Survival time of Sars-Cov-19 viruses

in the air

What can I do about it?

Survival time of corona viruses in the air
(on aerosols)

Covid virus survives much longer at low temperatures. Therefore, proper ventilation or the addition of a UV-C air purifier is very important.


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In rooms with 20°C and 30% humidity

In a heated room, the survival time of corona viruses is 18.06 hours, which is a very long time. This means that the viruses survive a whole day in the room. Infection is possible if a "superspreader" was in the room on the same day.

The source of the graphic is US Homeland Security.


In rooms with 16°C and 32% humidity

It becomes frightening when a window is permanently open, as is often the case in kindergartens and schools, daycare centers, or in companies. The survival time of coronaviruses increases markedly to over 111 hours. This makes the risk of infection very high. A "superspreader" may have scattered viruses in a room 4 ½ days ago, which are still active and dangerous during this time.


How long does it take to get infected with Corona?

A normal, average immune system can stay in a room with a high viral load for about 15 minutes. A very good immune system can manage with a higher viral load and can therefore stay a little longer in a room with a high viral load.

The opposite is the case if the own immune system is not very well developed or is even very low due to an immune deficiency disease. These persons should in no case be in rooms without at least an FFP2 mask, where there is a lot of traffic or change of persons.


How can I make a room safer?
What do I need to know about UV-C air purifiers?

To make a room safer, the total germ count in the room must be lowered. This works best with a UV-C air purifier. The Sars-Cov-19 virus is very susceptible to this radiation and can be inactivated very efficiently with it. It is important that the power of the UV-C air purifier as well as the wavelength of the radiation are chosen correctly. The most effective are 254nm, 262nm for LED. When selecting LED devices, it is important that the wavelength does not go out above 270nm. Above 270nm, the disinfection power is very low, and at 280nm there is no disinfecting radiation.


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UV-FAN-ST (190W)
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UV-FAN-XS (60W)
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UV-FAN-WALL (190W)
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NeutralAir Mini
Neutralair UV-Station Midi
Neutralair UV-Station Maxi

But then the air is sterile?
No, in no case. It also does not harm the strengthening of the immune system!

If an air purifier based on UV-C disinfection is in a room, it does not have any negative impact on the child's immune system. With such devices, the viruses and bacteria are inactivated, but a sterile environment is not established. The total germ count in the air is reduced, not completely sterilized. Even if there are only a few germs left in the air, the surfaces still have general germs.

A child in school or kindergarten, daycare is still exposed to enough germs that help build the immune system. In addition, they are also outdoors during recess, which is teeming with germs. As soon as it touches objects (table, toy, colored pencil or pen...) it is exposed to germs. This does not change.


But I can ventilate!  

Of course, the total germ count can also be reduced with ventilation. However, very often only the window is opened, which cools the room temperature and favors the survival of the coronavirus in the air. In addition, prolonged airing favors children catching a cold. In order to effectively reduce the total germ count in a room, the air content in a room must be completely exchanged. This can only be achieved by intermittent ventilation and drafts. The best way to do this is to ventilate several rooms at once, but this means that people should move out of the room.

So, if you have an average immune system, you should ventilate 3-4 times an hour. It is not enough just to open the windows so that the Co2 value drops again, but it must be ventilated so that the air content is exchanged; only in this way is the germ load removed from the room.


CO2 meters

These meters are a very good indicator of when to ventilate. But they do not indicate if there is a virus load in the air. The CO2 meters cannot detect the viruses, because viruses are not present on CO2, but on aerosols (smallest water droplets).


How do I detect the virus load?

In order to be able to determine a viral load or a total bacterial count, an air sampler is required. This draws in room air and passes it over a microbiological culture plate. This agar plate is then incubated in an incubator so that the germs can multiply and then identified and counted under the microscope. Such devices are very expensive (available from 7'600 CHF) and a quick result is not possible. In addition, a microscope and an incubator are also required. If all this is available, the know-how to operate and identify the germs must also be available. For these reasons, this test is rarely used. In the United States of America, a company has developed such a device. Unfortunately, the data (samples) still have to be sent to a laboratory and the results are available the next day at the earliest. 


Air sampler MAS-100-NT

These air samplers can be used to collect viruses and bacteria in the air.

This example is a MAS-100-NT air sampler and is available from us from 7'651 CHF excl. VAT.


 

Autor: Claude Haltiner

Calculator Source: US Homeland Security


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