Abstract
Background: The situation of air diffusion in ambulances has not been clarified for droplet nuclei smaller than the smoke particles verified by smoke machines, and it is necessary to understand the situation and take countermeasures.
Objective: To quantitatively evaluate the impact of air conditioning setting conditions in ambulances on the spread of droplet nuclei, and to take countermeasures against the spread of droplet nuclei.
Methods: We set the air conditioning and partitioning of the ambulance to inject CO2 gas from near the head of the injured or sick person, and installed CO2 concentration meters in the ambulance at eight locations to monitor and verify changes in the concentration of CO2.
Results: As with the smoke machine, the rear cooler had a significant impact, and the installation of partitions was found to reduce exposure to the crew, but diffusion into the storage compartment under the crew’s seats, which was not considered an exposure area, was observed.
Conclusions: It was suggested that the spread of droplet nuclei could be controlled by setting air conditioning and installing partitions, but it is necessary to exhaust the droplet nuclei out of the ambulance by forced ventilation for a certain period of time after the patient is admitted during ambulances transport.
