For sure air purifiers can counter the air pollution problem by removing smoke and dust in the air.
But, contrary to general misconception, these domestic air purifiers should not be solely relied upon to remove such impurities as bacteria, virus, allergen or mould.
This advice was contained in a test report of the Consumer Council, in conjunction with the Electrical and Mechanical Services Department, on 10 models of air purifiers within the price range of $1,000 to $3,000.
The samples varied in their overall score from 41/2 to 3 points on a 5-point scale. The overall score consisted of air purifying effectiveness (50%), noise (10%), ease of use (20%), safety (20%).
Considerable variations (from 4 to 2 points) were found in the air purifying performance of the samples measured in terms of their Clean Air Delivery Rate (CADR) for removal of smoke and dust in a controlled test room, and conducted in accordance with the U.S. Association of Home Appliance Manufacturers (AHAM) standard.
Overall, most samples were considered to be satisfactory in electrical safety in accordance with the requirements of the latest IEC (International Electrical Commission) standard. In fact, no non-compliance was found in three of the samples.
Relatively minor deficiencies in the remainder samples included: some materials used in purifiers were of insufficient strength to heat under pressure or resistance to hot metal wire; inadequate insulation distances; live parts or basic insulated metal parts were accessible.
In the report, it was noted that many air purifiers made claims of removal of bacteria, virus, dust mite allergen or mould.
But medical opinion observed that as these machines are designed mainly for domestic use, they cannot be solely relied upon for the removal of such impurities in the air - to the neglect of household hygiene and disease prevention.
In any case, inefficient filtering and/or leakage around the filter would release these biological agents back into the air. Maintenance of the air filters to ensure performance - and minimize the hazard - is therefore important.
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