Whether at school, when shopping, in a restaurant or in the supermarket: the risk of contracting corona virus is literally in the air. The SARS-CoV-2 virus enters the body with inhaled air via infectious aerosol particles in the room air, whereby the Covid-19 pathogen spreads in the respiratory tract. Researchers at the Technical University of Berlin recently calculated how high the risk of infection is in certain rooms and everyday situations.
Ventilation, air purifier or both? What is the best protection against infection?
Researchers from the Department of Infrastructure Security at the South Korean Institute of Construction Technology (KITC) have now presented another calculation of the corona infection risk. In a school near Seoul, scientists examined the efficiency of air purifiers in the fight against corona virus. High-performance air purifiers such as the TAC V+ with H14-HEPA Filter (certified according to DIN EN 1822) are being used worldwide during the corona pandemic to protect against airborne infection with regard to the SARS-CoV-2 virus.
In the South Korean study, virus-like salt microparticles were released into the indoor air as aerosols and their concentration was then measured at different points in the room. The decrease in aerosol concentration through passive window ventilation, through the use of air purifiers with closed windows and the combination of air purifiers with window ventilation was examined and compared with each other.
The combination of several measures is the most effective:
- According to the KICT’s calculations, ventilation with open windows reduced the risk of infection by 55 %.
- The use of a mobile air purifier with windows closed at the same time led to a comparable reduction in the risk of infection by 50 %.
- The combination of ventilation and air purification achieved the best result with a 73 % reduction in the risk of infection.
The test results confirm the research of Professor Dr. Christian Kähler, head of the Institute for Fluid Mechanics and Aerodynamics at the University of the Federal Armed Forces in Munich. The professor from the Munich university had already examined the effectiveness of the TAC V+ air purifier from Trotec in several studies last year. After numerous tests with the most modern laser measurement technology, the scientist came to the following conclusion:
“If you run this system continuously, it will be impossible for an infectious aerosol concentration to build up in the room!’’
We now know that the SARS-CoV-2 virus is transmitted primarily through tiny aerosols that are invisible to the eye in the room air. Virologists and epidemiologists estimate that about 80 percent of infections occur indirectly through the air.
An aerosol is a gaseous mixture containing virus-laden particles in people who are ill. These tiny airborne particles are produced in the lungs and released into the air mainly when breathing and speaking. While larger droplets fall to the floor after approx. 1.5 metres due to their weight (hence the social distancing rule of 1.5 m), light aerosol particles float in the room air for several hours due to their small size (approx. 0.1–0.3 µm), are distributed through ventilation systems and are even inhaled unnoticed many meters away.
TAC V+ air purifier – recommended for the best possible protection against infection in closed rooms
TAC air purifier with H14-HEPA Filter (certified according to DIN EN 1822), are able to safely filter microscope, virus-laden aerosols from indoor air and supply indoor rooms with clean, virus-filtered air despite closed windows. In combination with the usual hygiene measures such as AHA rules, Acrylic glass partitions and medical mouth-nose-masks, it is possible to achieve maximum effective protection in almost all closed rooms.
In a treatment room measuring up to 80 m², the TAC V+ high-performance air purifier demonstrably halves the airborne viral load within 6 minutes. In smaller rooms the viral load is even halved after just 3 minutes.
Science has already defined which requirements suitable air purifiers must meet:
- The volume flow of the air purifier must be sufficiently dimensioned to allow at least six air changes per hour. This is the only way to ensure that the aerosol concentration in the room is reduced within minutes. High performance air purifiers of the TAC V series even enable an air exchange rate of up to 16 times per hour and thus offer an even higher level of protection, for example for high-risk patients in medical practices, at hospital wards or in nursing homes.
- The filter used must be certified according to DIN EN 1822. Only H14 HEPA high-performance filters certified in accordance with EN 1822, such as those used in the TAC V+, TAC M and TAC Eco, can filter 99.995 % of small, virus-laden aerosols (0.1–0.3 µm) from the room air. This means that H14 HEPA filters already have a filter performance 10 times higher than H13 HEPA filters, whose filtration performance is still comparably good in the size range of bacteria. However, there are significant differences in the so-called MPPS range (Most Penetrating Particle Size), i.e. when filtering out viruses and aerosols. Here, the Laboratory Technology Project Group (ELATEC) of the Federal Institute for Occupational Safety and Health expressly advises in its statement on the topic “Use of HEPA filters in ventilation systems (Resolution 16/2010)”: “The HEPA filter should at least comply with class H14 according to DIN EN 1822-1.”
- The air purifier must be as sufficiently quiet, so that it does not interfere when in operation. Because if the noise is disturbing, there is a risk that the device will either be switched off or not be operated with the required air flow. Then there will no longer be a high level of safety against indirect SARS-CoV-2 infection. For this reason, the TAC V+ high performance air purifier has a noise-insulating sound-absorbing hood, making it the quietest unit of its performance class.
These criteria defined by Prof. Kähler are currently only exceeded by the mobile TAC V+ high performance air purifier. The device is developed and manufactured in Germany (Heinsberg), but it is delivered all over the world. A constantly updated overview on the company website, whereby restaurants, authorities, schools or medical institutions are already using the TAC V+ high-performance air purifier, underlines the proven effectiveness of TAC V+ air purification.
Trotec GmbH
Telephone: +49 2452 962-400, online-uk@trotec.com
