Indoor environmental quality, occupant perception, prevalence of sick building syndrome symptoms, and sick leave in a Green Mark Platinum-rated versus a non-Green Mark-rated building: A case study

The Building and Construction Authority Green Mark Scheme in Singapore encourages better indoor environmental quality for healthier workplaces for occupants. However, studies have shown that green buildings do not necessary ensure better indoor environmental quality. This case study aimed to compare the prevalence of sick building syndrome symptoms and sick leave in a Green Mark Platinum and a non-Green Mark-certified building. Thirty-two employees from the Green Mark Platinum building and 33 employees from the non-Green Mark-rated building were surveyed to investigate their perceptions of the indoor environmental quality and prevalence of sick building syndrome experienced. Information concerning the offices and absenteeism of staff was collected as well. Compared to the Green Mark Platinum-certified building, the non-Green Mark-certified building was more leaky and had a higher air change rate (between 2.5 to 3 times higher), was about 1°C cooler, and had a lower illuminance level. The statistical analysis of the data showed that there are significant differences in occupant perception; the Green Mark Platinum-certified building was cooler (p = 0.002); had fresher cleaner air and less odor (p = 0.002), had more relaxed monitor/keyboard comfort (p = 0.029), and had more satisfactory ergonomics (p = 0.033) at a 95% confidence level. Findings also suggested that the most frequent symptoms in the non-Green Mark-certified building were dry or irritated throat (15.2%) and lethargy or tiredness (15.2%), whereas the most frequent symptoms in the Green Mark Platinum building were blocked or stuffy nose (12.5%), dry or irritated throat (12.5%), dry skin (12.5%), and lethargy or tiredness (12.5%). However, there is no statistically significant association between sick building syndrome symptoms and the offices (p > 0.05). Furthermore, analysis of the sick leave records failed to show that occupants in the Green Mark Platinum-certified building took fewer sick leave days as compared to the non-Green Mark building. This unexpected finding is not affirmative due to aberrations attributable to (i) differences in industry type between the offices studied, (ii) plausible settling in effects of occupants in the Green Mark Platinum-rated office, and (iii) high leakage characteristics of the non-rated office that resulted in an unintended 2.5 to 3 times higher air change rate (ventilation) compared to that of the Platinum-rated office.