Haq Muhammed F, Cadnum Jennifer L, Carlisle Matthew, Hecker Michelle T, Donskey Curtis J
Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio.
Department of Infectious Diseases, MetroHealth Medical Center, Cleveland, Ohio.
Pathog Immun. 2022 Feb 2;7(1):19-30. doi: 10.20411/pai.v7i1.493. eCollection 2022.
Poorly ventilated enclosed spaces pose a risk for airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory viruses. Limited information is available on ventilation in motor vehicles under differing driving conditions.
We conducted carbon dioxide measurements to assess ventilation in motor vehicles under varying driving conditions with 2 to 3 vehicle occupants. During routine driving, carbon dioxide produced by the breathing of vehicle occupants was measured inside 5 cars and a van under a variety of driving conditions with or without the ventilation fan on and with windows open or closed. Carbon dioxide readings above 800 parts per million (ppm) were considered an indicator of suboptimal ventilation.
Carbon dioxide levels remained below 800 ppm in all vehicles if the ventilation fan was on and/or the windows were open while parked or during city or highway driving. With the ventilation system set on non-recirculation mode, carbon dioxide levels rose above 800 ppm in all vehicles when the fan was off and the windows were closed while parked and during city driving, and in 2 of the 6 vehicles during highway driving. With the ventilation system set on recirculation mode, carbon dioxide rose above 800 ppm within 10 minutes in all vehicles tested.
Carbon dioxide measurements could provide a practical and rapid method to assess ventilation in motor vehicles. Simple measures such as opening windows, turning on the fan, and avoiding the recirculation mode greatly improve ventilation.
通风不良的封闭空间存在严重急性呼吸综合征冠状病毒2（SARS-CoV-2）及其他呼吸道病毒空气传播的风险。关于不同驾驶条件下机动车通风情况的信息有限。
我们进行了二氧化碳测量，以评估有2至3名车内人员时机动车在不同驾驶条件下的通风情况。在常规驾驶过程中，在5辆汽车和1辆厢式货车内，于各种驾驶条件下，在通风风扇开启或关闭、车窗打开或关闭的情况下，测量车内人员呼吸产生的二氧化碳。二氧化碳读数超过百万分之800（ppm）被视为通风欠佳的指标。
如果停车时或城市或高速公路驾驶期间通风风扇开启和/或车窗打开，所有车辆内的二氧化碳水平均保持在800 ppm以下。通风系统设置为非循环模式时，停车时和城市驾驶期间风扇关闭且车窗关闭时，所有车辆内的二氧化碳水平均升至800 ppm以上，高速公路驾驶时6辆车中有2辆如此。通风系统设置为循环模式时，所有测试车辆内的二氧化碳在10分钟内升至800 ppm以上。
二氧化碳测量可为评估机动车通风情况提供一种实用且快速的方法。开窗、打开风扇及避免循环模式等简单措施可大大改善通风。
