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- Engvall, Karin, 1949-
(författare)
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A Sociological Approach to Indoor Environment in Dwellings : Risk factors for Sick Building Syndrome (SBS) and Discomfort
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The principal aim was to study selected aspects of indoor environment in dwellings and their association with symptoms compatible with the sick building syndrome (SBS). A validated questionnaire was developed specifically for residential indoor investigations, using sociological principles and test procedures. The questionnaire was mailed to 14,243 multi-family dwellings in Stockholm, selected by stratified random sampling. Females, subjects with a history of atopy, those above 65 y, and those in new buildings reported more symptoms. Subjects owning their own dwelling had less symptoms. A multiple regression model was developed, to identify residential buildings with a higher than expected occurrence of SBS. In total, 28.5% reported at least one sign of building dampness in their home (condensation on windows, humidity in the bathroom, mouldy odour, water leakage). All indicators of dampness were related to symptoms, even when adjusting for demographic data, and other building characteristics (OR=2.9-6.0). Associations between symptoms and other building data was evaluated in older houses, built before 1961. Subjects in older buildings with a mechanical ventilation system had fewer symptoms. Heating by electric radiators, and wood heating was associated with an increase of most types of symptoms (OR=1.2-5.0). Multiple sealing measures (OR=1.3), and major reconstruction (OR=1.1-1.9), was associated with an increase of symptoms. The effect of seasonal adapted ventilation (SAV) was studied in a small experimental study. A 20% reduction of ventilation flow from 0.5-0.8 ac/h to 0.4-0.5 ACH during the heating season increased the perception of poor indoor air quality in the dwelling in general, and in the bedroom. In conclusion, low building age, and building dampness in the dwelling are associated with SBS. In older houses, mechanical ventilation is beneficial. The thesis did not support the view that energy saving measures in general is an important risk factor for SBS, but major reconstruction and multiple sealing measures can be risk factor for symptoms. Reducing the outdoor ventilation flow below the current Swedish ventilation standard (0.5 ACH) may increase the perception of impaired air quality.
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| 2. |
- Lindgren, Torsten
(författare)
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Cabin Air Quality in Commercial Aircraft : Exposure, Symptoms and Signs
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of the dissertation was to study the cabin environment, and identify personal and environmental risk factors, associated with symptoms, and perception of cabin air quality. Another objective was to study if ban of smoking, and increased relative air humidity on intercontinental flights, could have a beneficial health effect. The studies were performed among Scandinavian cabin crew in one Airline Company. Office workers from the same company served as controls. Exposure differed between cruise and non-cruise conditions. Air humidity was very low during intercontinental flights (3-8%). Concentration of moulds, bacteria, formaldehyde, and ozone was low. Tobacco smoking increased respirable particles in the cabin air, from 3 to 49 mg/m3, and increased cotinine in urine. The ETS-exposure was highest in the aft part of the cabin. Symptoms and environmental complaints were more common among flight crew than office workers. We could identify personal factors of importance, and certain conditions that could be improved, to achieve a better cabin environment. There was an association between symptoms and environmental perceptions and work stress, lack of influence on working condition, and a history of atopy. After ban on smoking in aircraft, there was a decrease of ocular and general symptoms, and increased tear-film stability in aircrew. Air humidification reduced headache and ocular, nasal, and dermal dryness symptoms, increased tear-film stability, and increased nasal patency. Our result indicates that ETS and low air humidity are important environmental factors in aircraft, and that atopy, and work stress could be significant risk factors for symptoms and environmental perceptions.
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