The cold half of the year is approaching and with it, air purifiers are being massively advertised. They are supposed to rid the indoor air of corona viruses. Experts say: Active ventilation is usually a better alternative.
Expensive model of air purifiers for private use are supposed to remove up to 99.99 percent of possible corona viruses from indoor air. Such devices are just massively advertised. The consumer magazine “Super.Markt” of the Rundfunk Berlin-Brandenburg (rbb) has scrutinized four products and asked experts about them. These doubt the sense of such an investment and point to crucial gaps.
Thus it is possible to achieve a purification from Corona viruses in the air with built-in high quality filters. The crucial factor, however, is the amount of air that a single device can filter. Professor Martin Kriegel of the Technical University of Berlin , who has been studying the spread of airborne particles for years and, since Corona, also studies viruses in the air we breathe, takes a skeptical view: “One hundred cubic meters is nothing. If the device can do 100 cubic meters, then maybe I can get 0.5 percent change in overall risk, but not really make an impact.” Even if 400 cubic meters are cleaned, thorough and regular ventilation has the same effect as expensive devices, whose prices vary from several hundred to over 1,000 euros.
Low ionizer effect
Other devices advertise with a so-called ionizer. This is supposed to ensure that the air particles attract each other, clump together and thus become larger. This is supposed to make them easier to filter or cause them to sink to the ground more quickly. Professor Martin Kriegel is skeptical about this, too: “This effect, according to our studies here in our institute, is so small that it is actually negligible.”
Other manufacturers advertise UV-C rays for disinfection. That UV-C light neutralizes viruses has been known for a long time and is used in the disinfection of surfaces or to sterilize swimming pools. When cleaning air in indoor areas, however, it should be noted that UV-C rays are harmful to health when exposed directly to the skin and eyes. Professor Heinz-Jörn Moriske of the Federal Environment Agency therefore emphasizes “…that it must be prevented that any children play around with the devices and come into contact with the UV lamp.”
Conclusion of the rbb research
If you want to buy an air purifier, you have to pay attention to high-quality filters and the largest possible amount of air to be processed. Under this aspect none of the devices tested by the rbb could convince – despite the high purchase costs. Professor Moriske of the Federal Environment Agency sums up: “These air cleaners make sense as a supplement or in rooms where I simply cannot ventilate via windows… In individual cases, this can make sense. But please do not use it as a substitute for active ventilation.”