Newswise — RUDN University engineer with colleagues from Iran built an aerodynamic model of the spread of coronavirus in an apartment. The authors compared different heating systems and calculated which option is the safest in terms of the spreading the virus. The results are published in The European Physical Journal Plus.

Face masks and frequent hand washing are common ways to fight the virus. However, you can also get infected inside residential premises, where masks are usually removed. Therefore, it is important to consider the issue of the spread of viruses inside buildings. Their movement will be influenced by the aerodynamics of the room, which depends on the heating and ventilation system. A RUDN University scientist and colleagues from Iran have built a model to track the movement of the coronavirus in an apartment. It helps comparing the effect of different heating systems and choose the safest option.

“The spread of pathogenic particles inside buildings has become an important issue in the design of modern buildings. In times of the coronavirus pandemic, it is important to pay attention to how it spreads in residential apartments. To calculate the movement of a virus, you first need to study its physics. It is also important to know the aerodynamics of the spread of the virus. We tracked the particles of the coronavirus that are released when a sick person sneezes in the bedroom of an apartment, taking into account the heating system of the room,” said Esmail Lakzian, PhD, researcher at the RUDN Institute of Ecology.

To create a model, engineers have built a system of equations - the conservation of energy, momentum and the equation of continuity. For example, the authors considered an apartment of 44 square meters. It is assumed that a human carrier of the virus sneezes in the direction of the bedroom door and releases 40,000 virus particles in 0.25 seconds at a speed of 4.5 meters per second and a temperature of 39 ℃. On the other side of the door is a healthy person. It is also assumed that the heating system is turned on - warm air comes from a heater near the ceiling or from a warm floor.

It turned out that underfloor heating is safer from the point of view of the virus spreading - they inhibit its movement to a greater extent. Air conditioners mix the air in the apartment and help harmful particles spread faster. According to RUDN University ecologists, only 200 seconds after a sick person sneezes, the room becomes harmless. At the same time, areas with a high concentration of the virus last longer in an apartment with warm floors. Given these data, environmentalists proposed a combination that should maximize the safety of residential apartments - a floor heating system and low-power ventilation. Thus, areas of high concentration of the virus will disappear faster - in about a second.

“The underfloor heating system makes living spaces safer. However, the intensity of infection near the source is higher. To reduce the spread of the coronavirus, a low power exhaust fan should be used. Then it will take less than one second to remove particles from the environment, which is very convenient. Therefore, designers of ventilation systems in such apartments are strongly advised to use a suitable exhaust hood when using a floor heating system,” Esmail Lakzian, PhD, researcher at the RUDN Institute of Ecology.

##### CITATIONS

The European Physical Journal Plus volume 137