Bioaerosol distribution characteristics and potential SARS-CoV-2 infection risk in a multi-compartment dental clinic

Abstract

Dental clinics have a potential risk of infection, particularly during the COVID-19 pandemic. Multi-compartment dental clinics are widely used in general hospitals and independent clinics. This study utilised computational fluid dynamics to investigate the bioaerosol distribution characteristics in a multi-compartment dental clinic through spatiotemporal distribution, working area time-varying concentrations, and key surface deposition. The infection probability of SARS-CoV-2 for the dental staff and patients was calculated using the Wells-Riley model. In addition, the accuracy of the numerical model was verified by field measurements of aerosol concentrations performed during a clinical ultrasonic scaling procedure. The results showed that bioaerosols were mainly distributed in the compartments where the patients were treated. The average infection probability was 3.8% for dental staff. The average deposition number per unit area of the treatment chair and table are 28729 pcs/m² and 7945 pcs/m², respectively, which creates a possible contact transmission risk. Moreover, there was a certain cross-infection risk in adjacent compartments, and the average infection probability for patients was 0.84%. The bioaerosol concentrations of the working area in each compartment 30 min post-treatment were reduced to 0.07% of those during treatment, and the infection probability was <0.05%. The results will contribute to an in-depth understanding of the infection risk in multi-compartment dental clinics, forming feasible suggestions for management to efficiently support epidemic prevention and control in dental clinics.

Keywords: Airborne transmission; COVID-19; Risk assessment; Wells–Riley model.

Graphical abstract

Fig. 1

Layout of the multi-compartment dental clinic and the measuring points.

Fig. 2

Size distribution of the aerosols.

Fig. 3

The velocity comparisons among three grid numbers on the vertical line of the inlet and outlet.

Fig. 4

Comparison of experimental and simulated values of airflow velocity.

Fig. 5

Simulated and experimental concentration verification.

Fig. 6

Velocity vector and velocity streamline diagrams on the plane.

Fig. 7

Isosurface diagram of different air ages.

Fig. 8

Spatiotemporal distribution of bioaerosols in three cases.

Fig. 9

Concentration of bioaerosols of the working area in three cases: (a) source compartments and (b) other compartments during 90 min.

Fig. 10

Bioaerosol deposition on different surfaces in three cases: (a) source compartments and (b) public areas.

Fig. 11

Spatial distribution of breathing surface exposure risk in three cases, the treatment period (0–30 min).

Fig. 12

Spatial distribution of breathing surface exposure risk in three cases, after the treatment period (30–60 min).

Fig. 13

Spatial distribution of breathing surface exposure risk in three cases, 30 min post-treatment (60–90 min).