Researchers investigate how Paleolithic fire affected human health by recreating hearths inside an igloo

The PALFUEL project, led by Dr. Ethel Allué, researcher at IPHES-CERCA and professor at the Universitat Rovira i Virgili, studies how fuels were used during the Paleolithic and what effects fire may have had on human health and on the living conditions of hunter-gatherer groups.

Within this research framework, experimental reproductions of hearths are being carried out in different types of prehistoric dwellings in order to understand how fire behaved in various environments and what kinds of emissions it produced. The experiments allow researchers to analyse factors such as temperature, carbon dioxide (CO₂), suspended particles, volatile compounds, and environmental conditions associated with combustion.

These data are particularly relevant for evaluating the possible effects of smoke on the health of prehistoric populations, an aspect that remains poorly understood but is key to understanding everyday life in fire-inhabited spaces.

A pioneering experiment inside an igloo

One of the most distinctive experiments of the project has recently been carried out in the Alabaus area, at La Molina ski resort (about 1,600 metres above sea level), where an igloo was built to reproduce the conditions of a dwelling in a cold environment.

Inside this structure, a hearth and a lamp were recreated, generating a pilot experiment designed to study fire behaviour under extreme cold conditions, a scenario that had not previously been tested in the project.

The fuel used in this test consisted of Scots pine wood and horse bones, with the aim of analysing the use of alternative fuels in situations of firewood scarcity—an adaptive strategy that may have been common among Paleolithic populations.

The igloo was built with the support of Arnau and Pau from the Catalan Association of Igloo Builders Ohmamiglú, who collaborated in the development of this experimental scenario.

Reproducing hearths to understand the past

The experiments follow the protocol established in research carried out in recent years by Dr. Andrés Robledo (National University of Córdoba, Argentina), with the collaboration of Dr. Aitor Burguet-Coca and Dr. M. Joana Gabucio, members of IPHES-CERCA.

The procedure involves lighting a hearth with a controlled amount of fuel and monitoring multiple environmental variables, which makes it possible to obtain comparable data from different types of dwellings and climatic contexts.

In addition to the experiments conducted in cold environments, the project is also developing tests in ephemeral dwellings in temperate environments, using windbreak structures and brazier-type fires.

Modelling emissions from prehistoric fire

Once analysed, the experimental results will be used to model smoke and particle emissions in different types of prehistoric dwellings. These data will be combined with the results of other experiments conducted in rock shelters and huts, thereby expanding knowledge about the use of fire in the past.

At the same time, the study of biomarkers (organic molecules derived from combustion) will help increase the reference data used to interpret evidence of fire in archaeological contexts.

A project with international collaboration

A team of around a dozen people participated in these experiments, including researchers from several institutions. Among them are members of IPHES-CERCA such as Dr. Ethel Allué, Núria Ibáñez and Andrea Alías, as well as researchers from other Spanish universities: Dr. Marian Berihuete (UAB), Dr. Sabrina Bianco (UIB) and Dr. Nerea Herran (EHU), in addition to several volunteers.

Funding and support

This research is part of the projects PID2023-148678NB-100 (PALFUEL) and PID2024-157476NA-I00 (NEAN-SPARK), funded by the Spanish Ministry of Science, Innovation and Universities (MCIU), the State Research Agency (AEI), and the European Regional Development Fund (ERDF) – A way of making Europe.

The research team also wishes to acknowledge the support of Josep Zaragoza (Vinyets), the Ohmamiglú association, the Rectoria de Pedra and the Angelines and Isaac butcher shop at Tarragona Market, who contributed to the development of the experiments.