scholarly journals Quantifying the impact of heat on human physical work capacity; part II: the observed interaction of air velocity with temperature, humidity, sweat rate, and clothing is not captured by most heat stress indices

Author(s):  
Josh Foster ◽  
James W. Smallcombe ◽  
Simon Hodder ◽  
Ollie Jay ◽  
Andreas D. Flouris ◽  
...  

Abstract Increasing air movement can alleviate or exacerbate occupational heat strain, but the impact is not well defined across a wide range of hot environments, with different clothing levels. Therefore, we combined a large empirical study with a physical model of human heat transfer to determine the climates where increased air movement (with electric fans) provides effective body cooling. The model allowed us to generate practical advice using a high-resolution matrix of temperature and humidity. The empirical study involved a total of 300 1-h work trials in a variety of environments (35, 40, 45, and 50 °C, with 20 up to 80% relative humidity) with and without simulated wind (3.5 vs 0.2 m∙s−1), and wearing either minimal clothing or a full body work coverall. Our data provides compelling evidence that the impact of fans is strongly determined by air temperature and humidity. When air temperature is ≥ 35 °C, fans are ineffective and potentially harmful when relative humidity is below 50%. Our simulated data also show the climates where high wind/fans are beneficial or harmful, considering heat acclimation, age, and wind speed. Using unified weather indices, the impact of air movement is well captured by the universal thermal climate index, but not by wet-bulb globe temperature and aspirated wet-bulb temperature. Overall, the data from this study can inform new guidance for major public and occupational health agencies, potentially maintaining health and productivity in a warming climate.

2021 ◽  
Author(s):  
Josh Foster ◽  
James W Smallcombe ◽  
Simon G Hodder ◽  
Andreas D Flouris ◽  
Lars Nybo ◽  
...  

It is well-known that heat impacts human labour/physical work capacity (PWC), but systematic evaluations of solar radiation (SOLAR) effects and the interaction with air temperature and humidity levels and clothing are lacking, as most lab-studies are conducted in semi-nude subjects without radiation or only in a single climatic condition. Due to the high relevance of SOLAR in various occupations, this study quantified how SOLAR interacts with clothing and other primary environmental factors (air temperature/humidity) of importance to determine PWC in the heat. The data allowed the development of a SOLAR correction factor for predicting PWC in major outdoor industries. Fourteen young adult males (7 wearing a standardised work coverall (0.9 Clo), 7 with shorts and trainers (0.3 Clo) walked for 1-hour at a fixed heart rate of 130 b∙min-1, in seven combinations of air temperature (25 to 45 Celsius) and relative humidity (20 or 80%), with and without SOLAR (800 W/m2 from solar lamps). Cumulative energy expenditure in the heat, relative to the work achieved in a cool reference condition, was used to determine PWC%. Skin temperature was the primary determinant of PWC in the heat. In dry climates with exposed skin (0.3 Clo), SOLAR caused PWC to decrease exponentially with rising air temperature, whereas work coveralls (0.9 Clo) negated this effect. In humid conditions, the SOLAR-induced reduction in PWC was consistent and linear across all levels of air temperature, and clothing conditions. WBGT and UTCI based prediction equations of PWC represented SOLAR correctly. For heat indices not intrinsically accounting for SOLAR, correction factors are provided enabling forecasting of heat effects on work productivity.


Author(s):  
Josh Foster ◽  
James W. Smallcombe ◽  
Simon Hodder ◽  
Ollie Jay ◽  
Andreas D. Flouris ◽  
...  

AbstractHeat stress decreases human physical work capacity (PWC), but the extent to which solar radiation (SOLAR) compounds this response is not well understood. This study empirically quantified how SOLAR impacts PWC in the heat, considering wide, but controlled, variations in air temperature, humidity, and clothing coverage. We also provide correction equations so PWC can be quantified outdoors using heat stress indices that do not ordinarily account for SOLAR (including the Heat Stress Index, Humidex, and Wet-Bulb Temperature). Fourteen young adult males (7 donning a work coverall, 7 with shorts and trainers) walked for 1 h at a fixed heart rate of 130 beats∙min−1, in seven combinations of air temperature (25 to 45°C) and relative humidity (20 or 80%), with and without SOLAR (800 W/m2 from solar lamps). Cumulative energy expenditure in the heat, relative to the work achieved in a cool reference condition, was used to determine PWC%. Skin temperature was the primary determinant of PWC in the heat. In dry climates with exposed skin (0.3 Clo), SOLAR caused PWC to decrease exponentially with rising air temperature, whereas work coveralls (0.9 Clo) negated this effect. In humid conditions, the SOLAR-induced reduction in PWC was consistent and linear across all levels of air temperature and clothing conditions. Wet-Bulb Globe Temperature and the Universal Thermal Climate Index represented SOLAR correctly and did not require a correction factor. For the Heat Stress Index, Humidex, and Wet-Bulb Temperature, correction factors are provided enabling forecasting of heat effects on work productivity.


Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3338
Author(s):  
Ivan Vajs ◽  
Dejan Drajic ◽  
Nenad Gligoric ◽  
Ilija Radovanovic ◽  
Ivan Popovic

Existing government air quality monitoring networks consist of static measurement stations, which are highly reliable and accurately measure a wide range of air pollutants, but they are very large, expensive and require significant amounts of maintenance. As a promising solution, low-cost sensors are being introduced as complementary, air quality monitoring stations. These sensors are, however, not reliable due to the lower accuracy, short life cycle and corresponding calibration issues. Recent studies have shown that low-cost sensors are affected by relative humidity and temperature. In this paper, we explore methods to additionally improve the calibration algorithms with the aim to increase the measurement accuracy considering the impact of temperature and humidity on the readings, by using machine learning. A detailed comparative analysis of linear regression, artificial neural network and random forest algorithms are presented, analyzing their performance on the measurements of CO, NO2 and PM10 particles, with promising results and an achieved R2 of 0.93–0.97, 0.82–0.94 and 0.73–0.89 dependent on the observed period of the year, respectively, for each pollutant. A comprehensive analysis and recommendations on how low-cost sensors could be used as complementary monitoring stations to the reference ones, to increase spatial and temporal measurement resolution, is provided.


2021 ◽  
Vol 98 (6) ◽  
pp. 43-49
Author(s):  
V.B. DOROKHOV ◽  
◽  
N.YU. PINTELIN ◽  
D.YU. ZHELDAKOV ◽  
◽  
...  

The heat and humidity regime of the buried parts can be essential, and sometimes crucial, for the normalization of the microclimate of the entire monument. The experience of thermophysical studies in church architectural monuments shows a wide range of factors that determine the impact of the temperature and humidity regime of the buried volumes on the formation of conditions for the preservation of the monument as a whole. Currently, the Climate Laboratory of Museums and Architectural Monuments of GOSNIIR conducts research on this problem in order to create a methodology for studying and normalizing the heat and humidity regime of the aboveground and underground parts of the building as a whole to develop design and technological approaches to optimizing the conditions for the preservation of the monument. The article considers a practical example of providing heat and humidity conditions for the preservation of a monument with monumental painting.


2020 ◽  
Vol 10 (3) ◽  
pp. 1093 ◽  
Author(s):  
Marta Wiśniewska ◽  
Andrzej Kulig ◽  
Krystyna Lelicińska-Serafin

Biogas plants processing municipal waste are an important part of a circular economy (energy generation from biogas and organic fertiliser production for the treatment of selectively collected biowaste). However, the technological processes taking place may be associated with odour nuisance. The paper presents the results of pilot research conducted at six municipal waste biogas plants in Poland. It shows the relations between odour intensity and concentration and the occurring meteorological and ambient conditions (air temperature and relative humidity) and technological factors at biogas plants processing municipal waste. The impact of meteorological and ambient conditions was identified by measuring air temperature and relative humidity and observing their changes. The impact of technological factors was identified by measuring odorant concentration (volatile organic compounds and ammonia) and observing their changes between individual measurement series. At most analysed biogas plants, the influence of technological factors on odour emissions took place and was clearly noted. The elements of biogas installations characterised by the highest concentration of these odorants were indicated. Special attention should be paid to the choice of technological solutions and technical and organisational measures to reduce the impact of unfavourable atmospheric conditions on odour emissions.


1973 ◽  
Vol 105 (7) ◽  
pp. 975-984 ◽  
Author(s):  
Robert Trottier

AbstractEmergence from the water of Anax junius Drury normally occurred after sunset. The onset was affected independently by water temperature and air temperature; low water temperature and high air temperature delayed the onset of emergence. In the field, the net vrtical distance travelled above the water, before ecdysis, was positively correlated with air temperature. In the laboratory, the vertical distance travelled above the water was greatest when air and water temperatures were approximately the same. The average speed of climbing to the first resting position above the water surface was faster at high than low water temperature, but the average speed of climbing from there to the final position, where ecdysis occurred, was reduced due to the effects of air temperature and humidity. Air temperatures below 12.6 °C were found to retard ecdysis and larvae returned to the water and emerged early the following day making the final process of emergence and ecdysis diurnal instead of nocturnal. The duration of ecdysis was shorter at high than low air temperatures and only the first three stages, as arbitrarily defined, were longer at low than high relative humidity; stage 4, shortened with low relative humidity. This study shows that A. Junius, emerging from the water is affected at first by the temperature experienced when submerged, but it becomes gradually and cumulatively affected by air temperature and humidity while climbing to the ecdysial position and moulting.


2018 ◽  
Vol 3 (57) ◽  
Author(s):  
Wladyslaw Jagiello ◽  
Wlodzimierz Tkaczuk

On the basis of studies of 210 Greco-Roman wrestlers aged 11—18 the impact of training loads and sports selectionin the above sports event upon physical development and general work capacity of young athletes have beendetermined.Besides, age dynamics of changes of the major somatic indices (body length and mass) as well as physical workcapacity at the stage of initial and basic sports preparation has been determined.The studies have resulted in the determination of specific for Greco-Roman wrestlers changes in the examined indicesand development of evaluation scale of general physical work capacity.On the basis of findings we may conclude that Greco-Roman wrestling has a positive influence on developing body.In most cases mean values of examined somatic indices exceed those of children not engaged in sports as well aschildren practising other sports events. This sports event may be considered as a good means stimulating physicaldevelopment of children and youth.The age of 11—15 has turned to be the period of the greatest structural and functional changes in their ontogenesis.During this period the greatest rate of development is peculiar for body mass and height (11—12 years — mass 16%,length 6%; 14—15 years — mass 25%, length 6%), whereas development of work capacity occurs evenly. Along withrelative stabilization of the rate of body mass and height development beginning from the age of 16 high rate of workcapacity development is observed.Keywords: Greco-Roman wrestling, somatic development, performance abilities.


2018 ◽  
Vol 227 (2) ◽  
pp. 307-316
Author(s):  
Lect. Intisar Sukkar Khioun

     The relationship between man and climate is of great importance in climate studies, as climate is the most natural climatic element in the sense of comfort or distress of man, and humans can live comfortably if the degree of heat between (17-31 m) and the human feeling of heat and cold and then rest or discomfort not only caused by the air temperature but depends on many elements including solar radiation, air movement, relative humidity, the level of human activity and the type of clothing worn, and the presumption has used Biophysiological temperature and Cooling guide in this study to demonstrate the impact of climate on human comfort in the city of Rutba and relying on the climatic data for thirty years.


2021 ◽  
Vol 883 (1) ◽  
pp. 012079
Author(s):  
J M Matinahoru

Abstract This research was aimed to determine the impact of climate change on the resin productivity of dammar tree. This research will be useful as data and information for farmers and government to maintain the resin of dammar tree to be optimal and sustainable in production. This research was conducted in Inamosol Sub-district, West Seram District, Maluku Indonesia, during September-October 2020. Village and farmer samples were determined by purposive sampling technique. The selected villages were Honitetu, Hukuanakota and Rambatu. Furthermore, from each village, It was ten farmers to select for interviews and filling the questionnaire. The results showed that the average resin production of farmers in 2019 was 904.2 kg/farmer, while in 2020 was 523.7 kg/farmer. This means that it occurred a decline in resin production in 2020 about 42.08 % for each farmer—the leading cause of the decreased production as climate change factors, namely rainfall, temperature and humidity. Based on climate data of West Seram District in 2019 indicated that rainfall has occurred during six months with an average temperature of 27 °C and relative humidity of 82 %. Meanwhile, in 2020 the rainfall occurs for nine months with an average temperature of 26.5 °C, and relative humidity of 85 %.


2021 ◽  
pp. 1-42
Author(s):  
Emmanuel Panagiotakis ◽  
Dionysia Kolokotsa ◽  
Nektarios Chrysoulakis

The present paper aims to study the impact of Nature Based Solutions (NBS) on the urban environment. The Surface Urban Energy and Water balance Scheme (SUEWS) is used to quantify the impact of NBS in the city of Heraklion, Crete, Greece, a densely built urban area. Local meteorological data and data from an Eddy Covariance flux tower installed in the city center are used for the model simulation and evaluation. Five different scenarios are tested by replacing the city’s roofs and pavements with green infrastructure, i.e., trees and grass, and water bodies. The NBS impact evaluation is based on the changes of air temperature above 2m from the ground, relative humidity and energy fluxes. A decrease of the air temperature is revealed with the highest reduction (2.3%) occurring when the pavements are replaced with grass for all scenarios. The reduction of the air temperature is followed by a decrease in turbulent sensible heat flux. For almost all cases, an increase of the relative humidity is noticed, accompanied by a considerable increase of the turbulent latent heat flux. Therefore, NBS in cities change the energy balance significantly and modify the urban environment for the citizens' benefit.


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