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Corona trap interior: You should pay attention to this in autumn

2020-08-25T12:49:34.187Z


Corona infection is best avoided outdoors - most researchers are convinced of this. It becomes dangerous in certain enclosed spaces.


Corona infection is best avoided outdoors - most researchers are convinced of this. It becomes dangerous in certain enclosed spaces.

  • One of the simplest means of protection against Corona: Get some fresh air.
  • There - to put it simply - the wind whirls the viruses away, which makes an infection * less likely.
  • But that also means: By autumn at the latest, when we are indoors again and the windows remain closed, the risk of infection increases. Find out how helpful room air purifiers are here .

The majority of the research community is convinced that droplets and the even smaller aerosol particles play a decisive role in the transmission of Sars-CoV-2. Aerosol particles can float in the air for hours to days. The former president of the International Society for Aerosols in Medicine, Gerhard Scheuch, says with a view to symptomless infected people who have been shown to have transmitted the virus: “ I think that just breathing is enough. "

Covid-19: High risk in closed rooms even at a distance

And this is exactly where the problem lies: In a closed room, a sick person breathes, coughs and sneezes again and again in bursts of virus clouds. If there is no wind, the viruses spread throughout the room and the corona concentration increases. The Robert Koch Institute therefore warns: If you stay in small, poorly or non-ventilated rooms for a long time, the likelihood of transmission by aerosols can increase even over a distance greater than two meters .

How much higher is the danger indoors than outdoors? There are no concrete answers to this. Scheuch refers to a study from China, according to which of the 318 outbreaks examined with three or more cases of infection , only one took place in the fresh air .

But interior is not the same interior as explained Scheuch: "In fitness studios, the production of aerosols can be increased significantly through breathing naturally through the physical effort." In a classroom with many screaming, messed-running children the danger is even greater than in an office with few (well-behaved) adults. In the inn, on the other hand, loud speaking, noise and singing could increase the spread.

Also read : This way of speaking increases the risk of coronavirus infection .

Cross ventilation against corona: Even tilted windows bring more than a built-in ventilation system

The solution here is also: wind. And the air should ideally be as fresh as possible. The head of the Hermann Rietschel Institute, the Institute for Energy Technology at the TU Berlin, Martin Kriegel, and his team investigated how the particles are distributed in space. He comes to the conclusion: “In principle, it can be said that with typical air exchange rates in residential and office buildings, the pathogens remain in the room for hours. The rate of descent and the air renewal take a long time. Any increase in the outside air supply is therefore generally sensible . "

Dieter Scholz from the Department of Vehicle Technology and Aircraft Construction at the Hamburg University of Applied Sciences argues similarly. Cross ventilation with open windows on opposite sides of an apartment, for example, is best. Tilted windows also bring more than a built-in ventilation system, says Scholz. The problem, especially with a view to autumn, is that the heat disappears just as quickly as possible viruses are blown out.

More on the topic : Coronavirus symptoms: Confused and disoriented patients - Coronavirus leads to "Covid-19-Brain" .

What are the benefits of using room air purifiers?

The cold seasons of autumn, winter and probably also spring bring one more problem with them this year. What to do? A team from the Institute for Fluid Mechanics and Aerodynamics at the University of the Federal Armed Forces in Munich has examined a room air purifier with a filter combination of which 99.995 percent of even very small aerosol particles are separated from the room air. In an 80 square meter room, the aerosol concentration can be halved in six minutes. Because the aerosols are filtered out, the devices would not turn into viruses either, says the team around Christian J. Kähler. They recommend room air purifiers for schools, offices, shops, waiting rooms, club houses, lounges and dining rooms.

Aerosol expert Scheuch also considers CO2 measuring devices to be helpful in closed rooms. “The CO2 content is a measure of the air quality in a room with several people. Then they would help as a warning system, ”he explains. But if you use room air purifiers at the same time, they no longer help. “Because then the CO2 content in the room goes up, but the air remains pretty much virus aerosol-free.” An additional particle measuring device, which determines the aerosol concentration, could help here. (dpa)

Sources: RKI on transmission routes; Homepage Scheuch, study on viral load, study on transmission in the air, study on restaurant, report on Kriegel research, explanatory video by Scholz, study on intact viruses in aerosols, study on indoor transmission, study on room air purifiers

Read more : Air filter kills corona viruses - device is to be used in clinics.

Aerosols: mixtures of the finest particles

Aerosols are mixtures of solid or liquid particles in a gas mixture such as air. The tiny particles can float in it for a long time. In medicine, one usually speaks of aerosols when the particles they contain are smaller than five micrometers - that is, many times smaller than the diameter of a human hair. From a size of five micrometers, the particles are called droplets. However, the boundary is fluid.

Every person spreads aerosol particles in their immediate surroundings with the exhaled air. In contrast to the droplets that sink quickly to the ground, these tiny particles can float in the air for hours to days. When speaking, shouting and singing, but especially when coughing, sneezing and exercising, more particles are emitted.

If there are pathogens such as Sars-CoV-2 viruses in a person's airways, the exhaled aerosols can contain them. In the case of the current coronavirus, the formation of such aerosols is particularly problematic because infected people can also excrete viruses without symptoms.

These viruses and bacteria make us sick

These viruses and bacteria make us sick

Source: merkur

All life articles on 2020-08-25

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