Urban studies attempt to assess open space fragmentation and develop sustainable policies in high–density cities. However, the complex characteristics of open space fragmentation and the multiple ...scenarios comprising various fragmentation forms have not been adequately documented, potentially leading to irrelevant control strategies and controversial results. Therefore, this study aims to propose a systematic procedure for elaborating the patterns, forms and scenarios of open space fragmentation in Hong Kong's built–up area. The series of metrics proposed to capture the complex relationships among various fragmentation forms has been validated by principal components analysis for its wide application in open space fragmentation research. The results reveal that open space fragmentation takes the form of morphological (use, internal, extensive and shape) and connectional (location) fragmentation, which covers nine scenarios. Open space fragmentation shows spatial heterogeneity, as evidenced by the highest fragmentation index of 0.259 in the Kowloon region, followed by the Hong Kong Island and the New Territories regions with fragmentation indexes of 0.237 and 0.187. The average value of open space fragmentation in the old towns is 0.250, which is considerably higher than that of 0.187 in the new towns. Old towns manifest numerously more and complicated scenarios than new towns. The findings inform refined open space management in high–density cities.
•Understanding the characteristics of open space fragmentation in high–density cities.•Establishing metrics for capturing morphological and connectional fragmentation.•Nine scenarios based on various forms of open space fragmentation were identified.•Old towns have a higher level of open space fragmentation compared to the new towns.•Beneficial strategies are proposed for multiple open space fragmentation scenarios.
The global response to the COVID-19 pandemic has brought with it significant changes to human mobility patterns and working environments. We aimed to explore how social distancing measures affected ...recreational use of urban green space during the partial lockdown in Oslo, Norway. Mobile tracking data from thousands of recreationists were used to analyze high resolution spatio-temporal changes in activity. We estimated that outdoor recreational activity increased by 291% during lockdown relative to a 3 yr average for the same days. This increase was significantly greater than expected after adjusting for the prevailing weather and time of year and equates to approx. 86 000 extra activities per day over the municipality (population of 690 000). Both pedestrians (walking, running, hiking) and cyclists appeared to intensify activity on trails with higher greenviews and tree canopy cover, but with differences in response modulated by trail accessibility and social distancing preferences. The magnitude of increase was positively associated with trail remoteness, suggesting that green spaces facilitated social distancing and indirectly mitigated the spread of COVID-19. Finally, pedestrian activity increased in city parks, peri-urban forest, as well as protected areas, highlighting the importance of access to green open spaces that are interwoven within the built-up matrix. These findings shed new light on the value of urban nature as resilience infrastructure during a time of crisis. The current pandemic also reveals some important dilemmas we might face regarding green justice on the path towards urban planning for future sustainable cities.
In a globally connected world and increasingly smart cities, the demand for living in a physical neighborhood where one can walk and cycle among familiar people and a variety of services is always ...alive. It is a quality of life which meets the deep desire of community and place identity. In this regard, the 15-minutes city is the contemporary version of the classical “human measure”. The model offers a refreshing chrono-centric vision for the city that prioritizes people’s time, energy and physio-psychological health by relieving their daily commutes. The recent pandemic clearly showed this potential; the daily outdoor movement by soft mobility allowed for social life even during lockdown periods. The paper is subdivided into two main components: a theoretical discussion of the 15-minute city model as part of a broader sustainable urban planning narrative, and a practical application mapping the potentials of Milan as a 15-minute city, focusing on population distribution and urban fabric structure as a measure of performance evaluation. The emergence of the 15-minute model rebalances the building volume concentration of the consolidated Transit Oriented Development paradigm; suggesting an innovative and more articulated vision. The 15-minute approach, rooted in the organic planning of the ‘60, is pushed by the covid-19 emergency, making treasure of the experience of urban regeneration masterplans of the last decade. The approach falls in line with real estate strategies for place making, which aim to create new sustainable urban districts that are pedestrian oriented and carbon free. After interpreting the international framework of urbanism trends with respect to the 15-minute model, the paper focuses on the Milan case. The potentials for neighborhoods across the city of Milan is investigated to conform to an inclusive 15-minute city model, using fully-fledged and innovative mapping of proximity. This analysis aims to explore the resilience of urban resources to support walkable living environments with a guaranteed basic level of accessibility to daily needs by walking. The support to this model offered by soft mobility modes and micro-mobility devices is also raised. The results show, in a number of urban neighborhoods, a limited level of walkability although related to a spatial city structure which is able to be regenerated as a dense and effective network of 15-minute neighborhoods through tactical urbanism actions on existing open spaces and soft mobility policies, combined with long term strategies (infrastructure capacity and digital upgrading). It is a first methodological test which opens up the research towards a new inclusive concept of accessibility.
A significant cost of wildfires is the exposure of local and regional populations to air pollution from smoke, which can travel hundreds of miles from the source fire and is associated with ...significant negative health consequences. Wildfires are increasing in frequency and intensity in the United States, driven by historic fire management approaches and global climate change. These influences will take many decades or longer to reverse, so the main opportunities for mitigating health effects involve minimizing human exposure through changes in behavior or infrastructure. One key recommendation for reducing pollution exposures during wildfire smoke events is to limit time and physical activity outdoors, but there is limited evidence on the extent to which people make this change. We estimate how use of parks and playgrounds changes with air quality during wildfire season in the northwest United States. We find small reductions in park and playground visits on moderately polluted days, and large reductions, to 50–60% of baseline visits, when pollution levels are high. Disaggregating results by neighborhood characteristics, we find a significantly greater behavioral response to moderate levels of air pollution in neighborhoods with higher socio-economic status, although responses to high levels of pollution are similar across neighborhood types.
To investigate the combined effects of thermal, acoustic and visual comfort in open spaces, this study selected five typical spaces on a university campus with five common sounds (broadcasting music, ...running water & birdsong, wind (a gentle breeze) & insects, crowds, and machines) in a cold region of China. 418 volunteers were asked to complete a subjective sensory questionnaire in a randomly combined audio-visual environment while meteorological measures were taken on-site. Four primary outcomes emerged. First, broadcasting music improved individual subjective thermal comfort votes (TCV). Under the moderate heat stress (0.5 ≤ thermal sensation vote TSV ＜ 2.5), a comfortable acoustic environment helped reduce individuals' subjective TSV and increase TCV. Second, the subjective acoustic comfort vote (ACV) of broadcasting music, wind & insect sound and machine noise decreased with the increase of Universal Thermal Climate Index (UTCI); respondents perceived crowds, machines and wind & insects louder when TCV = 2 and −2. Third, under no thermal stress (−0.5 ≤ TSV ＜ 0.5)/moderate heat stress (0.5 ≤ TSV ＜ 2.5), TSV increased with increasing illumination intensity (LUX). Under the strong heat stress (2.5 ≤ TSV ≤ 3), there was no significant difference in TCV among subjective visual comfort vote (VCV) levels. Finally, when the LUX class was neutral/slightly bright, respondents felt darker in thermo-neutrality. Additionally, VCV and TCV were positively correlated under each LUX class.
Display omitted
•Combined effects of outdoor visual-acoustic-thermal comfort were investigated in Xi'an, China.•Broadcasting music was conducive to improving individual TCV.•Crowd and machine noise were louder when people felt thermally comfortable or uncomfortable.•Visual comfort did not affect TSV and TCV in a hot environment.•Respondents felt darker in thermo-neutrality when LUX was neutral/slightly bright.
PDF
