Résumé
Background@#Ironically, the hospital which is believed to be a healthy and safe place can be dangerous to health. Pollutants such as particulate matter 2.5 microns (PM₂.₅) can be present in hospital indoor air and may adversely affect the health of the hospital occupants. @*Objective@#Possible sources of indoor PM₂.₅ in an urban tertiary care hospital in the Philippines are identified and apportioned in this study. @*Methods@#PM₂.₅ measurements were conducted in two naturally ventilated wards (NVWs), two mechanically ventilated wards (MVWs), and a roof deck near the hospital. Mass concentrations with analytical uncertainties of thirteen elements (Al, Na, S, Si, Cl, K, Ca, V, Fe, Zn, Br, Hg, Pb) from PM₂.₅ measurements were utilized with Positive Matrix Factorization (PMF) receptor model to identify and apportion possible sources of indoor PM₂.₅. @*Results@#In NVWs and MVWs, four types of sources were identified including sodium and chlorine sources, crustal emissions, anthropogenic sulfur sources, and road dust. Cleaning agents used in the hospital were identified as an anthropogenic indoor source of sodium while the other factors mainly came from outdoor sources. @*Conclusion@#The contribution of anthropogenic outdoor pollutants such as road dust and sulfur sources to indoor PM₂.₅ are highlighted in the study. The types of both indoor and outdoor sources of indoor PM₂.₅ can be influenced by the type of ventilation.