After a test by consumer protectors, it should be clear: In the home, air purifiers are not an alternative to the usual measures such as masks, ventilation and spacing, and in a 50-square-meter classroom with nearly 30 students, a single air filter would be far too small. In general, they can only reduce the risk to a limited extent, according to the testers.
Germany’s Stiftung Warentest has sent the top three models from a spring 2020 air purifier test of seven devices back to the test lab, this time with the task of evaluating their effectiveness against SARS-CoV-2. The Philips AC2889/10, Soehnle’s Airfresh Clean and Rowenta’s Intense Pure Air Connect PU6080 were to filter aerosol particles with a diameter of 0.12 to 1 millionth of a meter from the room air, the Association for Consumer Information (VKI) reported in the March “Konsument” magazine.
Air purifiers: Effect against coronavirus spread investigated
A person exhales about 100 of these droplets per second when breathing. When speaking, the number doubles, and when sneezing, it jumps to about 20,000. The coronavirus measures about 0.12 millionths of a meter. 500 viruses side by side are about as thick as a hair.
With new filters and at maximum setting, the air purifiers performed convincingly, reported the consumer protectors: Converted to a room with a volume of 40 cubic meters, most aerosol particles with a diameter of 0.12 micrometers had disappeared after 20 minutes. Philips and Rowenta eliminated 95 percent, and Soehnle 90 percent.
Performance decreases over time
The performance of every air purifier decreases over time. In the test, aging was simulated by exposing the devices to the smoke of 100 cigarettes. In the case of the Philips model, the number of the smallest particles still dropped by around 90 percent after 20 minutes. The Rowenta model managed 80 percent, and the Airfresh Clean only 46 percent. To reduce viruses, the filter would have to be changed far more often than intended, the testers said, with one costing around 50 euros.
“When an infected person breathes, talks or even sings here, they are constantly expelling new virus particles.” But an air purifier can only reduce the risk of infection, they said. “Additional measures such as keeping your distance and wearing mouth-nose protection are still essential.”-
- source: vienna.at/APA/picture: pixabay.com
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