A review of different ventilation modes on thermal comfort, air quality and virus spread control

Abstract

In the era of Corona Virus Disease 2019 (COVID-19), inappropriate indoor ventilation may turn out to be the culprit of microbial contamination in enclosed spaces and deteriorate the environment. To collaboratively improve the thermal comfort, air quality and virus spread control effect, it was essential to have an overall understanding of different ventilation modes. Hence, this study reviewed the latest scientific literature on indoor ventilation modes and manuals of various countries, identified characteristics of different ventilation modes and evaluated effects in different application occasions, wherefore to further propose their main limitations and solutions in the epidemic era. For thermal comfort, various non-uniform ventilation modes could decrease the floor-to-ceiling temperature difference, draft rate or PPD by 60%, 80% or 33% respectively, or increase the PMV by 45%. Unsteady ventilation modes (including intermittent ventilation and pulsating ventilation) could lower PPD values by 12%–37.8%. While for air quality and virus spread control, non-uniform ventilation modes could lower the mean age of air or contaminants concentration by 28.3%–47% or 15%–47% respectively, increase the air change efficiency, contaminant removal effectiveness or protection efficiency by 6.6%–10.4%, 22.6% or 14%–50% respectively. Unsteady ventilation mode (pulsating ventilation) could reduce the peak pollutant concentration and exposure time to undesirable concentrations by 31% and 48% respectively. Non-uniform modes and unsteady modes presented better performance in thermal comfort, air quality and virus spread control, whereas relevant performance evaluation indexes were still imperfect and the application scenarios were also limited.

Occupancy-aided ventilation for airborne infection risk control: Continuously or intermittently reduced occupancies?

“…Like many existing studies (Dai and Zhao 2020;Morawska et al 2020;Stabile et al 2021;Wang et al 2021;Zhang and Lin 2021;Fig. 17 Variations in reduced airborne infection risk with reduced accumulated occupancy of continuously and intermittently reduced occupancy methods: quantum generation rate is 14 quanta/h (the benchmark is the normal occupancy method) Variations in reduced airborne infection risk with reduced accumulated occupancy of continuously and intermittently reduced occupancy methods: quantum generation rate is 1023 quanta/h (the benchmark is the normal occupancy method) Fan et al 2022;Wang et al 2022;Zhang et al 2022b;), this study focuses on the airborne transmission in a room which has regular cleaning and disinfection of contact surfaces for the infection risk control of contact route. The intermittently reduced occupancy method is compatible with the method for the infection risk control of contact route.…”

“…Although this study focuses on mixing ventilation with a uniform indoor thermal environment, the two-scenariosbased evaluation framework (Section 2.2) can be used to compare the performances of the two occupancy-aided ventilation methods under non-uniform air distribution such as stratum ventilation (Cheng et al 2022a), attachment ventilation (Yin et al 2021) and displacement ventilation (Fan et al 2022) in the future. This study evaluates the airborne infection risk from the perspective of the individual indicated by the mean rebreathed fraction as the existing studies do (Rudnick and Milton 2003;Andrews et al 2013;Li et al 2022).…”

“…Except for the physical elimination of pathogens, the engineering measure with ventilation is regarded as the most effective method for airborne infection risk control compared with the administrative and personal protective measures (Morawska et al 2020). Ventilation dilutes indoor contaminated air with clean air (Fan et al 2022;Gan et al 2022). Zhang et al (2022b) found two mechanisms for ventilation to control airborne infection risk.…”

Prophylaxis and Remediation for Future Pandemic Pathogens—(Lessons from a Post-COVID World)

“…Samples of a HEPA filter will be coated with metal nanoparticles using the low-cost copper alloys nanoparticles and their performance is compared to the more expensive silver and gold nanoparticles. Nanoparticles are synthesized via an atmospheric spark discharge method and deposited onto commercially available filters using forced convection flow [49]. A controlled number of nanoparticles were deposited on each filter sample; a variety of deposition patterns, sizes, and densities of nanoparticles were explored in parallel with mathematical models to examine the antiviral efficacies of the filter samples.…”

Transmission Probability of SARS-CoV-2 in Office Environment Using Artificial Neural Network

“…Many of these guidelines (as mentioned in Table 2) recommended boundary conditions for indoor relative humidity and temperature; considering both human comfort indoors as well as prevailing SC-2 spreading. Additionally, outdoor environmental conditions, occupant behaviour, and indoor occupant density are among other important parameters to reducing SC-2 spread in an indoor environment [59][60]. Several organizations and governments of different countries around the world had issued guidelines on COVID-19 appropriate behaviour in office environments [35,39,43,45,50,[61][62].…”