Evaluating size-fractioned indoor particulate matter in an urban hospital in Iran

Hospitals host vulnerable people with potentially enhanced sensitivity to air pollutants. We measured particulate matter (PM) including PM₁, PM_2.5, and PM₁₀ with a portable device in a hospital, a nearby reference building, and ambient air in Shiraz, Iran. Indoor/outdoor (I/O) ratio values were calculated to infer on the origin of size-fractioned PM. The mean hospital indoor concentrations of PM_2.5 and PM₁₀ (4.7 and 38.7 μg/m³, respectively) but not PM₁ were higher than in the reference building and lower than in ambient air. The highest hospital PM₁₀ mean concentrations were found in the radiotherapy ward (77.5 μg/m³) and radiology ward (70.4 μg/m³) while the lowest were found in the bone marrow transplantation (BMT) ward (18.5 μg/m³) and cardiac surgery ward (19.8 μg/m³). The highest PM_2.5 concentrations were found in the radiology (8.7 μg/m³) and orthopaedic wards (7.7 μg/m³) while the lowest were found in the BMT ward (2.8 μg/m³) and cardiac surgery ward (2.8 μg/m³). The I/O ratios and the timing of peak concentrations during the day (7 a.m. to 4 p.m.) indicated the main roles of outdoor air and human activity on the indoor levels. These suggest the need for mechanical ventilation with PM control for a better indoor air quality (IAQ) in the hospital.