Urban Environmental Challenges Research Articles

Assessing the Feasibility of Removing Graffiti from Railway Vehicles Using Ultra-Freezing Air Projection

Unauthorised graffiti is a challenge in urban environments, affecting railway structures, stations, tracks, and vehicles. Inefficient cleaning methods increase the costs and downtime of railcars, limiting passenger transport. In turn, they are harmful to the operator’s health and the environment, due to the VOCs they release. This study focuses on the feasibility of dry-ice blasting, replacing carbon dioxide with ambient air as an innovative and sustainable solution to remove graffiti from rail vehicles. Experimental tests have been carried out with 13 different aerosols, controlling the temperature (<−80 °C), pressure (up to 3 bar), projection distance (0.5 cm) and exposure times (30″/1′/2′/4′/6′/8′/++). The results showed that ultra-freezing with ambient air preserved the integrity of the support materials and altered the topography, colourimetry and adhesion of the aerosols tested, achieving the total removal of one of the paints. Preliminary results suggest that ultra-freezing with ambient air could be a viable and sustainable solution for graffiti removal on railway structures, transferable to other urban environments.

Milder, wilder, drier: Understanding preferences for urban nature-based solutions in China

Nature-based solutions have gained recognition for their potential to address urban environmental challenges, particularly in rapidly urbanising countries such as China. However, financial and spatial constraints hinder their widespread adoption. Here we explore urban residents' preferences for nature-based solutions targeting stormwater management, urban heat island reduction, and biodiversity support through monetary, time, and space contributions. We carried out three choice experiment surveys with 1536 Chinese respondents, employing three payment vehicles: willingness to pay (WTP), willingness to contribute time (WTCT), and a novel metric, willingness to contribute space (WTCS). The WTCS metric assesses individuals' willingness to voluntarily convert sealed surfaces on private land into greenspace. We found strong preferences for temperature and flooding reduction across all payment vehicles, reflecting substantial challenges of urban heat islands and flooding in China. Additionally, we reveal a preference for moderate greenspace management intensity, highlighting the potential for biodiversity benefits through reduced management intensities. The introduction of the WTCS payment vehicle expands the methodological toolkit for choice experiments and offers a novel approach to assess citizen support for nature-based solutions. These findings have practical implications for designing effective nature-based solutions programs to address urban environmental challenges and meet the preferences of urban residents in China and beyond.

Strengthening graduate education and addressing environmental challenges through solutions-oriented partnerships and interdisciplinary training

Graduate students across disciplines are eager for experiential training that enables them to address real-world environmental challenges. Simultaneously, communities across the world face numerous environmental challenges, including increased frequency of extreme heat in summer and poor air quality, and could benefit from the expertise and engagement of graduate students with the requisite skills and interests to address these challenges. In this paper we bring together lessons learned from three interdisciplinary graduate training programs focused on preparing graduate students to contribute to urban environmental solutions by working in partnerships with non-academic organizations. We discuss the multiple elements required for partnerships to be mutually beneficial, including using a T-shaped approach to training that incorporates both depth and breadth while making strong efforts to broaden participation. We share lessons with the goal of enhancing graduate programs to improve training of students to address urban environmental challenges globally. This training aligns with the United Nations Sustainable Development Goal 17, “Partnership for the Goals,” which aims to achieve sustainable development goals through partnerships among entities.

Tackling Noise: Technology Integration for Improved Noise Pollution Monitoring.

Noise pollution derived from motor vehicles, especially those with noisy engines, constitutes a significant challenge in urban environments, impacting quality of life and public health. In this context, the present study focuses on the implementation of an advanced technological solution: a web-based system specifically designed to monitor and manage noise pollution in Tarapoto, Peru. The execution of this project was structured in 4 key phases. The first phase involved extensive data collection and definition of the project scope. In the second phase, the system architecture was established based on initial observations. The third phase focussed on evaluating and improving system functionalities, while the fourth involved rigorous testing and corrections. The successful implementation of this system led to a significant improvement in the noise pollution monitoring process, reducing reporting times and improving data-driven decision making. This project not only provides a valuable tool for authorities in the management and mitigation of noise pollution, but also encourages community awareness and active participation in the sustainable management of the urban acoustic environment.

Does smart city pilot improve green total factor productivity? Evidence from Chinese cities.

In recent years, the construction of smart cities has gradually become an effective means of addressing urban economic and environmental challenges. Based on panel data of 249 Chinese cities from 2005 to 2020, this study uses a super-efficiency epsilon-based measure model and a Malmquist-Luenberger index to calculate the urban green total factor productivity (GTFP). Using the smart city pilot as a quasi-natural experiment, the time-varying difference-in-difference (DID) method is applied to determine the causal effect of smart city pilot on GTFP. Results show that smart city pilot increases urban GTFP in China, and a series of robust analyses have verified the reliability of the results. The heterogeneity analysis results show that the smart city pilot policy has a more significant positive effect on urban GTFP in the eastern and central regions, the high population group, and the high per capita GDP group. The mediating analysis further suggests that smart city pilot positively affects technological innovations and human capital which promotes urban GTFP. These findings are of great significance for smart city construction and coordinating the relationship between urban economic development and environmental protection.

A lack of focus on data sharing, stakeholders, and economic benefits in current global green infrastructure planning

Green infrastructure (GI) is increasingly popular in solving urban environmental challenges and enhancing ecosystem services. Yet the research status and challenges of GI planning have not been comprehensively benchmarked to date. We explored the GI types, actions, goals, and spatiotemporal characteristics of GI planning cases worldwide based on the available literature. The challenges of GI planning were also investigated by the cases included in this manuscript. Additionally, the urban governance solutions to address these challenges were proposed. We found that multi-type GI planning is the most popular. Data sharing, stakeholder participation, economic benefits and research funding for GI planning research were generally inadequate, although they have improved trend over time. Multiple-goal GI planning frequently has higher levels of data sharing, stakeholder participation and economic benefits than GI planning that just takes into account one purpose. We conclude that the future transformation of GI planning requires efficient data sharing mechanisms, effective co-design among stakeholders, systematic business models, and available research funding.

The Situation of Speech and Language Disorders in Morocco: A Comprehensive Analysis of the RSK Region

This research delves into the nuanced dynamics of speech and language development disorders and academic achievement disorders, unveiling disparities across demographic, environmental, and age-related dimensions. A distinct urban-rural divide emerges, emphasizing the influence of environmental factors on prevalence rates. Individuals in urban settings face higher rates of disorders, necessitating tailored interventions acknowledging the unique challenges of urban environments. Conversely, rural populations demonstrate lower prevalence, urging policymakers to consider resource allocation and intervention strategies attuned to the specific needs of diverse locales. A crucial revelation is the heightened prevalence among individuals under 18 years old, underscoring the imperative for early intervention strategies. Early childhood programs and educational interventions prove pivotal, requiring customization to address the evolving needs of different age groups. Gender-specific considerations become evident, with males exhibiting a higher prevalence. Tailoring interventions to understand and address gender-specific factors is paramount for enhancing support systems and intervention effectiveness.

Improving the urban wind flow prediction efficiency of target area by considering its surrounding buildings impact

Rapid urbanization has caused various urban environmental challenges, including the emergence of urban heat island and air pollution. Urban wind flow is a crucial factor shaping the urban environment, which needs effective prediction and design. Computational fluid dynamics is commonly used for prediction and design of urban wind environment. However, high-accuracy simulation of wind flow, especially considering the layouts of full-scale and complex buildings, requires intensive computational resources. Typically, simulations simplify the surrounding building layouts (e.g., building layers) of target areas, potentially impacting simulation accuracy. It is imperative to determine appropriate building layers around different-scale target areas for effective wind flow simulation. This work explored the simulated wind flow characteristics of multi-scale (local, micro, and building-scale) target areas with different building layers defined as H, L, H/L, and L/H (H and L representing the vertical and horizontal maximum sizes of target area). The recommended building layers for local-scale, micro-scale, and building-scale target areas were at least 3L, 4H, and 5H, respectively, ensuing the relative errors between simulated and measured wind velocities remained below 20 %. This method largely reduced the calculation time by 73 % compared with full-scale simulation. This work can provide guidelines for fast prediction and design of urban wind environment, further promoting the sustainable development of urban cities.

Understanding the drivers of green roofs and green walls adoption in Global South cities: Analysis of Accra, Ghana

Green infrastructure alternatives such as green roofs and walls (GRGW) are part of nature-based solutions for managing complex urban environmental, health, and well-being challenges. The burgeoning acceptance of GRGW, particularly in the Global North, is primarily ascribed to the wide recognition of multiple social, economic, and environmental benefits. To promote more GRGW adoption in the Global South, it is essential to understand its driving forces. However, such studies remain limited. This study aims to identify the GRGW adoption drivers in Ghana. Fourteen key benefits of GRGW were identified from a literature review and a questionnaire survey (N = 505) of stakeholders from 14 groups across five strata in the Greater Accra Metropolitan Area of Ghana. The findings reveal that Ghana's top five GRGW adoption drivers are promoting health and well-being, improving air quality and carbon sequestration, contributing recreational and leisure functions, raising property value, and augmenting aesthetics. Stakeholders prioritized socio-cultural and amenity drivers. Stormwater and flood abatement was weakly endorsed as a significant driver despite Accra’s history of flooding. The t-test analysis confirmed that 12 out of the 14 drivers were statistically significant, while Kendall's W test showed fair consensus within the 14 diverse stakeholder groups in their rankings of the driving forces. This study improves GRGW research and development in understudied regions. It may act as a catalyst for the GRGW movement in Ghana and other developing economies.

Identifying Earthquakes in Low-Cost Sensor Signals Contaminated with Vehicular Noise

The importance of monitoring earthquakes for disaster management, public safety, and scientific research can hardly be overstated. The emergence of low-cost seismic sensors offers potential for widespread deployment due to their affordability. Nevertheless, vehicular noise in low-cost seismic sensors presents as a significant challenge in urban environments where such sensors are often deployed. In order to address these challenges, this work proposes the use of an amalgamated deep neural network constituent of a DNN trained on earthquake signals from professional sensory equipment as well as a DNN trained on vehicular signals from low-cost sensors for the purpose of earthquake identification in signals from low-cost sensors contaminated with vehicular noise. To this end, we present low-cost seismic sensory equipment and three discrete datasets that—when the proposed methodology is applied—are shown to significantly outperform a generic stochastic differential model in terms of effectiveness and efficiency.

Promoting Sustainable Urban Farming Through Plant Clinic Consultations on Car Free Days

In the face of rapid urban growth, this community service activity addresses the problem of decreasing green open land and the lack of awareness of sustainable agriculture. Activities carried out during the car-free day on Jalan Slamet Riyadi, Surakarta, involved a plant clinic, demonstrations of sustainable maintenance and distribution of seeds. The aim is to increase the understanding of urban communities about the importance of sustainable agriculture and provide practical guidance. Through direct interaction with experts and hands-on practice, these activities increase people's understanding and confidence in caring for plants. The distribution of seedlings also stimulates interest in gardening and an increase in greenery. The results of this dedication encourage active participation in urban farming, providing benefits to the environment and the community's quality of life. This activity confirmed that direct approaches with communities, through clinics, demonstrations, and active participation, effectively address urban environmental challenges and raise awareness of sustainable agriculture.

The effects of the natural visual-aural attributes of urban green spaces on human behavior and emotional response.

Nature-based solutions (NBS) have been used to address a wide range of urban environmental challenges, an important aspect of which is to improve human health and well-being. However, most relevant studies focus either on what positive influences nature may have or on identifying what natural factors can have these benefits. Few have investigated the sensory composition of nature and the effects of nature in different sensory aspects on human health. Setting out from the multi-sensory perspective, this study aims to explore human behavior and emotional response from visual and aural contact with urban nature. Taking Jiangjia Art Garden in Chengdu as an example, natural attributes such as its visual (landscape) and aural (sound source) characteristics as well as people's activities (behavioral responses) were measured by on-site mapping analysis. This was done while a questionnaire-based survey was conducted to investigate people's emotional responses regarding their overall satisfaction, pleasantness, calm, and agreeableness. The results indicated that nature-dominated visual landscapes such as grassland, waterscapes, and woodlands, as well as natural sounds such as bird sounds, chirp sounds, and wind sounds were found to be positively correlated to the vitality of activities and people's emotional status. Regarding behavioral responses, it was shown that grasslands and woodlands are more likely to be attractive places for recreation, and the vitality measured became extremely high when these two were paired with lakes. As for the emotional responses, people's perceived overall satisfaction, calm, and agreeableness were equally reflected in their behavioral patterns, suggesting a strong relationship with natural factors. The research findings were visually presented in behavior and emotional maps to provide direct cues of informing the future design of high-quality urban green spaces and promoting the application of aural-visual experience in the design of urban nature areas.

A new GNSS outlier mitigation method for GNSS/INS integrated system

High-precision positioning with global navigation satellite systems (GNSS) remains a significant challenge in urban environments, due to the outliers caused by the insufficient number of accessible satellites and environmental interference. A GNSS outlier mitigation algorithm with effective fault detection and exclusion (FDE) is required for high-precision positioning. The traditional methods are designed to deal with zero-mean noise in GNSS, which leads to instabilities under biased measurements. Considering that GNSS data are typical time series data, a dynamic FDE scheme is constructed by combining a prediction-model-based method and a dissimilarity-based method. First, a hybrid prediction model which combines autoregressive integrated moving average (ARIMA) model and multilayer perceptron (MLP) model is proposed to provide pseudo-GNSS series by predicting the vehicle’s location for several future steps. Then, a dissimilarity-based method of dynamic time warping measure is utilized to analyze the pairwise dis-similarity between the pseudo-GNSS series and the received GNSS series. The performance of the different models in forecasting is evaluated, and the results show that the positioning accuracy is significantly improved by applying the ARIMA-MLP. The effectiveness of the proposed FDE method is verified through simulation experiments and real experiments based on a typical urban canyon public dataset collected in Tokyo.

Drought Stress Responses of Some Prairie Landscape C4 Grass Species for Xeric Urban Applications

Creating xeric landscapes in lawns and prairies is a significant challenge and practical need in arid urban environments. This study examined the drought resistance of some C4 grass species for constructing urban lawns and prairies. A factorial experiment based on randomized complete block designs with four replications was conducted. Experimental treatments were two irrigation levels (100% and 50% Field Capacity (FC)) and five warm-season grass species (Andropogon gerardii Vitman, Sorghastrum nutans (L.) Nash, Panicum virgatum L., Schizachyrium scoparium (Michx.) Nash, and Bouteloua curtipendula (Michx.) Torr.). The effects of drought on physiological, morphological, and qualitative characteristics of the grass species were analyzed. Drought conditions induced a decrease in all the measured traits. However, fewer physiological, morphological, and qualitative characteristics were affected by drought stress on Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, compared to the other two species. Overall, warm-season grasses of Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, had greater adaptability to drought stress, making them promising C4 grass species for prairie or lawn landscaping in arid urban environments. Landscape professionals and decision-makers should consider using Andropogon gerardii, Schizachyrium scoparium, and Bouteloua curtipendula, as these were the most resilient grass species for drought-tolerant prairie landscaping schemes. Sorghastrum nutans and Panicum virgatum may be used as a second priority if a more diverse variety of grasses is required for drought-resilient prairie or lawn landscaping in arid cities.

Resilient Pseudorange Error Prediction and Correction for GNSS Positioning in Urban Areas

Positioning, navigation and timing (PNT) is essential for internet of things (IoT) communications and location-based services. Although GNSS can provide accurate PNT in open areas, obtaining reliable PNT is still a considerable technical challenge in complex urban environments. This is because the GNSS signals are more likely to be affected by multipath interference and non-line of sight (NLOS) reception issues arising from the obstructions and reflections in built environments. These introduce range measurement errors that degrade the GNSS positioning accuracy. This paper proposes two resilient pseudorange error prediction and correction strategies to improve the GNSS positioning accuracy in urban environments. In particular, considering the carrier-to-noise density (C/N0), satellite elevation angle and local positional information, the random forest based pseudorange error prediction and correction models are constructed in two variations, including: 1) the point-based correction (PBC), and 2) the grid-based correction (GBC). The final improved positioning solution is then calculated by using the least square method (LSM) of the corrected pseudoranges. Kinematic test results in urban environments show that both variations of the proposed model can improve the positioning accuracy by 42.9% and 40.8% in horizontal, and by 60.1% and 63.3% in 3D, respectively, compared to the positioning results obtained by traditional method without pseudorange error corrections. The improvements are 41.1% and 38.9% in horizontal, and 45.7% and 50.0% in 3D, respectively, compared with traditional elevation angle weighting method.

Innovations in Utilizing Public Open Space in Sustainable Development

In this era, cities and urban spaces face social and environmental challenges that endanger their sustainability. These challenges are the result of years of development based solely on the economic dimension, where natural resources are exploited in an unsustainable way. The purpose of this study is to find out how innovations are used in the use of public open space from the perspective of sustainable development in Majalengka district. This study uses a descriptive qualitative approach, with secondary data collection and literature study as well as primary data taken by means of interviews with officials or authorized staff at the relevant agencies. The sampling technique used in this study was purposive sampling. The results of the research showed that the Department of the Environment, Cleanliness, and Landscaping in Majalengka Regency has several innovative products, both in the form of public goods and public services. The economic sustainability felt by visitors is almost nonexistent, because a lot of economic sustainability is felt by the surrounding community as traders, street vendors (PKL), and parking attendants.
 Keywords: urban spaces, Majalengka regency, innovative products

Evaluation and Validation of Microscale Atmospheric Modeling With Offline Weather Research and Forecasting Model to Parallelized Large-Eddy Simulation Model Forcing Conditions

Abstract As the rate of urbanization increases, local vegetation is being replaced with man-made materials, causing increasingly adverse impacts on the surface-atmosphere energy balance. These negative effects can be simulated by modeling the urban landscapes in question; however, the main challenges of modeling urban thermal environments are the scale and resolution at which to perform such tasks. Current modeling of urban thermal environments is typically limited to either mesoscale (1 –2000 km) or microscale (<1 km) phenomena. In the present work, an open-source framework for one-way upstream coupled multiscale urban thermal environment simulations is examined and validated. This coupled simulation can provide valuable insights into the flow behavior and energy transport between mesoscale and microscale interactions. The mesoscale to microscale boundary conditions are coupled together using simulated data from the advanced research weather research and forecasting model (WRF-ARW), a mesoscale numerical weather prediction software, and assimilating it into parallelized large-eddy simulation model (PALM), a computational fluid dynamics style (CFD-style) software designed for microscale atmospheric and oceanic flows. The multiscale urban thermal environment simulations are tested for grid sensitivity to variations in model input and control parameters, and then experimentally validated against distributed sensor measurements at the Georgia Institute of Technology (Georgia Tech) campus in Atlanta, GA. Validated microscale atmospheric models with heterogeneous domains can be used to project the thermal benefits of urban heat mitigation strategies (increase use of high-albedo surfaces, tree and vegetation cover, and smart growth practices) and advise building energy usage modeling and policies.

Smart-BIM for Smart Cities: Issues and Challenges

Building Information Modelling (BIM) is implemented in several sectors of the Architecture, Engineering, and Construction (AEC) industry. Faced with the challenges of urban management, smart cities are a response to this situation. Research indicates that BIM is one of the technological approaches with great potential for designing, constructing, and managing smart cities. Despite too few systematic reviews, this paper aims to highlight the potential, opportunities, and challenges of integrating BIM into the smart city environment through a literature review. Based on this review, a classification of issues, trends, and challenges has been made. The paper reveals current research gaps and possible future work in smart city management through information technology, specifically BIM. The focus of this paper contributes to the understanding and promotion of technology for smart cities to address the cumulative challenges of urban environments.

Utilizing green roofs to mitigate urban environmental challenges: application to Mashhad Metropolitan Area

Utilizing green roofs to mitigate urban environmental challenges: application to Mashhad Metropolitan Area

Urban environmental challenges associated with dynamics of slum settlement

The urban environmental quality is one of the major issues which need immediate attention as it has direct impact on the human life around the globe. The growing population in the urban areas has put a pressure on the housing sector, which leads to slum formation, and the decreased environmental quality due to it. The urban system cannot be imagined without the slums as these are inexorable part of urban areas, especially in the developing nations. There is a direct association between the complex spatial arrangement and the socio-economic fabric of the slum dwellers. In the present study, the statistical analysis has been performed to establish the interrelation between the determinants of social and economic status of the slum dwellers, and the air quality. Further, the space syntax analysis on the selected case has been performed to understand the spatial dynamics and its interrelation with the socio-behavioural pattern of the slum in the study area of Patna city. The present investigation advocated to improving the quality of slum settlements for improving the quality of the environment.