhaled for example with sneezing, or by contact with surfaces on which the droplets quickly fell back.
Thus it excluded the possibility of airborne transmission due to aerosols, the thinnest droplets emitted when speaking or breathing, which remain in the air for a long time. Chapin feared that airborne transmission would be associated with the miasma theory so painstakingly outdated, and believed that admitting this possibility would spread unmotivated panic among people or discourage hand washing.