Aerosol particle spreading in an operation room under dynamic condition

Kurzfassung

We report on the experimental acquisition of the spreading of aerosol particles in an operation room. Thereby, different configurations regarding the source position or representative movements of the staff in the room are analyzed. The data acquisition is performed using a sensor grid of more than 45 particulate matter sensors at approx. 1 Hz measurement frequency operated with the DLR’s mobile measurement system (MMS) [1,2], allowing for a reasonable resolution in space and time. The measurement campaign was performed in the framework of the c3vis project in the teaching operational room of the OTH Amberg-Weiden [3]. Details on the room including the installed ventilation system will be included in the paper and discussed at the conference. The investigated cases can be separated in two main classes: First, potentially infectious particles are generated at the operation place of the patient, i.e., the patient is the source and the particles are transported by the air flow of the room. Second, particles are released by the exhalation of one of the personnel in the room and might potentially settle in the operation wound, see Fig. 1 (left). Both cases are very critical and high effort is invested to avoid them by well-guided air flow from the ceiling to exhaust openings on floor-height [4], thus being similar to the ventilation of clean-room well known from e.g. space industry during the assembly of optical measurement systems. The first results showed, that the aerosol particles exhaled by the standing source, are down-washed by the air flow and reach, strongly diluted, one sensor position above the operation table located next to the standing source. Here, local concentrations as low as ≈1.5% of the exhalation concentration are found. All other positions above the operation table show an almost zero particle concentration. With a certain time delay the cloud of exhaled aerosol particles reaches single other sensor locations on its way towards the exhaust openings, while being further diluted (≈0.03% of the exhalation concentration).