An examination was conducted of thirty single family homes with either high or low house-dust mite allergen levels in mattress dust, with regard to ventilation, thermal climate, and air quality. High concentrations were associated with the difference in absolute humidity between indoor and outdoor air, also with low air change rates, especially in the bedroom. The research found no correlation between concentrations of TVOC or formaldehyde in bedroom air and HDM allergen concentration.
Describes and investigation of house-dust mites in 96 Danish homes with one or more members with asthma. All the homes were measured for air exchange rates, humidity and temperature. The study found a positive correlation between indoor air humidity and mite concentration and an inverse correlation between house-dust mite concentration and indoor air exchange. House-dust mite concentration was higher in the houses with mite-allergic persons. In 76% of the homes the concentration was above the proposed limit of 10 mites/0.1 g dust. This was so in 48% of the non-allergic homes.
This study investigates the connection between indoor climate and eczema. Nine patients suffering from atopic dermatitis (AD) were examined by doctors before and after moving to houses with better air exchange, low relative humidity and optimal temperature control. Every month for two years, three clinical and subjective assessments were made of disease activity, and compared with changes in suspended and respirable dust particles, room temperature, air exchange rate, number of house dust mites in bedrooms, and the levels of organic solvents in the indoor air.
States that poor ventilation is a factor in raising humidity levels in well insulation cold climate housing. Aimed to look at the ventilation rates in houses with varying ventilation systems, noting indoor air humidity, domestic mite allergen levels and VOCs. Enzyme-linked immunosorbent assay was used to measure levels in 59 similar one-storey single family houses. 22 houses had an added mechanical supply and exhaust ventilation system.
The study investigates the effect of mechanical ventilation and high-efficiency vacuuming on house dust mite numbers and allergen concentrations in dwellings of mite-sensitive asthmatics. Of forty houses, some received mechanical ventilation, some an HEVC, and some both, while a number acted as controls. The monitoring exercise lasted for twelve months. It was found that humidity was reduced in homes with mechanical ventilation and mite numbers reduced accordingly. Use of the vacuum cleaners enhanced the effect.
A move to mechanically ventilated low-dust mite affected, 'healthy' homes was investigated in relation to asthma control. Fourteen patients, allergic to dust mite allergens, were studied. Clinical improvements were significant in the patients, in contrast to the control patients. The study found a significant relation between reduction in medicine score and the fall in house dust mite exposure.
Describes a study of 424 homes in USA to analyse the presence of dust mite allergens. Seasonal fluctuations were identified. Air conditioning was found to reduce allergens. States that the findings imply that differences in the microclimate within homes may have a dramatic effect on mite populations.
Public facilities in Japan were investigated for the presence and distribution of allergenic mites. Dust was analysed from four hospitals, two hotels, two ryokans, one film theatre and four office buildings. Clinically important antigen levels were found in the theatre, and ryokans, but not in the hospitals, hotels or offices.
Attempts to determine the influence of the installation of highly insulated windows and central heating systems on indoor climate, and mite-allergen (Der f 1) and mould spore concentrations. A before and after study was carried out on 98 apartment bedrooms, with measurements taken of air exchange rate, temperature and humidity. A lifestyle and housing conditions questionnaire was undertaken by the occupants and dust on carpets and mattresses was analysed for mould spores and Der f 1.
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.
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