Hospital Indoor Environment: Screening for Micro-Organisms and Particulate Matter

The concentrations of air-borne micro-organisms and particulate matter were measured in the air and on solid surfaces in five rooms in a hospital. For comparison the same measurements were also made outdoors. The rooms were chosen because of their different needs in terms of indoor environment quality. The highest bacterial concentrations were found in the air of a patient's room that was `unventilated' other than through its doorway. Some of the rooms were supplied with filtered air. Compared to the rest, these rooms had the lowest microbial concentrations in their air but the highest on surfaces. A correlation was found between the count of the particulate size-range ≥1.0 μm and that of bacteria ( r=0.76) and between the count of the particulate size range ≥5.0 μm and those of bacteria ( r=0.88) and staphylococci ( r=0.80) in indoor air. No correlation was found between the particulate count and the mould count in the indoor air.