Reducing COVID-19 airborne transmission risks on public transportation buses: an empirical study on aerosol dispersion and control
Reducing COVID-19 airborne transmission risks on public transportation buses: an empirical study on aerosol dispersion and control
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DOI：
10.1080/02786826.2021.1966376
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发表时间：
2021-08-12
影响因子：
5.2
通讯作者：
Espinoza-Calvio, Angelica
中科院分区：
文献类型：
--
作者：
Edwards, Nathan J.;Widrick, Rebecca;Espinoza-Calvio, Angelica
这项研究是首批与新冠肺炎相关的公交车研究之一，目的是全面表征在高度动荡的现实环境中咳嗽气溶胶的扩散和控制，即在校车和公交车上驾驶常规公交车路线。虽然已经进行了其他几项巴士研究，但这些研究仅限于临床接触者追踪、模拟或部分描述有约束条件的乘客区域的气溶胶传播。考虑到SARS-CoV-2(新冠肺炎)和其他高度传染性的空中传播疾病的传播风险，地面公共交通系统是空中传播的高风险环境，特别是因为在大多数公交车上六英尺的社会距离是不现实的。这项研究表明，根据口罩的质量，佩戴口罩可以将排放到公交车中的总颗粒物数量平均减少50%或更多，并将分散距离缩短几英尺。研究还表明，在一些测试案例中，气溶胶颗粒减少了84.36%，平均气溶胶停留时间减少了80.28%。我们使用雾化的10%氯化钠和机械呼气模拟器进行了84次实验，产生了7830万个数据点和124英里的道路测试。我们的研究不仅使用28个联网颗粒计数器捕捉扩散模式，还量化了使用车载风扇、打开各种窗户、使用面罩或口罩以及使用公交暖通空调系统的有效性。此外，这项工作还提供了真实世界湍流空气环境中气溶胶扩散的经验观测，这与许多现有的流体动力学模拟显著不同，并就恶劣天气条件、驾驶员安全、改善巴士空气质量的改装应用以及公共交通组织的运营考虑因素进行了实质性讨论。
This study is one of the first COVID-19 related bus studies to fully characterize cough aerosol dispersion and control in the highly turbulent real-world environment of driving regular bus routes on both a school bus and a transit bus. While several other bus studies have been conducted, they were limited to clinical contact tracing, simulation, or partial characterization of aerosol transmission in the passenger areas with constraint conditions. When considering the risk of transmission of SARS-CoV-2 (COVID-19) and other highly infectious airborne diseases, ground based public transportation systems are high-risk environments for airborne transmission particularly since social distancing of six feet is not practical on most buses. This study demonstrates that wearing of masks reduced the overall particle count released into the bus by an average of 50% or more depending on mask quality and reduced the dispersion distance by several feet. The study also demonstrates an 84.36% reduction in aerosol particles and an 80.28% reduction in the mean aerosol residence time for some test cases. We conducted 84 experimental runs using nebulized 10% sodium chloride and a mechanical exhalation simulator that resulted in 78.3 million data points and 124 miles of on-the-road testing. Our study not only captures the dispersion patterns using 28 networked particle counters, it also quantifies the effectiveness of using on-board fans, opening of various windows, use of face coverings or masks, and the use of the transit bus HVAC system. This work additionally provides empirical observations of aerosol dispersion in a real-world turbulent air environment, which are remarkably different than many existing fluid dynamics simulations, and also offers substantial discussion on the implications for inclement weather conditions, driver safety, retrofit applications to improve bus air quality, and operational considerations for public transportation organizations.