Indoor Environmental Quality, Building-Related Symptoms and Perceived Productivity in Green-Certified and Conventional Tropical Offices

Abstract Although green building certification is widely promoted as a pathway to improved indoor environmental quality (IEQ) and occupant well-being, evidence of its effectiveness under tropical operating conditions remains limited and inconsistent. This study presents an integrated post-occupancy evaluation (POE) of indoor air quality (IAQ), occupant health, and workplace productivity across four office buildings in Colombo, Sri Lanka: two green-certified buildings (Buildings B and D) and two conventional buildings (Buildings A and C); the four buildings were broadly comparable in use but differed in age, size, occupancy, and HVAC configuration (Section 2.2). This exploratory, short-term (two-day per building) post-occupancy evaluation is intended as case-based screening evidence rather than a definitive assessment of green-building certification. Multi-parameter environmental monitoring (CO2, PM2.5/PM10, TVOC, formaldehyde, temperature, relative humidity, illuminance, and noise) was combined with a survey of 100 occupants covering thermal, air-quality, lighting, and acoustic comfort, self-reported building-related symptoms (SBS), and perceived productivity. Certified buildings recorded lower CO2 concentrations than conventional buildings (707 vs 841 ppm; p.adj < .001; d = -1.10), but higher relative humidity (66.0% vs 53.4%; d = 1.57) and noise (59.7 vs 56.6 dB(A); d = 0.47). The SBS symptom index was higher in certified buildings (2.51 vs 2.00; p.adj < .001), while comfort was lower (3.67 vs 4.18; p.adj = .003). Perceived productivity correlated most strongly with comfort (r = 0.62), IAQ satisfaction (r = 0.55), and acoustic comfort (r = 0.51). These findings reveal a case-specific divergence in which favorable ventilation performance coexisted with less favorable thermal, acoustic, and occupant-health outcomes. Certification alone therefore did not correspond to better occupant experience. The results support climate-responsive refinement of tropical green-building certification through consideration of humidity and acoustic performance, pending confirmation in seasonally sampled building cohorts.