Human Outdoor Thermal Comfort Assessment in a Tropical Region: A Case Study

The thermal environment where human beings dwell is vital to the proper functioning of the human body system. This study assesses the outdoor thermal comfort conditions of five southwestern states of Nigeria over a 30-year period using the Temperature–Humidity Index (THI) and Physiological Equivalent Temperature (PET) indices. The monthly and seasonal variation of thermal sensation levels were assessed as well as the frequency of occurrence of each thermal sensation category for each of the stations considered. The prominent thermal sensation levels for each of the station were also ascertained. Results from the study revealed that thermal conditions deteriorated between 0900 and 1500 local standard time (LST) and resulted in higher levels of thermal stress. Thermal conditions were observed to vary seasonally, with increased thermal stress levels occurring during the transition to wet months (TWS) and dry months (DM), while thermal comfort conditions improved the most during the little dry season (LDS). Abeokuta was noted to be the station with the highest level of thermal discomfort when compared with other stations. Temperature was observed to be the highest contributor to thermal conditions; this, therefore implies that, with the increasing regional mean temperature, bioclimatic condition information is imperative in urban planning.