Urban Environmental Health Research Articles

Multi-stage resilience analysis of the nexus flood-sanitation-public health in urban environments: a theoretical framework

ABSTRACT Water supply and wastewater systems are essential infrastructure affected by floods. Additional risk is posed in developing countries, where access to sanitation is not universal. Few studies assess the flood risk to the sanitation-health nexus. Therefore, this study aims to present a theoretical and general framework for assessing the resilience of flood-sanitation-public health nexus in urban environments, composed by risk estimation and risk management assessment. The framework was developed from a system analysis approach focusing on central supply systems. Regarding risk assessment, the main vulnerability and exposure factors identified were land use, social vulnerability, coverage of sanitation systems, occurrence of waterborne diseases, number of people affected by floods and intersection with the flood map. From the risk management assessment stage three main typologies of trade-offs and synergies were identified: urban territorial planning versus runoff control, water quality versus sanitation infrastructure and flood management policy versus social behavior.

Small-sized microplastics (< 500 μm) in roadside soils of Beijing, China: Accumulation, stability, and human exposure risk

The potential threats of microplastics (MPs) to human health in urban environment have received increasing attention. Small MPs substantially threaten soil organisms and human beings because they are easily ingested and may adsorb other pollutants to form composite compounds. However, roadside soils as a source and a sink of small MPs in urban environments have not been reported. Here, we studied the small-sized MPs (SMPs, < 500 μm) pollution and human exposure analysis by investigating the MPs in roadside soils in Beijing. SMPs contributed to 88.06% of the high average MPs abundance (22001.67 ± 24482.34 items/kg), and were categorized as uncontaminated to moderately contaminated, assessed by the geo-accumulation index (Igeo). SMPs mainly consisted of polypropylene (PP) and polyethylene (PE) with morphotypes of fragment and granule. In particular, highly stable and fragmented MPs were discovered by the conditional fragmentation model. And normal-sized MPs (NMPs 500–5000 μm) NMPs could further fragment into SMPs, indicating that SMPs in roadside soil were further enriched. The estimated infant exposure to SMPs was greater than that in adults, and independent of the polymer types and morphotypes. PP is currently the main pollutant, contributing 65% to the estimated human exposure. Combining the conditional fragmentation model and main polymer types, SMPs likely derived from containers/packaging and fertilizers, and affected by atmospheric transport. This study demonstrated the dominance and potential risk of SMPs in roadside soil, suggesting that health risk assessment for SMPs in urban environment necessitates critical investigation.

Research on health promotion strategies of public recreation space in the coastal area of Qingdao City Center, China

After the outbreak of the pandemic, people's travel and outdoor activities have been restricted or hindered, and urban environmental health has become the topic of most public concern. With the widespread of vaccination and the reduction of urban control, people's enthusiasm for travel has been released again, healthy urban life has gradually become the focus of the post-pandemic era. The coastal recreation space is rich in blue and green landscape resources and has good health benefits. It is a high-quality urban environment for traveling and outdoor sports. Based on a multidisciplinary perspective, this article proposes the relationship between coastal recreation space and people's health life and the changes of traditional recreation space in the post-pandemic era. The coastal recreation space in Qingdao city center is selected as a case, the popular routes of recreation APPs are selected as samples. The article uses SPSS to analyze the current space issues, and studies the strategies for promoting urban environmental health in coastal public recreation space, in order to improve the quality and efficiency of people's healthy life in the post-pandemic era.

Rethinking walkability and developing a conceptual definition of active living environments to guide research and practice

BackgroundWalkability is a popular term used to describe aspects of the built and social environment that have important population-level impacts on physical activity, energy balance, and health. Although the term is widely used by researchers, practitioners, and the general public, and multiple operational definitions and walkability measurement tools exist, there are is no agreed-upon conceptual definition of walkability.MethodTo address this gap, researchers from Memorial University of Newfoundland hosted “The Future of Walkability Measures Workshop” in association with researchers from the Canadian Urban Environmental Health Research Consortium (CANUE) in November 2017. During the workshop, trainees, researchers, and practitioners worked together in small groups to iteratively develop and reach consensus about a conceptual definition and name for walkability. The objective of this paper was to discuss and propose a conceptual definition of walkability and related concepts.ResultsIn discussions during the workshop, it became clear that the term walkability leads to a narrow conception of the environmental features associated with health as it inherently focuses on walking. As a result, we suggest that the term Active Living Environments, as has been previously proposed in the literature, are more appropriate. We define Active Living Environments (ALEs) as the emergent natural, built, and social properties of neighbourhoods that promote physical activity and health and allow for equitable access to health-enhancing resources.ConclusionsWe believe that this broader conceptualization allows for a more comprehensive understanding of how built, natural, and social environments can contribute to improved health for all members of the population.

Coupling Ecological Security Pattern Establishment and Construction Land Expansion Simulation for Urban Growth Boundary Delineation: Framework and Application

Reasonable delineation of the urban growth boundary (UGB) plays a vital role in guiding orderly urban space growth and ensuring urban environmental health. Existing methodologies for UGB delineation have failed to address the significance of ecological security. Therefore, this study presents a framework that couples ecological security pattern (ESP) establishment and construction land expansion (CLE) simulation to delineate the UGB. The proposed framework is applied to the Nanchang Metropolitan Area (NCMA) in southeastern China. First, we established the regional ESP of the NCMA in 2018 based on an improved minimum cumulative resistance model. The areas of low-, medium-, and high-level ESP were 1050.75, 736.42, and 720.59 km2, respectively. Second, we implemented a multi-scenario simulation of CLE in the NCMA in 2025 based on a cellular automata–Markov model. A natural development scenario was superior to urban growth and ecological protection scenarios for social, economic, and ecological development at the regional scale. Accordingly, we delineated the UGB of the NCMA in 2025 with a scale of 687.87 km2, based on dynamic adjustment using the results of ESP establishment and CLE simulation in the natural development scenario. The rationality and scientificity of the proposed framework were verified by comparing the scale and layout of the delineated UGB with the regional planning of Nanchang City. The framework incorporating dynamic adjustment with ESP establishment and multi-scenario CLE simulation provides a useful tool for the delineation of the UGB in similar urbanized cities. Its application is conducive to achieving a win–win outcome of regional ecological security and urban development.

Numerical Study on Microclimate and Outdoor Thermal Comfort of Street Canyon Typology in Extremely Hot Weather—A Case Study of Busan, South Korea

As cities are extremely vulnerable to the impacts of climate change, they are fundamental in addressing these changes. However, streets, which are external spaces accessed by citizens in daily life, play an important role in improving the urban environment and public health. This study considered Busan in South Korea as a case study to investigate street canyons, including street canyon geometries and tree configurations, of old, present, and new city centers. The influence of morphological factors on the microclimate and outdoor thermal comfort was evaluated using the ENVI-met program for extremely hot weather. Changes in the street width, street orientation, and street canyon aspect ratio had a significantly higher impact on the microclimate and thermal comfort index (p &lt; 0.01). These results indicated that the orientation of the main street should be consistent with the prevailing wind direction of Busan. Further, the shading of adjacent buildings improved the outdoor thermal comfort and reduced the significance of tree configuration in deeper street canyons. In addition, tree height had a more significant impact on street environment than other tree configuration factors, especially when the tree height increased from 9 m to 12 m. We recommended that the thermal comfort level can be improved by dynamically adjusting the relationship between the planting distance and tree height in streets having shallow street canyons.

Oxidative damage prevention in human skin and sensory neurons by a salicylic acid derivative

BackgroundIncreased protein carbonylation is a hallmark of oxidative stress, protein homeostasis dysregulation and aging in the nervous system and skin. Sensory neurons interact with skin cells and are involved in skin homeostasis. We have previously reported that the 5-octanoyl salicylic acid (C8-SA), a salicylic acid derivative, increased C. elegans lifespan and delayed the accumulation of carbonylated proteins, through the stimulation of autophagy. ObjectivesIn this study we aimed to investigate if C8-SA protects human sensory neurons and human skin from extrinsic oxidative stressors as an approach to delay skin aging. MethodsIn vitro reconstituted human epidermis innervated with hiPSc-derived human sensory neurons, as well as ex vivo human organotypic full skin models were used. The fully differentiated sensory neurons were pretreated with C8-SA before oxidative stress induction. Skin explants were maintained in culture and treated topically with C8-SA before the application of urban pollutants. Carbonylated proteins were detected using amino-oxy functionalized fluorophores and quantified. Chaperone mediated autophagy was monitored with LAMP2A immunofluorescence. Inflammation, ROS detoxification and autophagy were assessed by RT-PCR. ResultsC8-SA prevented the accumulation of carbonylated proteins, both in human sensory neurons and skin explants. C8-SA stimulated chaperone-mediated autophagy and modulated NRF2 antioxidant response genes, as well as catalase enzymatic activity. ConclusionsC8-SA acts at two levels to protect skin against oxidative stress: 1) it prevents protein oxidation by stimulating endogenous antioxidant defense and 2) it increases the clearance of oxidized proteins by stimulating chaperone-mediated autophagy. These results suggest that C8-SA maintains skin health in urban polluted environments.

Mycorrhizal Infection Can Ameliorate Abiotic Factors in Urban Soils.

Once abandoned, urban and post-industrial lands can undergo a re-greening, the natural regeneration and succession that leads to surprisingly healthy plant communities, but this process is dependent upon microbial activity and the health of the parent soil. This study aimed to evaluate the effects of arbuscular mycorrhizal fungi (AMF) in facilitating plant production in post-industrial soils. In so doing, we helped to resolve the mechanism through which AMF ameliorate environmental stress in terrestrial plants. An experiment was established in which rye grass (Lolium perenne) was grown in two heavy metal-contaminated soils from an urban brownfield in New Jersey, USA, and one non-contaminated control soil. One set of the treatments received an AMF inoculum (four species in a commercial mix: Glomus intraradices, G. mosseae, G. etunicatum and G. aggregatum) and the other did not. Upon harvest, dried plant biomass, root/shoot ratio, AMF colonization, and extracellular soil phosphatase activity, a proxy for soil microbial functioning, were all measured. Plant biomass increased across all treatments inoculated with AMF, with a significantly higher average shoot and root mass compared to non-inoculated treatments. AMF colonization of the roots in contaminated soil was significantly higher than colonization in control soil, and the root/shoot ratio of plants in contaminated soils was also higher when colonized by AMF. Mycorrhizal infection may help plants to overcome the production limits of post-industrial soils as is seen here with increased infection and growth. The application of this mechanistic understanding to remediation and restoration strategies will improve soil health and plant production in urban environments.

Generating 2m fine-scale urban tree cover product over 34 metropolises in China based on deep context-aware sub-pixel mapping network

Contrast to the global forest, few trees live in cities but contribute significantly to urban environment and human health. However, the classical satellite-derived land cover/forest cover products with limited resolution are not fine enough for the identification of urban tree, which is usually appeared in small size and intersected with infrastructure. To relieve the dilemma, this study developed an urban tree specific sub-pixel mapping (SPM) architecture with deep learning approach, which aimed to generate 2m fine-scale urban tree cover product from 10 m Sentinel-2 images for large-scale area of 34 metropolises in China. The proposed approach has remarkable reconstruction ability for delineating the contextual characteristic of the urban tree patterns, and reliable generalization ability to large-scale area. In addition, this study creates a large-volume urban tree cover dataset (UTCD) with 0.13 billion urban tree samples at 2 m resolution, which fills the deficiency of standard dataset in urban tree cover research field. Quantitative analysis of our products was conducted on two typical study sites of Beijing and Wuhan. The results show that our products recover averagely more than 58.72% of urban tree covers that have been underestimated in the existing land cover/forest cover products, and outperforms the state-of-the-art approach both visually and quantitatively, by averagely 11.31% improvement in overall accuracy. From our annual products during 2016–2020, we found an evolution characteristic of urban tree cover: it is more stable in developed cities like Beijing, while more fluctuated in developing cities like Wuhan, and the alteration are usually concentrated at the outer-ring of downtown, which may be caused by the municipal planning and the land development of real estate industry.

Usefulness of Tree Species as Urban Health Indicators.

We used the Air Pollution Tolerance Index (APTI), the amount of PM5 and PM10, and the elemental analysis of leaves to explore the sensitivity of tree species to air pollution. We assessed the tolerance of Robinia pseudoacacia, Acer saccharinum, Tilia × europaea, Acer platanoides, Fraxinus excelsior, Betula pendula, Celtis occidentalis, and Platanus × acerifolia to the amount of dust, APTI, and the elemental concentration of leaves. Leaves were collected in Debrecen (Hungary), which has a high intensity of vehicular traffic. The highest amount of PM (both PM10 and PM5) was found on the leaves of A. saccharinum and B. pendula. Our results demonstrated that A. saccharinum was moderately tolerant, while P. acerifolia was intermediate, based on the APTI value. There was a significant difference in the parameters of APTI and the elemental concentration of leaves among species. We found that tree leaves are reliable bioindicators of air pollution in urban areas. Based on the value of APTI, A. saccharinum and P. acerifolia, and based on PM, A. saccharinum and B. pendula are recommended as pollutant-accumulator species, while other studied species with lower APTI values are useful bioindicators of air pollution. The results support landscape engineers and urban developers in finding the best tree species that are tolerant to pollution and in using those as proxies of urban environmental health.

The acoustic quality and health in urban environments (SALVE) project: Study design, rationale and methodology

Sound pressure levels expressed in variations of decibel (dB) formulations are a common approach to describe the urban acoustic environment (AE) in regard to noise and health exposure. However, as noise descriptors mainly focus on sound pressure level, further concepts are needed to analyze the effects of the AE on human health. In recent years, different approaches to describe the AE have gained traction, like the soundscape ecology approach that focuses on sound in the natural environment. To determine the feasibility of applying this approach to cities, a comprehensive dataset of high-quality sound recordings with high spatial and temporal resolution is essential.The acoustic quality and health in urban environments (SALVE) project aims to establish a spatially and temporally high-resolution dataset of the urban AE to connect it to human health as well as to the built environment. Since 2019, we have assessed the AE at selected places in the densely populated city of Bochum, Germany. For a high temporal resolution, we used automatic devices at 52 locations that recorded every 26 min for three minutes. For a high spatial resolution, we used manual devices to perform a five-minute recording four times a year at 730 selected locations. So far, we sampled 1,500,493 min of sound recordings. Comprehensive health data used were already available from the ongoing epidemiological Heinz Nixdorf Recall Study, in the Ruhr Area, Germany.The aim here is to outline our sampling design, methods used, and applied quality procedures in order to achieve a well-defined and high-quality dataset. To the best of our knowledge, our study provides one of the most extensive datasets currently available. This will allow for the next steps, analyzing in-depth associations between the urban AE, urban fabric and human health.

Pollution characteristics, spatial distribution, and source identification of heavy metals in road dust in a central eastern city in China: a comprehensive survey.

Road dust enriched with heavy metals (HMs) is detrimental to ecosystems and human health in urban environments. In this study, it is to explore the concentrations, spatial distribution, contaminated levels, and source identification of six HMs (lead (Pb), zinc (Zn), copper (Cu), cobalt (Co), chromium (Cr), and nickel (Ni)) based on 130 road dusts in Xinyang urban area. The results indicated that the contents of Pb, Zn, Cu, and Co were higher than the background values in more than 99% of the samples, and their average concentrations were 15.2, 9.2, 8.6, and 6.3 times the background value, respectively. The spatial distribution of high-value areas for Pb, Zn, Cu, Cr, and Ni was more similar, which was associated with traffic density near major roads and population and settlement patterns. Co was relatively different from the five elements, which was distributed in the areas of residence, commerce, and industry. Furthermore, the investigated HMs were clearly polluted, with Pb, Zn, Cu, and Co indicating high levels of contamination, while Cr and Ni were moderately polluted. The comprehensive pollution of the six HMs was mostly moderate to heavy in this study. Moreover, three sources of HMs designated by correlation analysis (CA) and principal component analysis (PCA) were mixed traffic emissions and industrial waste for Cu and Cr; automotive emissions for Pb, Ni, and Zn; and mixed domestic waste and industrial activities for Co, with contributions of 42.3%, 46.4%, and 11.3% via the principal component analysis-multiple linear regression (PCA-MLR) model. The multi-factor index for pollution assessment combined with source identification is extremely effective and practical for providing reliable data support and a theoretical reference for pollution monitoring and governance.

Empirical Coastal Atmospheric Corrosion of Masonry Metal Wall Ties

Not counting domestic dwellings, it has been estimated that in Australia alone, some tens of thousands of masonry buildings and structures have exceeded their design life, with many of these being at risk of partial (or worse) collapse from falling or dislodged masonry. This has significant implications for human life but also for the urban environment and economic health of building owners, managers, and insurers and for local and national economies. This risk can mainly be attributed to the slow deterioration of masonry under atmospheric and other environments and the corrosion of so-called wall ties. Wall ties are relatively thin pieces of steel that tie the outer leaf of masonry walls to the stabilized inner leaf. The problem is likely severe for scenarios such as cyclonic and earthquake events, as they cause area-wide damage and the potential wide-spread loss of human life—losses that could be prevented by timely intervention. This paper reports on the in situ inspection of two case study buildings and the data obtained from controlled wall tie corrosion field trials, which are used to develop predictive models of structural response. These models will inform practical tools that will be developed for building assessment, cost-effective monitoring, and rectification, assisting in the management of existing masonry buildings.

Extending Our Scientific Reach in Arboreal Ecosystems for Research and Management

The arboreal ecosystem is vitally important to global and local biogeochemical processes, the maintenance of biodiversity in natural systems, and human health in urban environments. The ability to collect samples, observations, and data to conduct meaningful scientific research is similarly vital. The primary methods and modes of access remain limited and difficult. In an online survey, canopy researchers (n = 219) reported a range of challenges in obtaining adequate samples, including ∼10% who found it impossible to procure what they needed. Currently, these samples are collected using a combination of four primary methods: (1) sampling from the ground; (2) tree climbing; (3) constructing fixed infrastructure; and (4) using mobile aerial platforms, primarily rotorcraft drones. An important distinction between instantaneous and continuous sampling was identified, allowing more targeted engineering and development strategies. The combination of methods for sampling the arboreal ecosystem provides a range of possibilities and opportunities, particularly in the context of the rapid development of robotics and other engineering advances. In this study, we aim to identify the strategies that would provide the benefits to a broad range of scientists, arborists, and professional climbers and facilitate basic discovery and applied management. Priorities for advancing these efforts are (1) to expand participation, both geographically and professionally; (2) to define 2–3 common needs across the community; (3) to form and motivate focal teams of biologists, tree professionals, and engineers in the development of solutions to these needs; and (4) to establish multidisciplinary communication platforms to share information about innovations and opportunities for studying arboreal ecosystems.

Leisure sedentary time and physical activity are higher in neighbourhoods with denser greenness and better built environments: an analysis of the Canadian Longitudinal Study on Aging.

Associations of environmental variables with physical activity and sedentary time using data from the Canadian Longitudinal Study on Aging, and the Canadian Urban Environmental Health Research Consortium (Canadian Active Living Environments (Can-ALE) dataset, and Normalized Difference Vegetation Index (NDVI, greenness) dataset) were assessed. The main outcome variables were physical activity and sedentary time as measured by a modified version of the Physical Activity for Elderly Scale. The sample consisted of adults aged 45 and older (n = 36 580, mean age 62.6 ± 10.2, 51% female). Adjusted ordinal regression models consistently demonstrated that those residing in neighbourhoods in the highest Can-ALE category (most well-connected built environment) reported more physical activity and sedentary time. For example, males aged 75+ in the highest Can-ALE category had 2 times higher odds of reporting more physical activity (OR = 2.0, 95%CI = 1.1-3.5) and 1.8 times higher odds of reporting more sedentary time (OR = 1.8, 95%CI = 1.0-3.4). Neighbourhoods with higher greenness scores were also associated with higher odds of reporting more physical activity and sedentary time. It appears that an environment characterized by higher Can-ALE and higher greenness may facilitate physical activity, but it also facilitates more leisure sedentary time in older adults; research using device measured total sedentary time, and consideration of the types of sedentary activities being performed is needed. Novelty: Middle-aged and older adults living in neighbourhoods with higher Can-ALE scores and more greenness report more physical activity and leisure sedentary time Greenness is important for physical activity and sedentary time in middle-aged adults.

Navigating to urban environmental health: Professionalized and personalized healthy living assistant based on intelligent health risk management

Facing unbalanced and inadequate urban development, the environmental health risk management (EHRM) try to provide an unbiased scientific assessment and control of risk posed by specific hazards. Shortage of personal exposure scenarios and parameters, dynamic multimedia environment pollution data, multi-target applications, etc. make challenges in current EHRM. The booming smart phone, Internet plus and Internet of things (IoT) technologies provide cost-efficient opportunities for above challenges. Hence, the “EnvironMax” framework, namely a “4M” (multi-scale, multimedia, multi-exposure, multi-target) environmental health risk monitoring & management system, is proposed. EnvironMax is composed of the environmental multimedia data source layer, communication and preprocessing layer, cloud-based environmental health brain layer, and user-oriented healthy living assistant layer. Multi-source data (mainly including Portable IoT + Location Service + application programming interface) based EnvironMax realizes multi-scale and multi-exposure EHRM, especially “4R” (Right Time, Right Place, Right Information, Right Person) EHRM. A testbed with EnvironMax applications, mainly including environmental health navigation, healthy city planning and healthy exercises assistant, are presented to verify the feasibility of the proposed architecture under a case environmental multimedia risk scenarios. Professionalized and Personalized EnvironMax is proved to support scientific urban sustainable development with aim of multilevel users' environmental health initiative management and equity.

Characterisation of the soundscape of parks and green areas through the triangulation of methodologies proposed by ISO/TS 12913-2

The management of urban spaces and environmental health has been growing in recent years, and the sound aspects were highlighted during the Coronavirus pandemic (COVID-19). Locations that generally showed noises from vehicle traffic presented a diversity of sounds, generally not perceived in everyday situations before the pandemic. Awareness of the sound impacts generated before the pandemic has provided a broad discussion between the scientific community and managers regarding developing tools to improve urban planning and environmental health in cities. This study aims to characterise the soundscape of two parks in Curitiba by triangulating evaluation methodologies proposed in the ISO/TS 12913-2 (2018). Such triangulation included the descriptive analysis of objective and subjective sound data, analysis and elaboration of sound and perception maps, providing a systemic overview of the sonic environment of the investigated parks.

One Health in Urban environment- public health challenge for the future

Abstract Urban environment is a specific one in which are citizens and also their pets and other animals looking for a mutual place for a qualitative life. Humans are trying to make their life as good as possible, bringing the “nature” inside urban environment, but not always thinking through if urban environment will have effect on that “nature” - pets and plants in houses. The availability of data on number of pets in urban environments is being studied. It is estimated that in a city of 500.000 inhabitants, there are around 17.000 dogs, but number of cats is even more challenging to find. Which towns are the highlighted ones with developed culture of cohabitation? The ones with equally developed conditions for the life “of all. WHO (1990) suggests that dog ecology and related anthropological aspects can serve to establish background information for the planning and implementation of dog population management schemes and for the control of zoonotic diseases. Dog population density is related to different habitats, cultures, and social conditions of human populations (Fielding and Plumridge 2005). For example, Albert and Bulcroft (2015) in their study underline the important social and emotional roles that pets play in the urban household. People in cities demonstrate high levels of attachment, caring, and intimacy towards their pets. Pets are viewed as important members of households and owners are willing to spend high budget of money on needed medical or preventive care for their pets. One health concept in an urban environment has a specific significance from overcoming common risks for humans and animals point of view. The risk of infectious diseases is probably the most common one, including zoonotic diseases. This risk can even be a life threating one. There is also the risk of non-infectious diseases and influence of the mental health of owners to pet's life. Also, the influence of owner's life style to the life of pets - eating, walking and other habits.

The relation between social actions and auditory music basket of iranian citizens case study: Tehran and Karaj citizens in 2013

This paper aimed at studying the relation between social action indicators and listening to the common genres of music. This quantitative research was conducted based on the field method by designing questionnaire and direct surveys. Statistical samples were randomly selected then chosen and studied in various municipal regions of Tehran and Karaj. Statistical data analysis indicated a significant relation between social actions and behavior of citizens (including driving manner and violations due to lack of consideration for driving regulations, urbanization principles, and urban environmental health) and auditory music basket selection, which includes background music in routine social activities of individuals. According to the statistics obtained from traffic police of Tehran and Karaj there is a significant relationship between drivers’ attention to traffic rules and signs with the played music in the car.

Urban Heat Island and Its Interaction with Heatwaves: A Review of Studies on Mesoscale

With rapid urbanization, population growth and anthropogenic activities, an increasing number of major cities across the globe are facing severe urban heat islands (UHI). UHI can cause complex impacts on the urban environment and human health, and it may bring more severe effects under heatwave (HW) conditions. In this paper, a holistic review is conducted to articulate the findings of the synergies between UHI and HW and corresponding mitigation measures proposed by the research community. It is worth pointing out that most studies show that urban areas are more vulnerable than rural areas during HWs, but the opposite is also observed in some studies. Changes in urban energy budget and major drivers are discussed and compared to explain such discrepancies. Recent studies also indicate that increasing albedo, vegetation fraction and irrigation can lower the urban temperature during HWs. Research gaps in this topic necessitate more studies concerning vulnerable cities in developing countries. Moreover, multidisciplinary studies considering factors such as UHI, HW, human comfort, pollution dispersion and the efficacy of mitigation measures should be conducted to provide more accurate and explicit guidance to urban planners and policymakers.