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, PM2.5, 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 PM2.5 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 PM2.5 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.