Evaluation of thermal environment and human thermal comfort in 8 types of public places from 2019 to 2021 / 中华劳动卫生职业病杂志

Objective: To evaluate the thermal environment of different types of public places and the thermal comfort of employees, so as to provide scientific basis for the establishment of microclimate standards and health supervision requirements. Methods: From June 2019 to December 2021, 50 public places (178 times) of 8 categories in Wuxi were selected, including hotels, swimming pools (gymnasiums), bathing places, shopping malls (supermarkets), barber shops, beauty shops, waiting rooms (bus station) and gyms. In summer and winter, microclimate indicators such as temperature and wind speed were measured in all kinds of places, combined with the work attire and physical activity of employees in the places. Fanger thermal comfort equation and center for the built environment (CBE) thermal comfort calculation tool were used to evaluate the predicted mean vote (PMV), predicted percent dissatisfied (PPD) and standard effective temperature (SET) according to the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 55-2020. The modification effects of seasonal and temperature control conditions on thermal comfort were analyzed. The consistency of GB 37488-2019 "Hygienic Indicators and Limits in Public Places" and ASHRAE 55-2020 evaluation results on thermal environment was compared. Results: The thermal sensation of hotel, barber shop staff and the gym front-desk staff were moderate, while the thermal sensation of swimming place lifeguard, bathing place cleaning staff and gym trainer were slightly warm in summer and winter. Waiting room (bus station) cleaning and working staff, shopping mall staff felt slightly warm in summer and moderate in winter. Service staff in bathing places felt slightly warm in winter, while staff in beauty salons felt slightly cool in winter. The thermal comfort compliance of hotel cleaning staff and shopping mall staff in summer was lower than that in winter (χ(2)=7.01, 7.22, P=0.008, 0.007). The thermal comfort compliance of shopping mall staff in the condition of air conditioning off was higher than that in the condition of air conditioning on (χ(2)=7.01, P=0.008). The SET values of front-desk staff in hotels with different health supervision levels were significantly different (F=3.30, P=0.024). The PPD value and SET value of the front-desk staff, and the PPD value of cleaning staff of hotels above three stars were lower than those of hotels below three stars (P<0.05). The thermal comfort compliance of front-desk staff and cleaning staff in hotels above three stars was higher than that in hotels below three stars (χ(2)=8.33, 8.09, P=0.016, 0.018). The consistency of the two criteria was highest among waiting room (bus station) staff (100.0%, 1/1) and lowest among gym front-desk staff (0%, 0/2) and waiting room (bus station) cleaning staff (0%, 0/1) . Conclusion: There are different degrees of thermal discomfort in different seasons, under the condition of air conditioning and health supervision, and the microclimate indicators can not fully reflect the thermal comfort of human body. The health supervision of microclimate should be strengthened, the applicability of health standard limit value should be evaluated in many aspects, and the thermal comfort of occupational group should be improved.

Bioclimatic zoning and trend analysis applied to broilers / Zoneamento bioclimático e análise de tendência aplicados a frangos de corte

The objective of the present study was to establish the bioclimatic zoning by the temperature and humidity index (THI), considering a historical period and a future scenario, in order to represent the thermal environment for broiler breeding in the State of Minas Gerais. A historical series (1976 - 2014) of THI minimum, average and maximum calculated based on data from 48 conventional meteorological stations was used, belonging to the National Institute of Meteorology of the State of Minas Gerais. The analysis of the temporal series was based on the Mann-Kendall test and linear regression. A geostatistical analysis was also carried out to determine the comfort zoning of broilers as a function of the THI intervals. In this way, the THI spatial mapping methodologies and trend analysis for the prediction of a possible future climate scenario can help in the development of risk maps for monitoring thermal comfort of broilers, being indispensable in the planning of actions for the mitigation of the climatic change impacts on the productive chain of the State of Minas Gerais.(AU)

O objetivo do presente trabalho foi estabelecer o zoneamento bioclimático por meio do índice de temperatura e umidade (ITU), considerando-se um período histórico e um cenário futuro, de forma a representar o ambiente térmico para criação de frangos de corte no estado de Minas Gerais. Foi utilizada uma série histórica (1976 - 2014) de ITU mínimo, médio e máximo, que foram calculados com base em dados oriundos de 48 estações meteorológicas convencionais, pertencentes ao Instituto Nacional de Meteorologia do Estado de Minas Gerais. A análise da série temporal se baseou no teste de Mann-Kendall e na regressão linear. Procedeu-se, também, à análise geoestatística para determinação do zoneamento do conforto de frangos de corte segundo os intervalos de ITU. Dessa forma, as metodologias de mapeamento espacial do ITU e a análise de tendência para predição de um possível cenário climático futuro podem auxiliar no desenvolvimento de mapas de risco para o monitoramento do conforto térmico de frangos de corte, sendo indispensáveis no planejamento de ações para mitigação dos impactos das mudanças climáticas sobre a cadeia produtiva do estado de Minas Gerais.(AU)

Effects of exercise in thermal climates on human renal function and its mechanism of oxidative stress / 解放军医学杂志

Objective: To investigate the effect of exercise in thermal climates on the renal functions and explore the role of oxidative stress injury in the pathogenesis of exertional heat stroke (EHS). Methods: Totally 187 young soldiers in the subtropical area of Southeast China were divided randomly into two groups. All subjects underwent 1.5km, 3km and 5km cross-country running under two different environmental conditions: normal temperature and normal humidity [temperature (26 ± 2) °C, humidity 50% ± 5%]; high temperature and high humidity [temperature (33 ± 2) °C, humidity 65% ± 5%], and each soldiers' blood samples were taken at pre and post running. The level of Cr, BUN, CK, CK-MB, LDH and SOD were measured by automatic biochemical analyzer. The levels of serum 8-OHdG was detected by enzyme-linked immunosorbent assay (ELISA). Results: 1) After exercise, the Cr and BUN of the two groups increased, compared with the pre-exercise the differences were significant (P<0.05). As the amount of exercise increase, the level of Cr and BUN will be further elevated, and compared with 1.5 km cross-country running respectively, there were significant differences in 3.0 km and 5.0 km cross-country running (P<0.05). The level of Cr and BUN were significantly higher in the high-temperature and high-humidity group than those in the normal temperature and normal humidity group (P<0.05); 2) After exercise, the CK, CK-MB and LDH of the two groups increased, compared with the pre-exercise the differences were significant (P<0.05). As the amount of exercise increase, the level of CK, CK-MB and LDH will be further elevated, and compared with 1.5 km cross-country running respectively, there were significant differences in 3.0 km and 5.0 km cross-country running (P<0.05). After 5.0 km cross-country running, the level of Cr and BUN were significantly higher in the high-temperature and high-humidity group than those in the normal temperature and normal humidity group (P<0.05); 3) After exercise, the level of 8-OHdG increased and the level of SOD decreased in the two groups, compared with the pre-exercise the differences were significant (P<0.05). As the amount of exercise increase, the level of 8-OHdG increased significantly and the level of SOD decreased significantly, and compared with 1.5 km cross-country running respectively, there were significant differences in 3.0 km and 5.0 km cross-country running (P<0.05). After 5.0 km cross-country running, the level of 8-OHdG were significantly higher and the level of SOD were significantly lower in the high-temperature and high-humidity group than those in the normal temperature and normal humidity group (P<0.05). Conclusion: Long time strenuous exercise under the condition of high temperature and high humidity can easily induce heat stress damage. The muscle and renal are vulnerable to heat stress damage. Oxidative stress injury may play an important role in heat stress damage of renal.

Impact thermal environment of armored vehicle cabin on humans / 军事医学

Objective To prolong the working time of the crew under a high temperature and high humidity environment in armored vehicles , improve work efficiency , and to prevent excessive heat load from doing any harm to the human body . Methods The man-machine environment was analyzed , the corresponding environment and the conditions aboard were further quantitatively studied , and man-machine-environment interactions were analyzed .Also,a questionnaire survey was conducted at the same time .Results and Conclusion The thermal equilibrium and thermal comfort calculation program were compiled and validated through the questionnaire survey in order to provide support for environment assessment and protection design .

Physiological parameters, hair coat morphological characteristics and temperature gradients in holstein-gyr crossbred cows / Parâmetros fisiológicos, características morfológicas do pelame e gradientes térmicos de vacas cruzadas holandês-gir

The aim of this study was to assess physiological parameters, hair coat morphological characteristics and temperature gradients in crossbred Holstein-Gyr cows in the municipality of Tapira, Minas Gerais (MG), Brazil. Forty-nine lactating cows from six Holstein (H) and Gyr (G) genetic groups (1/4H 3/4G, 3/8H 5/8G, 1/2H 1/2G, 5/8H 3/8G, 3/4H 1/4G and 7/8H 1/8G) were distributed in a completely randomized design. The dry-bulb temperature and relative humidity were recorded, and the temperature and humidity index (THI) was calculated. The rectal temperature, respiratory rate and body surface temperature were measured, as were hair thickness, numbers, length and angle. Cows with a greater than 50% Holstein breed ratio (5/8H 3/8G, 3/4H 1/4G and 7/8H 1/8G) showed a higher respiratory rate and greater hair length than animals with genetic composition equal to or greater than 50% Zebu (1/2H 1/2G, 3/8H 5/8G and 1/4H 3/4G). Animals from the 1/2 and 1/4 HG genetic groups showed the greatest hair angle (P<0.05). With respect to climatic characteristics, the examined locality was within the thermoneutral zone and therefore did not impose conditions of thermal stress. The animals exhibited thermoregulation and hair coat characteristics that were within physiological parameters.

Objetivou-se avaliar parâmetros fisiológicos, características morfológicas de pelame e gradientes térmicos de vacas cruzadas Holandês-Gir no município de Tapira, MG. Foram utilizadas 49 vacas em lactação de seis grupos genéticos Holandês (H) e Gir (G): 1/4H 3/4G, 3/8H 5/8G, 1/2H 1/2G, 5/8H 3/8G, 3/4H 1/4G e 7/8H 1/8G distribuídas em delineamento inteiramente ao acaso. A temperatura de bulbo seco e umidade relativa foram registradas e calculou-se o índice de temperatura e umidade (ITU). A temperatura retal, frequência respiratória, temperatura da superfície corporal, espessura, número, comprimento e inclinação dos pelos foram mensurados. Vacas com proporção maior que 50% da raça Holandesa (5/8H 3/8G, 3/4H 1/4G e 7/8H 1/8G) apresentaram frequência respiratória e comprimento dos pelos maiores em comparação aos animais com composição genética igual ou superior a 50% do Zebu (1/2H 1/2G, 3/8H 5/8G e 1/4H 3/4G). Os animais do grupo genético 1/2 e 1/4 HG apresentaram a maior inclinação de pelo (P<0,05). As características climáticas da localidade estiveram dentro da zona de termoneutralidade, não impondo desta forma condições de estresse térmico e os animais apresentaram características de termorregulação e de pelame dentro dos parâmetros fisiológicos.

Redução da proteína bruta em rações sobre os balanços metabólicos de suínos mantidos em diferentes condições térmicas / Reducing crude protein in diets on the metabolic balances for pigs kept in different thermal conditions

O objetivo deste trabalho foi avaliar a redução da proteína bruta em rações sobre o balanço de nitrogênio, pH urinário e parâmetros sanguíneos de suínos na fase inicial. O peso médio inicial dos animais foi de 18,5 ± 0,73kg. Foram realizados dois experimentos de digestibilidade, sendo um em condições de ambiente de estresse (28,77˚C) e outro conforto térmico (18,13˚C). Em ambos os experimentos os animais foram distribuídos em um delineamento experimental de blocos ao acaso com quatro níveis de proteína bruta (20,5;19,4; 18,3 e 17,2%) e quatro repetições, totalizando 16 unidades experimentais em cada experimento, sendo cada uma representada por um animal, totalizando 32 animais. A metodologia utilizada foi a coleta total de fezes, e a urina coletada e filtrada diariamente. Para avaliar os parâmetros sanguíneos, as amostras foram obtidas mediante punção na veia jugular. Os parâmetros avaliados foram nitrogênio ingerido, excretado nas fezes e na urina, absorvido, retido, retido/absorvido, excreção total, utilização líquida de proteína, pH da urina, colesterol, triglicerídeos, glicose, uréia e creatinina no plasma sanguíneo. Conclui-se que a redução do nível de proteína da dieta, de 20,5 a 17,2%; é uma alternativa eficiente para reduzir a quantidade de nitrogênio excretado pelos suínos em condição de estresse térmico. Para condição de conforto térmico os suínos apresentaram maiores concentrações de creatinina e colesterol plasmático.

The objective of this study was to evaluate the reduction of crude protein diets on nitrogen balance, urinarypH and blood parameters of starter pigs. The average initial weight of the animals was 18.5 ± 0.73 kg. Two digestibility experiments were conducted, one in environmental conditions of stress (28.77 ˚ C) and another in thermal comfort condition (18.13 ˚ C). In both experiments, the animals were distributed in randomized blockswith four decreasing levels of crude protein (20.5, 19.4, 18.3 and 17.2%) and four replications, totaling 16experimental units in each experiment, each represented by an animal, totaling 32 animals. The methodology used was the total collection of feces and urine was collected and filtered daily. To assess blood parameters, samples were obtained by jugular vein puncture. The parameters evaluated were ingested nitrogen, excreted in feces and urine, absorbed, retained, retained/absorbed, total excretion, net protein utilization, urine pH,cholesterol, triglycerides, glucose, urea and creatinine in blood plasma. It is concluded that reducing the levelof protein in the diet, 20.5 to 17.2%; is an efficient alternative to reduce the amount of nitrogen excreted bypigs in heat stress condition. In thermal comfort condition pigs showed higher concentration of creatinine and serum cholesterol.

Estrés térmico en trabajadores expuestos al área de fundición en una empresa metalmecánica, Mariara: 2004-2005 / Heat stress in workers exposed to a foundries in a metal-mechanic company, Mariara 2004-2005

Esta investigación tiene como objetivo evaluar el riesgo de estrés térmico en trabajadores expuestos al área de fundición en una Empresa Metalmecánica. El estudio realizado es de tipo transversal, descriptivo de campo. El universo estuvo integrado por veinte trabajadores y la muestra representada por ocho trabajadores del área de fundición. El análisis e interpretación de los datos se realizó a través de medida de tendencia central, desviación estándar y correlación de pearson. En conclusión, en el área de fundición existe disconfort térmico; no obstante, los trabajadores se encuentran aclimatados en dicha área. Se recomienda establecer programa preventivo de ambiente térmico.

This research aims to assess the risk of heat stress in workers exposed to foundries in Metal-mechanic Company. The study is cross-sectional, field descriptive. The universe consisted of twenty workers and the sample represented by eight workers from the foundry. The analysis and interpretation of the data was performed using the measure of central tendency, standard deviation and Pearson correlation. In conclusion, in the foundry there is heat discomfort; however, workers are acclimated in this area. It is recommended to establish thermal environment preventive program.

A fuzzy system for cloacal temperature prediction of broiler chickens / Sistema fuzzy para a predição da temperatura cloacal de frangos de corte

Cloacal temperature (CT) of broiler chickens is an important parameter to classify its comfort status; therefore its prediction can be used as decision support to turn on acclimatization systems. The aim of this research was to develop and validate a system using the fuzzy set theory for CT prediction of broiler chickens. The fuzzy system was developed based on three input variables: air temperature (T), relative humidity (RH) and air velocity (V). The output variable was the CT. The fuzzy inference system was performed via Mamdani's method which consisted in 48 rules. The defuzzification was done using center of gravity method. The fuzzy system was developed using MAPLE® 8. Experimental results, used for validation, showed that the average standard deviation between simulated and measured values of CT was 0.13°C. The proposed fuzzy system was found to satisfactorily predict CT based on climatic variables. Thus, it could be used as a decision support system on broiler chicken growth.

A temperatura cloacal (TC) de frangos de corte é um importante parâmetro para classificar a sua condição de conforto, portanto, a sua predição pode ser usada no suporte à decisão de acionamento de sistemas de climatização. Objetivou-se com a presente pesquisa desenvolver e validar um sistema, utilizando a teoria dos conjuntos fuzzy para predição da TC de frangos de corte. O sistema fuzzy foi desenvolvido com base em três variáveis de entrada: temperatura do ar (T), umidade relativa (UR) e velocidade do ar (V), tendo, como variável de saída, a TC. A inferência fuzzy foi realizada por meio do método tipo Mamdani, que consistiu na elaboração de 48 regras e a defuzzificação por meio do método do Centro de Gravidade. O sistema fuzzy foi desenvolvido no ambiente computacional MAPLE® 8. Resultados experimentais, usados para a validação, mostraram que o desvio padrão médio entre os valores simulados e medidos de TC foi de 0,13°C. O sistema fuzzy proposto prediz satisfatoriamente a TC com base nas variáveis climáticas, podendo ser utilizado como suporte à decisão em sistemas de criação de frangos de corte.

Energia líquida e ractopamina para leitoas em terminação sob altas temperaturas ambientais / Net energy and ractopamine to finishing gilts under high temperature environment

O objetivo do trabalho foi avaliar níveis de energia líquida (EL) e ractopamina na dieta de leitoas em terminação sob altas temperaturas ambientais (29,5±2,3°C). Foram utilizadas 40 leitoas (peso inicial de 69,3±2,8kg) distribuídas no delineamento de bloco ao acaso em esquema fatorial 2x4 (0 e 20ppm de ractopamina e 2.300; 2.424; 2.548 e 2.668kcal de EL kg-1 de ração), com cinco repetições de um animal cada. Houve interação (P<0,05) entre EL e ractopamina, sendo que a inclusão de 20ppm em dietas com 2.548 e 2.668kcal reduziu (P<0,05) a espessura de toucinho e aumentou (P<0,05) a percentagem de carne magra das carcaças. A ractopamina melhorou (P<0,05) a conversão alimentar e a quantidade de carne magra nas carcaças (P<0,05), independente dos níveis de EL. Concluiu-se que a ractopamina na dose de 20ppm propicia benefícios no desempenho e características de carcaça de leitoas sob estresse térmico e que esse efeito é mais positivo em dietas contendo níveis energéticos mais elevados (2.548 e 2.668kcal de EL).

The objective of this paper was to assess net energy (NE) levels and ractopamine in the diet of finishing gilts maintained under high temperature environment (29.5±2.3°C). Forty gilts were used, with initial weight of 69.3±2.8kg, distributed in a randomized block design, in a factorial scheme 2x4 (0 and 20ppm of ractopamine; and 2,300; 2,424; 2,548 and 2,668kcal/kg NE kg-1 of feed), and five replications and one animal each. There was interaction (P<0.05) between NE levels and ractopamine, and the inclusion of 20ppm of ractopamine in the diets containing 2,548 and 2,668kcal reduced (P<0.05) backfat thickness and increased (P<0.05) the percentage of lean meat of carcasses. The use of ractopamine improved (P<0.05) feed gain ratio and increased (P<0.05) the amount of lean meat in carcasses. It was concluded that ractopamine at a dose of 20ppm provides benefits in performance and carcass traits of gilts under heat stress and this effect is more positive in diets containing higher energy levels (2,548 and 2,668kcal of NE kg-1).

Prediction of thermal environment via revision of PMV index with body temperature / 药物分析学报

PMV (Predicted Mean Vote) is a widely used index for evaluating the thermal environment. However, few studies have been conducted to take physiological values directly as evaluating indices. This paper assumes a linear relation between body temperature and both sweating rate and heat produced by shivering, and introduces the linear relation into the human heat balance equation to revise the classic PMV. And the assumption of linear relation is subsequently proved. The revised PMV possesses the same characteristic of dependent heat load as that of the classic one, and moreover it is convenient to be calculated.

Effects of decreasing air temperature on peripheral thermal reactions in males and females

<p><b>OBJECTIVES</b>This study was performed to determine the effects of decreasing ambient temperature on peripheral blood flow and body temperature of males and females in a thermal neutral zone for references to the thermal standard of office workers.</p><p><b>METHODS</b>Peripheral blood flows of the hand and feet, and body temperatures and so on of male and female subjects were measured in a climatic chamber. Air temperature was maintained at 28.5°C at the beginning. After this, air temperature was decreased linearly to 21.0°C over a period of 60 minutes. Finally, air temperature was maintained at 21.0°C.</p><p><b>RESULTS</b>Blood flows and skin temperatures of male and female subjects became similar or showed no significant difference at beginning and the end of the experiment. Skin blood flow of the hand and skin temperatures of the hand and fingers decreased, and these values in females were lower than in males, when air temperature was decreased linearly in a thermal neutral zone. However, there were no remarkable differences between males and females in sublingual and mean skin temperatures during the experiment.</p><p><b>CONCLUSION</b>Minimum air temperature at the thermal standard for offices in Japan is 17°C, which may be too low to be comfortable or neutral. Even in a neutral thermal condition, it is better that office workers are provided some protection such as a blanket or clothing, to protect peripheral body parts from cooling in winter, as there are individual differences in physiological thermal reactions.</p>

Effects of Decreasing Air Temperature on Peripheral Thermal Reactions in Males and Females

Objectives: This study was performed to determine the effects of decreasing ambient temperature on peripheral blood flow and body temperature of males and females in a thermal neutral zone for references to the thermal standard of office workers. Methods: Peripheral blood flows of the hand and feet, and body temperatures and so on of male and female subjects were measured in a climatic chamber. Air temperature was maintained at 28.5°C at the beginning. After this, air temperature was decreased linearly to 21.0°C over a period of 60 minutes. Finally, air temperature was maintained at 21.0°C. Results: Blood flows and skin temperatures of male and female subjects became similar or showed no significant difference at beginning and the end of the experiment. Skin blood flow of the hand and skin temperatures of the hand and fingers decreased, and these values in females were lower than in males, when air temperature was decreased linearly in a thermal neutral zone. However, there were no remarkable differences between males and females in sublingual and mean skin temperatures during the experiment. Conclusion: Minimum air temperature at the thermal standard for offices in Japan is 17°C, which may be too low to be comfortable or neutral. Even in a neutral thermal condition, it is better that office workers are provided some protection such as a blanket or clothing, to protect peripheral body parts from cooling in winter, as there are individual differences in physiological thermal reactions.

Research Summary About Evaluation System of Thermal Environment in Cabin(Room) / 医疗卫生装备

The domestic and foreign research status related to thermal environment in the cabin(room) is reviewed.Parameters which affect thermal environment and the index limits in the standards of the different cabin(room) are narrated overall.Measuring methods pertinent to parameters of thermal environment are introduced.Finally,the comprehensive evaluation indices of thermal comfort in the cabin(room) and their using fields are analyzed emphatically.It's essential to study thermal environment and it can establish theory foundation for research on thermal environment index system inside mobile medical equipments.