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Climate change and air pollution are pressing public health concerns, necessitating monitoring of their impact, particularly on respiratory diseases like obstructive lung diseases. This retrospective study analyzed medical records of patients hospitalized at the Warmia and Mazury Centre for Pulmonary Diseases in Olsztyn, Poland (2012–2021) for asthma and chronic obstructive pulmonary disease (COPD) exacerbations. Data included meteorological factors such as temperature, humidity, wind speed, precipitation, and levels of PM2.5 and PM10. The Humidex was utilized to assess thermal discomfort, considering various meteorological and thermal seasons. Findings indicated seasonal variability in asthma and COPD exacerbations. During winter, poorer air quality due to higher PM2.5 and PM10 levels correlated with increased exacerbations (r = 0.283, p < 0.05; r = 0.491, p < 0.001). In summer, discomfort from meteorological conditions led to more hospital admissions. Humidex values strongly correlated with admissions for obstructive diseases (R2 = 0.956 for asthma; R2 = 0.659 for COPD), with July and August showing statistically higher admission rates (p < 0.05). The study highlights the significant impact of air pollution and meteorological conditions on exacerbations of asthma and COPD, with Humidex serving as a valuable predictor during summer months. [ABSTRACT FROM AUTHOR]

To help with preparedness efforts of Canadian public health and safety systems for adaptation to climate change, the humidity index (humidex) and three threshold‐based humidex indices (annual number of days with humidex greater than 30, 35 and 40) were computed for a multi‐model ensemble of climate change projections, over Canada. The ensemble consists of one run from each 19 Coupled Model Intercomparison Project Phase 6 (CMIP6) global climate models and offers historical simulations starting in 1950 and future projections out to 2100 following Shared Socioeconomic Pathways (SSPs): SSP1‐2.6, SSP2‐4.5 and SSP5‐8.5. Each ensemble member was bias‐adjusted and statistically downscaled using the Multivariate bias correction—N‐dimensional probability density function transform (MBCn) with hourly data from ERA5‐Land as the target dataset and following a method proposed by Diaconescu et al. (2023; International Journal of Climatology, 43, 837) to calculate humidex from daily climate model outputs. This paper details the steps for data production including evaluation of the target historical gridded data and selection of downscaling method and presents some of the resulting humidex projections at the end of the century. [ABSTRACT FROM AUTHOR]

The 2021 heatwave over Western North America (WNA) led to record‐breaking air temperatures and human‐perceived heat stress (humidex) values. The event was accompanied by drier conditions driven by prolonged atmospheric blocking. During the heatwave, the maximum 6‐day means of humidex and temperature (HX‐6 and TX‐6) exhibited larger anomalies (6.70 and 5.57°C) compared to the 95th percentiles (HX95 and TX95) (4.12 and 3.73°C), relative to 1981–2021 extended summer (June‐September) averages. Extreme indices of humidex show faster and larger increases than those of temperature, reflecting the nonlinear positive relationship between humidex and temperature. Future projections from a multi‐model ensemble of 19 Coupled Model Intercomparison Project Phase six (CMIP6) Global Climate Models (GCMs) clearly show an increase in humidex and temperature extremes, especially under intermediate and high emissions scenarios. Humidex indices (HX‐6 and HX95) show faster and larger increases than temperature indices (TX‐6 and TX95) for the same future years and global warming levels. Controlling for differences in GCM climate sensitivity to greenhouse gas forcing yields robust projections at various global warming levels, reducing the ranges of projected changes from the multi‐model ensemble. At 3.0°C global warming from pre‐industrial, the multi‐model ensemble projects occurrences of HX‐6, TX‐6, HX95, and TX95 over WNA that exceed 2021 levels to occur every 3.9, 1.7, 1.4, and 2.2 years, respectively, increasing to almost annually at 4.0°C. Plain Language Summary: In 2021 summer, Western North America (WNA) experienced an unprecedented heatwave, breaking air temperature and human‐perceived heat stress (humidex) records despite lower humidity due to prolonged atmospheric blocking. During the heatwave, consecutive 6‐day means of heat stress (HX‐6) and temperature (TX‐6) showed larger anomalies (6.70 and 5.57°C) compared to the 95th percentiles (HX95 and TX95) (4.12 and 3.73°C) over the region, relative to their averages over the 1981–2010 summer period (June‐September). Heat stress increased faster and more significantly than air temperature due to their nonlinear relationship. Future projections from 19 climate models reveal clear increases in heat stress and temperature, especially under intermediate and high emission scenarios. Heat stress indices show larger and faster increases than temperature indices at the same future years and global warming levels. Accounting for uncertainty related to climate model sensitivity enhances projection reliability. At 3.0°C global warming from pre‐industrial levels, 2021‐level events over WNA are projected to occur every few years, becoming an almost annual occurrence at 4.0°C. The study underscores the critical need for robust projections using multi‐model ensembles. Key Points: Unprecedented 2021 summer heatwave over Western North America resulted in record‐breaking humidex and air temperature extremesLarger increases in humidex than temperature, exceeding their 2021 levels, under intermediate and high emissions scenariosRobust projections of multi‐model ensemble, mitigating climate sensitivity uncertainty of GCMs response to greenhouse gas emissions [ABSTRACT FROM AUTHOR]

Abstract Background Under a changing climate, the joint effects of temperature and relative humidity on tuberculosis (TB) are poorly understood. To address this research gap, we conducted a time-series study to explore the joint effects of temperature and relative humidity on TB incidence in China, considering potential modifiers. Methods Weekly data on TB cases and meteorological factors in 22 cities across mainland China between 2011 and 2020 were collected. The proxy indicator for the combined exposure levels of temperature and relative humidity, Humidex, was calculated. First, a quasi-Poisson regression with the distributed lag non-linear model (DLNM) was constructed to examine the city-specific associations between humidex and TB incidence. Second, a multivariate meta-regression model was used to pool the city-specific effect estimates, and to explore the potential effect modifiers. Results A total of 849,676 TB cases occurred in the 22 cities between 2011 and 2020. Overall, a conspicuous J-shaped relationship between humidex and TB incidence was discerned. Specifically, a decrease in humidex was positively correlated with an increased risk of TB incidence, with a maximum relative risk (RR) of 1.40 (95% CI: 1.11–1.76). The elevated RR of TB incidence associated with low humidex (5th humidex) appeared on week 3 and could persist until week 13, with a peak at approximately week 5 (RR: 1.03, 95% CI: 1.01–1.05). The effects of low humidex on TB incidence vary by Natural Growth Rate (NGR) levels. Conclusion A J-shaped exposure-response association existed between humidex and TB incidence in China. Humidex may act as a better predictor to forecast TB incidence compared to temperature and relative humidity alone, especially in regions with higher NGRs.

Background: Under a changing climate, the joint effects of temperature and relative humidity on tuberculosis (TB) are poorly understood. To address this research gap, we conducted a time-series study to explore the joint effects of temperature and relative humidity on TB incidence in China, considering potential modifiers. Methods: Weekly data on TB cases and meteorological factors in 22 cities across mainland China between 2011 and 2020 were collected. The proxy indicator for the combined exposure levels of temperature and relative humidity, Humidex, was calculated. First, a quasi-Poisson regression with the distributed lag non-linear model (DLNM) was constructed to examine the city-specific associations between humidex and TB incidence. Second, a multivariate meta-regression model was used to pool the city-specific effect estimates, and to explore the potential effect modifiers. Results: A total of 849,676 TB cases occurred in the 22 cities between 2011 and 2020. Overall, a conspicuous J-shaped relationship between humidex and TB incidence was discerned. Specifically, a decrease in humidex was positively correlated with an increased risk of TB incidence, with a maximum relative risk (RR) of 1.40 (95% CI: 1.11–1.76). The elevated RR of TB incidence associated with low humidex (5th humidex) appeared on week 3 and could persist until week 13, with a peak at approximately week 5 (RR: 1.03, 95% CI: 1.01–1.05). The effects of low humidex on TB incidence vary by Natural Growth Rate (NGR) levels. Conclusion: A J-shaped exposure-response association existed between humidex and TB incidence in China. Humidex may act as a better predictor to forecast TB incidence compared to temperature and relative humidity alone, especially in regions with higher NGRs. [ABSTRACT FROM AUTHOR]

Megacities, such as Lagos, Nigeria, face significant challenges due to rapid urbanization and climate change, resulting in a higher intensity of the urban heat island effect, coupled with high population density, making the city fall under the category of moderate to high heat stress/risk. Despite this, very few studies have analyzed the urban impact on heat stress over the coastal city, albeit with poor resolution data. In this study, we assessed the performance of an integrated high-resolution WRF-urban scheme driven by the readily available urban canopy information of the local climate zone (LCZ) to simulate local meteorological data for analyzing the spatiotemporal pattern of heat stress over the megacity. Our results show that the WRF-BEP scheme outperformed the other evaluated urban schemes, reducing the normalized root mean squared error by 25%. Furthermore, using humidex, we found a generally high incidence of intense discomfort in highly urbanized areas and noted the significant influence of urban morphology on the pattern of heat stress, particularly at night due to the combined effect of urban warming and higher relative humidity. The most socioeconomically disadvantaged urban areas, LCZ7, were most affected, with "hot" heat stress conditions observed over 90% of the time. However, during the afternoon, we found reduced heat stress in the core urban areas which might be due to the shading effect and/or cold air advection. Our findings would be relevant in the development of the urgently needed climate/heat adaptation plans for the city and other sub-Saharan African cities. [ABSTRACT FROM AUTHOR]

Abstract The 2021 heatwave over Western North America (WNA) led to record‐breaking air temperatures and human‐perceived heat stress (humidex) values. The event was accompanied by drier conditions driven by prolonged atmospheric blocking. During the heatwave, the maximum 6‐day means of humidex and temperature (HX‐6 and TX‐6) exhibited larger anomalies (6.70 and 5.57°C) compared to the 95th percentiles (HX95 and TX95) (4.12 and 3.73°C), relative to 1981–2021 extended summer (June‐September) averages. Extreme indices of humidex show faster and larger increases than those of temperature, reflecting the nonlinear positive relationship between humidex and temperature. Future projections from a multi‐model ensemble of 19 Coupled Model Intercomparison Project Phase six (CMIP6) Global Climate Models (GCMs) clearly show an increase in humidex and temperature extremes, especially under intermediate and high emissions scenarios. Humidex indices (HX‐6 and HX95) show faster and larger increases than temperature indices (TX‐6 and TX95) for the same future years and global warming levels. Controlling for differences in GCM climate sensitivity to greenhouse gas forcing yields robust projections at various global warming levels, reducing the ranges of projected changes from the multi‐model ensemble. At 3.0°C global warming from pre‐industrial, the multi‐model ensemble projects occurrences of HX‐6, TX‐6, HX95, and TX95 over WNA that exceed 2021 levels to occur every 3.9, 1.7, 1.4, and 2.2 years, respectively, increasing to almost annually at 4.0°C.

Abstract The change of temperature and weather parameters is a major concern affecting sustainable development and impacting various sectors, such as agriculture, tourism, and industry. Changing weather patterns and their impact on water resources are important climatic factors that society is facing. In Thailand, climatological features such as ambient temperature, relative humidity, and precipitation play a substantial role in affecting extreme weather events, which cause damage to the economy, agriculture, tourism, and livelihood of people. To investigate recent serious changes in annual trends of temperature, relative humidity, and precipitation in Thailand, this study used the Mann–Kendall (MK) test and innovative trend analysis (ITA) methods. The MK test showed that all six regions had an upward trend in temperature and humidity index (humidex, how hot the weather feels to the average person), while relative humidity and precipitation showed both upward and downward trends across different regions. The ITA method further confirmed the upward trend in temperature and humidex and showed that most data points fell above the 1:1 line. However, the upward trend in most variables was not significant at the 5% level. The southern and eastern regions showed a significant upward trend in relative humidity and humidex at a 5% level of significance according to the MK test. The output of this study can help in the understanding of weather variations and predict future situations and can be used for adaptation strategies.

Background The number of depression patients has exceeded 300 million worldwide, and its high disability rate has attracted global attention. However, the relationship between temperature-humidity index (Humidex) and depression remains to be explored. Objective To explore the relationship between Humidex of the twenty-four solar terms and depression. Methods Outpatient data of depression patients (n=18 289) admitted to the Psychology Department, Mental Health Center of Jiading District from 2016-10-08 to 2019-10-07 were collected, including gender, age, time of treatment, number of outpatient visits and specialist visits. The data of daily mean temperature, relative humidity, rainfall, air pressure and mean wind speed in Jiading District from 2016-10-08 to 2019-10-07 published by Shanghai Meteorological Bureau were collected to calculate Humidex. The included patients were divided into the groups of ≤18 years (n=157) , 19-44 years (n=3 099) , 45-59 years (n=4 848) , 60-74 years (n=6 270) and≥75 years (n=3 915) according to different ages. The relationship between Humidex of twenty-four solar terms and depression was estimated by using the combination of nonhomogeneous Poisson distribution and distributed-lag nonlinear model. Correlation between Humidex and meteorological variables was calculated using Pearson correlation analysis. Relative risk rates (RR) of Humidex and depression were calculated of twenty-four solar terms using median Humidex as control. Results A total of 18 289 patients with depression were included from 2016-10-08 to 2019-10-07, including 6 900 males and 11 389 females. The Lesser Cold solar term corresponded to the lowest average Humidex and highest number of depression patients, the Great Heat solar term corresponded corresponded to the highest average Humidex and lowest number of depression patients from 2016-10-08 to 2017-10-07. The Great Cold solar term corresponded to the lowest average Humidex and highest number of depression patients, the Great Heat solar term corresponded to the highest average Humidex and lowest number of depression patients from 2017-10-08 to 2018-10-07. The Great Cold solar term corresponded to the lowest average Humidex and highest number of depression patients, the Great Heat corresponded to the highest average Humidex and lowest number of depression patients from 2018-10-08 to 2019-10-07. Humidex in 24 solar terms showed a nonlinear relationship with the overall population risk of depression. The top two solar terms corresponding to Humidex of depression risk distribution for total population, male, female, ≤18 years, 19-44 years, 45-59 years, 60-74 years, and ≥75 years were the Great Cold and Beginning of Spring solar terms, Great Heat solar term corresponded to the lowest depression risk distribution. The maximum lag effect was observed on the 10th day of the Great Cold and Beginning of Spring solar terms (RR=1.020, 95%CI=1.001-1.040) , and the lag effect was observed on the 8th day of Great Heat solar term and lasted to the 9th day. The lag effect was observed on the 7th day after the Great Cold and Beginning of Spring and the maximum lag effect was observed on the 9th day (RR=1.054, 95%CI=1.007-1.104) , which lasted until the 11th day in the 60-74 years group. The lag effect was observed on the 1st day and 8th day after the Great Heat, and lasted to the 2nd day and 10th day, respectively, with the maximum lag effect on the 10th day (RR=0.952, 95%CI=0.911-0.994) in male depression patients. The lag effect was observed on the 8th day after the Great Heat solar term and lasted to the 9th day in the 60-74 years group. Conclusion Humidex in the Great Cold and Beginning of Spring solar terms are risk factors for depression. Clinically, accurate diagnosis and treatment should be provided for different depression patients according to Humidex in different solar terms, and individualized intervention programs should be formulated.

Recent climatic changes, most evident in air temperature, also significantly impact sensible conditions, particularly affecting the human body during the summer season in urban areas. This study utilized hourly values of air temperature (t, °C) and relative humidity (RH, %) for 2008–2022 obtained from nine measurement points located in the city of Poznań. The measurement network was set up and supported by the Department of Meteorology and Climatology of Adam Mickiewicz University in Poznań. Based on these data, thermal conditions were characterized using the Humidex (HD), as well as "hot days" (Tmax > 30 °C) and heat waves determined based on them. The conducted research revealed variability in thermal conditions across the city. The highest average Tmax (27.4 °C) and HD values (31.3 °C), as well as the greatest average number of hot days (15 days), were recorded in the compact, dense city center. In contrast, the lowest values (respectively: 25.9 °C, 27.5 °C, 8 days) were observed in areas with a significantly greater proportion of green spaces located further from the center. Furthermore, significant trends of change were observed: an annual average Tmax increase of 1.2–1.6 °C/decade and HD values showing an increase of 1.5–3.0 °C/decade. This study also highlighted the noteworthy impact of urbanization and the presence of urban greenery on the frequency and total duration of heat waves. Between 2008 and 2022, the area of compact development experienced 26 heat waves lasting a total of 115 days, whereas the area with a high proportion of greenery recorded 14 cases and 55 days, respectively. The longest recorded heat wave, spanning 9 days, occurred in July 2010. Individual heat waves identified based on Tmax (>30 °C) may exhibit significant variations in terms of perceived conditions, as indicated by HD. [ABSTRACT FROM AUTHOR]

BACKGROUND: Several heat indices have been developed in industrial health, but each has its limitations. OBJECTIVE: The objective of this article is to determine the validity and applicability of a temperature-humidity index, named Humidex compared with the Standard Wet-Bulb Globe Temperature (WBGT) index (ISO 7243). METHOD: This cross-sectional study was conducted in the summer of 2019, in a tile factory in the west of Iran. 59 measurements were performed in 8 different workstations. Environmental parameters including natural wet bulb temperature (Tnw), dry bulb temperature (Ta), globe bulb temperature (Tg), and heat stress (WBGT) were measured. Humidex was calculated according to an equation. SPSS software (version 16) was used for data analysis. RESULTS: There was a high correlation between Humidex and WBGT in the estimation of heat stress (R=0.912, P<0.001). The Kappa Coefficient between Humidex and WBGT was 0.298, P=0.001. CONCLUSION: Humidex is highly correlated with WBGT. Humidex can be used instead of the WBGT index, especially in hot and humid environments. [ABSTRACT FROM AUTHOR]

Abstract Background Many studies have reported the association between ambient temperature and mortality from cardiovascular disease (CVD). However, the health effects of humidity are still unclear, much less the combined effects of temperature and humidity. In this study, we used humidex to quantify the effect of temperature and humidity combined on CVD mortality. Methods Daily meteorological, air pollution, and CVD mortality data were collected in four cities in southwest China. We used a distributed lag non-linear model (DLNM) in the first stage to assess the exposure–response association between humidex and city-specific CVD mortality. A multivariate meta-analysis was conducted in the second stage to pool these effects at the overall level. To evaluate the mortality burden of high and low humidex, we determined the attributable fraction (AF). According to the abovementioned processes, stratified analyses were conducted based on various demographic factors. Results Humidex and the CVD exposure–response curve showed an inverted “J” shape, the minimum mortality humidex (MMH) was 31.7 (77th percentile), and the cumulative relative risk (CRR) was 2.27 (95% confidence interval [CI], 1.76–2.91). At extremely high and low humidex, CRRs were 1.19 (95% CI, 0.98–1.44) and 2.52 (95% CI, 1.88–3.38), respectively. The burden of CVD mortality attributed to non-optimal humidex was 21.59% (95% empirical CI [eCI], 18.12–24.59%), most of which was due to low humidex, with an AF of 20.16% (95% eCI, 16.72–23.23%). Conclusions Low humidex could significantly increase the risk of CVD mortality, and vulnerability to humidex differed across populations with different demographic characteristics. The elderly (> 64 years old), unmarried people, and those with a limited level of education (1–9 years) were especially susceptible to low humidex. Therefore, humidex is appropriate as a predictor in a CVD early-warning system.

The unprecedented 2021 June‐July heatwave in Western North America resulted in record‐breaking human‐perceived heat stress across the region, measured by the humidex considering both air temperature and humidity. During extended summer (June‐September), both 95th percentiles of daily maximum humidex (HX95) and air temperature (TX95) have increased over the 1940–2022 period, with even faster intensification in the last two decades (2001–2022). HX95 has increased more than TX95 because of the positive monotonic nonlinear relationship between humidex and air temperature at a given level of relative humidity. The Canadian Earth System Model version 5 (CanESM5) projects a larger increase in human‐perceived heat stress than air temperature across the region under low to high emission scenarios (HX95 increases 4.40–7.04°C and TX95 increases 2.92–4.65°C between 1981–2010 and 2041–2060). Moreover, CanESM5 projects significant increases in the frequency of HX and TX conditions that exceed the levels reached in 2021 under intermediate and high emission scenarios. Plain Language Summary: Using humidex, a measure that combines air temperature and humidity, we assessed the human‐perceived heat stress during the record‐breaking 2021 summer heatwave in Western North America. The 2021 heatwave broke records for both air temperature and humidex, and these two measures have been increasing in the past decades. The heatwave was drier than usual due to high pressure in the atmosphere, clear skies, and more heat warming up the air instead of evaporating water. Humidex will rise more than air temperature under various emission scenarios, making people feel even hotter in the region. The climate model used suggests that humidex values and temperatures that exceed the levels observed in 2021 will happen much more often and be much more intense across the region in the future, with estimates of three to ten times for humidex and two to seven times for air temperature more frequent under intermediate to high emission scenarios by the end of the century. However, the likelihood of extreme humidex in dry conditions, as observed in 2021, will remain low, like historical levels. Key Points: Unprecedented 2021 heatwave in Western North America resulted in record‐breaking human‐perceived heat stress, considering both air temperature and humidityExtreme human‐perceived heat stress increased at a faster rate than extreme air temperature, both showing rapid increases in recent decadesFor events exceeding 2021 level, a larger future increase in extreme human‐perceived heat stress is projected compared to air temperature [ABSTRACT FROM AUTHOR]

Long- and short-term biometeorological conditions in the Republic of Serbia were analyzed using official meteorological data from numerous weather stations located across the country. Selected biometeorological indices HUMIDEX, Physiologically Equivalent Temperature (PET), and Universal Thermal Climate Index (UTCI) are calculated based on air temperature, relative humidity, wind speed, and cloudiness data from the meteorological stations on annual and summer level as well as during selected heat wave periods during 2000–2020. Application of different biometeorological indices provides similar but somewhat different results. For example, average annual HUMIDEX and UTCI values indicate no thermal stress and no discomfort at all stations, while PET indicates the occurrence of slight to moderate cold stress at all stations. Average summer PET and UTCI indicate the occurrence of slight to moderate heat stress throughout the country, while HUMIDEX indicates no discomfort. Trends of biometeorological indices on annual and summer level show a general increase throughout the country. Furthermore, heat wave analysis indicated that the most populated cities of Serbia are under dangerous and extreme heat stress during these extreme temperature events, which can influence human health and well-being. The obtained biometeorological information can be used for the preparation of climate adaptation strategies that consider the human biometeorological conditions, with a special focus on developing climate-sensitive and comfortable cities. [ABSTRACT FROM AUTHOR]

The projected increase in the frequency and intensity of extreme heat events due to climate change means an associated increase in risk of heat‐related illnesses and mortality. Public health systems need to be prepared to identify and reduce the susceptibility of vulnerable populations to increased occurrence of heat‐related illness and stress. To facilitate this, climate services have begun developing climate change projections for heat‐stress indices based on exceedances of thresholds used operationally in meteorological heat warning systems. This task is complicated by the fact that heat‐stress indices are generally computed using hourly data whereas climate model outputs are often archived at daily or longer time steps. This study focuses on Humidex, a heat‐stress index used in heat alerts issued by the Meteorological Service of Canada. Several potential solutions for computing robust Humidex indices using daily data are examined, including a new approximation method. Indices obtained with the new method are compared with indices obtained using the classic method based on hourly data as well as with other two methods based on average daily values. The new approximation gives good estimations for humidex indices, while the daily‐average‐value methods present biases with respect to the hourly‐value method. [ABSTRACT FROM AUTHOR]

Regarding climatic diversity in Iran and the dependence of many outdoor activities (occupational, recreational, tourism attraction, etc.) on climatic conditions, this study conducted aiming to evaluate thermal comfort fluctuations in Iran. Thermal comfort fluctuations in different climates of Iran were investigated between 1985 and 2014 using recorded meteorological data in 40 synoptic stations. The Mann-Kendall test and Sen’s Slope were used to analyse the changing trends of the Humidex and to determine the actual slope of a trend over time, respectively. In overall, the southern areas of Iran have the longest period with unfavourable and extremely unfavourable climatic conditions in this study. Conversely, in the northern half of Iran, especially in North West areas, the appropriate summer season provides the best climatic conditions for outdoor activities.

Objective To study the association of humidex with bacillary dysentery (BD) incidence and its regional heterogeneity in North China. Methods The daily BD incidence and meteorological data from January 1, 2014 through December 31, 2016 in North China were collected from Chinese Center for Disease Control and Prevention and China Meteorological Science Data Sharing Service Network. Distributed lag non-linear model was used to assess associations of average ambient temperature, relative humidity and humidex with BD incidence. Multivariate meta-analysis was employed to pool region-specific analytic estimates and then meta-regression analysis was adopted to explore modifiers of the association between humidex and BD incidence. Results Approximately J-shaped relationships were observed between pooled BD risk and average ambient temperature, relative humidity and humidex. The humidex showed a promotion effect on BD incidence of the same day; the effect was the most obvious for the lag day 3 (relative risk [RR] = 1.07, 95% confidence interval [95% CI]: 1.05 – 1.09) and lasted until the lag day 7. Taking the median humidex as a reference, the humidex of 42.4 manifested a highest promotion effect on BD incidence, with the RR of 1.96 (95% CI: 1.52 – 2.53). The effect of humidex was more obvious in city-level regions at high latitude and longitude, with high natural population growth rate but low gross domestic production per capita. Conclusion The meteorological condition with high humidex may promote bacillary dysentery incidence in North China and the situation needs to be concerned in the control of the disease, especially in some vulnerable cities.

Background: This study aimed to illustrate the applicability of the Humidex index for assessment of outdoor thermal environments in a wide range of weather conditions in different climates in Iran. Study Design: This is a cross-sectional study. Methods: Both field measurements (1452 measurements) and the long-term meterological data (between 1965 and 2009) were used in this research. After determining the appropriateness of correlation coefficients between these two types of data, only meteorological stations data were used to generalize the results to climatic regions. For this purpose, Arc/GIS 10.2 software was used. Results: The results showed three levels of comfort including safe, caution and stress regions by graphical maps. The results showed that the center and south of the country, especially at the middle and the end of the shift hours, experienced more thermal stress in summer months (ranging from 39.60±1.07 to 49.29±2.13ºC for central areas and ranging from 47.76±2.59to 57.71±1.65ºC for southern areas. In the northern regions, most of the measurements in different stations and time periods at spring were in caution condition and less than 1% of them experienced stress conditions. Conclusion: The dependence of this index on the minimum metrological parameters (temperature and humidity), which are easily measured and reported daily in meteorological stations, and its non-dependence on the globe temperature, which is an unusual parameter in the measured metrological parameters, can be used as advantages of the humidex for assessment of the heat stress conditions in outdoor environments in different climates.

Saline habitats of the Pannonian plain are specific regarding their extraordinary biodiversity with many endemic species, yet they are among the most threatened European Communities with limited spatial distribution. These habitats are present in the Autonomous Province of Vojvodina in the North of Serbia, in the area of Srednja Mostonga, and they are in the procedure of protection as the II category protected area - "region of exceptional characteristics". Great variety of rare and endemic species makes this area interesting for recreational and educational activities. In this paper we investigate micrometeorological and outdoor thermal comfort conditions in different natural environments at the area of Srednja Mostonga. This is the first micrometeorological field measurement study conducted in this region. Measurements were performed during the daytime of a sunny autumn day in 2019. The results showed that daytime air temperature was up to 3.4 °C lower in forest compared to steppe, while relative humidity was up to 5-6% higher in forest than in steppe with up to 3.2 m/s lower wind speeds in forest than in steppe area. Micrometeorological values were similar between forest-steppe and steppe. However, the outdoor thermal comfort conditions expressed via Humidex showed that 'some discomfort' was most often observed in forest-steppe during 27% of measurement time, followed with 13% of 'some discomfort' observed in steppe and only 1% of 'some discomfort' was observed in forest. Accordingly, during the warmest daytime hours outdoor activities could be performed in forest, while early morning and evening hours could be spent in steppe and forest-steppe areas of Srednja Mostonga.

OBJECTIVES: The primary objective of this study was to assess the relationship between heat exposure and occupational traumatic injuries among construction workers. METHODS: We assessed the relationship between humidex, a measure of apparent temperature, and Washington State Fund workers’ compensation injuries among outdoor construction workers using a case-crossover design with time-stratified referent selection. Warm month (March–October) adult outdoor construction traumatic injury claims from 2000–2012 were spatiotemporally joined with high-resolution meteorological data. We used conditional logistic regression with linear splines to assess the association between maximum daily humidex and injuries. RESULTS: There were 63 720 occupational traumatic injury claims in construction that met our eligibility criteria during the study period. The traumatic injury odds ratio (OR) was 1.005 [95% confidence interval (CI) 1.003–1.007] per one °C change in humidex. In the spline analyses, we observed a nearly linear association of humidex with the risk of a traumatic injury. Effect estimates were higher among younger (18–24 years) and older (>54 years) workers, workers with lower extremity injuries, workers with less job experience, smaller employers, workers working in Western Washington, and time of injury before 12:30 hours, although CI of effect estimates overlapped in stratified analysis categories. CONCLUSIONS: In this study of Washington outdoor construction workers, increasing maximum daily humidex was associated with increasing traumatic injury risk. Further work should explore mechanisms of the association between heat exposure and traumatic injuries. Injury prevention efforts targeted at construction should address heat-related risk factors. In addition, heat awareness campaigns should address outcomes beyond heat-related illness.

The Guadalquivir and Segura Valleys are geographical areas in the south of the Iberian Peninsula where extreme summer temperatures have great recurrence of extremely high values, especially during the last summers. A comparison of the characteristics of extreme heat between the two zones is proposed, analyzing the statistical trend (1900-2017) of the cities of Seville and Murcia and a detailed cartography of the warm poles of maximum and minimum temperatures is provided using high resolution modeling tools (AROME 1.3 km) and remote sensing (MYD11A1). The results are conclusive, since there is a statistically significant increase of the days with extreme heat indices (TX35, TX40 and TN20), while periods of warm spells (WSDI) increase in recurrence and duration.

The combined effects of air pollution and extreme temperature on PTB remain unclear. To evaluate the independent effect and interaction effect of prenatal extreme exposure to air quality index (AQI) and Humidex, on PTB. Based on the National Health Care Data Platform of Shandong University, women who gave birth in 2019–2020 were selected for the study. First, the independent effects of AQI and Humidex on PTB were assessed by logistic regression model. Subsequently, the interaction effects of AQI and Humidex on PTB were estimated separately by calculation of the relative excess risk of interaction (RERI). A total of 34365 pregnant women were included and 1975 subjects were diagnosed with PTB. We observed a significant increase in the odds of PTB associated with maternal high AQI exposure, with an OR of 1.70 (95% CI : 1.59, 1.81). Similarly, extreme exposure to Humidex also demonstrated an elevated PTB odds, with a low Humidex OR of 2.48 (95% CI : 2.23, 2.76) and a high Humidex OR of 1.48 (95% CI : 1.31, 1.67). Finally, we observed an interaction between high AQI and extreme Humidex during the 1st trimester. Interaction effects were noted between high AQI and low Humidex throughout the entire trimester and the 2nd trimester. This study suggests that prenatal exposure to high AQI and extreme Humidex could increase the odds of PTB, with effects exhibiting the sensitivity window and a cumulative trend. Additionally, there is an interaction between AQI and Humidex. • The effect OR (95% CI) of high AQI on PTB was 1.70 (1.59, 1.81). • Extremely low Humidex was associated with PTB, with OR of 2.48 (2.23, 2.76), • Extremely high Humidex was associated with PTB, with OR of 1.48 (1.31, 1.67). • AQI and Humidex had interaction effect on PTB. [ABSTRACT FROM AUTHOR]

The bioclimatic analysis of the central area of the city of Niš conducted in this paper is based on the use of the bioclimatic index Humidex, which represents subjective outdoor temperature that one feels in warm and humid environment. The purpose of this research is to observe the index change on a daily basis during the hottest part of the year (June, July, and August) over the period from 1998 to 2017. For the purposes of this analysis, hourly (7:00, 14:00), maximum and mean daily values of meteorological parameters (air temperature and relative humidity) were used, for the period of 20 years (1998–2017), which were measured at Niš weather station (43°19'N, 21°53'E, at an altitude of 202 meters). The findings indicate a gradual change in the bioclimatic characteristics of this area during this period, especially over the last decade. After 2007 there has been a decrease in the total number of the days described as “comfortable”. However, there has been an increase in the index values in all the other heat stress categories characterized by a higher or lower degree of thermal discomfort. The years 1998, 2000, 2003, 2007, 2011, 2016, 2015, and 2017 stand out as adverse years.

With global climate change, there is growing concern about the effects of temperature changes on childhood asthma. However, current research only focuses on the effects of temperature, while ignoring the adverse effects of humidity on children. Our study aimed to quantify the impact of humidex on childhood asthma hospitalizations, which combined temperature and humidity, and further to assess how the effect is modified by individual-factors, such as age and gender. Poisson generalized linear models combined with distributed lag nonlinear models were used to estimate the association between daily childhood asthma hospitalizations and humidex from 2013 to 2016. Air pollutions (CO, O 3, and NO 2) and wind velocity were modelled simultaneously using DLNM, as well as day of week, seasonality and long-term trend. Low humidex was associated with an increased risk of admissions for asthma in children. The adverse effect appeared on the 4th day, with the RR of 1.045 (95% CI : 1.007–1.084) and lasted until the 7th day (RR : 1.045, 95% CI : 1.006–1.085). Compared with the male, there was an immediate effect on female exposed to low humidex. And the female seems to be more sensitive to low humidex. Besides, the significant effects of humidex on children asthma were detected in the children with preschool and school-age, whereas not for the subgroup of infants. And the school-age children are most sensitive to low humidex. Low humidex was associated with the increased risk of admissions for childhood asthma in Hefei. Children suffering from asthma should avoid exposure to the low humidex environment, especially in female and school-age children. In addition, the index of humidex was more significant for disease prevention and public health than the average temperature. These findings may provide epidemiology evidence for formulating precaution guidelines to reduce the risk of childhood asthma hospitalizations. Unlabelled Image • This is the first study to explore the Humidex-Childhood asthma association in Hefei. • Low humidex increased the incidence of Childhood asthma. • Female and school-age children appeared to be more vulnerable to low humidex. • The adverse effects occurred on lag4, lag5, lag6, lag7. • Humidex was more significant for prevention and public health than the average temperature. [ABSTRACT FROM AUTHOR]

Objectives The primary objective of this study was to assess the relationship between heat exposure and occupational traumatic injuries among construction workers. Methods We assessed the relationship between humidex, a measure of apparent temperature, and Washington State Fund workers' compensation injuries among outdoor construction workers using a case-crossover design with timestratified referent selection. Warm month (March--October) adult outdoor construction traumatic injury claims from 2000-2012 were spatiotemporally joined with high-resolution meteorological data. We used conditional logistic regression with linear splines to assess the association between maximum daily humidex and injuries. Results There were 63 720 occupational traumatic injury claims in construction that met our eligibility criteria during the study period. The traumatic injury odds ratio (OR) was 1.005 [95% confidence interval (CI) 1.003-1.007] per one °C change in humidex. In the spline analyses, we observed a nearly linear association of humidex with the risk of a traumatic injury. Effect estimates were higher among younger (18-24 years) and older (>54 years) workers, workers with lower extremity injuries, workers with less job experience, smaller employers, workers working in Western Washington, and time of injury before 12:30 hours, although CI of effect estimates overlapped in stratified analysis categories. Conclusions In this study of Washington outdoor construction workers, increasing maximum daily humidex was associated with increasing traumatic injury risk. Further work should explore mechanisms of the association between heat exposure and traumatic injuries. Injury prevention efforts targeted at construction should address heatrelated risk factors. In addition, heat awareness campaigns should address outcomes beyond heat-related illness. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to study the outdoor thermal comfort of the central urban zone of Belgrade during summer season in order to examine how different bioclimatic conditions affect human body. For this purposes Humidex, a simple heat index was applied. The research involved analyzing different Humidex values, the so-called "sub-indices" calculated based on hourly (7:00 and 14:00), mean daily and maximum values of meteorological parameters (air temperature and humidity) that were recorded at the meteorological station Belgrade - Vračar.), for the period 1999-2018. Outdoor thermal comfort in Belgrade is generally more adverse in July and August, resulting in most days belonging to the categories of "some discomfort" (30-39) and "great discomfort" (40-44), with periodic recording of the most severe categories of heat stress, as a category "very dangerous"(Humidex>55). Category of "very dangerous" heat stress shows linear increase during July, with positive trend of 0.03 days/10 years. The findings also show that from 1999 to 2018, mean index value gradually rose and values of sub-indices Humidex14h and HumidexTmax have exceeded thresholds 40 for great discomfort and 45 for dangerous heat stress more often then in the previous decades. [ABSTRACT FROM AUTHOR]

The study of urban climate change has to take into account two components: global warming and microclimate variability due to urban growth. The present article tries to quantify the global and local components in six Italian towns over the last fifty years: Milano, Bologna, Roma, Napoli, Bari and Palermo. Historical temperature series measured in the city centre and in the suburbs of the towns have been investigated: the Climatological Normals 1961-1990 and 1971-2000 have been compared with the mean data of the last 15 years (2001-2015). Everywhere the mean temperatures have been higher in the city centre than in the suburbs and both have progressively raised over time. Conversely, the differences between city centre temperatures and suburban ones have decreased. Mean temperature differences between the two kinds of monitoring sites can be considered as a first rough estimate of the urban contribution to local warming up. To better analyse the local effects of urban warming and their relation with health and welfare of urban residents, a quantitative spatial analysis of hot extreme events in Milano has been performed, as Milano is subject to stable atmospheric conditions in more than 60% of days per year. Such conditions contribute to the accumulation of waste heat generated by urban energy usage. Dry and moist heatwaves have been treated, resulting in quite different spatial distribution of such events, as a strict effect of built and green areas in urban texture. [ABSTRACT FROM AUTHOR]

The bioclimatic analysis of the central area of the city of Niš conducted in this paper is based on the use of the bioclimatic index Humidex, which represents subjective outdoor temperature that one feels in warm and humid environment. The purpose of this research is to observe the index change on a daily basis during the hottest part of the year (June, July, and August) over the period from 1998 to 2017. For the purposes of this analysis, hourly (7:00, 14:00), maximum and mean daily values of meteorological parameters (air temperature and relative humidity) were used, for the period of 20 years (1998-2017), which were measured at Niš weather station (43°19'N, 21°53'E, at an altitude of 202 meters). The findings indicate a gradual change in the bioclimatic characteristics of this area during this period, especially over the last decade. After 2007 there has been a decrease in the total number of the days described as "comfortable". However, there has been an increase in the index values in all the other heat stress categories characterized by a higher or lower degree of thermal discomfort. The years 1998, 2000, 2003, 2007, 2011, 2016, 2015, and 2017 stand out as adverse years. [ABSTRACT FROM AUTHOR]

The spatial distribution of heat stress in a Central European city and its surroundings was examined. We evaluated the length of time for which the threshold values of Humidex and air temperatures were exceeded at individual stations. The longest interval of temperature discomfort was detected at the border of open mid-rise development and open spaces. The shortest intervals were found in compact mid-rise development and near a forest. There are spatial differences between locations with long periods of high temperatures and locations with long intervals of high Humidex values. However, when the heat stress is being assessed in relation to the mortality rate, Humidex does not show better results than the air temperature.

Introduction: Regarding development of several thermal indices and limitations of each, in this research applicability and validity of temperature- humidity index (Humidex) were examined against the standard heat index, Wet Bulb Globe Temperature -WBGT, as well as tympanic temperature of subjects. Material and Method: This cross-sectional study was done on 163 subjects at spring and summer (2013) in outdoor jobs of arid and semi-arid climates of Iran. Environmental parameters as well as tympanic temperature of subjects were measured simultaneously and then heat indices were determined. Data were analyzed using linear correlation charts and Kappa coefficient of agreement by means of SPSS software version 20. Results: A strong correlation was obtained between WBGT and Humidex in both arid and semi-arid regions (r>0.98), while the correlation between Humidex and tympanic temperature was moderate (r=0.5-0.8). Based on the obtained Kappa value, the agreement coefficient between Humidex and WBGT was 0.878. This value was obtained equal to 0.226 for the Humidex and tympanic temperature. Conclusion: The results of this study showed that Humidex can be applied as an appropriate substitute for the WBGT index. However, if evaluation of environmental condition with low air temperature or very hot situation is considered, relying only on the Humidex results will not provide a realistic estimation of thermal strain imposed to individuals.

Air temperature and humidity conditions were monitored in Hradec Králové, Czech Republic, by a network of meteorological stations. Meteorological sensors were placed across a representative variety of urban and suburban environments. The data collected over the 2011–2014 period are analysed in this paper. The data from reference standard meteorological stations were used for comparison and modelling purposes. Air temperatures at the points of interest were successfully modelled using regression relationships. The spatial expression of point measurements of air temperatures was provided by GIS methods in combination with CORINE land cover layer, and satellite thermal images were used to evaluate the significance of these methods. The use of standard climate information has low priority for urban planners. The impact of the urban heat island on city residents and visitors was evaluated using the HUMIDEX index, as it is more understandable for urban planners than temperature conditions as such. The aim of this paper is the modification, description and presentation of urban climate evaluation methods that are easily useable for spatial planning purposes. These methods are based on comprehensible, easily available but quality data and results. This unified methodology forms a theoretical basis for better urban planning policies to mitigate the urban heat island effects.

Climate's change is one of the most important threats facing the world. That is because it causes a high ambient temperature. (UNEP, 2010). According to the report of the World Meteorological Organization (WMO, 2015), the period 2011- 2015 recorded the highest temperatures and was affected by Climate's change. Agriculture sector is strongly influenced by climatic conditions. A majority of works in agriculture are still performed outdoors under several weather conditions. High temperature, intensive insolatioo and elevated air humidity providing a dangerous work conditions. These weather conditions can lead to overheating (heat stress) and dehydration of the agricultural field workers. An index assessing heat stress in human beings, namely: Wet Bulb Globe Temperature (WBGT) was used in this study. This study presents the effect of heat stress from the point of view of agricultural field worker occupational health safety. Comparison of the three agricultural working conditions reveals significantly more severe heat stress in wheat threshing, rice transplanting and cotton harvesting, in terms of both the frequency of heat-stress episodes and the number of hours associated with heat stress. The WBGT maximum values during the time from 11 am up to 4 pm for wheat threshing, rice transplanting and cotton harvesting operations were 34.2 °C at 2 pm, 31.6 °C at 1 pm and 30.8 °C at 1:30 pm respectively. While the WBGT minimum values were 31.7 °C at 4 pm, 28.4 °C at 11 am, and 28.5 °C at 4 pm respectively. The three presented work conditions are affirmed that a dangerous situation for agriculture field workers is stand. The values of the environmental parameters and its relation with heat stress during the day work hours under the previous field operations cleared that the heat stress has direct proportion with humidex and reversible proportion with air velocity and relative humidity. The agriculture field workers have exposure to hazard levels of heat stress resulting in high levels of body temperature. It is recommended to establish a sunshade for wheat thresher to provide a shade working area. [ABSTRACT FROM AUTHOR]

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This study uses the MUKLIMO_3 urban climate model (in German, Mikroskaliges Urbanes KLImaMOdell in 3-Dimensionen ) and measurements from an urban climate network in order to simulate, validate and analyse the spatiotemporal pattern of human thermal comfort outdoors in the city of Brno (Czech Republic) during a heat-wave period. HUMIDEX, a heat index designed to quantify human heat exposure, was employed to assess thermal comfort, employing air temperature and relative humidity data. The city was divided into local climate zones (LCZs) in order to access differences in intra-urban thermal comfort. Validation of the model results, based on the measurement dates within the urban monitoring network, confirmed that the MUKLIMO_3 micro-scale model had the capacity to simulate the main spatiotemporal patterns of thermal comfort in an urban area and its vicinity. The results suggested that statistically significant differences in outdoor thermal comfort exist in the majority of cases between different LCZs. The most built-up LCZ types (LCZs 2, 3, 5, 8 and 10) were disclosed as the most uncomfortable areas of the city. Hence, conditions of great discomfort (HUMIDEX > 40) were recorded in these areas, mainly in the afternoon hours (from 13.00 to 18.00 CEST), while some thermal discomfort continued overnight. In contrast, HUMIDEX values in sparsely built-up LCZ 9 and non-urban LCZs were substantially lower and indicated better thermal conditions for the urban population. Interestingly, the model captured a local increase of HUMIDEX values arising out of air humidity in LCZs with the presence of more vegetation (LCZs A and B) and in the vicinity of larger bodies of water (LCZ G). [ABSTRACT FROM AUTHOR]

The urban heat island (UHI) effect alters local thermal environment and affects thermal comfort of urban dwellers. However, the similarities and differences of the UHI when characterized by different thermal indicators (i.e., different types of temperatures and thermal comfort indices) remain poorly understood. Taking 30 major Chinese cities as an example, here we compared the spatiotemporal patterns and drivers of the UHI intensity (UHII) represented by six different thermal indicators, i.e., I a (UHII represented by surface air temperature), I s (land surface temperature), I d (dew-point temperature), I HD (Humidex), I mrt (mean radiant temperature), and I UTCI (Universal Thermal Climate Index). These thermal indicators encompass temperature factors that capture changes in the natural environment and thermal comfort indices that reflect the human perception of changes in ambient heat and humidity. The results show that the ranking of the annual mean UHII is similar between the day and night (i.e., I s > I UTCI > I mrt > I a > I HD > I d). From a seasonal perspective, the daytime I s and I mrt exhibit the highest variability among all indicators, while the I UTCI demonstrates the largest difference among climate zones. Regarding the UHI drivers, most of the UHI indicators (except I d) are negatively correlated with the urban-rural difference in vegetation index during the day. At night, the UHI indicators are negatively related to the climatic variables and the urban-rural difference in albedo. Our results by using the I UTCI to assess outdoor thermal comfort across local climate zones (LCZs) show that the inter-LCZ standard deviation of the I UTCI is 1.94 °C during the day and 2.16 °C at night. We believe that these results deepen our understanding of the UHII when characterized by different thermal indicators, especially from the human perception perspective. • UHI intensity (UHII) represented by six thermal indicators is compared. • Compared the differences in UHIIs across multiple spatiotemporal scales. • Analyzed UHII drivers from surface attributes and climatic conditions. • Most types of UHII are negatively related to climatic controls at night. • The standard deviation of UTCI-based UHII in inter-LCZ is 2.16 °C at night. [ABSTRACT FROM AUTHOR]

Heat stress in urban areas is controlled mainly by the impact of anthropogenic land use on the active surface heat balance. This paper shows the role of land form superimposed on the land-use impact, using the example of Krakow, Poland. The city is located in a concave land form, on the Wisla (Vistula) River. The automatic measurements of air temperature and humidity were realised in Kraków from April to October, in the years 2010-2012. For the day time conditions, ANOVA test and Tukey’s test showed significant differences in the number of very hot days and number of heat waves, between urban areas in the valley and rural areas, both in the valley and on the slope. For the night time, significant differences were found for the number of tropical nights, not only between urban and rural areas, but also between urban areas located in various landforms and between urban areas in the valley floor and rural areas located in various landforms. Both urban and rural measurement points located in the river valley floor experienced the highest numbers of very hot days, heat waves and extreme air temperature duration. For measurement points elevated about 50 m above the valley floor, the indices’ values were lower by about 50 %.

The increasing frequency, intensity and duration of heat waves seem to follow the observed global warming in recent decades. Vulnerability to heat waves is expected to increase in urban environments mainly due to population density and the effect of the urban heat island that make cities hotter than surrounding non-urban areas. The present study focuses on a vulnerable area of the eastern Mediterranean, already characterized as a ‘hot spot’ with respect to heat-related risk and investigates the change in heat stress levels during heat wave compared to non-heat wave conditions as well as the way that heat stress levels respond to heat waves in urban, compared to non-urban, environments. The adoption of a metric accounting for both the intensity and duration of the hot event yielded a total of 46 heat wave episodes over a nearly 60-year period, but with very rare occurrence until the late 1990s and a profound increased frequency thereafter. The results reveal a difference of at least one thermal stress category between heat wave and non-heat wave periods, which is apparent across the entire range of the thermal stress distribution. The analysis demonstrates a robust intensification of nighttime heat stress conditions in urban, compared to non-urban, sites during severe heat waves. Nevertheless, severe heat waves almost equalize heat stress conditions between urban and non-urban sites during midday.