Evaluation of Human Thermal Comfort Ranges in the Respect of Urban Climate of Winter Cities on the Example of Erzurum City

Human thermal comfort conditions can be evaluated by using various indices based either on simple empirical approaches or on more complex and reliable human-biometeorological approaches. Latter ones are based on the energy balance models of the human body and their calculation is supplemented with some computer software. Facilitating the interpretation of the results, the generally applied indices express the effects of the thermal environment in the wellknown temperature-unit; just like in the case of the widely used PET (Physiological Equivalent Temperature) index. Several studies adopting PET index for characterizing the thermal component of the climate (climate of a region, urban climate at local scale or microclimate within different city structures) preferred to organize the resulted PET values into thermal sensation or thermal stress categories in order to demonstrate the spatial and/or temporal characteristics of human thermal comfort conditions. The generally adopted PET ranges, however, were derived by Central-European researchers and they are only valid for the assumed values of internal heat production of light activity and thermal resistance of clothing representing a light business suit. Based on the example of Erzurum city, the present work clearly demonstrates that in harsh winter conditions the original PET ranges show purely discomfort. Thus the generally adopted human thermal comfort ranges of PET index seem to be less applicable regarding cold climate conditions, and detailed investigations would be required in order to define new categorization being of greater importance for local residents who are adapted to this climatic background, and for tourists on the other hand who may perform winter sport activities and therefore perceive the thermal environment more comfortable.