[Transmission of Sars-Cov-2 and ventilation of indoor environments. Technical notes and preventive measures]

Knowledge about the new infectious disease COVID-19, which first spread in the city of Wuhan in China, in December 2019, is based on the evidence retrieved from coronaviruses previously known to humans. The main transmission ways of the new SARS-CoV-2 virus are respiratory droplets and direct and close contact with infected individuals and contaminated surfaces. To date, some scientific publications provide initial evidence that SARS-CoV-2 can be detected in the air, thus assuming a further route of infection, that airborne, although these results are to be considered preliminary and they need careful interpretation. In support of this hypothesis, ventilation systems, aimed to improve indoor air, could represent an easy way to spread and promote the virus infection especially in hospitals and in all health facilities where the presence of infected individuals is potentially high as well as the possibility of infection by air. Indeed, by generating jets of air at different speeds, they can interfere with the mission of respiratory particles and determine an environmental diffusion of the potentially contaminating droplet. Therefore, ventilation systems could provide a potential transmission channel for the viral load able to spread out in indoor air. Nonetheless, good management, technical and operational practices may lead to a low risk of contagion, both in community and health environments.