• Wed. Jan 19th, 2022

Covid, with infection risk masks already collapses to 1 meter: study


Jan 14, 2022

The use of the surgical mask, and even more of the Ffp2, proves to be “an excellent protection tool, reducing the risk of” covid “contagion which becomes negligible even at short distances (about 1 meter), regardless of environmental conditions or respiratory event considered “. This is the conclusion of the study conducted by an international research team from the universities of Padua, Udine, Vienna and Chalmers (Sweden), published in the ‘Journal of the Royal Society Interface’. The research proposes a model for quantifying the risk of contagion from Covid-19 as a function of interpersonal distance, environmental conditions of temperature and humidity and the type of respiratory event considered (speaking, coughing or sneezing), with or without the use of masks. The work shows that “without a mask, the infected droplets emitted when speaking can reach a distance of just over 1 meter, while sneezing can reach up to 7 meters in conditions of high humidity. These distances, estimated by the model, show full agreement with the more recent experimental evidence – the researchers highlight – From the application of the model to estimate the risk of contagion, it is clear that there is no ‘universal’ safety distance, as it depends on environmental conditions, viral load and the type of respiratory event . For example, considering a cough (with average viral load), there can be a high risk of contagion within 2 meters in conditions of average relative humidity, while they become 3 with high relative humidity, always without a mask “.” pandemic highlighted the importance of accurately modeling viral transmission operated by salivary droplets emitted by infected individuals during respiratory events how to talk, cough and sneeze – says Francesco Picano, of the Department of Industrial Engineering of the University of Padua – The rules of interpersonal distancing usually used are mainly based on the study proposed by William Firth Wells in 1934. In our work we have revised this theory using the most recent knowledge on respiratory sprays, leading to the definition of a new model to quantify the risk of direct respiratory infection. The application of the model provides a systematic assessment of the effects of spacing and masks on the risk of infection. “” The results indicate that the risk is strongly influenced by environmental conditions such as humidity, viral load and the type of respiratory activity. , suggesting that there is no universal safe distance. On the other hand – Picano points out – wearing masks provides excellent protection, effectively limiting the transmission of pathogens even at short interpersonal distances and in all environmental conditions. “” We know that the virus requires a vector to be transmitted from a person to a ‘other – recalls Alfredo Soldati, professor of fluid dynamics at the University of Udine and director of the Institute of Fluid Mechanics and Heat Transfer of the Technische Universit├Ąt of Vienna – We also know that the vector is the droplets of saliva emitted while we breathe, speak, sneeze, let’s sing. The medical indications that we are following are based on fluid dynamics studies of 1940. We are closing schools, limiting the capacity of the premises, limiting the distances between people based on studies of 1940. It is important – he urges – that engineers and physicists engage in the study of these phenomena, together with biologists and virologists, to provide precise indications that allow to relax the rules when possible and to reinforce them when necessary “.” Since the beginning of the pandemic – remarks Soldati – the international community has put to work and in just 2 years has produced a wealth of knowledge based on sophisticated experiments and accurate simulations on modern supercomputers. The management of this pandemic requires a continuous and rational commitment on the part of public administrations, the medical and scientific communities in order to identify sustainable and acceptable measures by society. My hope – he concludes – is that the health community that identifies the safety measures gladly welcomes our suggestions and our help “.