House-dust mite exposure reduction in specially designed, mechanically ventilated "healthy" homes.

Thirty asthmatic patients were tested for exposure to house dust mites before and after moving to mechanically ventilated homes. There was found to be a significant reduction in house dust mite numbers after four months in contrast to the control group of 23 patients. A further reduction had occurred after 15 months. Air change rates increased from 0.40 ACH to 1.52 ACH. There was also a reduction in absolute air humidity. Concludes that the reduction of air humidity through an increased supply of fresh air may significantly decrease and in certain cases even eliminate house dust mite presence in residences.