According to the American Journal of Respiratory and Critical Care Medicine, household cleaning products and air fresheners may be a cause of asthma in adults. Even using a spray just once a week may be enough to trigger the disease, researchers suggest.

Asthma has been recognised as an occupational hazard among cleaning professionals, but nobody had made the connection to occasional use of the chemicals in the family home. 

A new study — which recruited 3,500 people from 10 European countries — reckons that up to 15 per cent, or one in seven cases of adult asthma, could be caused by household cleaning sprays.

Even sporadic use of sprays resulted in a 6 per cent increase in asthma.  Not surprisingly, the risk increased with usage, and people who used them every other day or so increased their risk by a further 50 per cent.

The worst culprits were cleaning sprays, air fresheners, and furniture and glass cleaners.