Exposure to heat at work: development of a quantitative European job exposure matrix (heat JEM)

Sep 29, 2026

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Climate change is intensifying occupational heat stress, making objective and systematic exposure assessment critical for epidemiological research. This study developed a quantitative European job exposure matrix (heat JEM) that assigns job-title heat exposure across Europe. Using ISO-aligned methods and region- and year-specific meteorological data from 1970–2024, it estimates annual heat-stress hours and evaluates variation by job demands, clothing, region, and acclimatization.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Objective

Methods

Heat JEM construction

Exposure definitions and calculations

Results

Conclusions

Key terms

Original article This work is licensed under a Creative Commons Attribution 4.0 International License. ScandJ Work Environ Health. 2026;52(1):7–18. doi:10.5271/sjweh.4243 Exposure to heat at work: development of a quantitative European job exposure matrix (heat JEM) by Tosca OE de Crom, PhD, 1 Bernice Scholten, PhD, 1 Eugenio Traini, PhD, 1 Koen van derSanden, MSc,2 Boris Kingma, PhD,2,3 Floris Pekel, MSc, 1 Manosij Ghosh, PhD,4 Hilde Notø, PhD,5 Michelle C Turner, PhD,6-8 Miguel Angel Alba Hidalgo, PhD,6 Lisa Klous, PhD,2 Maria Albin, PhD,9,10 Henrik A Kolstad, PhD, 11 Jenny Selander, PhD, 10 Calvin Ge, PhD, 1 Anjoeka Pronk, PhD 1 de Crom TOE, Scholten B, Traini E, van der Sanden K, Kingma B, Pekel F, Ghosh M, Turner MC, Alba Hidalgo MA, Klous L, Albin M, Kolstad HA, Selander J, Ge C, Pronk A. Exposure to heat at work: development of a quantitative European job exposure matrix (heat JEM) . ScandJ Work Environ Health. 2026;52(1):7–18 Objective With climate change exacerbating occupational heat stress, objective and systematic exposure assessment is essential for epidemiological studies. We developed a job exposure matrix (JEM) to assign occupational heat stress exposure across Europe. Methods Aligned with the International Organization for Standardization (ISO: 7243, 8996 and 9920), the heat JEM provides region-and year-specific estimates of annual heat stress hours by job title, using the International Standard Classification of Occupations 1988 for Europe [ISCO-88(COM)] . Heat stress was defined as wet bulb globe temperature effective (WBGTeff) exceeding WBGT reference (WBGTref) . Outdoor and indoor WBGT were determined using historical, region-specific hourly meteorological data (temperature, radiation, humidity, wind speed) across Europe, between 1970 and 2024. WBGT values were adjusted for job-specific clothing to obtain WBGTeff. WBGTref was based on metabolic rate, calculated using body surface area and job-specific physical activity, and adjusted for acclimatization status. Further adjustments were made for the job title-specific presence of local heat and cooling sources, time spent indoors versus outdoors, and working schedules. Results The number of annual hours workers experience heat stress is highest among jobs involving local heat sources and physical demanding tasks, especially when work clothing is mandatory. Southern Europe has a higher annual heat stress burden compared to other regions. Exposure varies across calendar years and is substantially higher among unacclimatized versus acclimatized workers. Conclusions Incorporating job-, region-, and year-specific factors, the heat JEM provides a harmonized tool for studying occupational heat stress. Its transparent framework allows for updates with new data and extensions to other years and regions. Key terms epidemiology; exposure assessment; heat stress; occupational exposure; wet bulb globe temperature. 1 Department of Risk Analysis for Prevention, Innovation & Development, Netherlands Organization for Applied Scientific Research TNO, Utrecht, The Netherlands. 2 Department of Human Performance, Netherlands Organization for Applied Scientific Research TNO, Soesterberg, The Netherlands. 3 Section for Integrative Physiology, Department of Nutrition, Exercise and Sport, University of Copenhagen, Copenhagen, Denmark. 4 Department of Public Health and Primary Care, Centre for Environment and Health, Katholieke Universiteit, Leuven, Belgium. 5 National Institute of Occupational Health (STAMI), Oslo, Norway. 6 Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain. 7 Universitat Pompeu Fabra (UPF), Barcelona, Spain. 8 CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain. 9 Department of Occupational and Environmental Medicine, Lund University Hospital, Lund, Sweden. 10 Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. 11 Department of Occupational Medicine, Danish Ramazzini Cen

FAQs

What is the main objective of the heat JEM study?

To create an objective, systematic job exposure matrix that assigns occupational heat-stress exposure across Europe for epidemiological studies.

How is heat stress defined in the heat JEM?

Heat stress is defined as wet bulb globe temperature effective (WBGTeff) exceeding a reference value (WBGTref), with adjustments for clothing, metabolism, acclimatization, and work-related factors.

What factors most influence annual heat-stress hours in the results?

Jobs involving local heat sources and physically demanding tasks, especially when work clothing is mandatory, show the highest annual exposure; exposure is also higher in Southern Europe and varies substantially between unacclimatized and acclimatized workers.

Sep 29, 2026

Upload by Adam