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Urban ventilation corridors are designed to enhance air quality, alleviate urban thermal conditions, reduce pollution and energy consumption, as well as improve human comfort within cities. They play a pivotal role in mitigating environmental impacts, particularly in densely populated urban areas. Based on satellite remote sensing data, meteorological observations, basic geographic information of Zhengzhou City and its surroundings, and urban planning data, we analyzed the urban wind environment, urban heat island, ecological cold sources, and ventilation potential. The findings reveal several key insights: (1) Dominant winds in Zhengzhou City predominantly originate from the northwest, northeast, and south, influenced by topography and the monsoon climate, with seasonal variations. These wind patterns are crucial considerations for designing primary ventilation corridors. (2) The urban heat island exhibits a polycentric spatial distribution, with intensity decreasing from the city center towards the periphery. Ecological cold sources, primarily situated in the city outskirts, act as reservoirs of fresh air that mitigate the urban heat island effect through designated corridors. (3) A preliminary corridor system, termed "eight primary and thirteen secondary corridors", is proposed for Zhengzhou City based on an integrated assessment of ventilation potential, urban surface roughness, and sky view factor. This research contributes to advancing the understanding of urban ventilation systems and provides practical insights for policymakers, urban planners, and researchers seeking sustainable solutions to mitigate climate impacts in rapidly urbanizing environments in the region. [ABSTRACT FROM AUTHOR]

The establishment of urban ventilation corridors (UVCs) aims to mitigate the urban heat island effect. While most studies focus on the construction and assessment of the environmental benefit of UVCs, they often overlook the analysis of UVCs’ topological features. This research integrates multi-source data including 3D urban buildings, historical meteorological observations, high-resolution remote sensing, and land use planning, combined with multiple models, including geographic information system spatial analysis, circuit theory, and complex networks. Based on an assessment of urban ventilation potential, the circuit model was applied to extract UVCs aligned with the prevailing wind direction for both summer and winter seasons. Complex network modeling was employed to analyze the topological features of the ventilation network. From the analytical results, a multi-level wind corridor system for Chengdu was quantitatively developed. The results indicate that the city’s overall ventilation resistance is high, with notable spatial clustering, and the southeastern region faces substantial ventilation obstructions. A total of 143 critical ventilation nodes were identified, with the number of air inlets and outlets in summer being significantly fewer than in winter. However, the cooling effect of ventilation corridors in the prevailing summer wind direction is superior to that in winter. The ventilation network comprises 16 communities with distinct ventilation characteristics, exhibiting moderate connectivity, lacking small-world properties, and showing congestion and instability.

In the context of global warming and rapid urbanization, urban wind-heat environment has become increasingly prominent. Although the identification of ventilation corridors has been well investigated, the impact of ventilation corridors on thermal environment remains unclear. Here, we use the single-window algorithm and circuit theory method to analyze the characteristics of land surface temperature (LST) and ventilation corridors in four megacities of China, so as to quantify the effect of ventilation corridors on thermal environment. Results show that circuit theory works well for identifying ventilation corridors. Moreover, we find that spatial distribution of ventilation corridors in one city is remarkably different from another. Interestingly, ventilation corridors, which consist of green spaces, waters, and roads, have a remarkable mitigation effect on thermal environment. LST of each city is mitigated by 2.39 ℃, 3.22 ℃, 2.11 ℃ and 2.60 ℃, respectively, and the cooling intensity in summer is better than that in winter. Thus, it is of great significance to arrange urban form and ventilation corridors to alleviate the impact of high temperature on urban residents.

The precise building performance assessment of residential housings in subtropical regions is usually more difficult than that for the commercial premises due to the much more complicated behavior of the occupants with regard to the change in indoor temperature. The conventional use of a fixed schedule for window opening, clothing insulation and cooling equipment operation cannot reflect the real situation when the occupants respond to the change in thermal comfort, thus affecting the appropriateness of the assessment results. To rectify the situation, a new modeling strategy in which the modification of the various operation schedules was based on the calculated thermal comfort (TC), was developed in this study. With this new TC-based strategy, the realistic building performances under different cooling provision scenarios applied to a high-rise residential building under the near extreme weather conditions were investigated and compared. It was found that sole provision of ventilation fans could not meet the zone thermal comfort by over 68% of the time, and air-conditioning was essential. The optimal use of ventilation fans for cooling could only help reduce the total cooling energy demand by less than 12% at best which could only be realistically evaluated by adopting the present strategy. Parametric studies were conducted which revealed that some design factors could offer opportunities for reducing the total cooling energy under the near extreme weather conditions. [ABSTRACT FROM AUTHOR]

• Constructing two models to identify and evaluate ventilation corridors. • Determining two types of source areas and optimizing the calculation formula for the resistance surface. • dentifying and evaluating the ventilation corridor network pattern at two scales during winter and summer. • Integrating ventilation corridors at both regional and urban scales. The construction of a ventilation corridor network is of great significance for alleviating the urban heat island effect, controlling air pollution, and improving environmental problems. Based on the "source–sink" theory and climatology, this study has developed the identification model for ventilation corridors and the evaluation model for the significance of ventilation corridors. Focusing on Shijiazhuang City as the study area, we integrated meteorological data, remote sensing, and fundamental geographic information to study the distribution characteristics of resistance surfaces, the delineation of source areas, the assessment of ventilation corridor potential, and the amalgamation of the ventilation corridor distribution pattern across various scales. The results showed the following: (1) In Shijiazhuang City, a comprehensive assessment identified a total of 55 supply–type sources and 20 demand–type sources. 19 ventilation corridors were identified in winter, with a commensurate count of 20 in summer. In the urban district of Shijiazhuang City, 42 supply–type sources and 24 demand–type sources underwent screening, leading to the identification of 27 ventilation corridors in both summer and winter. (2) Through a process of amalgamating and streamlining ventilation corridors with superior connectivity in both winter and summer, we identified and designated seven first–level ventilation corridors and six second–level corridors within the regional area. Similarly, within the urban district, ten first–level ventilation corridors and six second–level ventilation corridors were singled out. This selection serves as a preliminary establishment of the spatial configuration, delineating "five horizontal and eight vertical" ventilation corridors in Shijiazhuang City (regional area) and "seven horizontal and seven vertical" ventilation corridors in the urban district. Finally, leveraging geospatial analysis tools facilitated the seamless connection of ventilation corridors across different scales. These research results furnish a theoretical framework for urban planning, offering a valuable reference in the determination of ventilation corridors. [Display omitted] [ABSTRACT FROM AUTHOR]

Ventilation corridors in cities can decrease air pollution and alleviate heat island problems but there remains a need to fully assess their effectiveness. Few urban managers have been able to take city-scale approaches to the construction of urban ventilation corridors. This study aimed to introduced the Ventilation Corridor Planning (VCP) model, which is a multi-criteria evaluation method combined with a geographical information system (GIS) to determine where the ventilated environment is most appropriate. Specifically, the VCP model took Bozhou, China as the research object and contained two scales, including mesoscale and local scale. In mesoscale scale, we got three outputs to build urban ventilation corridors, including 1) background wind environment, 2) ventilation potential, 3) heat island intensity. In local scale, we used traditional computational fluid dynamics (CFD) model to verify the impact of VCP criteria. The results revealed that compared with the traditional CFD model, the proposed VCP model has advantages in establishing a comprehensive evaluation standard. In addition, the application of VCP model in macro and micro also enhances the efficiency of ventilation corridor construction. Overall, this study introduced a effective modeling method to urban ventilation corridors planning, and provide a way to study the urban climate.

Ventilation corridors in cities can decrease air pollution and alleviate heat island problems but there remains a need to fully assess their effectiveness. Few urban managers have been able to take city-scale approaches to the construction of urban ventilation corridors. This study aimed to introduced the Ventilation Corridor Planning (VCP) model, which is a multi-criteria evaluation method combined with a geographical information system (GIS) to determine where the ventilated environment is most appropriate. Specifically, the VCP model took Bozhou, China as the research object and contained two scales, including mesoscale and local scale. In mesoscale scale, we got three outputs to build urban ventilation corridors, including 1) background wind environment, 2) ventilation potential, 3) heat island intensity. In local scale, we used traditional computational fluid dynamics (CFD) model to verify the impact of VCP criteria. The results revealed that compared with the traditional CFD model, the proposed VCP model has advantages in establishing a comprehensive evaluation standard. In addition, the application of VCP model in macro and micro also enhances the efficiency of ventilation corridor construction. Overall, this study introduced a effective modeling method to urban ventilation corridors planning, and provide a way to study the urban climate. [ABSTRACT FROM AUTHOR]

• Constructed a comprehensive evaluation model of urban ventilation potential (UVP) • UVP has a negative correlation with Land Surface Temperature (LST) • Circuit theory is more suitable for the identification of ventilation corridors. • Ventilation corridors have seasonal differences in mitigating LST. In the context of global warming and rapid urbanization, urban wind-heat environment has become increasingly prominent. Although the identification of ventilation corridors has been well investigated, the impact of ventilation corridors on thermal environment remains unclear. Here, we use the single-window algorithm and circuit theory method to analyze the characteristics of land surface temperature (LST) and ventilation corridors in four megacities of China, so as to quantify the effect of ventilation corridors on thermal environment. Results show that circuit theory works well for identifying ventilation corridors. Moreover, we find that spatial distribution of ventilation corridors in one city is remarkably different from another. Interestingly, ventilation corridors, which consist of green spaces, waters, and roads, have a remarkable mitigation effect on thermal environment. LST of each city is mitigated by 2.39 ℃, 3.22 ℃, 2.11 ℃ and 2.60 ℃, respectively, and the cooling intensity in summer is better than that in winter. Thus, it is of great significance to arrange urban form and ventilation corridors to alleviate the impact of high temperature on urban residents. [ABSTRACT FROM AUTHOR]

Urban heat islands (UHIs) are mainly caused by mismanaged urban development. Urban ventilation corridors (UVCs) can effectively reduce UHIs. Hangzhou, a large, dense city in eastern China, is one of the nation's hottest cities and must urgently improve its ventilation. In this study, a newly developed method combining land surface temperature retrieval, GIS spatial analysis, and weather data was employed to design city-level UVCs. The functional space and compensation space of UVCs are identified based on the LandsatETM8 image data inversion of surface temperature. The contribution of affect factors, such as building density, building height, green land area, waterbody, roads, and urban terrain, to the urban ventilation potential is calculated using AHP and GIS. Areas with tremendous ventilation potential were identified as possible ventilation corridors by using an evaluation model and considering wind characteristics. Fifty-four high-temperature zones and 48 low-temperature zones were identified as functional and compensative spaces in Hangzhou, respectively. On the urban scale, green space (area >500ha), water bodies (area >300ha or width >100 m), and roads (width >50 m) were considered to be the factors that have the greatest impact on urban ventilation potential. The LCP method was used to verify the accuracy and rationality of the method proposed in this study to determine the city-scale UVC. UVC planning schemes and construction measures were proposed to provide rich information and a reference basis for the new general land and space planning of Hangzhou. However, to improve the accuracy of the potential ventilation results, the urban underlying surface criteria should be re-evaluated more comprehensively. [ABSTRACT FROM AUTHOR]

Abstract: We introduce the ventilation potential (VP) as a statistical, climate-dependent measure to assess the removal of scalars, such as heat and pollutants, from courtyards or urban street canyons. The VP is obtained following a three-step approach. First, the magnitude of the flux through a horizontal surface situated at the top of the courtyard or canyon is determined by means of computational fluid dynamics (CFD) simulations for various courtyard geometries and ambient wind directions. Then, this exchange flux is normalized with the free-stream wind speed and subsequently parameterized as a function of the courtyard’s length-to-width ratio and the incidence angle of the wind flow. Finally, the combination of the parameterization with site-specific wind data yields the VP. This study reveals that the normalized exchange flux is maximal when the angle between the prevailing flow direction and the main courtyard axis is about 15–30°, regardless of the courtyard length. The normalized exchange flux increases with increasing courtyard length, and approaches the optimum for courtyards with a length-to-height ratio of ten. Longer courtyards behave as urban street canyons. Unsteady (LES) simulations lead to a much higher VP and thus favor scalar removal when compared with steady (RANS) simulations. These observations can have a decisive impact on urban planning, human comfort and health. [Copyright &y& Elsevier]