Allergen reduction claims bite the dust

Researchers at the North West Lung Centre have found that vacuum cleaners with HEPA filters are no more efficient at reducing exposure to allergens than standard models.


Researchers at The University of Manchester’s North West Lung Centre have found that vacuum cleaners with high-efficiency particulate air (HEPA) filters are no more efficient at reducing exposure to allergens than standard models.



The team compared five new high-efficiency vacuum cleaners, using an old previously used one as a control. Tests took place at five homes. Nasal allergen levels were measured when vacuuming, emptying the dust container and when mimicking vacuuming but with the machine turned off.



They took nasal air samples using a specially-designed nasal air sampler (NAS) which fits in the nostrils and contains an adhesive membrane capable of collecting over 90% of particles over the size of 5µm. Allergen levels were determined using a modified immunoblotting and colorimetric detection technique or eluted from the tapes and subjected to allergen-specific Enzyme-Linked Immunosorbent Assay (ELISA).



The team found that there was an increase in personal mite allergen exposure during cleaning, with no difference between high-efficiency and regular cleaners. Personal mite and cat allergen increased when the dust compartments were emptied.



Lead investigator Dr Robin Gore says, “These vacuum cleaners are marketed to allergy-sufferers on the basis that they reduce a person’s exposure to air-borne particles raised from carpeted floors. For allergy sufferers, such particles can trigger asthma attacks. However, we have already found that both HEPA- and non-HEPA vacuum cleaners can actually increase an individual’s exposure to particles containing cat allergens.



“These latest findings further suggest that there is no significant advantage to using a HEPA vacuum cleaner to reduce exposure to air-borne particles like dust-mites.”



Previous studies at the University of Sydney showed that when an old, used vacuum cleaner was tested in a clean testing chamber with cat-allergen laden dust, there is a three-fold increase in nasal allergens. A new HEPA filter gave the same results, despite having proven the machine did not leak.



Dr Gore says “As the machines don’t leak, the level of allergens is probably a combination of the beating bar disturbing carpet dust and the contents of exhaust air.



“We’re not saying that these cleaners are worse, just that it was inappropriate to market them as reducing allergens to asthma suffers. Long term use of a HEPA filter may have an effect, but current literature is inconclusive.



“However, the level of allergen exposure during vacuuming is insignificant when compared to the cumulative exposure of lying in bed.”