JBI Evidence Implementation

This study explored the association between greening and social capital in neighborhoods, considering demographics and zoning by urban planning. The target area encompassed the urban areas of Kyoto City, Japan, which has a long tradition of landscape policy and neighborhood associations. Greening was evaluated using two automated methods: 1) horizontal green coverage of the land was calculated via the Normalized Difference Vegetation Index in satellite images, and 2) green visibility in streetscape from a human perspective was estimated by combining Google Street View images and a machine learning model. Public government data were used for demographics and zoning, and social capital was evaluated using survey data from the local government. After performing the elastic net models, variables that had explanatory power for each greening index were selected. Similar reasonable associations were found for each of the indices with the zoning categories. However, for both zoning and demographics, different variables were selected. Importantly, the social capital variable was selected only for the green visibility in streetscape, showing a negative correlation between them, unlike in previous studies. These results suggest that the association between urban greening and social relationships can change depending on the context of the target regions and measurements of greening.

Urban heat island (UHI) and nitrogen dioxide (NO2) concentration in the air are two significant health hazards arising from urbanization. While much research has focused on the local urban context and micro-conditions for sources and exposures in particular case-studies, the effect of the overall level of urban agglomeration, as measured by population size, remains underreported. We compile the literature that explicitly discusses the relationship between UHI or NO2 and population size. We synthesize methods and findings qualitatively, then perform a quantified meta-analysis using comparable data from the corpus. We find that the corpus from which population size effects can be retrieved is very thin given the level of urbanization trends and the health impact. Despite a variety of functional specifications, data gathering processes, and metrics, the literature generally agrees on a significant effect of population size on both UHI and NO2. After pooling data we estimate that each 10-fold increase in population, increases the temperature gap between the city and countryside by almost 2 °C or a 40 % increase when cities get very large. We find that NO2 scales similarly, with a 40 % increase in concentration each time the city population is multiplied by 10. These numbers represent very important health threat given the current urbanization rate and the distribution of city population sizes. We also call for more studies to be conducted, across larger sets of cities, using observed data at higher resolution and comparable city definitions.

Urbanization has resulted in a significant accumulation of waste in densely populated areas. Effective household waste separation practices within urban areas are crucial for advancing the concept of circular economy. The informal system has contributed remarkably to urban material circulation, but it has not been appropriately valued. Through the partnership among the municipal solid waste authorities, condominium building residents, and waste pickers, the latter can be engaged in the community to assist in household waste separation. This initiative would not only enhance their income and reduce probable occupational risks but also augment the recycling rate in the community. Based on the insights from the current waste picker assignment policy in Taichung City, this study has established a mathematical programming model by considering the overall waste separation volume and proximal distance to the neighborhood, facilitating the assignment of individual waste picker to multiple communities within the neighborhood area. Consequently, concerned waste pickers may increase their income and avoid the constraints of picking up recyclables in high-occupational-risk areas. Additionally, it may reduce the volume of unsorted garbage in the community. According to the findings of case studies, the developed model could obtain an optimal solution or acceptable approximate solution in a short timeframe. In contrast to the outcomes from the existing waste picker assignment policy, the application of the developed model could increase the total volume of sorted recyclables, which was directly proportional to the income of waste pickers, by 2.3 to 2.6 times.

The 6th assessment report by IPCC underscores the necessity to switch from immediate to timely actions to foster (urban) climate change adaptation and mitigation. Green areas such as tactical urban parks could represent a strategic asset towards healthier and more sustainable cities and societies. Specifically studied greenery may indeed improve local microclimate and air quality conditions, supporting the socio-ecological resilience of cities while enhancing social interactions. Using a multidisciplinary approach, this study aims to evaluate the environmental quality and local community needs of a neighbourhood located near the historic centre of Perugia (Italy) to provide guidelines for its requalification, especially for outdoor spaces. To achieve this goal, the study conducted dedicated environmental monitoring, demonstrating the massive thermal behavior differences (by about 5K in summer) within the same urban area all over the year, and carried out surveys campaigns focusing on outdoor perceptions and needs reported by the local community. The results confirm that local residents mainly use the area as a thoroughfare to access established activities by car (63% of respondants), leading to high vehicular traffic and pollutants emissions during peak hours, with PM10 concentration peaks reaching 55 μg/m3 and 180 μg/m3 close to the parking lot in winter and spring, respectively. An effective intervention was recognized in the introduction of furniture in the area, creating attractive places to spend the lunch break, enabling people to enjoy the outdoors and maximize thermal comfort benefits. Moreover, reducing vehicular traffic and fostering slow mobility also demonstrated to be attractive measures to improve comfort, health and well-being and reduce negative consequences on air quality.

As summer heat events cause a further increase of heat load in buildings, the need for indoor overheating assessment by building performance simulations (BPS) for planning is rising. Besides other boundary conditions, the selection of proper weather data is known to significantly influence the outcome of overheating evaluation. Our research pointed out that current standards do not consider weather data including regional differences, urban climate effects or future climate in a sufficient way. We suggest a new approach to create weather data sets for an average present and an average future summer based on meteorological data from weather stations. Therefore, we define characteristic summer values as indicators. In addition, urban climate is taken into account by mapping the outdoor temperature differences between urban areas and surrounding countryside using Local Climate Zones. We analyse the developed weather data sets for four regions in Germany by comparing the indoor overheating risk by BPS for an exemplary building. The results show that the overheating risk differs significantly between the regions. It is very low for the region of Hamburg, moderate for Dresden and Potsdam and highly critical for Stuttgart. The indoor heat load is at least more than doubled if the building is located in the city centre instead of its surroundings or if future climate conditions are applied. Furthermore, high night-time outdoor temperatures appear to significantly increase indoor overheating. Our approaches are first suggestions and show the relevance of regional and urban climate for indoor overheating assessment by BPS.