Adaptive behaviors during heat wave among residents of Shenzhen city, 2014

BackgroundIn many parts of the world, including in China, extreme heat events or heat waves are likely to increase in intensity, frequency, and duration in light of climate change in the next decades. Risk perception and adaptation behaviors are two important components in reducing the health impacts of heat waves, but little is known about their relationships in China. This study aimed to examine the associations between risk perception to heat waves, adaptation behaviors, and heatstroke among the public in Guangdong province, China.MethodsA total of 2,183 adult participants were selected using a four-stage sampling method in Guangdong province. From September to November of 2010 each subject was interviewed at home by a well-trained investigator using a structured questionnaire. The information collected included socio-demographic characteristics, risk perception and spontaneous adaptation behaviors during heat wave periods, and heatstroke experience in the last year. Chi-square tests and unconditional logistic regression models were employed to analyze the data.ResultsThis study found that 14.8%, 65.3% and 19.9% of participants perceived heat waves as a low, moderate or high health risk, respectively. About 99.1% participants employed at least one spontaneous adaptation behavior, and 26.2%, 51.2% and 22.6% respondents employed <4, 4–7, and >7 adaptation behaviors during heat waves, respectively. Individuals with moderate (OR=2.93, 95% CI: 1.38-6.22) or high (OR=10.58, 95% CI: 4.74-23.63) risk perception experienced more heatstroke in the past year than others. Drinking more water and wearing light clothes in urban areas, while decreasing activity as well as wearing light clothes in rural areas were negatively associated with heatstroke. Individuals with high risk perception and employing <4 adaptation behaviors during heat waves had the highest risks of heatstroke (OR=47.46, 95% CI: 12.82-175.73).ConclusionsThere is a large room for improving health risk perception and adaptation capacity to heat waves among the public of Guangdong province. People with higher risk perception and fewer adaptation behaviors during heat waves may be more vulnerable to heat waves.

The impact of global climate change is also felt in Hungary. An undesirable effect of climate change (associated with rising temperatures) is mainly the increase in the frequency, intensity, and length of summer heat waves. In this respect, the region of the Southern Great Plain and the Danube-Tisza Region are particularly endangered, but the number of heat wave days has increased throughout the country in recent decades. This study takes the climatic data sets of Baja into account, and on this basis, it gives the probability that a particular day falls into a heat wave period. Based on this information we draw a general conclusion about the long-term change of this climatic characteristic of the Southern Great Plain. The mathematical model used in the research applies the theory of Markov chains, which is relatively new in statistical analysis.

Heat waves may become a serious threat to the health and safety of people who currently live in temperate climates. It was therefore of interest to investigate whether more deprived populations are more vulnerable to heat waves. In order to address the question on a fine geographical scale, the spatial heterogeneity of the excess mortality in France associated with the European heat wave of August 2003 was analysed. A deprivation index and a heat exposure index were used jointly to describe the heterogeneity on the Canton scale (3,706 spatial units). During the heat wave period, the heat exposure index explained 68% of the extra-Poisson spatial variability of the heat wave mortality ratios. The heat exposure index was greater in the most urbanized areas. For the three upper quintiles of heat exposure in the densely populated Paris area, excess mortality rates were twofold higher in the most deprived Cantons (about 20 excess deaths/100,000 people/day) than in the least deprived Cantons (about 10 excess deaths/100,000 people/day). No such interaction was observed for the rest of France, which was less exposed to heat and less heterogeneous in terms of deprivation. Although a marked increase in mortality was associated with heat wave exposure for all degrees of deprivation, deprivation appears to be a vulnerability factor with respect to heat-wave-associated mortality.

THE IMPACT OF SUMMER 2003 HEAT WAVE ON MORTALITY AMONG ELDERLY PEOPLE IN THE ITALIAN CITY OF GENOA

Understanding the differences in the contribution and impact of urbanization on urban warming during heatwave and non-heatwave periods in China

Excess deaths during the August 2003 heat wave in Paris, France

Research on heat waves (periods of excessively hot weather, which may be accompanied by high humidity) is a newly emerging research topic within the field of climate change research with high relevance for the whole of society. In this study, we analyzed the rapidly growing scientific literature dealing with heat waves. No summarizing overview has been published on this literature hitherto. We developed a suitable search query to retrieve the relevant literature covered by the Web of Science (WoS) as complete as possible and to exclude irrelevant literature (n = 8,011 papers). The time evolution of the publications shows that research dealing with heat waves is a highly dynamic research topic, doubling within about 5 years. An analysis of the thematic content reveals the most severe heat wave events within the recent decades (1995 and 2003), the cities and countries/regions affected (USA, Europe, and Australia), and the ecological and medical impacts (drought, urban heat islands, excess hospital admissions, and mortality). An alarming finding is that the limit for survivability may be reached at the end of the twenty-first century in many regions of the world due to the fatal combination of rising temperatures and humidity levels measured as “wet-bulb temperature” (WBT). Risk estimation and future strategies for adaptation to hot weather are major political issues. We identified 104 citation classics, which include fundamental early works of research on heat waves and more recent works (which are characterized by a relatively strong connection to climate change).

Association between environmental factors and emergency hospital admissions due to Alzheimer's disease in Madrid

China experienced major heat waves in summer 2013, being the worst the last 140 years in Eastern China. The RegCM-Chem4 climate-chemistry model was applied over China for the summer 2013 with a spatial resolution of 60 km and hourly temporal analysis. This study focuses on the examination of the RegCM-Chem4 performance in the simulation of ozone levels during two prolonged heat wave periods (24/07/2013–31/07/2013 and 07/08/2013–14/08/2013) and a non heat wave period (05/06/2013–12/06/2013) in Central and Eastern China. Near surface model results for ozone are compared with hourly observational data from 45 monitoring stations of the Chinese air quality network. The RegCM-Chem4 validation in the non-HW period presents good results. In August HW, the model underestimates the O3 values and variability, in line with RegCM-Chem4 temperature values underestimation in the same period, showing at almost all stations a performance that is not as good as that in the non-HW period. The performance of the model in the July HW requires further analysis; RegCM-Chem4 also underestimates the O3 levels and variability at almost all stations, however the model performance is not as good as that in the non-HW period only at a part of the AQ stations.

&amp;lt;p&amp;gt;Both heat and cold waves cause extreme human thermal discomfort and a clear excess in mortality. This shows the importance of knowing the prevailing thermal comfort conditions and how thermal comfort conditions vary in various environments so measures can be taken. Microclimatic and outdoor human thermal comfort conditions are investigated in various built-up and green areas in the city of Ghent (Belgium) using meteorological measurements of six weather stations of the MOCCA (Monitoring the Cities Climate and Atmosphere) network in combination with calculations done by RayMan.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Normal to extreme summer heat wave periods show that dangerous strong heat stress prevails during the daytime periods at all locations. Comparison of thermal comfort during normal and extreme summer heat wave periods showed that heat stress is more extreme when a heat wave is more intense. Overall the urban park in Ghent was the most comfortable location during heat waves since it effectively mitigates heat stress in the city. These results should be taken into account in urban planning and design to keep mid-latitude cities livable.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;Further, a one year data series revealed that outdoor cold stress was more apparent during 2017 in the mid-latitude city of Ghent that experiences a mild maritime climate. During spring and summer, both heat stress and cold stress occurred due to the larger diurnal temperature range compared to the other seasons. Even though high Physiological Equivalent Temperatures (PET) were obtained during a heat wave in summer, heat stress did not occur as intensely and as frequently compared to cold stress on annual level. It could thus be stated that outdoors, cold stress is a bigger threat than heat stress. However, one should keep in mind that the study was executed for outdoor thermal heat comfort and that people will take shelter or take measures when feeling uncomfortable. The question is thus rather, how are citizens protected against heat and cold stress? Currently, the Belgian society is better adapted to cold stress since most buildings contain central heating, while air conditioning is not standard. Future projections predict an increase in temperature, causing more occurrence of extreme heat stress, while extreme cold stress will be reduced. Additionally, the urban heat island effect currently has mainly a positive effect on the average annual outdoor thermal comfort conditions, while it will become a negative effect in the warmer future. Measures should thus be taken to reduce the threat of future heat stress.&amp;lt;/p&amp;gt;

Atmospheric oxidative pollutants, air temperature, and heatwave events pose potential threats to public health. However, the combined effects of these factors on the risk of mortality from circulatory disease remain insufficiently studied. This study aims to evaluate the synergistic effects of ozone (O₃), oxidant (Ox), and nitrogen dioxide (NO₂) with temperature and heat waves, and to explore their impact on circulatory disease mortality, providing evidence to support public health interventions. Based on the mortality, meteorological, and environmental protection data of residents in Fuzhou City from January 1, 2016, to December 31, 2022, we employed a generalized additive model (GAM) and a distributed lag nonlinear model (DLNM) to assess the effects of atmospheric oxidative pollutants interacting with temperature and heat waves on the risk of death from circulatory diseases, where temperature includes the daily maximum temperature and diurnal temperature range (DTR). A bivariate three-dimensional model was used to visualize their synergistic effects, and stratified analyses were conducted to compare differences between heat wave and non-heat wave periods. O3, Ox, and NO2 exhibit synergistic effects with ambient temperature, and their combined exposure significantly increases the mortality risk of circulatory system diseases, myocardial infarction, and stroke, with some health effects showing a "nonlinear exposure-response relationship with an inverted U-shaped pattern." Under heatwave conditions, the synergistic effect between NO2 and high temperatures is markedly enhanced, leading to a greater increase in mortality risk compared to O3 and Ox, and demonstrating both a same-day lag and a cumulative effect. After introducing other pollutants into the dual-pollution model, NO2 still shows a strong independent health effect on major causes of death during heatwaves, with the most pronounced risk elevation observed for stroke. Atmospheric oxidative pollutants interact with high temperatures, diurnal temperature range, and heatwaves, significantly increasing the risk of mortality. It is essential to integrate air pollution and meteorological factors to strengthen health protection during high-risk periods.

&amp;lt;p&amp;gt;This study investigates the diurnal variations of the planetary boundary layer (PBL) during heatwaves (HWs) based on a decade-long data record of hourly profiles from the Aircraft Meteorological Data Reports (AMDAR) at 54 major airports over the Contiguous United States. The results are also corroborated by the surface observations from weather station data. Temperature differences between HW and non-HW periods show strong diurnal and vertical variations in the PBL. Under HWs, the daytime convective PBL becomes higher while the nocturnal residual layer becomes excessively hotter, which creates a positive feedback on HW intensity and duration by providing heat for the next day through entrainment. Changes in wind speed in the PBL during HWs are dependent on the relative location between the observational site and the center of the high-pressure system and do not always show decreases. The specific humidity often increases in humid regions mainly due to the higher evaporation demand which causes more surface evaporation, but decreases in arid regions due to the dry air entrainment and subsidence. In addition, moisture advection could also play an important role in modulating the change of PBL humidity. This study improves our scientific understanding of HW-related changes in the PBL structure and highlights their possible connections with the synoptic-scale atmospheric circulation patterns and land-atmosphere feedbacks. However, future research examining the role of PBL in the onset and demise of HWs and examining whether meteorological models can capture the observed response of the PBL to HWs is strongly needed.&amp;lt;/p&amp;gt;

Extreme weather events, such as heat waves, are increasingly common during summers in theMediterranean area. The effect of urban overheating -known as the increase of the averagetemperature within the urban canopy caused by the heat storage on their surfaces thanks to theiroptical and thermal characteristics, in addition to the heat emissions due to anthropogenic activities-can cause the thermal stress of the population in the city to increase significantly during theseepisodes, leading to serious health consequences. The study of this type of impact must bequantified by means of thermal comfort indices that establish a relationship between themeteorological conditions observed or predicted by a model and the physiological response ofhuman beings, such as the Universal Thermal Climate Index (UTCI). In this work, we study thespatial-temporal behaviour of the UTCI in the city of Valencia (east coast of Spain) during a heatwave (HW) and non-heat wave (NHW) period in August 2023 using the mesoscale meteorologicalmodel (WRF, Weather Research and Forecasting) and in situ observations. For this purpose, acomparison of atmospheric conditions in the planetary boundary layer (PBL) is performed, as well asa study of the influence of temperature, shortwave and longwave radiation (from the mean radianttemperature, TMR), wind speed and relative humidity on the behaviour of the UTCI. The mainresults show a similar spatial distribution and temporal evolution of the UTCI for both periods,differing in the magnitude of the UTCI. The positive (negative) temperature anomaly with regards tothe rest of the month is mainly the factor that causes a greater increase (decrease) in UTCI duringthe HW (NHW). There is also a less developed PBL during the HW, as a consequence of the lowerintensity of the coastal breeze in the city during this period, which also has a significant effect on theincrease in UTCI during the HW.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous pulmonary disease affecting 16 million Americans. Individuals with COPD are susceptible to environmental disturbances including heat and cold waves that can exacerbate disease symptoms. Our objective was to estimate heat and cold wave-associated mortality risks within a population diagnosed with a chronic respiratory disease. We collected individual level data with geocoded residential addresses from the Veterans Health Administration on 377,545 deceased patients with COPD (2016 to 2021). A time stratified case-crossover study was designed to estimate the incidence rate ratios (IRR) of heat and cold wave mortality risks using conditional logistic regression models examining lagged effects up to 7 d. Attributable risks (AR) were calculated for the lag day with the strongest association for heat and cold waves, respectively. Effect modification by age, gender, race, and ethnicity was also explored. Heat waves had the strongest effect on all-cause mortality at lag day 0 [IRR: 1.04; 95% confidence interval (CI): 1.02, 1.06] with attenuated effects by lag day 1. The AR at lag day 0 was 651 (95% CI: 326, 975) per 100,000 veterans. The effect of cold waves steadily increased from lag day 2 and plateaued at lag day 4 (IRR: 1.04; 95% CI: 1.02, 1.07) with declining but still elevated effects over the remaining 7-d lag period. The AR at lag day 4 was 687 (95% CI: 344, 1,200) per 100,000 veterans. Differences in risk were also detected upon stratification by gender and race. Our study demonstrated harmful associations between heat and cold waves among a high-risk population of veterans with COPD using individual level health data. Future research should emphasize using individual level data to better estimate the associations between extreme weather events and health outcomes for high-risk populations with chronic medical conditions. https://doi.org/10.1289/EHP13176.

Supplementary material to "Diurnal Asymmetry in Nonlinear Responses of Canopy Urban Heat Island to Urban Morphology in Beijing during Heat Wave Periods"