Heat Stress in Indoor Environments of Scandinavian Urban Areas: A Literature Review

Occupational Heat Exposure-related Symptoms Prevalence and Associated Factors Among Hospitality Industry Kitchen Workers in Ethiopia: Wet Bulb Globe Temperature

Background

Occupational heat stress caused by excessive environmental heat gain disrupts thermoregulatory mechanisms and harm workers' health and productivity. Kitchens are known for their thermal risks; however, research on heat stress in kitchen is limited. This study aimed to bridge this knowledge gap by assessing, the prevalence of heat-stress-related symptoms, and associated factors among kitchen workers in Gondar City, Ethiopia.

Methods

This institutional-based cross-sectional study (April to June 2023) evaluated heat stress among hospitality kitchen workers in Ethiopia. Heat exposure was measured using hygrometers. A simple random sample of 605 participants completed a survey and data was exported to Statistical Package for Social Science version 26. To assess strength and direction an adjusted odds ratio with 95% confidence interval (CI) was employed. A p-value of less than 0.05 was utilized to identify significant associations.

Results

Over the last 6 months 67.1% (95% CI: 63.0, 71.1), of the participants reported heat-stress symptoms. Multivariable analysis revealed that age ≥40 years [AOR: 2.28; 95% CI (1.08, 4.82)], high workload [AOR: 1.89; 95% CI (1.04, 3.49)], poor heat mitigation practice [AOR: 2.39; 95% CI (1.58, 3.59), wood fuel [AOR: 2.60; 95% CI (1.54, 4.40)], improper ventilation [AOR: 3.28; 95% CI (1.56, 6.87)], and higher heat index value [AOR: 2.15; 95% CI (1.35, 3.42)] were factors significatly associated with heat stress related symptoms.

Conclusion

This study identified a high prevalence of heat-stress-related symptoms among kitchen workers. Mitigation strategies include improved ventilation, cooling, advanced building designs, and heat reduction technologies. Future research should utilize standard heat-stress assessment tools.

Human adaptation to heat in the context of climate change: A conceptual framework

Climate change is causing serious damage to natural and social systems, as well as having an impact on human health. Among the direct effects of climate change is the rise in global surface temperatures and the increase in the frequency, duration, intensity and severity of heat waves. In addition, understanding of the adaptation process of the exposed population remains limited, posing a challenge in accurately estimating heat-related morbidity and mortality. In this context, this study seeks to establish a conceptual framework that would make it easier to understand and organise knowledge about human adaptation to heat and the factors that may influence this process. An inductive approach based on grounded theory was used, through the analysis of case studies connecting concepts. The proposed conceptual framework is made up of five components (climate change, vulnerability, health risks of heat, axes of inequality and health outcomes), three heat-adaptation domains (physiological, cultural and political), two levels (individual and social), and the pre-existing before a heat event. The application of this conceptual framework facilitates the assistance of decision-makers in planning and implementing effective adaptation measures. Recognizing the importance of addressing heat adaptation as a health problem that calls for political solutions and social changes. Accordingly, this requires a multidisciplinary approach that would foster the participation and collaboration of multiple actors for the purpose of proposing effective measures to address the health impact of the rise in temperature.

The influence of occupational heat stress on serum inflammatory cytokines among traditional bakery workers in Iran

Heat exposure exceeding the ISO7243:1989 standard limit can contribute to health problems among employees in a variety of workplaces. Ignoring heat standard requirements in hot working conditions such as bakeries results in physiologic and health problems, as well as an elevated risk of later illnesses. In this analytical case-control study, the serum levels of four inflammatory factors (interleukin-1 beta, interleukin-6, tumor necrosis factor-α, and C-reactive protein) were assessed using an enzyme-linked immunosorbent assay. 105 male artisan bakers (in four job classifications in bakeries and staff) were compared based on demographic characteristics and inflammatory factors. The findings of the study showed correlations between serum interleukin-1β, interleukin-6, and C-reactive protein levels and thermal exposure in the occupational environment and employment type. Moreover, some differences in serum level of interleukin-1β and job type were observed. Heat overexposure affected the increase of interleukin-1β and C-reactive protein secretion. As a result of years of working in high-temperature conditions, inflammation can lead to subsequent diseases in workers. To protect their health from this occupational hazard, additional safeguards are needed. Our recommendations could also be applied to overly hot work environments that may cause heat stress in workers.

Pressures of the urban environment on the endocrine system: Adverse effects and adaptation

With an increasing collective awareness of the rapid environmental changes, questions and theories regarding the adaptability of organisms are emerging. Global warming as well as chemical and non-chemical pollution have been identified as triggers of these adaptative changes, but can we link different kinds of stressors to certain phenotypic traits? The physiological adaptation, and particularly endocrine system adaptation, of living beings to urban environments is a fascinating way of studying urban endocrinology, which has emerged as a research field in 2007. In this paper, we stress how endocrine disruption in humans and environment can be studied in the urban environment by measuring the levels of pollution, endocrine activities or adversity. We broaden the focus to include not only exposure to the chemicals that have invaded our private spheres and their effects on wild and domestic species but also non-chemical effectors such as light, noise and climate change. We argue that taking into account the various urban stress factors and their effects on the endocrine system would enable the adoption of new approaches to protect living organisms.

The effects of heatwaves on hospital admissions in the Edirne province of Turkey: A cohort study

Studies show that heat waves (HWs) are among the most important atmospheric phenomena that negatively affect human health. This study aims to determine the effects of HWs on hospital admissions (HA) in the Edirne province of Turkey. Polyclinic admission and atmospheric data, including daily maximum temperatures, were used. HW is defined as temperature at the % 90 threshold of daily maximum temperatures that persists for at least 3 consecutive days or more. With this definition, a 6-day HW was detected, and a lag of 3 days was added to this HW. Logarithmic Z test was used for the analysis. As a result of the study, The Risk Ratio (RR) showing the relationship between 9-day HW and HAs was calculated as 1.19 (95% confident interval [CI]: 1.17-1.21, P < .05), and it was determined that there were 2557 extra HAs in total. When HAs were analyzed according to sex, it was observed that female admissions were higher than male admissions. To analyze admissions by age, the data were divided into 3 groups: children (<15 years), adult (15-64 years), and elderly (≥65 years). As a result of the analysis, the highest increase was observed in patients < 15 years of age, and the RR was 1.33 (95% CI: 1.24-1.42 P < .05). When the patient density in polyclinics was analyzed, the Cardiology polyclinic had the highest number of patient admissions with an RR, 1.36 (95% CI: 1.30-1.43 P < .05). The results of this study will guide measures to be taken against HWs.

Assessment of indoor thermal comfort temperature and related behavioural adaptations: a systematic review

Thermal comfort is linked to our health, well-being, and productivity. The thermal environment is one of the main factors that influence thermal comfort and, consequently, the productivity of occupants inside buildings. Meanwhile, behavioural adaptation is well known to be the most critical contributor to the adaptive thermal comfort model. This systematic review aims to provide evidence regarding indoor thermal comfort temperature and related behavioural adaptation. Studies published between 2010 and 2022 examining indoor thermal comfort temperature and behavioural adaptations were considered. In this review, the indoor thermal comfort temperature ranges from 15.0 to 33.8 °C. The thermal comfort temperature range varied depending on several factors, such as climatic features, ventilation mode, type of buildings, and age of the study population. Elderly and younger children have distinctive thermal acceptability. Clothing adjustment, fan usage, AC usage, and open window were the most common adaptive behaviour performed. Evidence shows that behavioural adaptations were also influenced by climatic features, ventilation mode, type of buildings, and age of the study population. Building designs should incorporate all factors that affect the thermal comfort of the occupants. Awareness of practical behavioural adaptations is crucial to ensure occupants' optimal thermal comfort.

Effect of the cooling clothing integrating with phase change material on the thermal comfort of healthcare workers with personal protective equipment during the COVID-19

Wearing Personal Protective Equipment (PPE) is essential to protect healthcare workers during the COVID-19, but the traditional cooling methods do not meet the requirements of epidemic prevention during the COVID-19. Therefore, the cooling clothing integrated with phase change material (PCM-CC) was proposed for healthcare workers performing nucleic acid sample collection outdoors. Human experiments and subjective questionnaires were used to test the effect of wearing PCM-CC on the thermal sensations of healthcare workers and to analyze the effectiveness of PCM-CC in relieving thermal stress and thereby, improving the thermal comfort of healthcare workers. Results showed that wearing PCM-CC was effective in alleviating various heat symptoms associated with wearing PPE in a hot-temperature environment. Wearing PCM-CC reduced head and facial discomfort by 25% and 41% under the 26 °C thermal environment, while it improved the mean thermal sensation vote (TSV) values by 0.71 and 1.85 under the 26 °C and 32 °C thermal environments, respectively, and made the mean TSV value close to the neutral value. Meanwhile, wearing PCM-CC reduced mean skin temperatures by 0.65 °C, and the pronounced cooling effect was found in the chest. Wearing PCM-CC could be an effective thermoregulation measure to refine the thermal comfort of healthcare workers during the COVID-19 pandemic.

A Multistate Study on Housing Factors Influential to Heat-Related Illness in the United States

As climate change increases the frequency and intensity of devastating and unpredictable extreme heat events, developments to the built environment should consider instigating practices that minimize the likelihood of indoor overheating during hot weather. Heatwaves are the leading cause of death among weather-related causes worldwide, including in developed and developing countries. In this empirical study, a four-step approach was used to collect, extract and analyze data from twenty-seven states in the United States. Three housing characteristic categories (i.e., general housing conditions, living conditions, and housing thermal inertia) and eight variables were extracted from the American Housing Survey database, ResStock database and CDC's National Environmental Public Health Tracking Network. Multivariable regression models were used to understand the influential variables, a multicollinearity test was used to determine the dependence of those variables, and then a logistic model was used to verify the results. Three variables-housing age (HA), housing crowding ratio (HCR), and roof condition (RC)-were found to be correlated with the risk of heat-related illness (HRI) indexes. Then, a logistic regression model was generated using the three variables to predict the risk of heat-related emergency department visits (EDV) and heat-related mortality (MORD) on a state level. The results indicate that the proposed logistic regression model correctly predicted 100% of the high-risk states for MORD for the eight states tested. Overall, this analysis provides additional evidence about the housing character variables that influence HRI. The outcomes also reinforce the concept of the built environment determined health and demonstrate that the built environment, especially housing, should be considered in techniques for mitigating climate change-exacerbated health conditions.

First evidence of microplastics isolated in European citizens' lower airway

Microplastics (MPs) have been detected in all environmental locations, including the atmosphere. However, few studies have investigated the presence of airborne MPs in the human respiratory system. Our research purpose was to investigate these pollutants in the lower human airways of 44 adult European citizens, using bronchoalveolar lavage fluid (BALF) collection as a minimally invasive method, that enables the detection of these pollutants in living patients. We studied the relationship between the patients' life habits and physiological parameters, based on background information and medical and occupational history, and the concentration of MPs isolated from their respiratory systems. Our results indicate that most MPs were in the form of microfibers (MFs) (97.06%), with an average concentration of 9.18 ± 2.45 items/100 mL BALF, and only 5.88% (0.57 ± 0.27 items/100 mL BALF) were particulate MPs, without a significant relationship with environmental, physiological, or clinical factors. The average size was 1.73 ± 0.15 mm, with the longest dimension (9.96 mm) corresponding to a polyacrylic fiber. Taken together, the results demonstrated the occurrence of MPs in the lower human airway, although more studies are necessary to elucidate the negative effects these pollutants could induce in the human respiratory system and its associated diseases.

Use of Thermoregulatory Models to Evaluate Heat Stress in Industrial Environments

Heat stress in many industrial workplaces imposes significant risk of injury to individuals. As a means of quantifying these risks, a comparison of four rationally developed thermoregulatory models was conducted. The health-risk prediction (HRP) model, the human thermal regulation model (HuTheReg), the SCENARIO model, and the six-cylinder thermoregulatory model (SCTM) each used the same inputs for an individual, clothing, activity rates, and environment based on previously observed conditions within the Portuguese glass industry. An analysis of model correlations was conducted for predicted temperatures (°C) of brain (TBrain), skin (TSkin), core body (TCore), as well as sweat evaporation rate (ER; Watts). Close agreement was observed between each model (0.81-0.98). Predicted mean ± SD of active phases of exposure for both moderate (TBrain 37.8 ± 0.25, TSkin 36.7 ± 0.49, TCore 37.8 ± 0.45 °C, and ER 207.7 ± 60.4 W) and extreme heat (TBrain 39.1 ± 0.58, TSkin, 38.6 ± 0.71, TCore 38.7 ± 0.65 °C, and ER 468.2 ± 80.2 W) were assessed. This analysis quantifies these heat-risk conditions and provides a platform for comparison of methods to more fully predict heat stress during exposures to hot environments.

A holistic modeling framework for estimating the influence of climate change on indoor air quality

The IPCC 2021 report predicts rising global temperatures and more frequent extreme weather events in the future, which will have different effects on the regional climate and concentrations of ambient air pollutants. Consequently, changes in heat and mass transfer between the inside and outside of buildings will also have an increasing impact on indoor air quality. It is therefore surprising that indoor spaces and occupant well-being still play a subordinate role in the studies of climate change. To increase awareness for this topic, the Indoor Air Quality Climate Change (IAQCC) model system was developed, which allows short and long-term predictions of the indoor climate with respect to outdoor conditions. The IAQCC is a holistic model that combines different scenarios in the form of submodels: building physics, indoor emissions, chemical-physical reaction and transformation, mold growth, and indoor exposure. IAQCC allows simulation of indoor gas and particle concentrations with outdoor influences, indoor materials and activity emissions, particle deposition and coagulation, gas reactions, and SVOC partitioning. These key processes are fundamentally linked to temperature and relative humidity. With the aid of the building physics model, the indoor temperature and humidity, and pollutant transport in building zones can be simulated. The exposure model refers to the calculated concentrations and provides evaluations of indoor thermal comfort and exposure to gaseous, particulate, and microbial pollutants.

Knowledge Gaps and Research Priorities on the Health Effects of Heatwaves: A Systematic Review of Reviews

Although extreme weather events have played a constant role in human history, heatwaves (HWs) have become more frequent and intense in the past decades, causing concern especially in light of the increasing evidence on climate change. Despite the increasing number of reviews suggesting a relationship between heat and health, these reviews focus primarily on mortality, neglecting other important aspects. This systematic review of reviews gathered the available evidence from research syntheses conducted on HWs and health. Following the PRISMA guidelines, 2232 records were retrieved, and 283 reviews were ultimately included. Information was extracted from the papers and categorized by topics. Quantitative data were extracted from meta-analyses and, when not available, evidence was collected from systematic reviews. Overall, 187 reviews were non-systematic, while 96 were systematic, of which 27 performed a meta-analysis. The majority evaluated mortality, morbidity, or vulnerability, while the other topics were scarcely addressed. The following main knowledge gaps were identified: lack of a universally accepted definition of HW; scarce evidence on the HW-mental health relationship; no meta-analyses assessing the risk perception of HWs; scarcity of studies evaluating the efficacy of adaptation strategies and interventions. Future efforts should meet these priorities to provide high-quality evidence to stakeholders.

Spatial-Temporal Changes and Associated Determinants of Global Heating Degree Days

The heating degree days (HDDs) could indicate the climate impact on energy consumption and thermal environment conditions effectively during the winter season. Nevertheless, studies on the spatial-temporal changes in global HDDs and their determinants are scarce. This study used multi-source data and several methods to explore the rules of the spatial distribution of global HDDs and their interannual changes over the past 49 years and some critical determinants. The results show that global HDDs generally became larger in regions with higher latitudes and altitudes. Most global change rates of HDDs were negative (p < 0.10) and decreased to a greater extent in areas with higher latitudes. Most global HDDs showed sustainability trends in the future. Both the HDDs and their change rates were significantly partially correlated with latitude, altitude, mean albedo, and EVI during winter, annual mean PM2.5 concentration, and nighttime light intensity (p = 0.000). The HDDs and their change rates could be simulated well by the machine learning method. Their RMSEs were 564.08 °C * days and 3.59 °C * days * year-1, respectively. Our findings could support the scientific response to climate warming, the construction of living environments, sustainable development, etc.

A Review of Studies Involving the Effects of Climate Change on the Energy Consumption for Building Heating and Cooling

The world is faced with significant climate change, rapid urbanization, massive energy consumption, and tremendous pressure to reduce greenhouse gases. Building heating and cooling is one primary source of energy consumption and anthropogenic carbon dioxide emissions. First, this review presents previous studies that estimate the specific amount of climate change impact on building heating and cooling energy consumption, using the statistical method, physical model method, comprehensive assessment model method, and the combination method of statistical and physical model methods. Then, because the heating and cooling degree days indices can simply and reliably indicate the effects of climate on building heating and cooling energy consumption, previous studies were reviewed from the aspects of heating and cooling degree days indices, regional spatial-temporal variations in degree days and related indices, influencing factors of the spatial distributions of degree days, and the impacts of urbanization on degree days. Finally, several potential key issues or research directions were presented according to the research gaps or fields that need to be studied further in the future, such as developing methods to simply and accurately estimate the specified amounts of climate change impact on building cooling and heating energy consumption; using more effective methods to analyze the daytime, nighttime, and all-day spatial-temporal changes in different seasons in the past and future under various environment contexts by considering not only the air temperature but also the relative humidity, solar radiation, population, etc., and further exploring the corresponding more kinds of driving forces, including the various remotely sensed indices, albedo, nighttime light intensity, etc.; estimating the daytime, nighttime, and all-day impacts of urbanization on heating degree days (HDDs), cooling degree days (CDDs), and their sum (HDDs + CDDs) for vast cities in different environmental contexts at the station site, city, regional and global scales; producing and sharing of the related datasets; and analyzing the subsequent effects induced by climate change on the energy consumption for building heating and cooling, etc.

The effect of cold waves on daily mortality in districts in Madrid considering sociodemographic variables

While there is much research that focuses on the association between cold waves and their impacts on daily mortality at the city level, few analyze the impact related to social context and demographic variables at levels lower than the municipal. The objective of this study was to determine the role of the percentage of people over age 65, income level and percentage of homes without heating in the analysis of the impact of cold waves on daily mortality between January 1, 2010 and December 31, 2013 in different districts of the municipality of Madrid. We calculated Relative Risks (RR) and Attributable Risks (RA) for each of 17 districts to determine correlations between the effect of cold waves and daily mortality due to natural causes (CIEX: A00-R99) using Generalized Linear Models (GLM) of the Poisson family (link log). The pattern of risks obtained by district was analyzed using binomial family models (link logit), considering socioeconomic and demographic variables. In terms of results, an impact of cold on mortality was detected in 9 of the 17 districts analyzed. The analysis of risk patterns revealed that the probability of detecting an impact in a district increases in a statistically significant way (p-value <0.05) with a higher percentage of homes without heating systems and a higher percentage of population over age 65. The results obtained identify the factors that should be considered in public health policies that target the district level to reduce the impact of cold waves.

Variability and role of long-wave radiation fluxes in the formation of net radiation and thermal features of grassy and bare soil active surfaces in Wrocław

The paper examines the variability of long-wave radiation fluxes in two contrasting types of urban active surfaces - grassy surface and surface without plants (bare soil) in Wrocław (Poland) within a 12-year period (August 2007-July 2019). The study used net radiation and heat balance formulas to calculate the share of individual radiation fluxes in these balances, and then utilized the Stefan-Boltzmann formula to calculate the effective temperatures of researched surfaces. The analysis showed the temporal variability of these fluxes against the background of weather and climatic conditions and in relation to the variability of short-wave radiation fluxes. The role of long-wave radiation fluxes in forming net radiation was examined in detail to show the buffering role of vegetation surfaces regarding the variability of solar radiation fluxes and their heat effects. The mean monthly values of outgoing long-wave radiation fluxes change from 309.0 W·m^-2 for bare soil, 309.8 W·m^-2 for grassy surface, and 288.8 W·m^-2 for downward atmospheric radiation to respectively 435.8, 425.0 and 369.4 W·m^-2 in July. The coefficient of variability for long-wave radiation daily fluxes are approximately one order of magnitude lower than for the short-wave radiation. The differences between values of long-wave radiation fluxes for bare soil and grassy surfaces vary from slight negative values in winter to relatively sizable positive values during the vegetation period (March-October). The weakening of the buffering effect for grassy surface and how air temperature then changes considerably compared to the effective temperature of the active surfaces were explained using the dry summer period of August 2015 as example. The obtained results are important, as they provide empirical arguments for urban planning to extend plant areas' share in big cities as well as to introduce there a friendly environmental system of irrigation in these areas using renewable solar energy.

The impact of heat waves on daily mortality in districts in Madrid: The effect of sociodemographic factors

Although there is significant scientific evidence on the impact of heat waves, there are few studies that analyze the effects of sociodemographic factors on the impact of heat waves below the municipal level. The objective of this study was to analyze the role of income level, percent of the population over age 65, existence of air conditioning units and hectares (Ha) of green zones in districts in Madrid, in the impact of heat on daily mortality between January 1, 2010 and December 31, 2013. Seventeen districts were analyzed, and Generalized Linear (GLM) Poisson Regression Models were used to calculate relative risks (RR) and attributable risks (RA) for the impact of heat waves on mortality due to natural causes (CIEX:A00-R99). The pattern of risks obtained was analyzed using GLM univariates and multivariates of the binomial family (link logit), introducing the socioeconomic and demographic variables mentioned above. The results indicate that heat wave had an impact in only three of the districts analyzed. In the univariate models, all of the variables were statistically significant, but Ha of green zones lost significance in the multivariate model. Income level, existence of air conditioning units, and percent of the population over age 65 in the district remained as variables that modulate the impact of heat wave on daily mortality in the municipality of Madrid. Income level was the key variable that explained this behavior. The results obtained in this study show that there are factors at levels below the municipal level (district level) that should be considered as focus areas for health policy in order to decrease the impact of heat and promote the process of adaptation to heat in the context of climate change.

Risk perception of heat related disorders on the workplaces: a survey among health and safety representatives from the autonomous province of Trento, Northeastern Italy

Introduction

This study will investigate knowledge, attitude and practices towards heat-related health issues in a sample of safety representatives from Northern Italy (H&SRs).

Methods

A cross-sectional questionnaire survey was conducted in 2016-2017 among 298 H&SR. Knowledge status was measured both in general but as well and focusing on first-aid issues. Assessment of risk perception included severity and frequency of heat-related events. Multivariate logistic regression analysis assessed individual and work-related characteristics associated with H&SRs’ risk perception.

Results

258 questionnaires were retrieved (participation rate 86.6%; mean age 48.2 ± 8.4 years). Knowledge status was relatively good on technical/preventive issues (62.3% ± 16.8) and first aid measures (72.6% ± 27.2), but a large share of respondents ignored the risk from exertional heat stroke (35.9%), and for heat strokes elicited by non-environmental heat (e.g. machineries, use of protective equipment, etc. 47.9%). The majority of respondents acknowledged the high frequency of extreme events like heat waves (62.0%), but only 44.6% agreed on their potential health threat, with an unsatisfying cumulative risk perception score (55.4% ± 23.5). A specific first-aid formation course was reported by 49.2% of respondents, while 10.9% had any previous interaction with heat-related disorders. Specific countermeasures for heat waves had been put in place by parent company in 20.1% of cases. Eventually, higher educational achievements (mOR 2.239, 95% CI 1.184-4.233) and a better general knowledge status (mOR 1.703, 95% CI 1.073-2.979) were positive predictors for higher risk perception.

Conclusions

Although H&SRs exhibited a good understanding of heat-related health issues, stakeholders should improve the implementation of specific countermeasures on the workplaces.

Sensitivity of Radiative and Thermal Properties of Building Material in the Urban Atmosphere

In the context of the impact of urbanization on climate change, this work aims to evaluate the sensitivity of the thermal and radiative properties of building surfaces in urban areas to the urban heat island intensity, a local scale meteorological phenomenon. For this, variations of albedo values, emissivity, thermal conductivity and heat capacity of roofs, streets and walls were simulated through an urban scheme coupled with the BRAMS mesoscale atmospheric model for the metropolitan area of São Paulo, considering two main urban types. The simulations show that, in general, looking for cold surface situations, the change of building material can contribute to a reduction of up to 3 °C for São Paulo. In addition, the role of orientation and the typological characteristics of constructions should be taken into account. In this sense, it is expected that this work guides civil engineers and builders to search for new materials in order to reduce the effects of urbanization on the local climate.

Is There a Need to Integrate Human Thermal Models with Weather Forecasts to Predict Thermal Stress?

More and more people will experience thermal stress in the future as the global temperature is increasing at an alarming rate and the risk for extreme weather events is growing. The increased exposure to extreme weather events poses a challenge for societies around the world. This literature review investigates the feasibility of making advanced human thermal models in connection with meteorological data publicly available for more versatile practices and a wider population. By providing society and individuals with personalized heat and cold stress warnings, coping advice and educational purposes, the risks of thermal stress can effectively be reduced. One interesting approach is to use weather station data as input for the wet bulb globe temperature heat stress index, human heat balance models, and wind chill index to assess heat and cold stress. This review explores the advantages and challenges of this approach for the ongoing EU project ClimApp where more advanced models may provide society with warnings on an individual basis for different thermal environments such as tropical heat or polar cold. The biggest challenges identified are properly assessing mean radiant temperature, microclimate weather data availability, integration and continuity of different thermal models, and further model validation for vulnerable groups.

Heat Warnings in Switzerland: Reassessing the Choice of the Current Heat Stress Index

High temperatures lead to heat-related human stress and an increased mortality risk. To quantify heat discomfort and the relevant dangers, heat stress indices combine different meteorological variables such as temperature, relative humidity, radiation and wind speed. In this paper, a set of widely-used heat stress indices is analyzed and compared to the heat index currently used to issue official heat warnings in Switzerland, considering 28 Swiss weather stations for the years 1981–2017. We investigate how well warnings based on the heat index match warning days and warning periods that are calculated from alternative heat stress indices. The latter might allow for more flexibility in terms of specific warning demands and impact-based warnings. It is shown that the percentage of alternative warnings that match the official warnings varies among indices. Considering the heat index as reference, the simplified wet bulb globe temperature performs well and has some further advantages such as no lower bound and allowing for the calculation of climatological values. Yet, other indices (e.g., with higher dependencies on humidity) can have some added value, too. Thus, regardless of the performance in terms of matches, the optimal index to use strongly depends on the purpose of the warning.

Multi-Temporal Effects of Urban Forms and Functions on Urban Heat Islands Based on Local Climate Zone Classification

Urban forms and functions have critical impacts on urban heat islands (UHIs). The concept of a “local climate zone” (LCZ) provides a standard and objective protocol for characterizing urban forms and functions, which has been used to link urban settings with UHIs. However, only a few structure types and surface cover properties are included under the same climate background or only one or two time scales are considered with a high spatial resolution. This study assesses multi-temporal land surface temperature (LST) characteristics across 18 different LCZ types in Beijing, China, from July 2017 to June 2018. A geographic information system-based method is employed to classify LCZs based on five morphological and coverage indicators derived from a city street map and Landsat images, and a spatiotemporal fusion model is adopted to generate hourly 100-m LSTs by blending Landsat, Moderate Resolution Imaging Spectroradiometer (MODIS), and FengYun-2F LSTs. Then, annual and diurnal cycle parameters and heat island and cool island (HI or CI) frequency are linked to LCZs at annual, seasonal, monthly, and diurnal scales. Results indicate that: (1) the warmest zones are compact and mid and low-rise built-up areas, while the coolest zones are water and vegetated types; (2) compact and open high-rise built-up areas and vegetated types have seasonal thermal patterns but with different causes; (3) diurnal temperature ranges are the highest for compact and large low-rise settings but the lowest for water and dense or scattered trees; and (4) HIs are the most frequent summertime and daytime events, while CIs occur primarily during winter days, making them more or less frequent for open or compact and high- or low-rise built-up areas. Overall, the distinguishable LSTs or UHIs between LCZs are closely associated with the structure and coverage properties. Factors such as geolocation, climate, and layout also interfere with the thermal behavior. This study provides comprehensive information on how different urban forms and functions are related to LST variations at different time scales, which supports urban thermal regulation through urban design.

New and Old Indices for Evaluating Heat Stress in an Indoor Environment: Some Considerations. Comment on Kownacki, L.; Gao, C.; Kuklane, K.; Wierzbicka, A. Heat Stress in Indoor Environments of Scandinavian Urban Areas: A Literature Review. Int. J. Environ. Res. Public Health 2019, 16 (4), 560. doi:10.3390/ijerph16040560

In their review, Kownacki et al. showed some practical and easy to use workplace heat indices that are useful for indoor environments, namely the “Wet Bulb Globe Temperature” (WBGT), the “Predicted Heat Strain” (PHS) model, the “Thermal Work Limit” (TWL), the “Equivalent Temperature” (ET) and the thermal comfort index “PMV/PPD”. In this letter, the authors explain why the modified PMV/PPD method together with the indices combining temperature with humidity, such as the “Humidex Index” and the “Heat Index”, could be a more feasible and useful tool for evaluating potential thermal stress in indoor environments for both the occupational and general population.