Effect of equipment layout on bioaerosol temporal-spatial distribution and deposition in one BSL-3 laboratory

Abstract

Reasonable equipment layout is essential for creating a healthy and safe environment, especially in a three-level biosafety laboratory with high potential risk factors of infection. Since 2019, COVID-19, an emerging infection has swept the world and caused severe losses. Biosafety laboratories are mandatory sites for detecting high-risk viruses, so related research is urgently needed to prevent further laboratory-acquired infections of operators. This study investigated the effects of obstacles on exposure infection of staff in a biosafety laboratory with related experimental equipment. The numerical simulation results are highly verified by the measured results. The results indicate that although the equipment layout does not affect the bioaerosol removal time, nearly 17% of the pollutant particles in the actual laboratory cannot be discharged effectively compared with the ideal situation. These particles lingered in the lower space under the influence of vortex, which would increase the respiratory risk of operators. In addition, after the experiment a large part of bioaerosol particles would be captured by equipment and floor, and the deposition rate per unit area is 0.45%/m 2 and 0.8%/m 2 , respectively. Although the results show that the equipment layout could reduce the pollution on the floor, the disinfection is still an important link, especially on the surfaces of equipment. Meanwhile, the result also indicates that the action should be light and slow when operating in BSL-3 laboratory, so as to avoid the secondary suspension pollution of bioaerosol particles on the equipment surface and floor.

The impact of ventilation rate on reducing the microorganisms load in the air and on surfaces in a room‐sized chamber

“…The deposition rate of bioaerosols on the ceiling and walls was substituted by a percentage equal to 23% and 44% of the deposited microorganisms' concentration on the floor, respectively, based on Liu et al 18 Although this is an estimation and it allows for biased results because the inlet and outlet for ventilation for Liu et al 18 were located in the ceiling, which may change the surface deposition pattern. Assuming that the floor and the ceiling have the same surface area, Equation 5 uses the same principle as Equation 3 and calculates the loss rate due to deposition, taking into account the deposition onto the walls and ceiling as a percentage of the deposition on the floor (based on real data from the experiment).$$$$ {\lambda}_d={\lambda}_{d,f}+{\beta}_w{\lambda}_{d,f}\frac{2H\left(L+W\right)}{LW}+{\beta}_c{\lambda}_{d,f}, $$$$Where, $$$ {\beta}_w $$$ and $$$ {\beta}_c $$$ are the percentages of $$$ {C}_{sf} $$$, which is the indoor deposited microorganisms' concentration on the floor ($$$ cfu.{m}^{-2}.$…”

“…The deposition rate of bioaerosols on the ceiling and walls was substituted by a percentage equal to 23% and 44% of the deposited microorganisms' concentration on the floor, respectively, based on Liu et al 18 Although this is an estimation and it allows for biased results because the inlet and outlet for ventilation for Liu et al 18 were located in the ceiling, which may change the surface deposition pattern. Assuming that the floor and the ceiling have the same surface area, Equation 5 uses the same principle as Equation 3 and calculates the loss rate due to deposition, taking into account the deposition onto the walls and ceiling as a percentage of the deposition on the floor (based on real data from the experiment).…”

“…(2) The deposition rate of bioaerosols the ceiling and walls was substituted by a percentage equal to 23% and 44% of the deposited microorganisms' concentration on the floor, respectively, based on Liu et al 18 Although this is an estimation and it allows for biased results because the inlet and outlet for ventilation for Liu et al 18…”

The influence of air supply inlet location on the spatial-temporal distribution of bioaerosol in isolation ward under three mixed ventilation modes

“…Based on these three ventilation strategies, the effects of different air supply inlets in isolation ward on bioaerosol deposition, spatial distribution and removal efficiency were studied. Our previous research found that facility layout may influence aerosol distribution [35] . Therefore, two scenarios were considered: empty room and actual room.…”

Ventilation in worker dormitories and its impact on the spread of respiratory droplets

“…However, this study will look at droplets across an entire distribution. A lab study found that equipment layout stopped 17% of pollutant particles' effective discharge since they lingered under vortex influence ( Liu et al., 2020 ). However, this will not be included in this paper's scope since worker dorms do not have much equipment except for their personal belongings and bed structures, which are included in this study.…”