Elemental characterization of indoor breathable particles at a Portuguese urban hospital

Hospitals are a specific indoor environment with highly susceptible individuals for whom indoor air pollution represents additional health risks. Particulate matter (PM) is one of the most health-relevant indoor pollutants due to its association with respiratory and cardiovascular diseases. Particles can also act as a carrier for various harmful organisms present in the air of hospitals, thus leading to airborne transmission of infectious diseases. Thus, the objective of this study was to characterize indoor PM collected in a hospital in consideration of concentration, size distribution, and elemental composition. Emission sources of indoor PM were indentified and risks associated with indoor PM estimated. Sampling was performed at radiology ward of a Portuguese urban hospital where PM₁₀, PM(2.5), and PM₁ were collected during a period of 4 wk; PM elemental composition was determined by proton-induced x-ray emission (PIXE) analysis. Data showed that indoor PM₁₀ concentrations ranged from 13 to 58.8 μg/m³ and from 10.5 to 41.9 μg/m³ for PM(2.5). Fine particles constituted 77% of PM₁₀, indicating that PM(2.5) made a significant contribution to indoor air quality at the hospital. PM₁ ranged from 9.9 to 35.6 μg/m³, accounting for 93% of PM(2.5). PIXE identified 21 elements in PM, including health-hazardous metals (manganese, iron, copper, and vanadium) and carcinogenic elements (nickel, chromium, arsenic, and lead). However, no significant indoor source of PM emissions was identified, while outdoor air was the major contributor of indoor particles. Further, no significant risks existed through PM₁₀ inhalation for population at the respective hospital.