If you have allergic asthma, you may well be exposed to allergens in the air while you sleep – including mould spores, pollen grains and house dust mite. Do you wake up coughing? If so, it could be a good idea to use an air purifier which cleans the air as you sleep. Professor John Warner of Imperial College, London, with colleagues at other European centres, looked at the impact of a HEPA filtration system on a group of patients with asthma. The air HEPA air purifiers deliver clean, purified air to the breathing zone of the patient, capturing and retaining airborne allergens from the air.
The study involved a group of 282 patients with atopic asthma from six countries, aged between 7 and 70. Fifty-four British children were included. These were all patients whose asthma was poorly controlled, so they had much to gain if the trial proved successful. Two-thirds had an active HEPA air purifier in their bedroom and the rest had a placebo (dummy) machine. It was switched on at bedtime and switched off again on waking.
At the end of one year, patients’ quality of life was assessed using the Asthma Quality of Life Questionnaire. There was a significant improvement of 15 per cent in those who had been exposed to the HEPA air cleaner compared to those who had only been exposed to the placebo. Improvements were most marked among those with the most severe asthma. However, no differences in lung function were noted between treatment and exposure groups, although those on active treatment were found to have less airway inflammation.
This study is interesting because it suggested that allergen avoidance, by air purification, does have a very positive impact. The cost of the HEPA air cleaner used in this study is £4,000. This could prove a cost-effective investment because long-term use may lead to savings in medication costs and hospital admissions. This is particularly so for those with poorly controlled asthma where the next step may be stepping up the medication. Costs aside, many do not want to depend upon medication to control their asthma. Particularly, parents may not wish to see their children with asthma having to take so many drugs.
Less pricy HEPA air cleaners, but yet with the same high filtration efficiency can be found for a fraction of the price. The IQAir HealthPro 250, for example, can be a fantastic choice, which offers medical grade H13 filtration as well has high-quality gas and chemical filtration.
Source: Boyle et al (2011). Nocturnal temperature controlled laminar airflow for treating atopic asthma: a randomised controlled trial. Thorax87; 215-221