Controlling house dust mites through ventilation: development of a model of mite response to varying hygrothermal conditions

There is clear evidence that house dust mite populations in many climatic regions can potentially be controlled by modifying temperature and humidity within dwellings. This paper describes a current multi-disciplinary UK funded research project to develop a predictive model of house dust mite response to varying hygrothermal conditions. The project involves the development of two component models, the first simulating transient hygrothermal conditions in bedding and the second simulating the effect of these conditions on mite populations. The bed model is being developed by adapting existing hygrothermal modelling techniques, starting with a model of conditions within the dwelling and extending it to include the bed environment. It is being tested and validated by comparing predictions with temperatures and humidities measured in a fully instrumented bed in a test laboratory, as well as in normally occupied beds in dwellings. The development of the mite population model is hampered by a lack of available physiological data in certain key areas. Nevertheless the framework for a prototype model has been established, supported by experimental mite studies being carried out in the laboratory. In order to test its output, a series of population growth experiments will be carried out in a computer controlled incubator chamber, where temperature and humidity can be varied to replicate conditions in bedding. Mite samples from field study beds are also being monitored. The aim of the project is to integrate the bed an