Bioaerosols in an industrial park and the adjacent houses: Dispersal between indoor/outdoor, the impact of air purifier, and health risk reduction.

11 Aerosols of biological origins, known as bioaerosols, in addition to having the aerosol 12 properties, have those of a living system that offers them some enabling functionalities. From 13 science to technology, visible progress around the world has been made in bioaerosol field before 14 and especially during the COVID-19 pandemic. Here the roles of bioaerosol across various 15 disciplines, including air quality, climate and human health are highlighted and appreciated in light 16 of Anthropocene and one health concept. In particular, we recognized the importance of 17 aerobiology under haze air pollution, allergenic pollen and bioaerosol involvement in infectious 18 and inflammation-related non-communicable diseases. Future interdisciplinary studies focusing 19 on the chemical and biological process of microorganisms in air, airborne transmission of 20 emerging pathogens and allergens and the association between bioaerosol exposure and the 21 development and variations of human microbiome and immune response are needed to elucidate 22 the interactions of bioaerosols with the earth system.

Bioaerosol nexus of air quality, climate system and human health

With the wide spread of COVID-19, numerous cases demonstrate that proper ventilation method can reduce the cross-infection risk obviously. Interactive cascade ventilation (ICV) as a recently proposed ventilation method, the advantage of indoor environment construction has been proven. However, few studies are conducted to investigate the virus prevention and control characteristics of ICV, which is particularly important under epidemic normalizing. Hence, this study explored and compared the cross-infection control performance of three ventilation strategies, namely mixing ventilation (MV), stratum ventilation (SV), and interactive cascade ventilation (ICV), with a validated CFD model. A typical office was selected as the background scene, where an infected person coughs, sneezes with standing or sitting at different positions. Exposure doses, health infection risk, and disease burden (DB) were employed as the evaluation indicators under different ventilation methods of multi-scenario. The research results indicated that the average aerosol exposure dose among the human respiratory region under ICV was 0.29 g/day, which was reduced by 67 % and 50 % compared with MV and SV. In addition, only in ICV can the health infection risk meets the EPA standard. The average disease health burden for exposed persons under ICV was 0.93 × 10−6 DALYs pppy, which was 37 % and 70 % lower than SV and MV. The findings obtained from this study confirm that ICV performs excellently in reducing the cross-infection risk, providing the theoretical basis for future epidemic prevention and control. 

Investigation on the cross-infection control performance of interactive cascade ventilation in multi-scenario of winter

Quantitative risk assessment for bacterial community in residential kitchens

Abstract Aerosols can transmit infectious diseases including SARS-CoV-2, influenza and norovirus. Flushed toilets emit aerosols that spread pathogens contained in feces, but little is known about the spatiotemporal evolution of these plumes or the velocity fields that transport them. Using laser light to illuminate ejected aerosols we quantify the kinematics of plumes emanating from a commercial flushometer-type toilet, and use the motion of aerosol particles to compute velocity fields of the associated flow. The toilet flush produces a strong chaotic jet with velocities exceeding 2 m/s; this jet transports aerosols to heights reaching 1.5 m within 8 seconds of initiating a flush. Quantifying toilet plumes and associated flow velocities provides a foundation for future design strategies to mitigate plume formation or to disinfect pathogens within it. 

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Ling Gong

Papers

Emission characteristics and quantitative health risk assessment of bioaerosols in an indoor toilet after flushing under various ventilation scenarios