HU Minghao¹ ，GUO Meng¹ ，WANG Kang¹ ，YUE Bin¹ ，YANG Weiqiang¹ ，LI Hang¹ ，HUANG Xiaowei^1，2，XIANG Wenfeng¹

1. College of New Energy and Materials， China University of Petroleum（Beijing）， Beijing 102249， China；

Abstract

Objective To investigate the transmission characteristics of indoor pathogenic aerosols under different ventilation strategies.

Methods In this study， silica aerosol was used as a safe substitute to simulate indoor pollution. Three ventilation strategies were examined： no ventilation， floor ventilation，and vertical laminar flow ventilation. The experiments were conducted in a controlled ultra-clean laboratory， where silica aerosols were released， and real-time monitoring of aerosol concentration and dynamic changes was carried out using a high-precision air quality sensor network.

Results and Discussion The data under no ventilation revealed the complex mechanisms and dynamic changes of aerosol transmission， detailing the release， indoor diffusion， and eventual saturation of aerosols. By analyzing three key parameters， i. e. ，initial detection time， saturation time， and saturation concentration， the study explored aerosol transmission characteristics and spatial distribution. The data showed that the transmission speed from near to mid-range was approximately 1. 81 times faster than from mid-range to far-range， highlighting the decay of transmission speed with increasing distance. The presence of obstacles （such as biosafety cabinets） significantly extended the saturation time and increased concentration levels in specific areas. Under floor ventilation conditions， the dynamic changes in aerosol concentration indicated that ventilation significantly accelerated transmission， with the initial detection time reduced to 100~150 seconds and transmission speed increased by 7. 86 to 14. 2 times. Vertical laminar flow ventilation showed distinct advantages， with the initial detection time reduced to approximately 167 seconds and an average transmission speed increased to 0. 03 m/s， significantly higher than in the no-ventilation environment. The average concentration was reduced by about 23% compared to the no-ventilation environment， indicating that the top-to-bottom airflow pattern accelerated particle deposition. Vertical laminar flow ventilation effectively removed aerosols，significantly improving indoor air quality.

Conclusion The study explores the transmission characteristics of indoor aerosols under three ventilation strategies： no ventilation， floor ventilation， and vertical laminar flow ventilation. Without ventilation， aerosol transmission is slow， and the concentration shows a normal distribution. Floor ventilation significantly increases the transmission speed， leading to a more uniform and higher concentration distribution. Vertical laminar flow ventilation provides a direct and efficient transmission path， reducing the complexity of aerosol diffusion and accelerating aerosol deposition and indoor air renewal through high-speed airflow，maintaining lower aerosol concentrations. Vertical laminar flow ventilation can effectively reduce aerosol concentrations and lower the risk of disease transmission.

Keywords：indoor environment； ventilation method； aerosol； respiratory infectious diseases