Germicidal ultraviolet irradiation in air conditioning systems: effect on office worker health and wellbeing: a pilot study.
OBJECTIVES: The indoor environment of modern office buildings represents a new ecosystem that has been created totally by humans. Bacteria and fungi may contaminate this indoor environment, including the ventilation systems themselves, which in turn may result in adverse health effects. The objectives of this study were to test whether installation and operation of germicidal ultraviolet (GUV) lights in central ventilation systems would be feasible, without adverse effects, undetected by building occupants, and effective in eliminating microbial contamination. METHODS: GUV lights were installed in the ventilation systems serving three floors of an office building, and were turned on and off during a total of four alternating 3 week blocks. Workers reported their environmental satisfaction, symptoms, as well as sickness absence, without knowledge of whether GUV lights were on or off. The indoor environment was measured in detail including airborne and surface bacteria and fungi. RESULTS: Airborne bacteria and fungi were not significantly different whether GUV lights were on or off, but were virtually eliminated from the surfaces of the ventilation system after 3 weeks of operation of GUV light. Of the other environmental variables measured, only total airborne particulates were significantly different under the two experimental conditions--higher with GUV lights on than off. Of 113 eligible workers, 104 (87%) participated; their environmental satisfaction ratings were not different whether GUV lights were on or off. Headache, difficulty concentrating, and eye irritation occurred less often with GUV lights on whereas skin rash or irritation was more common. Overall, the average number of work related symptoms reported was 1.1 with GUV lights off compared with 0.9 with GUV lights on. CONCLUSION: Installation and operation of GUV lights in central heating, ventilation and air conditioning systems of office buildings is feasible, cannot be detected by workers, and does not seem to result in any adverse effects. (+info)
Visual analogue scales for detecting changes in symptoms of the sick building syndrome in an intervention study.
OBJECTIVES: This study tested questionnaires using visual analogue scales (VAS) in a cleaning intervention study and attempted to find a simple way of analyzing the replies to the questionnaires. METHODS: A VAS questionnaire made up of 26 questions was developed and marked once a week for 28 weeks by the room occupants in 3 buildings. A total of 1248 questionnaires was used in the analysis of the results. A simple model based on the differences between a person's average responses during 2 different periods was used in the analysis. RESULTS: No clear effect of the cleaning was found. Several significant correlations between different questions were established. Estimates for the design of future studies are given. CONCLUSIONS: The VAS questionnaire proved to be feasible for this type of study. It is suggested that each intervention period should last 4 weeks if the questionnaire is used once a week. However, the length of the period also depends on the expected latency of the symptoms, on how long it takes for environmental conditions to be affected by the intervention, and on how quickly conditions return to "normal" during control periods. (+info)
Reactions of healthy persons and persons suffering from allergic rhinitis when exposed to office dust.
OBJECTIVES: Reactions to airborne office dust among healthy subjects and subjects suffering from allergic rhinitis were investigated. METHODS: Twelve healthy and 11 subjects suffering from allergic rhinitis were exposed to clean air [17 (SD 2) microg/m3] and office dust [439 (SD 68) microg/m3] for 245 minutes. The effect measurements included subjective sensations (questionnaire and potentiometer ratings), mood scale, peak flow, bronchial provocation with histamine using forced expiratory volume in 1 second as the effect measure, nasal mucosal swelling, tear film stability, epithelial damage, foam formation in the eye canthus, threshold for eye irritation with carbon dioxide, eye redness, cellular content of conjunctival fluid, and an addition test for distraction. As many investigations were made and as many statistical analyses (including subgroup analyses) were carried out, the risk of mass significance appeared. This problem was dealt with using the Bonferroni correction for multiple significance tests. RESULTS: The mean ratings of the potentiometer were higher (the subjects showed more irritation) during the dust exposure. The objective investigations showed only indications of effects of dust exposure, and some of the indications were in biologically unexplainable directions. No difference in the reactions to dust was observed between the healthy subjects and the subjects suffering from allergic rhinitis. CONCLUSIONS: Dust does not seem to have objective or subjective effects on humans, as only indications of dust effects were found. Subjects suffering from allergic rhinitis do not appear to be a risk group in relation to dust exposure. (+info)
Office equipment and supplies: a modern occupational health concern?
The Helsinki Office Environment Study, a population-based cross-sectional study was carried out in Finland in 1991 among 2,678 workers in 41 randomly selected office buildings. The aim was to evaluate the relations between work with office equipment and supplies and the occurrence of eye, nasopharyngeal, skin, and general symptoms (often denoted as sick building syndrome (SBS)), chronic respiratory symptoms, and respiratory infections. Work with self-copying paper was significantly related to weekly work-related eye, nasopharyngeal, and skin symptoms, headache and lethargy, as well as to the occurrence of wheezing, cough, mucus production, sinusitis, and acute bronchitis. Photocopying was related to nasal irritation, and video display terminal work to eye symptoms, headache, and lethargy. (+info)
An animal model for allergic penicilliosis induced by the intranasal instillation of viable Penicillium chrysogenum conidia.
BACKGROUND: A study was undertaken to determine the consequences of long term intranasal instillation of Penicillium chrysogenum propagules in a mouse model. METHODS: C57 Black/6 mice were inoculated intranasally each week for six weeks with 10(4) viable and non-viable P chrysogenum conidia. Cytokine levels and cellular responses in these animals were then measured. RESULTS: Compared with controls, mice inoculated intranasally each week for six weeks with 10(4) P chrysogenum conidia (average viability 25%) produced significantly more total serum IgE (mean difference 1823.11, lower and upper 95% confidence intervals (CI) 539.09 to 3107.13), peripheral eosinophils (mean difference 5.11, 95% CI 2.24 to 7.99), and airway eosinophilia (rank difference 11.33, 95% CI 9.0 to 20.0). With the exception of airway neutrophilia (mean difference 20.89, 95% CI 3.72 to 38.06), mice inoculated intranasally with 10(4) non-viable conidia did not show significant changes in total serum IgE, peripheral or airway eosinophils. However, when compared with controls, this group (10(4) non-viable) had a significant increase in total serum IgG(2a) (mean difference 1990.56, 95% CI 790.48 to 3190.63) and bronchoalveolar lavage (BAL) fluid levels of interferon (IFN)-gamma (mean difference 274.72, 95% CI 245.26 to 304.19). In addition, lung lavages from mice inoculated intranasally with 10(4) viable P chrysogenum conidia had significantly increased levels of interleukin (IL)-4 (mean difference 285.28, 95% CI 108.73 to 461.82) and IL-5 (mean difference 16.61, 95% CI 11.23 to 21.99). The IgG(2a)/IgE ratio and the IFN-gamma/IL-4 ratio was lower in the group of mice inoculated intranasally with 10(4) viable conidia than in the 10(4) non-viable conidia group and the controls. When proteins were extracted from P chrysogenum conidia, attached to microtitre plates and incubated with serum from the 10(4) viable group, significant increases in conidia-specific IgE and IgG(1) were observed compared with controls, while serum from the 10(4) non-viable group was similar to controls. CONCLUSIONS: These data suggest that long term inhalation of viable P chrysogenum propagules induces type 2 T helper cell mediated (Th2) inflammatory responses such as increases in total and conidia-specific serum IgE and IgG(1), together with BAL fluid levels of IL-4 and IL-5 and peripheral and airway eosinophilia, which are mediators of allergic reactions. (+info)
Emergence and preservation of a chronically sick building.
STUDY OBJECTIVE: To investigate the merits of case studies as complementary methodological approaches in the study of the sick building syndrome. SETTING AND PARTICIPANTS: A Swedish office building with longstanding health problems, and its inhabitants. DESIGN: This paper is a case study based both on historical and present, quantitative as well as qualitative, documentary material, produced over the years by distinct parties, and on semi-structured interviews. RESULTS: Long drawn conflictive processes within the building were identified. It was revealed that the organisation for dealing with environmental problems was split, and ineffective with poor patterns of communication. It was suggested that this generated a situation of chronic stress leading to the persistence of symptoms. CONCLUSIONS: By their capacity to identify internal processes within building contexts, case study methodology can contribute to a better understanding and management of sick building syndrome. The results of this study suggest that psychosocial factors, among them organisational structures and communication patterns, should be given close attention. (+info)
Model development and research vision for the future of multiple chemical sensitivity.
Multiple chemical sensitivity (MCS) is characterized by heightened self-reported sensitivity to extremely low concentrations of chemicals. It has numerous symptoms in common with the sick building syndrome, the Gulf War syndrome, and chronic fatigue. Despite much research, reproducible objective findings are lacking for MCS, as is a sound model to explain it. This paper proposes a 2-step model combining the needed epidemiologic terminology with that of psychophysiological activation and sensitization. It is suggested that different environmental stressors act as initiators. After initiation, the limbic system and other parts of the brain become sensitized and hyperreactive to environmental triggers. Odor acts as one important trigger. Future research should use more biological assessments in combination with environmental and psychosocial data and involve patient groups with similar symptoms, although diagnosed as suffering from different entities. The similarities and differences of patients with such entities need to be understood before the entities themselves can be understood, diagnosed, treated, and prevented. (+info)
Challenges for indoor environment research in the new office.
This paper discusses new directions for indoor environment research for the following 4 themes: (i) the current change in office work pattern, workplace design, and increasing demands from the work force, (ii) the large individual variation in requirements for optimal conditions pointing at the key factors of individual response and individual control options based on trade-off experiments, (iii) psychosocial factors as determinants of symptoms, comfort, and productivity, and (iv) transient, nonspecific symptoms in the indoor environment, the identification of causes, and long-term consequences. (+info)