Hearth management at a middle Paleolithic rock shelter site: Smoke density analysis at Tor Faraj, Jordan

Paleolithic rock shelters often include several hearths located in different parts of the site. In this paper, we analyze relevant data from Middle Paleolithic Tor Faraj rock shelter as a case study of smoke density in correlation with hearth location and functionality. Since one of the major negative fire products is smoke, which has an immediate effect on human health, we used computer simulations to analyze the effect of various parallel hypothetical hearth configurations on smoke density in the shelter, as categorized by the average smoke exposure recommendations from the World Health Organization (WHO) and Environmental Protection Agency (EPA). The simulations enable us to investigate various hearth activation possibilities affecting smoke density in all the site areas, thus enhancing the understanding of hearth location and functionality in Paleolithic rock shelter sites. The results correspond with ethnographic studies of sites where hearths for sleeping are located at the back wall of the shelter and explain, for the first time, the reason for this placement. The number of parallel active hearths was found to be limited by smoke density factors, despite the ventilation afforded by the rock shelter's high, wide opening, which also left it vulnerable to the effects of wind. The distance between the hearths also influenced smoke density, especially between the drip line up to the rock shelter center. Thus, these areas were probably more suitable for short-duration activities such as cooking. We further concluded that the hearths at Tor Faraj were most probably activated at the time of need and not necessarily simultaneously. By correlating wind statistics from the Meteoblue website with our smoke density simulation results, we could deduce that intensive occupations at Tor Faraj in the middle of winter (January) would have been problematic due to wind affecting smoke dispersal at the site.