RELATIONSHIP OF MULTIPLE INDOOR AIR POLLUTANTS AND SICK BUILDING SYNDROME AT AIR-CONDITIONED OFFICE BUILDINGS IN TAIWAN

Abstract

ISEE-5 Abstract: Exposures to various indoor factors, particularly air pollutants, have been implicated in several health outcomes; yet most investigations had been conducted only with measurements of selected hazards. Our study was designed to examine associations between indoor air quality and sick building syndrome (SBS) of employees in 8 air-conditioned office buildings through a series of comprehensive environmental assessments and questionnaire administration. Airborne microbes, carbon dioxide (CO2), particulate matter (PM10), formaldehyde, and total volatile organic compounds (TVOC) were measured in every sampling site inside the study buildings. Frequency of reporting symptoms and other environmental variables, such as environmental tobacco smoke exposure and air change rate, were documented by self-administrated questionnaires. Information on gender, age of the occupant, degree of job satisfaction, recent experience of stress, and personal history of diagnosed allergic diseases were also obtained for adjustment in statistical analysis. Multiple logistic regression analysis was used to identify associations between dichotomous scales of air pollutants and health outcomes of interest, after adjusting for variables described above. Our data show that concentrations of indoor formaldehyde, TVOC and airborne microbes are higher than most recommended levels quoted. Estimates of crude odds ratios show that most air pollutants, when analyzed by continuous scales, are associated with SBS of one or more types. Similar relationships are seen with environmental factors of interest and personal characteristics acquired. PM10 exposures were significantly associated with mostly irritant outcomes, in addition to headache in multivariate analysis. Interestingly, indoor TVOC concentrations appeared to be protective with respect to symptom of sneezing, while exposure to greater concentrations of indoor HCHO did not present additional adverse effects with concurrent presence of other indoor pollutants. Most strikingly, statistical associations were found between selected SBS and microbial concentrations, dichotomized at 1000 CFU/m3 for its being a reference concentrations adopted in many proposed guidelines. The critical role of exposure to indoor microbes and PM10 is quantitatively demonstrated in this investigation. Further work should be designed to clarify the exact contribution of indoor TVOC exposures for increasing use of modern compounds, like essential oils, and decoration of synthetic materials are likely to result in rising concentrations of indoor TVOC in future indoor environments.