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.

The emission rate of VOCs and aldehydes from materials typically found in ventilation ducts was measured. It was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket - in fact approaching the odour threshold. Exposure to ozone was found to increase the emission rate of aldehydes from a duct liner, duct sealing caulk and neoprene gasket. When exposed to ozone, the removal efficiency for a lined duct diminished to less than 4% over 10 days. It was much lower for an unlined duct.

Used a trained sensory panel and chemical and microbial measurements to examine the odour generation of the various components of air handling units. States that the results revealed that the supply air perceived air quality can be affected by the system. Nearly all the components of the system were sources of pollution, with used fibre filters the worst, although there were significant differences between the different components. Oily, dusty and dirty surfaces were the worst sources. Increasing the airflow did not improve the perceived air quality downstream of the components.

Study aimed to assess the effectiveness of domestic air duct sanitation services in reducing indoor aeroallergens. Sampling for fungal colony forming units was carried out in eight residences in winter and seven in summer, before and after a local company carried out duct sanitation procedures. Two houses were used as controls. Baseline CFUs were similar in control and study houses. The study homes showed an overall CFU reduction of 92% in winter and 84% in summer, eight weeks after cleaning. The controls showed no reduction.

A study examined by chemical analysis (without prior culture) bacterial levels in dust collected from hospital air conditioning filters. Gas chromatography-mass spectrometry methods were used to analyse the dust. Concludes that there is potential for the chemical assessment of the microbial content of airborne dust.

Analyses possible biocontamination of fibreglass duct materials used for thermal insulation and noise control in both residential and commercial heating, ventilation and air conditioning systems, in the light of concerns about the safety of their use in high humidity conditions. Static environmental chamber tests were carried out over six weeks to investigate conditions which might support the growth of a fungus, Penicillium chrysogenum.

Identified thermophilic actinomycetes contamination of the forced air systems as the sensitizing agents for most of the cases of hypersensitivity pneumonitis in eight patients. Concludes that patients should avoid the contaminated systems and use corticosteroids in severe cases as therapy for the disease.