Evaluation and a predictive model of airborne fungal concentrations in school classrooms.
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Exposure to airborne fungal products may be associated with health effects ranging from non-specific irritation of the respiratory tract or mucus membranes to inflammation provoked by specific fungal antigens. While concentrations of airborne fungi are frequently measured in indoor air quality investigations, the significance of these measurements in the absence of visual mold colonization is unclear. This study was undertaken to evaluate concentrations of airborne fungal concentrations in school classrooms within a defined geographic location in British Columbia, Canada, and to build a model to clarify determinants of airborne fungal concentration. All elementary schools within one school district participated in the study. Classrooms examined varied by age, construction and presence or absence of mechanical ventilation. Airborne fungal propagules were collected inside classrooms and outdoors. Variables describing characteristics of the environment, buildings and occupants were measured and used to construct a predictive model of fungal concentration. The classrooms studied were not visibly contaminated by fungal growth. The data were evaluated using available guidelines. However, the published guidelines did not take into account significant aspects of the local environment. For example, there was a statistically significant effect of season on the fungal concentrations and on the proportional representation of fungal genera. Rooms ventilated by mechanical means had significantly lower geometric mean concentrations than naturally ventilated rooms. Environmental (temperature, outdoor fungal concentration), building (age) and ventilation variables accounted for 58% of the variation in the measured fungal concentrations. A methodology is proposed for the evaluation of airborne fungal concentration data which takes into account local environmental conditions as an aid in the evaluation of fungal bioaerosols in public buildings. (+info)
Seasonal variation in perceived indoor environment and nonspecific symptoms in a temperate climate.
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Few epidemiological studies have examined the effects of season on symptoms typical of sick building syndrome (SBS). The present study aims to clarify seasonal variation in a perceived indoor environment and SBS symptoms in a temperate climate. A total of 116 workers were recruited from office buildings in southern Japan that presented no apparent serious indoor problems. A validated questionnaire was distributed four times, once at the end of each season. Seasonal effects on the perceived indoor environment and SBS symptoms were investigated with a parametric test for repeated measurement of categorical data. Logits were used as the response function, and were compared to overall logits to determine the relevant odds ratios (OR). The effect of season/building interaction was also evaluated. Significant seasonal variation in the perceived indoor environment was found for temperature, dryness, air stuffiness, and static electricity (p for season, <0.05), although the seasonal patterns for temperature and dryness differed according to the building (p for interaction, <0.05). Symptoms in the mucous membrane (eyes, nose, and throat) and skin increased considerably in the winter and spring (p for season, <0.05), whereas general symptoms varied little, but such seasonality of symptoms was not modified by the building factor. The associations between perception of indoor environments and mucous and skin symptoms became stronger during winter and spring. The present results suggest that perceived indoor environments, nonspecific symptoms and their associations are closely associated with the season among office workers in a temperate climate. (+info)
Workplace air-conditioning and health services attendance among French middle-aged women: a prospective cohort study.
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OBJECTIVES: To assess the relationship between type of ventilation in the workplace, health services attendance, and sickness absence among middle-aged women. METHODS: In a national sample of 920 professionally active women aged 49-65 yr from the SU.VI.MAX cohort, recruited from the general population in France, health services attendance and sickness absence were assessed prospectively during 1999. RESULTS: Being exposed to heating, ventilation, and air-conditioning (HVAC) systems in the workplace proved to be a risk factor for attendance at global and several specialist medical services. The adjusted odds ratio for otorhinolaryngologist attendance was 2.33 (95% CI = 1.35-4.04) in the HVAC group compared with the natural ventilation group, and 1.70 (1.13-2.58) for sickness absence. Dermatologist and global medical services attendance rates may also be higher in this group (P = 0.06 in both cases). CONCLUSIONS: Exposure to HVAC systems was a strong and significant risk factor for otorhinolaryngologist attendance and sickness absence. HVAC systems are prevalent in recent office buildings and have been shown to be associated with several adverse health effects in terms of morbidity and mortality. From a public-health perspective, our results outline the need for a quantitative assessment of the health impact of ventilation systems, taking into account the possible loss of production that exists in addition to the direct costs of medical services use. (+info)
A case of sick building syndrome in a Japanese office worker.
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The adverse health effects caused by indoor air pollution are termed "sick building syndrome". We report such a patient whose symptoms appeared in the workplace. A 36-year-old female office worker developed nausea and headache during working hours in a refurbished office. After eight months of seeking help at other clinics or hospitals without improvement, she was referred to our hospital. At that time she reacted to the smells of various chemicals outside of the office building. Biochemical findings were all within normal ranges. Specific IgE antibody to cedar pollen was positive and the ratio of TH1/TH2 was 4.5. In the Eye Tracking Test (ETT), vertical eye movement was saccadic. Her anxiety level was very high according to the State-Trait Anxiety Inventory (STAI) questionnaire. Subjective symptoms, ETT findings and anxiety levels on STAI gradually improved during two years of follow-up. One year after the onset of her illness, the formaldehyde concentrations in the building air ranged from 0.017-0.053 ppm. Even though relatively low, chemical exposure from building materials such as formaldehyde induced a range of symptoms. Also, lack of recognition by superiors and doctors that sick building syndrome might have been the source of her illness coupled with her high state of anxiety may have exacerbated her symptoms and led to the onset of multiple chemical sensitivity. Thus psychosocial factors may contribute to sick building syndrome in the workplace. (+info)
Polluted air--outdoors and indoors.
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Many air pollutants which are considered important in ambient (outdoor) air are also found, sometimes at higher levels, in indoor air. With demanding standards having been set for many of these pollutants, both in the workplace and ambient air, consideration of the problems posed by indoor pollution is gaining pace. Studies on exposure to pollutants found in the indoor domestic environment are increasing and are contributing to an already significant compilation of datasets. Improvement in monitoring techniques has helped this process. Documented reports of fatalities from carbon monoxide poisonings are still worrying. However, studies on health effects of non-fatal, long term, low dose, indoor exposure to carbon monoxide and other pollutants, are still inconclusive and too infrequently documented. Of particular concern are the levels of air pollutants found in the domestic indoor environment in developing countries, despite simple interventions such as vented stoves having shown their value. Exposure to biomass smoke is still a level that would be considered unacceptable on health grounds in developed countries. As in the occupational environment, steps need to be taken to control the risks from exposure to the harmful constituents of indoor air in the home. However, the difficulty regarding regulation of the domestic indoor environment is its inherent privacy. Monitoring levels of pollutants in the home and ensuring regulations are adhered to, would likely prove difficult, especially when individual behaviour patterns and activities have the greatest influence on pollutant levels in indoor air. To this end, the Department of Health is developing guidance on indoor air pollution to encourage the reduction of pollutant levels in indoor domestic air. The importance of the effects of domestic indoor air on health and its contribution to the health of the worker are increasingly appreciated. Occupational physicians, by training and interest, are well placed to extend their interests into the environmental field and to focus on this important area. (+info)
Effect of chlorine dioxide gas on fungi and mycotoxins associated with sick building syndrome.
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The growth of indoor molds and their resulting products (e.g., spores and mycotoxins) can present health hazards for human beings. The efficacy of chlorine dioxide gas as a fumigation treatment for inactivating sick building syndrome-related fungi and their mycotoxins was evaluated. Filter papers (15 per organism) featuring growth of Stachybotrys chartarum, Chaetomium globosum, Penicillium chrysogenum, and Cladosporium cladosporioides were placed in gas chambers containing chlorine dioxide gas at either 500 or 1,000 ppm for 24 h. C. globosum was exposed to the gas both as colonies and as ascospores without asci and perithecia. After treatment, all organisms were tested for colony growth using an agar plating technique. Colonies of S. chartarum were also tested for toxicity using a yeast toxicity assay with a high specificity for trichothecene mycotoxins. Results showed that chlorine dioxide gas at both concentrations completely inactivated all organisms except for C. globosum colonies which were inactivated an average of 89%. More than 99% of ascospores of C. globosum were nonculturable. For all ascospore counts, mean test readings were lower than the controls (P < 0.001), indicating that some ascospores may also have been destroyed. Colonies of S. chartarum were still toxic after treatment. These data show that chlorine dioxide gas can be effective to a degree as a fumigant for the inactivation of certain fungal colonies, that the perithecia of C. globosum can play a slightly protective role for the ascospores and that S. chartarum, while affected by the fumigation treatment, still remains toxic. (+info)
Building health: an epidemiological study of "sick building syndrome" in the Whitehall II study.
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OBJECTIVES: Sick building syndrome (SBS) is described as a group of symptoms attributed to the physical environment of specific buildings. Isolating particular environmental features responsible for the symptoms has proved difficult. This study explores the role and significance of the physical and psychosocial work environment in explaining SBS. METHODS: Cross sectional data on the physical environment of a selection of buildings were added to individual data from the Whitehall II study--an ongoing health survey of office based civil servants. A self-report questionnaire was used to capture 10 symptoms of the SBS and psychosocial work stress. In total, 4052 participants aged 42-62 years working in 44 buildings were included in this study. RESULTS: No significant relation was found between most aspects of the physical work environment and symptom prevalence, adjusted for age, sex, and employment grade. Positive (non-significant) relations were found only with airborne bacteria, inhalable dust, dry bulb temperature, relative humidity, and having some control over the local physical environment. Greater effects were found with features of the psychosocial work environment including high job demands and low support. Only psychosocial work characteristics and control over the physical environment were independently associated with symptoms in the multivariate analysis. CONCLUSIONS: The physical environment of office buildings appears to be less important than features of the psychosocial work environment in explaining differences in the prevalence of symptoms. (+info)
Visual display terminal work and sick building syndrome--the role of psychosocial distress in the relationship.
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The present study investigated the association between visual display terminal (VDT) work and sick building syndrome (SBS) and the role of psychosocial factors in the relationship. Subjects were 2,161 Japanese office workers who responded to a cross-sectional anonymous self-administered questionnaire survey. Questions included were derived from the Miljomedicin 040, a validated questionnaire on SBS symptoms. After exclusion of data with missing information, data for 1,881 subjects were used for analysis. Multivariate logistic regression was used to estimate the odds ratio for SBS with adjustment for potential confounding factors, including psychosocial work stress. In multivariate analysis, the odds ratio for SBS was significantly elevated for men engaged in VDT work for 4 or more hours a day (OR=2.5, 95%CI: 1.0, 5.9) compared with less than 1 hour a day, showing a significant trend association (P for trend=0.04). In women, although the odds ratio for SBS with VDT use of 4 or more hours a day was somewhat elevated with adjustment for non-psychosocial factors (OR=1.5, 95%CI: 0.5, 4.3), the increase was greatly attenuated after adjustment for psychosocial work distress (OR=1.1). In conclusion, our study suggests that extended hours of VDT use might be related to increased SBS symptoms. Moreover, psychosocial distress related to VDT work might mediate the relationship between VDT use and SBS symptoms in women. (+info)