Indoor Climate Performance in Intensive Care Units: A Seasonal Field Study in the Democratic Republic of the Congo

Indoor environmental quality (IEQ) in naturally ventilated hospitals presents significant challenges in tropical regions, where seasonal climatic variability and limited environmental control may compromise indoor air quality (IAQ) and thermal comfort (TC). However, comparative field evidence from African healthcare facilities remains limited. This study investigated seasonal IEQ conditions in two naturally ventilated intensive care units (ICUs) in the Democratic Republic of the Congo (DRC). Environmental monitoring and questionnaire-based assessments were conducted during rainy and dry seasons at Jason Sendwe Hospital (JSH), Lubumbashi, and Hôpital du Cinquantenaire (HDC), Kinshasa. Measurements included operative temperature, relative humidity, CO2, PM2.5, PM10, and a VOC-based IAQ index. Subjective assessments from 348 healthcare workers examined perceived IAQ, thermal sensation, and self-reported symptoms. Exploratory PMV–PPD calculations complemented the thermal assessment. The CO2 concentrations ranged from 1977 to 2600 ppm at JSH and 1437–2733 ppm at HDC, with higher values during the dry season. Reported PM2.5 concentrations reached 228 and 237 µg/m3, respectively, indicating potentially substantial particulate pollution. VOC-based IAQ indices were higher during the rainy season. At JSH, 80% and 74% of respondents rated IAQ as poor or very poor during rainy and dry seasons, respectively. Both hospitals exhibited a pronounced seasonal reversal in thermal conditions, characterized by warm rainy-season conditions and predominantly cold dry-season thermal sensations. Exploratory PMV–PPD estimates indicated greater predicted warm discomfort at HDC. The findings identify a dual seasonal thermal challenge in naturally ventilated tropical ICUs, where warm-season and cool-season discomfort coexist with substantial IAQ concerns. By demonstrating this pattern across hospitals in contrasting climatic and urban environments, the study extends existing evidence beyond the predominant focus on overheating and highlights the need for integrated, seasonally adaptive ventilation and pollutant-control strategies in resource-constrained healthcare facilities.