高密人群室内环境空气中病原体吸入暴露的通风控制方法研究

Airborne and droplet-borne infection risks significantly elevate when the susceptible are close to the index patient. In indoor environments with high occupancies, the mutual distances among people are small. The performance of ventilation and air distribution system that supplies clean air and dilutes the airborne pathogens, is critical to protect indoor occupants. Current ventilation regulation recommends to supply a large amount of clean air to the classrooms, theatres, waiting rooms, etc. The effectiveness is in question, due to the existence of human microenvironment. When travelling with human exhalation airflows, human body plumes, the airborne pathogens do not follow the ventilation airflow. Particularly, when human microenvironments merge at a short mutual distance, the airborne pathogens cannot be diluted by the ventilation airflow in time. .This study proposes to measure the airborne pathogen exposure in typical high-occupancy indoor environments, in order to obtain the first-hand data for the first time in Western China. Local ventilation control method is further proposed to control the airborne pathogen. By comparing the inhaled pathogen concentration by a breathing thermal manikin, the optimization will be processed by varying combination of ventilation rates of the local ventilation system and general ventilation system.

2003年非典型性肺炎疫情，2009年H1N1流感爆发等呼吸道感染病威胁人们的健康和正常生活。由于呼吸道疾病在近距离的传染风险远高于远距离，高密人群室内环境是呼吸道疾病传播的高危环境。我国现行的建筑通风设计规范针对影剧院、教室、等候室等高密人群室内环境的通风方案为使用大风量稀释的全面通风，所规定的最小通风量已经达到甚至超过了发达国家水平。考虑到我国人口基数大，高密人群建筑多，能耗负担远超发达国家。研究发展在不增加能耗负担和不影响控制其他室内污染物的前提下，能够在高密人群室内环境中有效控制呼吸道疾病的近距离飞沫和空气传播的建筑通风方式具有很迫切的现实意义。本项目拟通过测量获得典型的高密人群室内环境空气中的病原体种类、大小和数量等数据，并探讨其与季节、气候、人群密度等影响因素的相关性。同时在实验室中测试并优化全面通风与局部通风相结合的分级控制通风方法。

本研究关注高密人群室内环境中病原体的吸入暴露。先后研究了西部地区自然通风教室（平均人际间距米）内空气中的微生物组成，细菌对液滴蒸发特性的量化影响，探讨了颗粒物在呼吸道的沉积情况、眼部及嘴唇粘膜的输送剂量。新冠疫情发生后，本项目借助前期研究基础，迅速聚焦通风系统对人体微生物吸入暴露的影响，讨论了采用置换通风的方舱医院等近距离接触病患的场所应该采取何种措施降低交叉感染风险。围绕通风系统对室内环境颗粒物及病原体的防控研究问题，通过五种模型评价了个性化通风的保护效应，实地测量病比对了室外气流率对新冠疫情时医院感染的风险影响，讨论了近距离及超近距离下飞沫及飞沫核人际间的传播机理及风险。研究成果发表高水平学术论文10篇，申请发明专利5项，授权2项，在新冠疫情期间有效支撑了一线抗疫医院的诊疗安全。