The effects of warm weather on children's outdoor heat stress and physical activity in a preschool yard in Gothenburg, Sweden.

Hot weather conditions can have negative impacts on the thermal comfort and physical activity of vulnerable groups such as children. The aim of this study is to analyze the effects of warm weather on 5-year-old children's thermal comfort and physical activity in a preschool yard in Gothenburg, Sweden. In situ measurements were conducted for 1-1.5 h in the early afternoon on 8 days in May, June, and August of 2022. The thermal comfort and physical activity was estimated with GPS-tracks, heart rate monitors, and step counts and compared to observed weather conditions. Results show that physical activity decreases under warmer weather conditions, depicted by a decrease in distance moved, step counts, and highest registered pulse. Moreover, on warm days, the children avoid sunlit areas. For 50% or more of the time spent in sunlit areas, the children are exposed to cautious levels of heat. In shaded areas, on the other hand, the children are less exposed, with five out of 8 days having 50% or more of the time at neutral levels. The study demonstrates the importance of access to shaded areas in preschool yards where children can continue their active play while simultaneously maintaining a safe thermal status.

Is Physiological Equivalent Temperature (PET) a superior screening tool for heat stress risk than Wet-Bulb Globe Temperature (WBGT) index? Eight years of data from the Gothenburg half marathon.

BACKGROUND: The Wet-Bulb Globe Temperature (WBGT) index is a common tool to screen for heat stress for sporting events. However, the index has a number of limitations. Rational indices, such as the physiological equivalent temperature (PET) and Universal Thermal Climate Index (UTCI), are potential alternatives. AIM: To identify the thermal index that best predicts ambulance-required assistances and collapses during a city half marathon. METHODS: Eight years (2010-2017) of meteorological and ambulance transport data, including medical records, from Gothenburg's half-marathon were used to analyse associations between WBGT, PET and UTCI and the rates of ambulance-required assistances and collapses. All associations were evaluated by Monte-Carlo simulations and leave-one-out-cross-validation. RESULTS: The PET index showed the strongest correlation with both the rate of ambulance-required assistances (R2=0.72, p=0.008) and collapses (R2=0.71, p=0.008), followed by the UTCI (R2=0.64, p=0.017; R2=0.64, p=0.017) whereas the WBGT index showed substantially poorer correlations (R2=0.56, p=0.031; R2=0.56, p=0.033). PET stages of stress, match the rates of collapses better that the WBGT flag colour warning. Compared with the PET, the WBGT underestimates heat stress, especially at high radiant heat load. The rate of collapses increases with increasing heat stress; large increase from the day before the race seems to have an impact of the rate of collapses. CONCLUSION: We contend that the PET is a better predictor of collapses during a half marathon than the WBGT. We call for further investigation of PET as a screening tool alongside WBGT.

Medical Emergencies During a Half Marathon Race - The Influence of Weather.

The aim was to analyze the influence of weather conditions on medical emergencies in a half-marathon, specifically by evaluating its relation to the number of non-finishers, ambulance-required assistances, and collapses in need of ambulance as well as looking at the location of such emergencies on the race course. Seven years of data from the world's largest half marathon were used. Meteorological data were obtained from a nearby weather station, and the Physiological Equivalent Temperature (PET) index was used as a measure of general weather conditions. Of the 315,919 race starters, 104 runners out of the 140 ambulance-required assistances needed ambulance services due to collapses. Maximum air temperature and PET significantly co-variated with ambulance-required assistances, collapses, and non-finishers (R2=0.65-0.92; p=0.001-0.03). When air temperatures vary between 15-29°C, an increase of 1°C results in an increase of 2.5 (0.008/1000) ambulance-required assistances, 2.5 (0.008/1000) collapses (needing ambulance services), and 107 (0.34/1000) non-finishers. The results also indicate that when the daily maximum PET varies between 18-35°C, an increase of 1°C PET results in an increase of 1.8 collapses (0.006/1000) needing ambulance services and 66 non-finishers (0.21/1000).

Can participants predict where ambulance-requiring cases occur at a half marathon?

OBJECTIVES: Despite endurance races leading to a substantial number of ambulance-requiring cases (ARC), little is known regarding where they occur, meaning that knowing where to place medical teams, ambulance pick-up points, etc, is difficult. This article investigates whether the location of ARCs can be identified by race participants. METHODS: Using the world's largest half marathon (Gothenburg half marathon) as a case, 237 runners were asked, post-race, to mark on a map which geographical point of the race was most exhausting. Using the level of agreement tests, these geographical points were then compared with the GPS positions of ARCs. RESULTS: According to the level of agreement tests, the most exhausting positions (MEP), as identified by participants, seem to be highly correlated to the location of ARCs. This study can also show that ambulance-requiring cases seem to be more prevalent towards the end of the race and in uphill sections. CONCLUSIONS: By asking participants where they found the race most exhausting it seems possible to identify high-risk places for an ARC. From a practical perspective, using this method could considerably increase the safety of competitors as well as improving the cost-effectiveness of safety interventions at endurance races. Further studies are needed to understand the specific risk factors of the high-risk areas as well as characteristics of collapsed runners.

Effect of urban design on microclimate and thermal comfort outdoors in warm-humid Dar es Salaam, Tanzania.

Due to the complexity of built environment, urban design patterns considerably affect the microclimate and outdoor thermal comfort in a given urban morphology. Variables such as building heights and orientations, spaces between buildings, plot coverage alter solar access, wind speed and direction at street level. To improve microclimate and comfort conditions urban design elements including vegetation and shading devices can be used. In warm-humid Dar es Salaam, the climate consideration in urban design has received little attention although the urban planning authorities try to develop the quality of planning and design. The main aim of this study is to investigate the relationship between urban design, urban microclimate, and outdoor comfort in four built-up areas with different morphologies including low-, medium-, and high-rise buildings. The study mainly concentrates on the warm season but a comparison with the thermal comfort conditions in the cool season is made for one of the areas. Air temperature, wind speed, mean radiant temperature (MRT), and the physiologically equivalent temperature (PET) are simulated using ENVI-met to highlight the strengths and weaknesses of the existing urban design. An analysis of the distribution of MRT in the areas showed that the area with low-rise buildings had the highest frequency of high MRTs and the lowest frequency of low MRTs. The study illustrates that areas with low-rise buildings lead to more stressful urban spaces than areas with high-rise buildings. It is also shown that the use of dense trees helps to enhance the thermal comfort conditions, i.e., reduce heat stress. However, vegetation might negatively affect the wind ventilation. Nevertheless, a sensitivity analysis shows that the provision of shade is a more efficient way to reduce PET than increases in wind speed, given the prevailing sun and wind conditions in Dar es Salaam. To mitigate heat stress in Dar es Salaam, a set of recommendations and guidelines on how to develop the existing situation from microclimate and thermal comfort perspectives is outlined. Such recommendations will help architects and urban designers to increase the quality of the outdoor environment and demonstrate the need to create better urban spaces in harmony with microclimate and thermal comfort.

A framework for assessing urban greenery's effects and valuing its ecosystem services.

Ongoing urban exploitation is increasing pressure to transform urban green spaces, while there is increasing awareness that greenery provides a range of important benefits to city residents. In efforts to help resolve associated problems we have developed a framework for integrated assessments of ecosystem service (ES) benefits and values provided by urban greenery, based on the ecosystem service cascade model. The aim is to provide a method for assessing the contribution to, and valuing, multiple ES provided by urban greenery that can be readily applied in routine planning processes. The framework is unique as it recognizes that an urban greenery comprises several components and functions that can contribute to multiple ecosystem services in one or more ways via different functional traits (e.g. foliage characteristics) for which readily measured indicators have been identified. The framework consists of five steps including compilation of an inventory of indicator; application of effectivity factors to rate indicators' effectiveness; estimation of effects; estimation of benefits for each ES; estimation of the total ES value of the ecosystem. The framework was applied to assess ecosystem services provided by trees, shrubs, herbs, birds, and bees, in green areas spanning an urban gradient in Gothenburg, Sweden. Estimates of perceived values of ecosystem services were obtained from interviews with the public and workshop activities with civil servants. The framework is systematic and transparent at all stages and appears to have potential utility in the existing spatial planning processes.

Present and projected future mean radiant temperature for three European cities.

Present-day and projected future changes in mean radiant temperature, T mrt in one northern, one mid-, and one southern European city (represented by Gothenburg, Frankfurt, and Porto), are presented, and the concept of hot spots is adopted. Air temperature, T a , increased in all cities by 2100, but changes in solar radiation due to changes in cloudiness counterbalanced or exacerbated the effects on T mrt. The number of days with high T mrt in Gothenburg was relatively unchanged at the end of the century (+1 day), whereas it more than doubled in Frankfurt and tripled in Porto. The use of street trees to reduce daytime radiant heat load was analyzed using hot spots to identify where trees could be most beneficial. Hot spots, although varying in intensity and frequency, were generally confined to near sunlit southeast-southwest facing walls, in northeast corner of courtyards, and in open spaces in all three cities. By adding trees in these spaces, the radiant heat load can be reduced, especially in spaces with no or few trees. A set of design principles for reducing the radiant heat load is outlined based on these findings and existing literature.

Transpiration of urban trees and its cooling effect in a high latitude city.

An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and surface permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea, Quercus robur, Betula pendula, Acer platanoides, Aesculus hippocastanum, Fagus sylvatica and Prunus serrulata. Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m(-2) s(-1) (B. pendula) to over 3 mmol m(-2) s(-1) (Q. robur). Daytime stomatal conductance was positively related to the fraction of permeable surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional surface permeability within the crown area, was found to explain 68% of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20% of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m(-2), tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m(-2), a cooling effect of tree transpiration was not observed during the day.

The effect of urban geometry on mean radiant temperature under future climate change: a study of three European cities.

Future anthropogenic climate change is likely to increase the air temperature (T(a)) across Europe and increase the frequency, duration and magnitude of severe heat stress events. Heat stress events are generally associated with clear-sky conditions and high T(a), which give rise to high radiant heat load, i.e. mean radiant temperature (T(mrt)). In urban environments, T mrt is strongly influenced by urban geometry. The present study examines the effect of urban geometry on daytime heat stress in three European cities (Gothenburg in Sweden, Frankfurt in Germany and Porto in Portugal) under present and future climates, using T(mrt) as an indicator of heat stress. It is found that severe heat stress occurs in all three cities. Similar maximum daytime T(mrt) is found in open areas in all three cities despite of the latitudinal differences in average daytime T(mrt). In contrast, dense urban structures like narrow street canyons are able to mitigate heat stress in the summer, without causing substantial changes in T(mrt) in the winter. Although the T(mrt) averages are similar for the north-south and east-west street canyons in each city, the number of hours when T(mrt) exceeds the threshold values of 55.5 and 59.4 °C-used as indicators of moderate and severe heat stress-in the north-south canyons is much higher than that in the east-west canyons. Using statistically downscaled data from a regional climate model, it is found that the study sites were generally warmer in the future scenario, especially Porto, which would further exacerbate heat stress in urban areas. However, a decrease in solar radiation in Gothenburg and Frankfurt reduces T(mrt) in the spring, while the reduction in T(mrt) is somewhat offset by increasing T(a) in other seasons. It suggests that changes in the T(mrt) under the future scenario are dominated by variations in T(a). Nonetheless, the intra-urban differences remain relatively stable in the future. These findings suggest that dense urban structure can reduce daytime heat stress since it reduces the number of hours of high T(mrt) in the summer and does not cause substantial changes in average and minimum T(mrt) in the winter. In dense urban settings, a more diverse urban thermal environment is also preferred to compensate for reduced solar access in the winter. The extent to which the urban geometry can be optimized for the future climate is also influenced by local urban characteristics.

Characteristics of the mean radiant temperature in high latitude cities--implications for sensitive climate planning applications.

Knowledge of how the mean radiant temperature (T mrt ) is affected by factors such as location, climate and urban setting contributes to the practice of climate sensitive planning. This paper examines how T mrt varies within an urban setting and how it is influenced by cloudiness. In addition, variations of T mrt in three high latitude cities are investigated in order to analyse the impact of geographical context and climate conditions. Results showed large spatial variations between sunlit and shaded areas during clear weather conditions, with the highest values of T mrt close to sunlit walls and the lowest values in the areas shaded by buildings and vegetation. As cloudiness increases, the spatial pattern is altered and the differences are reduced. The highest T mrt under cloudy conditions is instead found in open areas where the proportion of shortwave diffuse radiation from the sky vault is high. A regional comparison between three Swedish coastal cities showed that T mrt during summer is similar regardless of latitudinal location. On the other hand, large differences in T mrt during winter were found. Shadows, both from buildings and vegetation are the most effective measure to reduce extreme values of T mrt. However, extensive areas of shadow are usually not desired within outdoor urban environments at high latitude cities. One solution is to create diverse outdoor urban spaces in terms of shadow and also ventilation. This would provide individuals with access to a choice of thermal environments which they can use to assist their thermal regulation, based on personal needs and desires.

Carbon monoxide concentrations in outdoor wood-fired kitchens in Ouagadougou, Burkina Faso--implications for women's and children's health.

A majority of households in developing countries rely on biomass fuel for cooking, typically burned in open fires or simple stoves. The incomplete combustion of these fuels causes adverse health effects such as respiratory diseases, especially among women and children. However, quantitative data on pollution levels and on associated diseases are limited. We examined cooking habits and self-reported health in 31 households with outdoor open wood fires in Ouagadougou, Burkina Faso, using structured interviews. In eight households, carbon monoxide (CO) was measured using passive sampling. In addition, meteorology and ambient CO concentrations were assessed. The average CO concentration during cooking was 4.3 ppm, with a maximum of 65.3 ppm and minimum of 0.3 ppm (1-min values). A clear daily pattern was observed, with relatively low concentrations during the day and high during the evening, occasionally exceeding the World Health Organization 1- and 8-h guidelines when the air stabilised. On average, CO concentrations were 43 % higher in kitchens located in closed yards than in those located in open yards, showing that fireplace location affected the levels. Eye irritation and coughing among women and children were reported by 30 % of the households. Based on previously reported relations between CO concentrations and fine particles (<2.5 µm), the exposure to biomass smoke appears to be high enough to pose a considerable health risk among women and children in households with outdoor open wood fires. The results suggest that burning should be limited between sunset and dawn and in areas with limited ventilation to reduce pollutions levels.

Sub-arctic palsa degradation and the role of climatic drivers in the largest coherent palsa mire complex in Sweden (Vissátvuopmi), 1955-2016.

Substantial palsa degradation has occurred in Fennoscandia, which is considered to be driven by global climate change. Deeper understanding of the role of different climatic drivers on palsa decay, however, is lacking. We use meteorological data and aerial photographs from 1955 to 2016 to statistically identify the most important climatic drivers affecting changes in lateral-temporal palsa decay rates in the largest coherent palsa complex in Sweden, Vissátvuopmi. We show that wetter, warmer and shorter winters are the main causes of large and rapid changes in lateral-palsa extent since the mid-1950s. By analyzing meteorological data from the 1880s to present, we show that average annual temperature conditions have been unfavourable for palsas for more than a century and average annual precipitation conditions have been unfavourable since the 1940s. The decay rates have likely been amplified over the past 50-60 years, and in particular over the most recent decades, due to the combined effect of adverse air temperature and precipitation conditions. Palsa loss is expected to continue, most likely at a higher rate than today, with serious ecological impacts as a consequence.

Profiling Collapsing Half Marathon Runners-Emerging Risk Factors: Results from Gothenburg Half Marathon.

Among several serious medical conditions, arrhythmia and heat stroke are two important causes of death during endurance races. Clinically, collapsing might be the first sign of these serious conditions and may mimic the more common and benign exercise-associated collapse. Several risk factors have been reported in the literature. We aimed to conduct a qualitative study to find a perceived risk profile among runners who collapsed and who were transported by ambulances to the nearest hospital during Gothenburg's half marathon (2010-2017). Collapsing runners seem to lack the ability to make a decision to withdraw from the contest despite being exhausted. They feel the pain, but are unable to put meaning to their feeling, to adjust their pacing, and to handle other influences. Consequently, they do not overcome the problem or assess the situation. These individual mental characteristics may indicate a unique profile for collapsing runners. Pre-race health control and educational initiatives aiming at mental preparedness and information before endurance races might be a necessary step to avoid life-threatening complications.

Psychological mechanisms in outdoor place and weather assessment: towards a conceptual model.

The general aim has been to illuminate the psychological mechanisms involved in outdoor place and weather assessment. This reasoning was conceptualized in a model, tentatively proposing direct and indirect links of influence in an outdoor place-human relationship. The model was subsequently tested by an empirical study, performed in a Nordic city, on the impact of weather and personal factors on participants' perceptual and emotional estimations of outdoor urban places. In line with our predictions, we report significant influences of weather parameters (air temperature, wind, and cloudlessness) and personal factors (environmental attitude and age) on participants' perceptual and emotional estimations of outdoor urban places. All this is a modest, yet significant, step towards an understanding of the psychology of outdoor place and weather assessment.

SOLWEIG 1.0--modelling spatial variations of 3D radiant fluxes and mean radiant temperature in complex urban settings.

The mean radiant temperature, T(mrt), which sums up all shortwave and longwave radiation fluxes (both direct and reflected) to which the human body is exposed is one of the key meteorological parameters governing human energy balance and the thermal comfort of man. In this paper, a new radiation model (SOLWEIG 1.0), which simulates spatial variations of 3D radiation fluxes and T(mrt) in complex urban settings, is presented. The T(mrt) is derived by modelling shortwave and longwave radiation fluxes in six directions (upward, downward and from the four cardinal points) and angular factors. The model requires a limited number of inputs, such as direct, diffuse and global shortwave radiation, air temperature, relative humidity, urban geometry and geographical information (latitude, longitude and elevation). The model was evaluated using 7 days of integral radiation measurements at two sites with different building geometries--a large square and a small courtyard in Göteborg, Sweden (57 degrees N)--across different seasons and in various weather conditions. The evaluation reveals good agreement between modelled and measured values of T(mrt), with an overall good correspondence of R (2) = 0.94, (p < 0.01, RMSE = 4.8 K). SOLWEIG 1.0 is still under development. Future work will incorporate a vegetation scheme, as well as an improvement of the estimation of fluxes from the four cardinal points.

Influences of culture and environmental attitude on thermal, emotional and perceptual evaluations of a public square.

The main objective of the present quasi-experimental study was to examine the influence of culture (Swedish vs Japanese) and environmental attitude (urban vs open-air person) on participants' thermal, emotional and perceptual assessments of a square, within the PET (physiological equivalent temperature) comfortable interval of 18-23 degrees C. It was predicted that persons living in different cultures with different environmental attitudes would psychologically evaluate a square differently despite similar thermal conditions. Consistent with this prediction, Japanese participants estimated the current weather as warmer than did Swedish participants and, consistent with this, they felt less thermally comfortable on the site, although participants in both countries perceived similar comfortable thermal outdoor conditions according to the PET index. Compared to the Japanese, the Swedes estimated both the current weather and the site as windier and colder, indicating a consistency in weather assessment on calm-windy and warm-cold scales in participants in both cultures. Furthermore, Swedish participants felt more glad and calm on the site and, in line with their character (more glad than gloomy), they estimated the square as more beautiful and pleasant than did Japanese participants. All this indicates that thermal, emotional and perceptual assessments of a physical place may be intertwined with psychological schema-based and socio-cultural processes, rather than fixed by general thermal indices developed in line with physiological heat balance models. In consequence, this implies that thermal comfort indices may not be applicable in different cultural/climate zones without modifications, and that they may not be appropriate if we do not take into account the psychological processes involved in environmental assessment.

Thermal bioclimatic conditions and patterns of behaviour in an urban park in Göteborg, Sweden.

People in urban areas frequently use parks for recreation and outdoor activities. Owing to the complexity of the outdoor environment, there have only been a few attempts to understand the effect of the thermal environment on people's use of outdoor spaces. This paper therefore seeks to determine the relationship between the thermal environment, park use and behavioural patterns in an urban area of Sweden. The methods used include structured interviews, unobtrusive observations of the naturally occurring behaviour and simultaneous measurements of thermal comfort variables, i.e., air temperature, air humidity, wind speed and global radiation. The thermal environment is investigated through the mean radiant temperature (Tmrt) and the predicted mean vote (PMV) index. The outcome is compared to the subjective behaviour and thermal sensation of the interviewees. It is found that the thermal environment, access and design are important factors in the use of the park. In order to continue to use the park when the thermal conditions become too cold or too hot for comfort, people improve their comfort conditions by modifying their clothing and by choosing the most supportive thermal opportunities available within the place. The study also shows that psychological aspects such as time of exposure, expectations, experience and perceived control may influence the subjective assessment. Comparison between the thermal sensation of the interviewees and the thermal sensation assessed by the PMV index indicates that steady-state models such as the PMV index may not be appropriate for the assessment of short-term outdoor thermal comfort, mainly because they are unable to analyse transient exposure.

A geographical information system model for creating bioclimatic maps - examples from a high, mid-latitude city.

This paper presents a method for creating large-scale bioclimatic maps with the aid of a geographical information system, GIS. Meteorological data are linked with geographical information about land use, elevation and distance to the coast, in order to generate spatial distributions of physiological equivalent temperature, PET. The model combines an air temperature map and a wind map in order to create different zones for which the thermal component is to be calculated. The advantage of the model presented is that it uses generally available information about land use, altitude and distance to the coast. Further, the model uses a GIS application, which makes it non-static. Compared to most other models, a wide range of observations are used as input. Few biometeorological studies have been performed in high-latitude areas. This paper presents bioclimatic maps for the Göteborg urban area, in Sweden, for the month of July. The results show large variations in PET during a clear, calm day at 1200 hours (Delta T 13.4 degrees C) and during average conditions in July (Delta T 6.8 degrees C), which gives an indication of the magnitude and the spatial variations within high, midlatitude, urban area in summer. The highest PET values were found in the central built-up areas and the lowest PET values in the coastal and green areas. The model generates valuable information for urban planners and decision makers when planning and constructing new areas for outdoor activities etc. This information is also useful in the fields of health and energy.