High Negative Pressure Limits Dispersion of Airborne Contaminants in Hospitals

airborne contaminants

Maintaining a high negative pressure in airborne infection isolation rooms of hospitals (over -10 Pa) and in renovation sites (over -5 Pa) effectively limits the dispersion of airborne contaminants, a new study from the University of Eastern Finland shows.

Inhaled airborne particles at work can cause adverse health effects, and this is why it is important to prevent exposure to them. Moreover, the control of contaminants released from internal sources within an enclosed workspace also plays an important role in protecting other persons working in or occupying adjacent areas from adverse biological and chemical exposure.

Better ventilation is needed in hospital anterooms

The containment capability of airborne infection isolation rooms, AIIRs, was studied by measuring air change rates of the patient room and anteroom, pressure differences, contaminant removal, and contaminant transmission during door openings and human movement. The researchers used a tracer gas method to simulate the release of infectious agents from a patient.

The findings indicate that a high air change rate in AIIRs does not ensure efficient removal of infectious agents in the breathing zone of a healthcare worker. Instead, the local airflow patterns are more important. A high mean negative pressure between an AIIR and its surroundings was shown to significantly limit particle transmission outside an AIIR. An anteroom aided in controlling the particle transmission.

The findings were originally published in Indoor and Built Environment, and in Annals of Work Exposures and Health.

The doctoral dissertation, entitled Control of Particle Dispersion from Enclosed Spaces, is available for download.

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