Collaborative Research: Geoengineering of Urban Green Infrastructure to Improve Outdoor Livability

美国城市人口面临着空气质量下降和热应力增加的问题，尤其是在热浪下。这两个影响人类健康的环境应激源对城市的宜居性提出了新的挑战。城市绿色基础设施(UGI)作为建筑环境的组成部分，被认为是潜在改善空气质量和减少热应力的有效缓解策略之一。过去的研究广泛地单独评估了UGI对热污染或空气污染的影响，但最近的一些研究解释了热和空气污染之间的不平凡的相互作用。这种相互作用提出了一个问题，即在实施城市规划时，是否总是可以实现缓解高温和空气污染的目标。因此，该项目旨在阐明城市地理信息系统如何在多个空间尺度上影响城市热环境和空气污染之间的相互作用。此外，该项目将开发一种新的方法来评估UGI的设计策略，考虑到热应激和空气污染对人类健康的影响。该项目将解决两个科学问题：1)极端高温事件的发生如何影响热和空气质量的联合影响？2)在正常和极端高温条件下，UGI的不同设计策略预计会产生什么样的缓解结果？为了回答这些问题，研究小组将应用天气研究和预报模型(WRF)与化学(CHEM)和城市树冠模型(UCM)相结合，改进了UGI的表示。耦合模式将利用正常夏季和高温条件下的观测数据进行评估。纽约市和凤凰城目前的UGI在缓解高温压力和空气污染方面的效果将通过考虑衡量联合健康影响的综合统计数据来量化。将评估社区和城市尺度上的不同UGI实施(空间上未区分的和有针对性的)。这项研究将包括：(I)城市冠层模型中邻近尺度的城市植被的综合表示；(Ii)基于综合统计的基于过程的方法，以评估热应激和空气污染对邻近和城市尺度的健康影响；(Iii)通过与景观设计师和利益相关者的协同活动，在多个空间尺度上融合宜居性评估、城市气候和城市规划。先进的大气物理和化学数值模拟，结合分析和量化UGI设计情景的新方法，旨在为工程解决方案和环境可持续性提供新的线索。预期的主要研究成果是：(1)基于过程的方法，系统地研究植被对当地气候带和城市层面的影响；(2)邻里尺度的城市景观规划战略组合，可扩展到城市层面；(3)基于热-污染耦合的新科学提供的户外宜居性的新客观指标。与景观设计师和利益相关者的密切互动将有助于公众认识到城市绿色基础设施的重要性，特别是对于对可持续和健康的户外宜居性具有重要影响的环境应激源。在项目结束时，将为不同UGI情景下的城市宜居指标建立一个共享数据库的倡议，供其他学术研究人员、公民和利益相关者访问。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Urban population in the United States is confronted with degraded air quality and elevated thermal stress, especially under heat waves. These two environmental stressors impact human health impose new challenges to urban livability. Urban green infrastructure (UGI), as an integral part of the built environment, has been considered as one of the effective mitigation strategies for potentially improving air quality and reducing thermal stress. Past research extensively evaluated the impact of UGI on either heat or air pollution separately but a few recent studies account for the non-trivial interactions between heat and air pollution. Such interactions raise the question of whether heat and air pollution mitigation is always achievable when implementing UGIs. This project therefore aims to elucidate how UGIs impact the interactions between urban thermal environment and air pollution across multiple spatial scales. Additionally, this project will develop a new method for evaluating the design strategies of UGI by considering the human health implications of heat stress and air pollution combined. The project will address two scientific questions: 1) How does the occurrence of extreme heat events affect the joint impacts of heat and air quality? 2) What mitigation outcomes are expected given different design strategies of UGI under normal and extreme heat conditions? To answer these questions, the research team will apply the Weather Research and Forecast model (WRF) coupled with chemistry (Chem) and urban canopy model (UCM) with improved representation of UGI. The coupled model will be evaluated with observational data under normal summer and high temperature conditions. The effects of the present UGI in both NYC and Phoenix in mitigating heat stress and air pollution will be quantified by considering a combined statistic that measures the joint health impacts. Different UGI implementations (spatially undifferentiated vs. targeted) at both the neighborhood and city scales will be evaluated. The study will include: (i) integrated representation of urban vegetation at the neighborhood scale in the urban canopy model; (ii) a process-based method based on a combined statistic to evaluate the health impacts of heat stress and air pollution at the neighborhood and city scales; (iii) fusing livability assessment, urban climates, and urban planning on multiple spatial scales through synergistic activities with landscape architects and stakeholders. Advanced numerical atmospheric physics and chemistry modeling, in conjunction with a new approach for analysis and quantification of UGI design scenarios is targeted to shed new light on engineering solutions and environmental sustainability. The main research outcomes anticipated are: (1) a process-based approach to systematically examine the influence of vegetation for both local climate zones and city level; (2) a portfolio of urban landscape planning strategies at the neighborhood scale, that is scalable to the city level; (3) a novel objective indicator of outdoor livability informed by new science based on heat- pollution coupling. Close interaction with landscape architects and stakeholders will facilitate public awareness of the importance of urban green infrastructure, particularly for environmental stressors that have important consequences of sustainable and healthy outdoor livability. An initiative for establishing a shared database for the urban livability indicators with different UGI scenarios will be established at the end of the project, accessible to other academic researchers, citizens, and stakeholders.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.