Managing Air for Green Inner Cities

这份提案中阐述的挑战是：如何在2050年前发展没有空气污染和没有热岛效应的城市？很难准确预测城市的未来，但到2050年，由于技术进步、人口变化、社会期望和气候变化，城市将出现重大的适应和变化。我们需要一个路线图，以确保随着城市的发展而做出的决策能够带来可持续的未来。城市中大约一半的能源使用、二氧化碳排放和空气污染是由于建筑物或交通造成的，而且这一能源使用总量正在增加。预计到2050年，空气污染将成为全球主要的死亡原因。因此，这里提出的空气质量和温度上升问题本身就很重要。然而，这些量一起也提供了（也许是唯一的）覆盖整个城市的具体可测量的物理属性，并为评估全系统决策的可持续性提供了一个衡量标准。传统的城市环境控制方法依赖于消耗能源和产生碳/有毒物质的供暖、通风和空调（HVAC）系统。这些传统的方法产生了一个不可持续的循环，即增加能源使用，同时排放二氧化碳和污染物，导致温度上升，这反过来又意味着更多地使用HVAC。打破这种恶性循环需要一个完全不同的工程解决方案，一个与自然系统相结合的解决方案，而不仅仅依赖于机械系统。该项目将开发一个设施，包括一套集成的模型和相关的管理和决策支持系统，共同允许城市设计及其运营管理空气，使其成为自己的HVAC系统，清洁，凉爽的空气提供健康和舒适的低能耗解决方案。这将通过在建筑物中使用自然通风来减少对能源的需求，并确保空气污染物被稀释到对健康造成不利影响的水平以下，再加上增加空气污染以减少热岛效应，加上绿色（公园）和蓝色（水）空间，以提供冷却和过滤污染物。我们召集了一个跨学科的研究团队来建造这个设施。它将由三个部分组成：㈠完全解析的空气质量模型，与传感器数据相互作用，提供复杂城市几何形状中空气流动、污染物和温度分布的详细计算，并与自然通风建筑物以及绿色和蓝色空间充分耦合; ㈡降阶模型，能够快速计算，用于真实的时间分析和应急反应;及（iii）成本效益模式，以评估各项方案及决定的经济、社会及环境可行性。科学空气质量组件是一个完全解析的计算模型，在建筑物，街区和市镇尺度上耦合自然通风建筑物的外部和内部流动。它将得到选定地点的实地测量以及风洞和盐浴实验室研究的支持和验证。降阶模型将从计算模型和实验室过程研究中发展出来，并将能够产生诸如平均污染物浓度和温度等总体特征。它们将用于提供范围研究以及实时和应急反应的能力。成本效益模式将在科学和工程模式与执行建议之间提供联系。它将包括建筑环境、公共空间和交通模块，并提供单个建筑、城市街区和市镇规模的各种方案的生命周期成本和效益估计。最终，预计这还将包括社会和健康影响。

The challenge articulated in this proposal is: how to develop cities with no air pollution and no heat-island effect by 2050?It is difficult to predict with precision the future of cities, but there will be significant adaptations and changes by 2050, due to advances in technology, changing populations, social expectations and climate change. A roadmap is needed to ensure that decisions taken as the city evolves lead towards a sustainable future. Approximately half of the energy use, carbon dioxide emissions and exposure to air pollution in cities is due to either buildings or transportation, and this total energy use is increasing. Air pollution is projected to be the leading global cause of mortality by 2050. Therefore the question posed here in terms of air quality and temperature rise is important in its own right. However, these quantities together also provide, perhaps uniquely, specific measurable physical properties that cover an entire city and provide a metric for assessing the sustainability of system-wide decisions. Traditional approaches to urban environmental control rely on energy-consuming and carbon/toxics-producing heating, ventilation and air conditioning (HVAC) systems. These traditional approaches produce an unsustainable cycle of increasing energy use with associated emissions of carbon dioxide and pollutants leading to rising temperatures implying, in turn, greater use of HVAC. Breaking this vicious cycle requires a completely different engineered solution, one that couples with natural systems and does not depend solely on mechanical systems. This project will develop a facility consisting of an integrated suite of models and an associated management and decision support system that together allow the city design and its operation to manage the air so that it becomes its own HVAC system, with clean, cool air providing low-energy solutions for health and comfort. This will be achieved by using natural ventilation in buildings to reduce demand for energy and ensuring air pollutants are diluted below levels that cause adverse health effects, coupled with increased albedo to reduce the heat island effect plus green (parks) and blue (water) spaces to provide both cooling and filtration of pollutants. We have brought together a trans-disciplinary research team to construct this facility. It will be comprised of three components: (i) a fully resolved air quality model that interacts with sensor data and provides detailed calculations of the air flow, pollutant and temperature distributions in complex city geometries and is fully coupled to naturally ventilated buildings, and green and blue spaces; (ii) reduced order models that allow rapid calculations for real time analysis and emergency response; and (iii) a cost-benefit model to assess the economic, social and environmental viability of options and decision. The scientific air quality component is a fully-resolved computational model that couples external and internal flows in naturally ventilated buildings at the building, block and borough scales. It will be supported and validated by field measurements at selected sites and by wind tunnel and salt-bath laboratory studies. The reduced order models will be developed from the computational model and from laboratory process studies, and will be capable of producing gross features such as mean pollutant concentrations and temperatures. They will be used to provide capabilities for scoping studies, and real-time and emergency response. The cost-benefit model will provide the link between the scientific and engineering models and implementation advice. It will include modules for the built environment, public spaces and transportation, and provide estimates of the life-cycle costs and benefits of the various scenarios at the individual building, city block and borough scales. Eventually, it is envisaged that this will also include social and health effects.