Indoor environmental quality, occupant satisfaction, and acute building-related health symptoms in Green Mark-certified compared with non-certified office buildings.

Indoor environmental quality (IEQ) has become an important component of green building certification schemes. While green buildings are expected to provide enhanced IEQ, higher occupant satisfaction, and less risks of occupant health when compared with non-green buildings, the literature suggests inconsistent evidence due to diverse research design, small sample size, and weak statistical analysis. This study compared several outcomes pertinent to IEQ performance in green and non-green office buildings in Singapore. Adopting a cross-sectional study design, objective measurements were taken in eight green and six non-green buildings, and satisfaction and acute health symptom risks of 367 occupants were obtained. Green buildings exhibited lower concentration of PM2.5, bacteria, and fungi and maintained temperature and humidity more consistently compared to non-green counterparts. The mean ratings for satisfaction with temperature, humidity, lighting level, air quality, and indoor environment were higher in green buildings (with statistical significance P < 0.05). There was statistically significant reduction in risk of occupants having headache, unusual fatigue, and irritated skin in green buildings. Although matching of buildings and occupant characteristics, survey participation bias, and sampling duration (a 1-week snapshot) of IEQ monitoring remain as limitations, this study offered positive association of green buildings with qualitatively and quantitatively measured performance of IEQ.