Heat Health Risk Research Articles

Assessment of Fine-Scale Urban Heat Health Risk and Its Potential Driving Factors Based on Local Climate Zones in Shenzhen, China

Cities are facing increased heat-related health risks (HHRs) due to the combined effects of global warming and rapid urbanization. However, few studies have focused on HHR assessment based on fine-scale information. Moreover, most studies only analyze spatial HHR patterns and do not explore the potential driving factors. In this study, we estimated the potential HHRs based on the “hazard–exposure–vulnerability” framework by using multisource data, including the modified thermal–humidity index (MTHI), population density, and land cover. Then, the variations in the HHRs among different local climate zones (LCZs) at the fine spatial scale were analyzed in detail. Finally, we compared the different contributions of the LCZs and types of land cover to the HHRs and their three components by using multiple linear regression models. The results indicate that the spatial pattern of the HHRs was different from those of the individual components, and high-hazard regions do not mean high HHRs. There were huge variations in the HHRs among the different LCZs. The built-up LCZs typically had much higher HHRs than the natural ones, with compact LCZs facing the most severe risk. LCZ 6 (open low-rise buildings) had a relatively low HHR and should be paid more attention in future urban planning. Compared to the LCZs, the land covers better explained the variations in the HHR. In contrast, the LCZs better predicted the land surface temperatures. However, both the LCZs and land covers made only slight contributions to the heat exposure and vulnerability. Furthermore, the manmade buildings and impervious surface areas contributed much more to the HHR than the natural land covers. Therefore, the arrangement of the warming LCZs and land cover types is worthy of further investigation from the perspective of HHR mitigation.

Container buildings used for residential and business purposes in Johannesburg, South Africa and potential heat-related health risks

Background Outdoor and indoor air temperature affects human health and wellbeing. Climate change projections suggest that global temperatures will continue to increase, and this poses a threat to health. Buildings (for housing and business purposes) that can protect humans from the adverse effects of temperature are essential, especially in the context of climate change. Method In this cross-sectional study, we measured the indoor temperature inside shipping containers comprising a seven-storey block of apartments and businesses in Johannesburg, South Africa for 14 days. We assessed indoor temperature and relative humidity; evaluated measured temperatures in relation to thresholds known to be associated with adverse health risks; and sought to understand heat-health perceptions and symptoms of people living and working in shipping container units. Results Median indoor apparent temperature (AT) (a combination of temperature and relative humidity) was 16°C with values ranging from 6°C (observed at 8:00) to 42°C (observed at 17:00). Insulated units had temperatures between 2°C and 9°C cooler than the uninsulated unit. Heat-health risks from AT exposure were likely in all units, although there was variation in the number of occurrences that AT measurements exceeded the four symptom bands of caution, extreme caution, danger and extreme danger. Indoor AT was found to be 7°C higher on average when compared to outdoor AT. Some participants believed that their units were hot during hot weather and most people opened windows or did nothing during hot weather. Few participants reported experiencing adverse heat-health impacts, except for experiencing headaches (58%) and feeling tired or weak (40%). Conclusion Residents, tenants, or business owners using shipping containers should consider insulation installation and adequate windows/air conditioning for ventilation, especially in hot climates. Further research and awareness regarding heat-health risks of living or working in these spaces is needed.

Assessing 7-year heat-stress exposures and adaptation strategies for children using a real-time monitoring network in Taiwan

Wet-bulb globe temperature (WBGT) serves as a suitable heat-stress indicator not only for outdoor workers but also for the general public. However, studies on WBGT exposure among the general population are scarce. This research represents the first attempt to assess WBGT exposure of school-aged children. Utilizing a real-time monitoring network in Taiwan, WBGT exposure of school-aged children (7–15 years) were estimated during May to October from 2016 to 2022. Important determinants and spatiotemporal variability of WBGT levels were explored, with hot spots and peak hours of WBGT identified. Macro- and micro-scale adaptation strategies applicable at schools were also evaluated for their effectiveness in reducing heat stress for students. Results showed that the mean daily maximum WBGT (WBGTmax) was 33.1 ± 3.8 °C at 20 stations across Taiwan but could reach/exceed 36 °C (threshold of the dangerous category) at certain hot spots for 42.3–52.0 % of days between May and October. Local geographic features sometimes outweigh the latitude in explaining the spatial variations. Contrary to temperature, WBGT peaked during 10 am to noon rather than from noon to 1:59 pm in most schools, due to clouds blocking solar radiation in the afternoon. This finding has significant implications for scheduling outdoor physical classes/activities to reduce children's heat-health risks. Setting up on-site WBGT monitoring on surfaces that children mostly encounter at schools or utilizing data from nearby weather stations could provide a near real-time heat-health warning. Moreover, providing shades outdoors, relocating outdoor classes indoors, and using air-conditioning would reduce WBGT by 2.1–5.8, 3.7–7.3, and 2.5–5.9 °C, respectively; and would significantly decrease the percentages of WBGT ≥34 °C, which is associated with increased heat-related emergency visits among children in Taiwan. The methodology applied serves as a useful reference for assessing WBGT exposure and adaptation strategies, providing the scientific foundation for heat-health adaptation measures.

Health risk assessment of residential overheating under the heat waves in Guangzhou

During extreme heatwave events, indoor overheating caused by power outages poses a significant threat to human health, especially for low-income groups exposed to hot and humid conditions for extended periods. However, currently, the definition and quantification standards for indoor overheating are not well-defined, and relying solely on thermal comfort indicators is insufficient to accurately assess the health risks associated with indoor overheating. This study proposes the use of maximum heat index (HImax) and heat index hazard hours when the heat index exceeds the caution level (HIHHCaution) to assess the health risk of indoor overheating. Taking various types of residential buildings in Guangzhou as examples, the study employs field surveys, simulation analysis, and statistical regression to analyze the impact of power outages during heatwaves on the indoor thermal environment and key human thermal physiological parameters, thereby establishing the basis for measuring indoor overheating and reference thresholds for assessing heat health risks. The results indicate that for young adults and the elderly, HIHHCaution exceeding 1174 °C·h and 850 °C·h respectively, or HImax nearing 55 °C, are likely to result in heat-related illnesses. In Guangzhou, most urban village housing with poor insulation cannot withstand the risk of power outages lasting more than a day during heatwaves, while old housing and commodity housing that meets the energy-efficiency standards of different periods still face varying degrees of indoor overheating risk. The findings enhance understanding of indoor overheating health risks and provide a scientific basis for strategies to improve living environments during heatwaves.

Reexploring the conception of heat-health risk: From the perspectives of dimensionality and spatiality.

Extreme heat events are more frequent and intense as a result of global climate change, thus posing tremendous threats to public health. However, extant literature exploring the multidimensional features of heat-health risks from a spatial perspective is limited. This study revisits extreme heat-health risk and decomposes this concept by integrating multi-sourced datasets, identifying compositional features, examining spatial patterns, and comparing classified characteristics based on local conditions. Using Maryland as the focal point, we found that the components of heat-health risk are different from traditional risk dimensions (i.e., vulnerability, hazards, and exposure). Through a local-level clustering analysis, heat-health risks were compared with areas having similar features, and among those with different features. The findings suggest a new perspective for understanding the socio-environmental and socio-spatial features of heat-health risks. They also offer an apt example of applying cross-disciplinary methods and tools for investigating an ever-changing phenomenon. Moreover, the spatial classification mechanism provides insights about the underlying causes of heat-health risk disparities and offers reference points for decision-makers regarding identification of vulnerable areas, resource allocation, and causal inferences when planning for and managing extreme heat disasters.

The potential burden from urbanisation on heat-related mortality in São Paulo, Brazil

Heatwave events are associated with increased hospital admissions and mortality rates worldwide. Heat exposure is often exacerbated by the Urban Heat Island (UHI) effect, especially in large cities. However, an accurate quantification of the additional burden related to heat from urbanisation is understudied in Latin American cities. Therefore, we used advanced meteorological modelling to simulate 2 m air temperature at 1 km spatial resolution across São Paulo, estimating UHI intensity attributing of all-cause mortality to heat and UHI during the 2014 heatwave. The Local Climate Zone classification system provided input land use parameters. Our model was validated against 31 weather stations and bias-corrected using linear regression. We calculated heat-related all-cause mortality, stratified by age, using the modelled temperature data, estimating 394 heat-related deaths. A counterfactual experiment, replacing urban areas with natural land, quantified the additional UHI burden. We found that the UHI may contribute to 69–70% of heat-related mortality (modelled temperature scenario). This work motivates the use of appropriate urban climate data, including careful model validation and bias correction, when assessing heat exposure and health risk assessment. It also highlights the health impacts from heatwaves in cities such as São Paulo, which are likely to increase due to climate change.

Spatial distribution of old neighborhoods based on heat-related health risks assessment: A case study of Changsha City, China

Assessing the heat-related health risks is crucial for promoting the sustainable development of cities, particularly in the face of extreme climates and urban human settlement governance. Heat health risk assessment serves as a foundational element within the risk governance framework, serving to mitigate heat-related morbidity and mortality rates. The revitalization of old neighborhoods, especially those situated in city centers with deficient facilities, emerges as a critical imperative within this context. This study chose Changsha, a city in Central China that is severely affected by high temperatures and has numerous old neighborhoods, as a case study. We developed a heat risk framework that incorporates city level risk, exposure, vulnerability, and the adaptation of old neighborhoods. Validated through data accessed from medical facilities visit, the framework effectively reflects the distribution of heat risks. By combining qualitative and quantitative methods, we investigated the correlation between heat health risk levels and the behaviors of residents in old neighborhoods. The results indicate that urban planners should prioritize comprehensive renovations in medium-risk neighborhoods, resident behavior management in low-risk neighborhoods, and the indoor thermal environment in high-risk neighborhoods. This framework plays an important role in the assessment of future spatial risk for old neighborhoods renewal.

Evaluating heat health risk in Indian cities: Geospatial and socio-ecological analysis

India is home to 11 % of the global urban population and is ranks as the second-largest urban system in the world. This study introduces a Heat Health Risk Index (HHRI) rankings for 37 major Indian cities with more than one million residents, using geospatial and socio-ecological data to identify potential heat health risk areas. In this study, the Otsu method was employed to determine the critical parameters in the heat health index, considering factors such as Land Surface Temperature (LST), solar radiation, population density, mean temperature, urban green cover, rainfall, specific humidity, and wind speed. All data values were standardized to a uniform scale (0–1) for comparability. The standardized values, integrated with the assigned weights, formed the HHRI. Results indicate that cities such as Chennai, Mumbai, Kolkata, and Ahmedabad, each with populations exceeding 10 million, are deemed less livable due to their high HHRI (>0.50). Both Chennai and Mumbai stand out with highest hazard index as 0.66, followed by Kolkata (0.62) and Ahmedabad (0.56). Cities that lack sufficient green spaces are often more vulnerable, display elevated risk levels, and have decreased adaptability. In contrast, cities such as Ludhiana, Theni, Amritsar, and Nabarangpur are perceived as the most livable, with a mean HHRI of 0.21, owing to their higher adaptive capacity and lower exposure. Overall, this study serves as a foundation for conceiving future perspective plans for existing urban and peri‑urban areas, compared to living standards within the realms of sustainability.

Children With Cardiac Disease and Heat Exposure: Catastrophic Converging Consequences?

To highlight the worrying paucity of investigative research aimed at differentiating how higher ambient temperatures further tax an already compromised cardiovascular system in children. This commentary describes basic thermoregulatory concepts relevant to the healthy pediatric population and summarizes common heart diseases observed in this population. We describe how heat stress and exercise are important factors clinicians should more readily consider when treating children with heart disease. Countermeasures to physical inactivity are suggested for children, parents, clinicians, and policymakers to consider. As sudden, excessive heat exposures continue to impact our rapidly warming world, vulnerable populations like children with underlying heart conditions are at greater heat health risk, especially when coupled with the negative physical activity and fitness trends observed worldwide.

Systemic inequalities in heat risk for greater London

The temperature rise and increases in extreme heat events related to global climate change is a growing public health threat. Populations in temperate climates, including the UK, must urgently adapt to increased hot weather as current infrastructure primarily focusses on resilience to cold. As we adapt, care should be taken to ensure existing health inequalities are reduced. Lessons can be learned from regions that experience warmer climates and applied to adaptation in the UK.We identified known indicators of heat-health risk and explored their distribution across area level income for London. Understanding these indicators and their distributions across populations can support the development of interventions that have the dual aim of improving health and reducing inequalities. An exploratory analysis was conducted for each indicator at neighbourhood level to assess existence of disparities in their distributions across London. A systems-thinking approach was employed to deduce if these amount to systemic inequalities in heat risk, whereby those most exposed to heat are more susceptible and less able to adapt. Using this information, we proposed interventions and made recommendations for their implementation.We find inequalities across indicators relating to exposure, vulnerability, and adaptive capacity. Including inequalities in urban greening and access to greenspace, physical and mental health and access to communication and support. Through a system diagram we demonstrate how these indicators interact and suggest that systemic inequalities in risk exist and will become more evident as exposure increases with rising temperatures, depending on how we adapt. We use this information to identify barriers to the effective implementation of adaptation strategies and make recommendations on the implementation of interventions. This includes effective and wide-reaching communication considering the various channels and accessibility requirements of the population and consideration of all dwelling tenures when implementing policies relating to home improvements in the context of heat.

Assessment of heat stress contributing factors in the indoor environment among vulnerable populations in Klang Valley using principal component analysis (PCA)

Rising global temperatures can lead to heat waves, which in turn can pose health risks to the community. However, a notable gap remains in highlighting the primary contributing factors that amplify heat-health risk among vulnerable populations. This study aims to evaluate the precedence of heat stress contributing factors in urban and rural vulnerable populations living in hot and humid tropical regions. A comparative cross-sectional study was conducted, involving 108 respondents from urban and rural areas in Klang Valley, Malaysia, using a face-to-face interview and a validated questionnaire. Data was analyzed using the principal component analysis, categorizing factors into exposure, sensitivity, and adaptive capacity indicators. In urban areas, five principal components (PCs) explained 64.3% of variability, with primary factors being sensitivity (health morbidity, medicine intake, increased age), adaptive capacity (outdoor occupation type, lack of ceiling, longer residency duration), and exposure (lower ceiling height, increased building age). In rural, five PCs explained 71.5% of variability, with primary factors being exposure (lack of ceiling, high thermal conductivity roof material, increased building age, shorter residency duration), sensitivity (health morbidity, medicine intake, increased age), and adaptive capacity (female, non-smoking, higher BMI). The order of heat-health vulnerability indicators was sensitivity > adaptive capacity > exposure for urban areas, and exposure > sensitivity > adaptive capacity for rural areas. This study demonstrated a different pattern of leading contributors to heat stress between urban and rural vulnerable populations.

Heat health risks for the elderly

Heat health risks for the elderly

A multiscale examination of heat health risk inequality and its drivers in mega-urban agglomeration: A case study in the Yangtze River Delta, China

Increased frequency of extreme urban heat and its exposure to urban populations is one of the challenges presented by climate change, especially in urban clusters. Due to the rapid but unequal development, heat exposure disproportionately increased in the underdeveloped regions compared to the developed regions in urban agglomeration. To address this issue, it is crucial to clarify the spatial pattern of heat health risk (HHR) inequality for urban heat resilience. However, analyses for the disparity of HHR inequality often used a single scale, neglecting important spatial context effects at other scales. Moreover, the rationale of HHR inequality remains unclear. Here, we took the well-developed and highly urbanized Yangtze River Delta (YRD) region as a case study and employed multiscale approaches to examine how and why the HHR inequality varied at and within the regional scale. We first assessed HHR using a comprehensive assessment framework at a 1 km grid level. Then, we quantified the inequality between regions using local Moran's I and KS distance. Therefore, we utilized the Gini coefficient and Bayes quantile regression to quantify inequality and identify its drivers within the regional scale. Finally, we proposed a conceptual framework to inform policymaking in regions with different patterns of multiscale equality. Our results found that the HHR in YRD exhibited significant spatial inequality at the regional scale (Moran's I = 0.562, P < 0.001) and within the regional scale (Gini coefficient: 0.27–0.54). Higher population concentrations and building densities often led to higher HHR. In high HHR areas, intra-regional inequality was often lower due to high and coordinated socioeconomic levels (Gini coefficient: 0.27–0.34). Additionally, in areas with low and medium levels of risk, healthcare resource availability and local temperatures had a greater impact on intra-regional inequities, which varied at different levels of inequality. This study contributes to a better understanding of multiscale HHR inequality, which helps optimize heat risk management strategies and regional sustainable development.

The Roles of Housing and Household Characteristics in U.S. Residential Heat Risk

This study uses data from the 2020 nationally-representative U.S. Residential Energy Consumption Survey (RECS) to analyze the under-explored relationship between housing type, household characteristics, and two novel heat health risk measures. We use a combination of descriptive analysis and logistic regression models. The results show that renters and residents of lower-cost housing types – multifamily and manufactured housing – are much more likely to keep their homes at unhealthy temperatures and require medical attention due to hot indoor temperatures. We also find stark disparities in heat risk for households with lower incomes, seniors, and Black, Native American, multiracial, and Hispanic households.

Spatio-temporal assessment of heat health risk in Chinese metropolitan cities based on the modified multi-indicators coupled risk framework

Extreme heat events are the leading cause of climate-related disease and death globally. Heat health risk assessment is an effective tool to understand and reduce heat-related morbidity and mortality. However, the indicators of previous studies made it difficult to characterize risk accurately, especially the most important hazard. Besides, studies prefer to focus on spatial variation and ignore the temporal variation. Based on these challenges, this study constructed a modified framework from three components including heat hazard, human exposure, and social vulnerability to propose an assessment of heat health risk in Chinese metropolitan cities from 2000 to 2020. The results indicated that (1) Compared to the traditional framework using a single indicator, the R² has been improved 0.16. (2) Spatially, in the large city, the city with a larger size has a higher risk index except supercity. And more open space has the ability to reduce the damage caused by heat. (3) Temporally, the average heat health risk index of cities increased gradually about 24.72 % from 2020 to 2000. This framework can help to improve the accuracy and flexibility of heat health risk assessment and provide support for sustainable urban development.

Beliefs and behaviors associated with the first named heat wave in Seville Spain 2022

Heat waves pose a substantial and increasing risk to public health. Heat health early warning systems (HHEWSs) and response plans are increasingly being adopted to alert people to the health risks posed by days of extreme heat and recommend protective behaviors. However, evidence regarding the effectiveness of HHEWSs remains limited. We examined the impact of heat wave naming on heat-related beliefs and behaviors to ascertain the potential effectiveness of heat wave naming as a heat health risk communication and management tool. Specifically, we surveyed members of the public exposed to the proMETEO Sevilla HHEWS messaging campaign which in the summer of 2022 applied a name to heat waves considered to pose the greatest risk to public health. During the heat season we evaluated, the proMETEO Sevilla HHEWS campaign applied a name to one heat wave, heat wave “Zoe”. Our analysis of the post-survey of 2022 adults indicated that the 6% of participants who recalled the name Zoe unaided reported greater engagement in heat wave safety behaviors and more positive beliefs about naming heat waves and their local governments’ heat wave response. These results provide initial evidence for potential utility in naming heat waves as part of HHEWSs and HAPs.

Shared insights for heat health risk adaptation in metropolitan areas of developing countries

Global warming has led to a surge in heat health risks (HHRs), the impacts of which are particularly pronounced in metropolitan areas of developing countries. In the current study, six metropolitan areas - Beijing, China; Cairo, Egypt; Jakarta, Indonesia; Mumbai, India; Rio de Janeiro, Brazil; and Tehran, Iran - were selected as the study area to further differentiate the built-up landscapes by utilizing the concept of local climate zones. Moreover, we assessed the similarities and differences in HHR associated with the landscape. Results revealed a 30.67% higher HHR in compact built-up landscapes than in the open built-up type. Urban green spaces played an effective but differentiated role in mitigating HHR. That is, low vegetation in urbanized areas and trees in suburban areas significantly mitigated HHR. Collectively, our findings emphasize the role of effective planning and management in addressing HHR and provide empirical support for implementing HHR mitigation and adaptation strategies.

Container buildings used for residential and business purposes in Johannesburg, South Africa and potential heat-related health risks

Background Outdoor and indoor air temperature affects human health and wellbeing. Climate change projections suggest that global temperatures will continue to increase, and this poses a threat to health. Buildings (for housing and business purposes) that can protect humans from the adverse effects of temperature is essential, especially in the context of climate change. Method In this cross-sectional study, we measured indoor temperature inside shipping containers comprising a seven-storey block of apartments and businesses in Johannesburg, South Africa for 14 days. We assessed indoor temperature and relative humidity; evaluated measured temperatures in relation to thresholds known to be associated with adverse health risks; and sought to understand heat-health perceptions and symptoms of people living and working in shipping container units. Results Median indoor apparent temperature (AT) (a combination of temperature and relative humidity) was 16 °C with values ranging from 6 °C (observed at 8:00) to 42 °C (observed at 17:00). Insulated units had temperatures between 2°C and 9°C cooler than the uninsulated unit. Heat-health risks from AT exposure were likely in all units, although there was variation in the number of occurrences that AT measurements exceeded the four symptom bands of caution, extreme caution, danger and extreme danger. Some participants believed that their units were hot during hot weather and most people opened windows or did nothing during hot weather. Few participants reported experiencing adverse heat-health impacts, except for experiencing headaches (58%) and feeling tired or weak (40%). Conclusion Residents, tenants, or business owners using shipping containers should consider insulation installation and adequate windows/air conditioning for ventilation, especially in hot climates. Further research and awareness regarding heat-health risks of living or working in these spaces is needed.

Analysis of Heat and Associated Health Risks in Delhi, India

Climate change has added significant challenges to nation’s worldwide, particularly in Asian countries due to their heavy reliance on climate-sensitive industries like forestry, fisheries, and tourism, Asian countries struggle economically and are slow to seize development opportunities. It has a significant impact on human health, with extreme heat and air pollution leading to thermal discomfort and health problems for city dwellers. Amplified heat waves, elevated levels of air pollution, and extreme weather occurrences are some of the issues faced by city dwellers. Climate change has aggravated health issues in Delhi, India, that includes respiratory and heat-related illness. The present study explores a link between temperature variations, land surface temperatures, and health outcomes to assess climate change risks with heat as the prime focus area in Delhi. It investigates the relationship between average maximum temperature and mortality and find strong positive correlations. It explores yearly land surface temperature variations and the hospital visits and strong correlation exists with temperature for health outcomes like stroke and diabetes. This study analyzes the impact of temperature variations on specific health conditions. Accordingly, the proposals could be framed through understanding of the relationship between heat and health on vulnerable population.

Spatially explicit assessment of the heat-related health risk in the Yangtze River Delta, China, using multisource remote sensing and socioeconomic data

With frequent extreme heat events (EHEs), rapid urbanization, and uneven social development, comprehensive assessment of heat-related health risks is important for tolerating hot weather. This paper proposed a quantitative method for assessing heat-related health risks at the grid scale. A combination of multisource remote sensing and socio-economic data was utilized to develop an integrated heat health risk index (HRI) considering three dimensions of heat hazards, exposure, and vulnerability in the Yangtze River Delta (YRD), China. Compensating for the limitations of land surface temperature (LST) and station data, daily air temperatures were retrieved to calculate heat hazard index. Gridded population density data were developed using nighttime light data to calculate the exposure index. By combining them and other indicators, an HRI map of the YRD was developed. Furthermore, the spatial heterogeneity and dominant factors of the heat health risk were examined. The results showed that 13.2 % of the areas in the YRD were in high and medium high risk, while 58.6 % were in low and medium low risk. The high-risk areas were primarily concentrated in the Shanghai-Hangzhou Bay urban agglomeration, suggesting synergy between increased exposure and hazards in these metropolitan areas. The high-risk areas were predominantly dominated by hazard/exposure (H-E) and exposure/vulnerability (E-V), accounting for 27.2 % and 21.9 % of the YRD's total area respectively. This study contributes to the identification of areas vulnerable to heat stress and provides references for optimizing heat risk management strategies.