The Consumer Council (CC) announced today (Sept. 15) that it has tested 10 types of portable negative ion air purifiers and found that the effectiveness of these samples in removing bacteria and air pollutants is limited even when they are used in small enclosed spaces.
After placing all the samples in a small airtight space for an hour, the decontamination rate was only about 70% to 80%, which is quite disappointing. According to the report, the highest score in the test was 5, with 8 samples scoring 2.5 or less and the remaining 2 scoring only 3.
In another test conducted on the removal of PM2.5 pollutants, 6 samples scored the lowest mark of 1, while the 2 highest-scored samples only scored 3. The PM2.5 removal rate of the 6 samples was less than 15% after 2 hours of operation in a small enclosed space.
CC said that such portable air purifiers are not equipped with filters, claiming that they can generate negative ions which can cause pollutant particles in the air to carry a negative charge and adsorb to other pollutant particles so as to add weight to the air, which will then settle or attach to the surfaces of other objects, thereby purifying the air.
However, pollutants that settle or adhere to surrounding surfaces can easily become airborne and re-circulate in the air, posing a risk of secondary contamination. Consumers who touch contaminated surfaces and then touch their mouths, noses or eyes are also at risk of infection.
CC stressed that the effectiveness of these air purifiers in removing bacteria and pollutants in the air is questionable in real-life situations, and urged consumers not to rely on them blindly, thinking that wearing it will keep out germs and pollutants, while other basic precautionary measures such as washing hands frequently and wearing masks properly are not taken seriously.
Comment