RESUMO
COVID-19 has already claimed over 7 million lives and has infected over 775 million people globally [1]. SARS-CoV-2, the virus that causes Covid-19, spreads primarily through droplets from infected people's airways, rendering Heating, Ventilation, and Air Conditioning (HVAC) systems critical in controlling infection risk levels in the indoor environment. To understand the dynamics of exhaled droplets and aerosols and the percentage of particles that are inhaled, escaped, recirculated, or trapped on different surfaces for a variety of environmental settings, we have presented our findings from the Computational Fluid Dynamics (CFD) modeling to investigate the impact of changing HVAC parameters in this paper. When combined with the spatial and temporal distribution of droplets, this method can be used to assess the potential risk and strengthen resilience. This finding demonstrates the viability and usefulness of CFD for modeling the distribution and dynamics of droplets and aerosols in confined environments. Our study demonstrates that raising the Air Change per Hour (ACH) from 2 to 8 reduces the risk of particle inhalation by nearly 70 %. Additionally, limiting the amount of air recirculation or increasing the amount of fresh air helps to reduce the number of airborne particles in an indoor space. To reduce the potential for respiratory droplet-related transmission and to provide relevant recommendations to the appropriate authority, the same computational approach could be applied to a wide range of ventilated indoor environments such as public buses, restaurants, exhibitions, and theaters.
RESUMO
The current coronavirus disease 2019 (COVID-19) pandemic has reinforced the necessity of understanding and establishing baseline information on the fate and transport mechanisms of viruses under indoor environmental conditions. Mechanisms governing virus interactions in built spaces have thus far been established based on our knowledge on the interaction of inorganic particles in indoor spaces and do not include characteristics specific to viruses. Studies have explored the biological and kinetic processes of microbes' attachments on surfaces in other fields but not in the built environment. There is also extensive literature on the influence of indoor architecture on air flow, temperature profiles, and forces influencing aerosol transport. Bridging the gap between these fields will lead to the generation of novel frameworks, methodologies and know-how that can identify undiscovered pathways taken by viruses and other microbes in the built environment. Our study summarizes the assessment of the influence of surface properties on the adhesion kinetics of vaccinia virus on gold, silica, glass, and stainless-steel surfaces. We found that on gold the virus layer was more viscoelastic compared to stainless-steel. There was negligible removal of the layer from the stainless-steel surface compared to the others. The results further highlight the importance of converging different fields of research to assess the fate and transport of microbes in indoor built spaces.