The study provides new evidence of the role of dampness-related alkaline degradation of di-(2-ethylhexyl) phthalate (DEHP) in polyvinyl chloride (PVC) building material. Emissions related to degradation of DEHP due to dampness in the floor, indicated by increased 2-ethyl-1-hexanol in the air, seem to increase both the secretion of lysozyme from the nasal mucosa and the occurrence of ocular and nasal symptoms. The indoor environment of the specially designed building with high ceilings and no fluorescent lighting or interior plastics seemed to have a positive influence on the nasal and ocular mucous membranes.

The sensation of dryness and irritation is essential in the sick building syndrome (SBS), and such symptoms are common in both office and hospital employees. In Scandinavia, the indoor relative humidity in well ventilated buildings is usually in the range 10-35% in winter. The aim of this study was to evaluate the effect of steam air humidification on SBS and perceived air quality during the heating season. The study base consisted of a dynamic population of 104 hospital employees, working in four new and well ventilated geriatric hospital units in southern Sweden. Air humidification raised the relative air humidity to 40-45% in two units during a four months period, whereas the other two units served as controls with relative humidity from 25-35%. Symptoms and perceived indoor air quality were measured before and after the study period by a standardised self administered questionnaire. The technical measurements comprised room temperature, air humidity, static electricity, exhaust air flow, aerosols, microorganisms, and volatile organic compounds in the air. The most pronounced effect of the humidification was a significant decrease of the sensation of air dryness, static electricity, and airway symptoms. After four months ofair humidification during the heating season, 24% reported a weekly sensation of dryness in humidified units, compared with 73% in controls. No significant changes in symptoms of SBS or perceived air quality over time were found in the control group. The room temperature in all units was between 21-231C, and no significant effect of air humidification on the air concentration of aerosols or volatile organic compounds was found. No growth of microorganisms was found in the supply air ducts, and no legionella bacteria were found in the supply water of the humidifier. Air humidification, however, significantly reduced the measured personal exposure to static electricity. It is concluded that air humidification during the heating season in colder climates can decrease symptoms of SBS and perception of dry air. (Occup Environ Med 1994;51:683-688)

Objectives-Sick building syndrome (SBS) involves symptoms such as irritation to the eyes, skin, and upper airways, headache, and fatigue. The relations between such symptoms and both personal and environmental factors were studied in 225 female hospital workers, working in eight hospital units in the south of Sweden. Methods-Symptoms of SBS and personal factors were measured by means of a standardised self administered questionnaire. The technical investigation comprised a building survey and measurements of room temperature, supply air temperature, air humidity, and exhaust air flow.Results-The prevalence of symptoms differed from one unit to another. The mean value of weekly complaints of fatigue was 30%, of eye citation 23%, and of dry facial skin 34%. Eye irritation was related to work stress, self reported exposure to static electricity, and was also more common in buildings with a high ventilation flow and a high noise level (55 dB(A)) from the ventilation system. Nasal symptoms were related to asthma and hay fever only. Throat symptoms were more common in smokers, subjects with asthma or hay fever, new buildings, and in buildings with a high ventilation flow. Facial skin irritation was related to a lack of control of the work conditions, and was more common in new buildings, and buildings with a high ventilation flow and ventilation noise.General symptoms, such as headache and fatigue, were related to current smoking, asthma or hay fever, work dissatisfaction, and static electricity. Conclusion-As the prevalence of symptoms was high, there is a need to improve the indoor environment as well as the psychosocial environment in hospitals. These improvements could include a reduction of ventilation noise, minimised smoking, and improvements in the psychosocial climate. Further have been shown to be related to the occurrence of symptoms of SBS. Most of the research on SBS has been performed in office workers. A large proportion (17%) of the female workforce in Sweden are employed in the medical services.9 As many aspects of the working conditions, and indoor environments, may differ between hospitals and offices, it is not clear whether knowledge gathered from the large office studies245 is valid also in the hospital environment. There are, however, indications that symptoms of SBS are also common in the medical services,I 10 1 but little information is available on relations between symptoms and indoor climate in hospitals. To provide further insights into the effects of the hospital environment on health, we started several field studies in hospitals. These studies are focused on the perception of air quality, on symptoms of SBS, and on the health effects of air humidification.The first aim of this investigation was to study the relation between symptoms of SBS and measured physical environment in hospitals. The second aim was to examine the influence of personal factors on such symptoms.The following hypotheses about the indoor environment were tested: the prevalence of symptoms of SBS is related ...

Use of a CO(2)-controlled ventilation system, reducing elevated levels of CO(2), may slightly reduce headache and tiredness and improve perceived air quality. The high levels of pet allergens, due to track in of allergens from the home and possible accumulation due to electrostatic forces, illustrate a need for improved cleaning.

Computer classrooms may have CO(2) above 1,000 ppm and temperatures above 22 degrees C. Increased temperature and CO(2) may affect mucosal membrane symptoms, headaches and tiredness. Room temperature was most important. CO(2) associations may partly be temperature effects.