The UK has the highest global prevalence of adolescent asthma. The last 25 years has seen the incidence of asthma episodes increase four-fold in adults and six-fold in children. The rapidity of this increase must be due to environmental factors. If these factors can therefore be identified and indexed, it may be possible to reduce or even reverse this trend. The disease is on the increase in many first world countries, but the rate of increase in Scotland is significantly greater. A systematic literature review identified house dust mite (HDM) allergen as both a causal mechanism in the aetiology of the disease, and an irritant likely to trigger and exacerbate symptoms.
In a drive for energy efficiency new build housing is highly insulated and as a result, much warmer than traditionally built older properties. New housing is also much "tighter" with lower air change rates. This has produced a warm and humid indoor environment. The timber frame housing industry in Scotland now dominates the market. Timber frame dwellings have two unique features that make them particularly NHS but would probably need some clonical input http://www.nihr.ac.uk/funding-opportunities/prone to HDM infestation: they incorporate polythene vapour barriers behind the plasterboard and have little thermal mass to regulate diurnal temperature fluctuations. This results in micro-climates in bedding, carpets and soft furnishings being regularly 'saturated'. The ideal environment for the colonisation and proliferation of HDM. This research programme thus aims to address the role that the on-going drive for energy efficiency has on occupant health.
We will test this hypothesis by taking dust samples from randomly identified dwellings. These samples will be analysed for HDM concentrations and the ratios correlated with house type and household characteristics.
The following research questions will be addressed:
1. What are the main factors affecting HDM colonisation and metabolic activity across the Scottish housing stock?2. Are 'tight' modern house types (lightweight timber frame with polythene vapour barriers) more prone to HDM infestation than traditional heavyweight dwellings?
SupervisorDr Catherine Lawrence
Sharpe T, Farren P, Howieson S, Tuohy P, McQuillan J. 2015. Occupant interactions and effectiveness of natural ventilation strategies in contemporary new housing in Scotland, UK. International Journal of Environmental Research and Public Health 12:8480-8497
McSharry C., Vesper S., Wymer L., Howieson S., Chaudhuri R., Wright G.R., Thomson N.C. 2015
Decreased FEV1% in asthmatic adults in Scottish homes with high environmental relative moldiness index values. Clinical and Experimental Allergy, (2015) http://dx.doi.org/10.1111/cea.12482
Howieson S. 2014 Are our homes making us ill? The impact of energy efficiency on indoor air quality. Perspectives in Public Health Vol 134, pp. 318-319, (2014)