HEPA Filters No Help To Asthmatic Children
Reuters Health Central News November 17, 2000

BOSTON (Reuters Health) - While high-efficiency particulate air (HEPA) filters have been promoted as an inexpensive way to reduce allergens in homes, new study findings suggest that these filters may offer no benefit whatsoever to children with asthma. 

"All kinds of allergens exacerbate asthma in children, notably pet allergens, mold, dust mites and cockroaches," said lead researcher Kelly A. Quinn of La Rabida Children's Hospital and Research Center in Chicago, Illinois, in an interview with Reuters Health. 

To see if, by clearing these allergens from the air, HEPA filters would reduce asthma symptoms, Quinn and her team of researchers enlisted 60 families from Chicago with at least one severely asthmatic child aged 6 to 13 years. They reported their findings at the meeting of the American Public Health Association here this week. 

The investigators measured levels of cat allergens and dust mites in all homes at the start of the study. They also monitored asthma symptoms of the children with the help of parents and their doctors. 

Half of the families in the study used air filters that contained a HEPA filter, the other half of the group had non-HEPA filters. Neither the families nor the researchers knew which family had which type of filter.  

After 3 months, allergen levels were measured, then the families stopped using the filters for 2 weeks after which time the two groups switched filters. Those with HEPA filters received the non-HEPA filter and vice versa.

"We found that the HEPA air filters did not change the level of the cat allergen or dust mite allergen in the air," Quinn told Reuters Health. "There were no significant differences, and not surprisingly, the children's symptoms remained the same. In other words, the kids didn't do any better or worse with the HEPA filters in their homes," she added. 

However, Quinn noted that levels of the two allergens that were tested for in the homes "were not especially high to begin with." 

The study underscores the fact that commonsense housekeeping methods are still the best way to keep down the levels of allergens in the home, Quinn explained. 

For instance, removing allergen-trapping carpeting, wet mopping several times each week and using anti-dust mite covers on pillows and mattresses are all tactics that have been proven to help asthmatics, according to Quinn. 

"The bottom line is that parents shouldn't run out and buy these filters, because we didn't detect a benefit," Quinn stated. 

Calls to HEPA filter manufacturers for comment were not returned by deadline.