It is accepted that the earth’s climate is changing in an accelerating pace, with already documented implications for human health and the environment. This literature review provides an overview of existing research findings about the effects of heat stress on the working population in relation to climate change. In the light of climate change adaptation, the purpose of the literature review was to explore recent and previous research into the impacts of heat stress on humans in an occupational setting. Heat stress in the workplace has been researched extensively in the past however, in the contemporary context of climate change, information is lacking on its extent and implications. The main factors found to exacerbate heat stress in the current and future workplace are the urban ‘heat island effect’, physical work, individual differences, and the developing country context where technological fixes are often not applicable. There is also a lack of information on the effects on vulnerable groups such as elderly people and pregnant women. As increasing temperatures reduce work productivity, world economic productivity could be condensed, affecting developing countries in the tropical climate zone disproportionately. Future research is needed taking an interdisciplinary approach, including social, economic, environmental and technical aspects.
The growing need for valid assessment procedures of the outdoor thermal environment in the fields of public weather services, public health systems, urban planning, tourism & recreation and climate impact research raised the idea to develop the Universal Thermal Climate Index UTCI based on the most recent scientific progress both in thermo-physiology and in heat exchange theory. Following extensive validation of accessible models of human thermoregulation, the advanced multi-node ‘Fiala’ model was selected to form the basis of UTCI. This model was coupled with an adaptive clothing model which considers clothing habits by the general urban population and behavioral changes in clothing insulation related to actual environmental temperature. UTCI was developed conceptually as an equivalent temperature. Thus, for any combination of air temperature, wind, radiation, and humidity, UTCI is defined as the air temperature in the reference condition which would elicit the same dynamic response of the physiological model. This review analyses the sensitivity of UTCI to humidity and radiation in the heat and to wind in the cold and compares the results with observational studies and internationally standardized assessment procedures. The capabilities, restrictions and potential future extensions of UTCI are discussed.
In the context of climate change, concomitant exposure to heat stress and chemicals takes on great importance. However, little information is available in this regard. The purpose of this research, therefore, was to develop an approach aimed at identifying worker groups that would be potentially most at risk. The approach comprises 5 consecutive steps: – Establishment of a list of occupations for all industry sectors – Determination of heat stress parameters – Identification of occupations at risk of heat stress – Determination of exposure to chemicals – Identification of occupations potentially most at risk. Overall, 1,010 occupations were selected due to their representativeness of employment sectors in Québec. Using a rating matrix, the risk stemming from exposure to heat stress was judged “critical” or “significant” for 257 occupations. Among these, 136 occupations were identified as showing a high potential of simultaneous exposure to heat stress and chemicals. Lastly, a consultation with thirteen experts made it possible to establish a list of 22 priority occupations, that is, 20 occupations in the metal manufacturing sector, as well as roofers and firefighters. These occupations would merit special attention for an investigation and evaluation of the potential effects on workers’ health.
Global warming will increase heat stress at home and at work. Few studies have addressed the health consequences in tropical low and middle income settings such as Thailand. We report on the association between heat stress and workplace injury among workers enrolled in the large national Thai Cohort Study in 2005 (N=58,495). We used logistic regression to relate heat stress and occupational injury separately for males and females, adjusting for covariate effects of age, income, education, alcohol, smoking, Body Mass Index, job location, job type, sleeping hours, existing illness, and having to work very fast. Nearly 20% of workers experienced occupational heat stress which strongly and significantly associated with occupational injury (adjusted OR 2.12, 95%CI 1.87–2.42 for males and 1.89, 95%CI 1.64–2.18 for females). This study provides evidence connecting heat stress and occupational injury in tropical Thailand and also identifies several factors that increase heat exposure. The findings will be useful for policy makers to consider work-related heat stress problems in tropical Thailand and to develop an occupational health and safety program which is urgently needed given the looming threat of global warming.
Global climate change has great potential for escalating the number and duration of extreme heat events in California. California accounts for 16% of U.S. crop production, and over 450,000 people are employed in agriculture, with more than two-thirds being of Latino ethnicity. Despite Cal/OSHA regulations which specify that potable water, toilets, shade and rest be provided to agricultural workers, heat related illnesses and deaths still occur. The MICASA Study is a population-based sample of 467 hired farm worker households from Mendota, in California’s Central Valley. 474 study participants completing follow-up interview and working in agriculture in the year prior are included in this analysis. Men reported an average of 222 d (SD=69.7) of work compared to 148 d (SD=67.3) for women (p<0.0001). Over 91% of participants reported receiving training on heat-related illness, but level of heat illness knowledge was moderate with 70% responding correctly to 4–5 questions. Knowledge about acclimatization was low, with 44% severely underestimating the time required, and water consumption was low at an average of 10.7 drinks per day. Results suggest important areas to target for heat illness prevention in farm worker populations and that gender specific approaches may be needed for effective heat illness prevention.
A feature of climate impacts on occupational health and safety are physiological limits to carrying out physical work at high heat exposure. Heat stress reduces a workers work capacity, leading to lower hourly labour productivity and economic output. We used existing weather station data and climate modeling grid cell data to describe heat conditions (calculated as Wet Bulb Globe Temperature, WBGT) in South-East Asia. During the hottest month in this region (March) afternoon WBGT levels are already high enough to cause major loss of hourly work capacity and by 2050 the situation will be extreme for many outdoor jobs.
The potential impacts of climate change (CC) on Occupational Health and Safety (OHS) have been studied a little in tropical countries, while they received no attention in northern industrialized countries with a temperate climate. This work aimed to establish an overview of the potential links between CC and OHS in those countries and to determine research priorities for Quebec, Canada. A narrative review of the scientific literature (2005–2010) was presented to a working group of international and national experts and stakeholders during a workshop held in 2010. The working group was invited to identify knowledge gaps, and a modified Delphi method helped prioritize research avenues. This process highlighted five categories of hazards that are likely to impact OHS in northern industrialized countries: heat waves/increased temperatures, air pollutants, UV radiation, extreme weather events, vector-borne/zoonotic diseases. These hazards will affect working activities related to natural resources (i.e. agriculture, fishing and forestry) and may influence the socioeconomic context (built environment and green industries), thus indirectly modifying OHS. From this consensus approach, three categories of research were identified: 1) Knowledge acquisition on hazards, target populations and methods of adaptation; 2) Surveillance of diseases/accidents/occupational hazards; and 3) Development of new occupational adaptation strategies.
The wet bulb globe temperature index (WBGT) is a common method to assess the environmental contribution to heat stress as part of an occupational exposure assessment. The two purposes of this study were (1) to compare empirical relationships of some meteorological conditions to WBGT, and (2) to evaluate a smaller globe and alternative method to assess natural wet bulb using a relative humidity sensor. Data were collected in six West-central Florida locations over multiple days for a total of 14 measurement days. Multiple linear regression was used to explore relationships relevant to the two purposes. It was clear that estimating WBGT directly from meteorological data or through estimates of the components of WBGT can be accomplished with a 95% confidence of ± 2°C-WBGT. The 50 mm globe size is a reasonable approximation of the standard size (150 mm). The relative humidity method of the waterless natural wet bulb provides a very good estimation of natural wet bulb temperature. The determination of WBGT from the electronic instruments (small globe with or without the relative humidity method) provided a good estimate of the WBGT.
The current system of International Standards (ISO) is assessed to consider whether standards are fit for purpose for the future in the context of climate change. ISO 7243, ISO 7933 and ISO 9886 provide the current ISO system for the assessment of heat stress. These involve a simple monitoring index, an analytical approach and physiological monitoring, respectively. The system relies on accurate measurement of the thermal conditions experienced by the worker (ISO 7726); and estimations of metabolic heat production due to work (ISO 8996) and the thermal properties of clothing (ISO 9920). As well as standards for heat stress assessment, the full range of ISO standards and the physical environment is listed as well as current work and proposed standards. A particular ‘gap’ in anticipating requirements for ISO standards in the future is the link between meteorological data and ISO standards. This is important for predicting the global consequences of a changing climate and anticipating potential impacts on occupational health across countries and cultures.
This paper intends to analyse responses of the working people to heat stress in Nepal’s Tarai region. Here, the heat stress responses refer to the working environments– indoor and outdoor settings, prevailing diseases, and adaptive measures by the workers. Data were gathered from the sample households by using household survey, observation, and informal discussions. Environmental conditions in terms of heat exposure in the working areas have been measured with heat index, humidity index, and WBGT, based on the HOTHAPS approach. The findings are that: the average temperature during the peak hot months reached to over 39°C and the environmental conditions in the selected factories during the hot summer months were too hot to the workers to work continuously during the day, where there was inadequacy of facilities to combat against the hot. Males were more exposed than females to the heat due to heavy type of works in outdoor settings. Few workers found to have adapted coping measures such as shift in working time, wearing thin cotton clothes, etc but they were inadequate against the heat stress. More quantitative measurements of workers’ health effects and productivity loss will be of interest for future works.
Extreme climatic heat is a major health concern among workers in different occupational pursuits. People in the regions of western India confront frequent heat emergencies, with great risk of mortality and morbidity. Taking account of informal occupational groups (foundry and sheet metal, FSM, N=587; ceramic and pottery, CP, N=426; stone quarry, SQ, N=934) in different seasons, the study examined the body temperature profiling as indicator of vulnerability to environmental warmth. About 3/4th of 1947 workers had habitual exposure at 30.1–35.5°C WBGT and ~10% of them were exposed to 38.2–41.6°C WBGT. The responses of FSM, CP and SQ workers indicated prevailing high heat load during summer and post-monsoon months. Local skin temperatures (Tsk) varied significantly in different seasons, with consistently high level in summer, followed by post-monsoon and winter months. The mean difference of Tcr and Tsk was ~5.2°C up to 26.7°C WBGT, and ~2.5°C beyond 30°C WBGT. Nearly 90% of the workers had Tcr within 38°C, suggesting their self-adjustment strategy in pacing work and regulating Tcr. In extreme heat, the limit of peripheral adjustability (35–36°C Tsk) and the narrowing down of the difference between Tcr and Tsk might indicate the limit of one’s ability to withstand heat exposure.
While climate change continues to increase ambient temperatures, the resulting heat stress exposure to workers in non-climate controlled settings is not well characterized, particularly in low and middle income countries. This preliminary report describes current heat stress in Nicaraguan work places and estimates occupational heat stress in 2050. From over 400 measurements of heat exposure using wet bulb globe temperature, more than 10% of all measurements exceeded the safety threshold for the combination of light work and rest at the ratio of 25:75. By 2050, that percentage of “over-heated” days is projected to increase to over 15%. These findings support the idea that common working conditions in Nicaragua already represent a threat to the health and safety of the workers and that climate change driven trends could mean either a necessary curbing of economic productivity or an increased threat to worker health and safety.
The purpose of this study is to investigate the potential impact of differing lung cancer risks in study populations on estimating population attributable fraction (PAF) from asbestos exposure. Studies were identified via a MEDLINE search up to September 2009 and from the reference lists of publications about asbestos exposure and lung cancer risk. Relative risk estimates were extracted from 160 studies and meta-relative risks were calculated according to random-effect models. Hypothetical PAFs were calculated based on the meta results and on the difference exposure scenarios. The risks for lung cancer from asbestos exposure were variable according to the region as well as other study characteristics. The risk estimates proved higher in Asian countries (RR=3.53), in studies with 500 or fewer subjects (RR=2.26), and papers published in the 1990s or earlier (RR=1.91), than did those for European or North American countries, studies with more than 500 subjects, and papers published in the 2000s, respectively. The differences in PAFs between Asian and North American studies were 15.5%, 30.3%, and 36.2% when the exposure prevalence was 10%, 30%, and 50%, respectively. This study suggested that it is important to apply appropriate lung cancer estimates to each study population when calculating PAF from asbestos exposure.
The Finnish forest industry has undergone extensive transition in recent years. This study investigates the effect of restructuring on the well-being of blue-collar employees who continued working in the organization after the changes. All six factories selected for the study were in the process of restructuring between baseline and the follow-up survey. The factories were grouped according to personnel reduction (dismissals): Change group 1 – no dismissals; and Change group 2 – dismissals. The majority of the analyses were carried out using longitudinal data (n=382). The associations between the changes in personnel and functional and psychological well-being were analysed using ANCOVA (adjusted for age, gender, education, and outcome at baseline). In both change groups the level of functional well-being improved after restructuring, but the level of psychological well-being decreased. The content of the changes, regardless of whether they involved personnel dismissals, did not affect the magnitude of the decrease in psychological well-being. It seems that the effect of restructuring on the psychological well-being of employees working in the restructuring organization is considerable, even when no dismissals are involved. The impact of change on functional well-being seems to be different.