Particle transport characteristics in indoor environment with an air cleaner: The effect of nonuniform particle distributions

Lin, Chen; Jin, Xinming; Yang, Linlin; Du, Xiaoze; Yang, Yongping

doi:10.1007/s12273-016-0310-7

Cited by 30 publications

(12 citation statements)

References 24 publications

(36 reference statements)

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“…This approach not only enhances the efficiency of the PAC but also minimizes potential dispersion and recirculation of infectious droplets within the immediate environment. This is consistent with the conclusions obtained by Chen et al [23] who noted that the orientation of the air cleaner had impact on its performance. And they also found that more particles were removed by the air cleaner when it was placed with a face-to-face layout as particles were more likely to join the main flow of the circulating airflow.…”

Section: The Influence Of the Opening Configuration Of Pac On Droplet...supporting

confidence: 93%

“…where u pi is the velocity component of the droplet; å F i denotes the sum of all external forces on the droplet in the i direction; F , drag i , F g i , and F a i , are drag force, gravity force and additional force respectively. The additional forces on the droplet include the pressure gradient force, virtual mass force, Bassett force, Brownian force, thermophoretic force and Saffman force, etc [23]. In indoor environment, the pressure gradient force, virtual mass force and Bassett force are much less than drag force and have a sufficiently small effect on the droplet motion to be negligible [37].…”

Section: Discrete Phase Modelmentioning

confidence: 99%

“…Jennifer et al [22] simulated the complex transient flow field in the room by CFD method, and investigated the effect of using portable air cleaners to reduce the risk of cross-contamination in a classroom ventilated by intermittent air jet system. Chen et al [23] used Lagrangian discrete trajectory model combined with Eulerian fluid method to simulate airflow patterns and particle transport in a room and explored the performance of PACs in reducing two types of inhomogeneous particle distribution from smoking and coughing, concluding that both the distance and relative orientation of the PAC to the person affect particle removal. John et al [24] evaluated the role of PAC use in thermally stratified scenarios in a conference room on exposure levels to airborne diseases.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Li,

Kong,

Cheng

et al. 2024

Phys. Scr.

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Portable air cleaners (PACs) have shown promising potential in reducing the risk of SARS-CoV-2 infection by effectively removing pollutant particles and optimizing airflow patterns. This study focused on a simulated scenario where an infected source and a susceptible person engage in conversation within a naturally ventilated room. By combining the Eulerian fluid method with the Lagrangian particle tracking model, a comprehensive insight into indoor airflow patterns and the dispersion of virus-laden droplets was gained. As deposited droplets may be resuspended or in contact thereby increasing the potential risk of infection, the deposition of droplets of different sizes in different susceptible areas was also specifically analyzed. The impacts of three variables, namely the configuration of the PAC’s opening, air flow rate, and positioning, on the transmission of virus-laden droplets were investigated. The results highlighted the significant role of PAC utilization in effectively capturing droplets emitted by the infected source and reducing virus concentration in the vicinity of the susceptible person, thereby mitigating the risk of transmission. Notably, the design and orientation of the suction opening emerged as crucial factors. Among the various cases studied, the optimal control and prevention performance against the virus was achieved with a virus concentration reduction rate of 97.4% when the PAC had an opening configuration with a larger single-sided suction opening facing the infected source, an airflow rate of 200 m³/h, and was positioned at the center of the tabletop between the infected source and the susceptible person. This research underscored the importance of employing PACs with appropriate settings to enhance indoor air quality and minimize the potential for SARS-CoV-2 transmission in similar scenarios.

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Section: The Influence Of the Opening Configuration Of Pac On Droplet...supporting

confidence: 93%

Section: Discrete Phase Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Li,

Kong,

Cheng

et al. 2024

Phys. Scr.

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“…When airborne particles were distributed uniformly indoors, the flow rate had the greatest impact on the indoor particle concentration, and the position of the air cleaner affected the particle concentration at low volumetric flow rates; little difference was found between the effects of horizontal and upward ejection ( Jin et al., 2016 ). By contrast, under non-uniform aerosol distributions, caused by smoking and coughing, the position of the air cleaner significantly impacted the particle concentration, which was also affected by the expiratory airflow velocity and the orientation of the air cleaner ( Chen et al., 2017 ). When the PACs were applied in wards, Mousavi et al.…”

Section: Infection Control Strategiesmentioning

confidence: 99%

Recent research on expiratory particles in respiratory viral infection and control strategies: A review

Ooka

Kikumoto

et al. 2021

Sustainable Cities and Society

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The global spread of coronavirus disease 2019 poses a significant threat to human health. In this study, recent research on the characteristics of expiratory particles and flow is reviewed, with a special focus on different respiratory activities, to provide guidance for reducing the viral infection risk in the built environment. Furthermore, environmental influence on particle evaporation, dispersion, and virus viability after exhalation and the current methods for infection risk assessment are reviewed. Finally, we summarize promising control strategies against infectious expiratory particles. The results show that airborne transmission is a significant viral transmission route, both in short and long ranges, from infected individuals. Relative humidity affects the evaporation and trajectories of middle-sized droplets most, and temperature accelerates the inactivation of SARS-CoV-2 both on surfaces and in aerosols. Future research is needed to improve infection risk models to better predict the infection potential of different transmission routes. Moreover, further quantitative studies on the expiratory flow features after wearing a mask are needed. Systematic investigations and the design of advanced air distribution methods, portable air cleaners, and ultraviolet germicidal irradiation systems, which have shown high efficacy in removing contaminants, are required to better control indoor viral infection.

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“…Then, the amount of pollutant removed by air cleaners depends on the concentration distribution of the pollutants, resulting in a nonlinear phenomenon. Therefore, although optimal operating conditions for air cleaners have been studied based on comparisons through experiments and computational fluid dynamics models, [11][12][13][14] it is unclear why these conditions are optimal.…”

Section: Introductionmentioning

confidence: 99%

Study on influence of air cleaner on room dispersion field and its optimal placement using adjoint concentration

Kikumoto

Ooka

2022

Japan Architectural Review

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Based on the assumption of a nonuniform pollutant concentration distribution and stochastic determination of pollutant sources and receptors in indoor space, this study shows how to formulate the expected pollutant concentration observed by the receptors in the presence of an air cleaner, using adjoint concentration and parameters related to probability of pollutants passing through the cleaner. Using this formulation, the structure of the concentration reduction effect of the cleaner and its optimal placement are discussed. The studies with the formulation are also conducted under the assumption of instantaneous uniform diffusion and for a problem in one‐dimensional space.

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Particle transport characteristics in indoor environment with an air cleaner: The effect of nonuniform particle distributions

Cited by 30 publications

References 24 publications

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Effectiveness of portable air cleaners in mitigating respiratory virus transmission risk

Recent research on expiratory particles in respiratory viral infection and control strategies: A review

Study on influence of air cleaner on room dispersion field and its optimal placement using adjoint concentration

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