Saturday , January 23 2021

Scientists assess the risk of Covid-19 air using masks



New York, October 28 (IANS): The continuing rise in Covid-19 infections around the world has prompted scientists to study the dynamics of airborne transmission.

In the study, published in the journal Fluid Physics, researchers, including those of Indian descent, used a model to understand airborne transmission designed to be accessible to a wide range of people.

Using the basic concepts of fluid dynamics and known factors in airborne disease transmission, the researchers proposed the airborne transmission inequality (CAT) model.

Although not all factors in the CAT inequality model can be known, it can still be used to assess relative risks because the risk of the situation is proportional to the exposure time.

Using the model, the researchers found that transmission protection increases with physical distance in approximately linear proportion.

“If you double your distance, you generally double your protection. This kind of scaling or rule can help inform policy,” said study author Rajat Mittal of Johns Hopkins University in the United States.

Scientists have also found that even simple cloth masks provide significant protection and can reduce the spread of Covid-19.

“We also show that any physical activity that increases the rate of respiration and the volume of people will increase the risk of transmission,” Mittal said.

These findings have important implications for reopening schools, gyms or shopping malls.

The CAT inequality model is inspired by the Drake equation in astrobiology and develops a similar factorization based on the idea that airborne transmission occurs if the susceptible person inhales a viral dose that exceeds the minimum infectious dose.

The Drake equation is a probable argument used to estimate the number of active, communicative alien civilizations in the Milky Way galaxy.

The model includes variables that can be added to each of the three phases of airborne transmission: generation, expulsion and aerosolization of droplets containing virus from the mouth and nose of an infected host, dispersion and transport by ambient air currents; and inhalation of droplets or aerosols and deposition of the virus in the respiratory mucosa of a susceptible person.

The researchers hope to take a closer look at the effectiveness of the face mask and the details of high-density outdoor transmission.

Outside of Covid-19, this CAT-based inequality model can be applied to the airborne transmission of other respiratory infections, such as influenza, tuberculosis, and measles.




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