Simulating urban air pollution in the lab

该项目旨在解决建筑内部和周围的气流问题，从而更好地了解城市空气污染。根据世界卫生组织（世卫组织）的数据，80%生活在城市地区的人暴露在不安全的空气污染中，从而增加了患心脏病、肺癌和呼吸系统疾病的风险。这项研究将研究污染如何在城市地区扩散，以改进用于空气质量预测和为城市规划和政策提供信息的污染扩散模型。实验将在一个受控的实验室流动设备中按比例进行。测量的气流模式可以与全尺寸的大气气流相关联，就像对比例模型的风洞测试提供了对车辆空气动力学的见解一样。大多数实验将在水槽设施中进行，被动示踪剂将在模型周围的关键点释放，作为空气污染的替代品。水槽的使用允许使用先进的基于激光的测量工具，可以在污染源附近的细尺度和城市尺度上捕获扩散过程的完整二维定量图像。这是将该工作与以前的风洞和现场分散测量区分开来的关键特征，这些测量通常仅限于点测量。由于她在实验技术方面的专业知识以及她之前分析规范湍流剪切流中的相干结构和混合的背景，研究员在进行这些新颖的空间测量方面处于独特的地位。南安普顿大学特别适合进行这项研究，因为它拥有合适的水槽设施以及所需的高分辨率相机和激光系统。在各国政府关注改善城市环境可持续性和空气质量之际，这项研究尤为及时。这些结果将提高我们向地方议会和工业界通报污染如何在城市周围扩散的能力，帮助他们做出影响财政和环境可持续性以及公共健康和安全的决策。除了这些社会影响之外，这些结果还将通过改进气象模型产生学术影响。现有的色散模型侧重于时间平均预测；然而，这些模型难以预测时空波动和峰值暴露，特别是在源附近。了解这些动态对空气质量很重要，因为即使短期接触有毒气体和空气中的颗粒物也会对健康产生不利影响。这些结果将提高我们对基础物理的理解，从而指导理论和改进预测复杂城市地区污染扩散动力学的模型。

This project aims at resolving airflow in and around buildings to better understand urban air pollution. According to the World Health Organization (WHO), 80% of people living in urban areas are exposed to unsafe levels of air pollution and with it an increased risk of heart disease, lung cancer, and respiratory disease. This research will study how pollution disperses in urban areas, in order to improve the pollution dispersion models used to make air quality forecasts and that inform urban planning and policy. Experiments will be conducted on scale models in a controlled laboratory flow facility. The measured flow patterns can then be related to full-scale atmospheric flows, in the same way wind tunnel tests of scale models provide insights to vehicle aerodynamics. The majority of experiments will take place in a water flume facility and passive tracers will be released at key points around the model, as a surrogate for air pollution. The use of the water flume permits the use of advanced laser-based measurement tools that can capture full two-dimensional quantitative images of the dispersion process both at the fine scales near the pollution sources and at the city scale. This is the key feature that differentiates this work from previous wind tunnel and in-situ measurements of dispersion, which are typically limited to point measurements. The fellows is uniquely positioned to conduct these novel spatial measurements due to her expertise with the experimental techniques and her previous background analysing coherent structures and mixing in canonical turbulent shear flows. The University of Southampton is particularly suitable location for this research because of the combination of having a suitable water flume facility as well as the required high-resolution camera and laser systems.This study is particularly timely as governments focus on improving environmental sustainability and air quality in cities. These results will improve our ability to inform local council and industry on how pollution disperses around the city, aiding them in making decisions impacting financial and environmental sustainability and public health and safety. In addition to these societal impacts, these results will have academic impact by improving meteorological models. Existing dispersion models focus on time-averaged predictions; however, these models struggle to predict spatio-temporal fluctuations and peak exposures, especially near the source. Understanding these dynamics is important for air quality, as even short term exposure to toxic gases and airborne particulate matter can have adverse health impacts. These results will improve our understanding of the underlying physics in order to guide theories and improve models for predicting the dynamics of pollution dispersion in complex urban regions.