Indoor Environmental Quality and Occupant Comfort in Educational Buildings in a Tropical Climate: A Critical Review of the Nigerian Evidence

Abstract

Educational buildings in tropical, low-resource settings are routinely occupied under conditions of high ambient heat, humidity, natural ventilation and constrained energy supply, yet the indoor environmental quality (IEQ) delivered by these buildings, and its consequences for occupant comfort, health and learning, remains unevenly documented. This narrative review critically synthesises the empirical literature on thermal, indoor air quality (IAQ), visual and acoustic conditions in Nigerian primary, secondary and tertiary educational buildings, situating this evidence within the broader international literature on IEQ in schools. Sources were identified through structured searching of multidisciplinary and subject-specific databases, institutional repositories and citation tracking, with eligibility restricted to empirical or review studies addressing measured or perceived IEQ parameters in occupied educational settings. The review finds consistent evidence that naturally ventilated Nigerian classrooms operate with neutral and acceptable comfort temperatures several degrees above internationally codified thresholds, reflecting genuine adaptive capacity among occupants, although this evidence remains geographically concentrated, methodologically heterogeneous in exposure duration and thermal indices used, and drawn disproportionately from few climatic zones. Indoor air quality studies reveal a persistent tension between ventilation-adequacy indicators, which frequently appear satisfactory by carbon dioxide criteria, and simultaneously elevated particulate, biological and thermal loads linked to overcrowding, combustion sources and inadequate sanitation infrastructure. Daylighting studies point to widespread underperformance against recommended illuminance thresholds despite abundant equatorial solar resource, a paradox attributable to fenestration design, glare-avoidance behaviour and unreliable electricity supply. Acoustic evidence, though sparse, associates externally generated traffic and generator noise with reported disturbance and adverse health symptoms among students. Across domains, the strength of causal inference linking IEQ to academic performance remains limited by cross-sectional designs, reliance on self-report, small and geographically clustered samples, and an almost complete absence of longitudinal or intervention studies within Nigeria specifically. The review identifies methodological convergence around adaptive thermal comfort theory as a genuine advance, alongside persistent, unresolved gaps in multi-domain IEQ assessment, socioeconomic and gender-differentiated exposure, and the translation of empirical comfort data into enforceable design guidance and building regulation. Priorities for future research include longitudinal and intervention-based designs, standardised multi-parameter monitoring protocols suited to resource-constrained institutions, and closer integration between empirical comfort science and Nigeria’s building regulatory framework. The synthesis offers a defensible evidence base for architects, engineers, educational planners and policymakers seeking to improve learning environments in tropical, energy-constrained contexts, while cautioning against uncritical transfer of temperate-climate comfort standards to Sub-Saharan African educational settings.