Thermal stress risk assessment using Physiological Equivalent Temperature (PET) in Iran

Asghari, Mehdi; Safari Palangi2, Hossein; Fallah Ghalhari, , Gholamabbas; Akhlaghi Pirposhteh, Elham; Shakeri, Fahimeh; Abbasinia, Marzieh; Farhang Dehghan, Somayeh

Volume 22, Issue 1 (2025) ioh 2025, 22(1): 0-0 | Back to browse issues page

Ethics code: IR.IUMS. REC.1403.144

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Asghari M, Safari Palangi2 H, Fallah Ghalhari , G, Akhlaghi Pirposhteh E, Shakeri F, Abbasinia M et al . Thermal stress risk assessment using Physiological Equivalent Temperature (PET) in Iran. ioh 2025; 22 (1) : 9
URL: http://ioh.iums.ac.ir/article-1-3667-en.html

Thermal stress risk assessment using Physiological Equivalent Temperature (PET) in Iran

Mehdi Asghari

, Hossein Safari Palangi2

, , Gholamabbas Fallah Ghalhari

, Elham Akhlaghi Pirposhteh

, Fahimeh Shakeri

, Marzieh Abbasinia

, Somayeh Farhang Dehghan ^*

Shahid Beheshti University of Medical Sciences , somayeh.farhang@gmail.com

Abstract: (14 Views)

Background and Aim

Climate change and rising temperatures pose significant challenges to public health and the environment. Weather conditions critically influence human health and physiological performance. The Physiologically Equivalent Temperature (PET) index serves as a reliable measure for assessing heat and cold stress. In Iran, with its diverse climate, physiological stress shows distinct patterns. This study evaluates heat stress levels over 30 years (1990-2020) in Iran using the PET index.

Methods

Meteorological data, including mean dry temperature, radiant temperature, relative humidity, wind speed, and cloud cover, were collected from 49 stations across Iran via the Iranian Meteorological Organization. The PET index was calculated for all seasons using RayMan software, and spatial distribution maps were created using the kriging method in ArcGIS 10.3.

Results

The highest average PET value was recorded in summer at Bandar Abbas station (44.57°C, "extreme heat stress"). The lowest was during winter at Saez station (-7.95°C, "extreme cold stress"). Analysis showed the highest frequency of physiological stress in arid (42.85%) and semi-arid (38.77%) climates, with lower frequencies in Mediterranean (4.08%), semi-humid (2.04%), humid (4.12%), and very humid (6.12%) climates.

Conclusion

The study indicates that arid and semi-arid regions face higher risks of heat stress in summer and cold stress in winter. These areas are particularly vulnerable to climate change. In contrast, northern humid regions experience lower heat stress risks. The findings can inform operational plans to reduce community vulnerability and enhance adaptation to climate change.

Article number: 9

Keywords: Heat stress, PET index (Physiologically Equivalent Temperature), Climate change, Climatic zoning, Climate vulnerability