Krzysztof Błażejczyk
Polish Academy of Sciences
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Featured researches published by Krzysztof Błażejczyk.
International Journal of Biometeorology | 2012
George Havenith; Dusan Fiala; Krzysztof Błażejczyk; Mark Richards; Peter Bröde; Ingvar Holmér; Hannu Rintamäki; Yael Benshabat; Gerd Jendritzky
The Universal Thermal Climate Index (UTCI) was conceived as a thermal index covering the whole climate range from heat to cold. This would be impossible without considering clothing as the interface between the person (here, the physiological model of thermoregulation) and the environment. It was decided to develop a clothing model for this application in which the following three factors were considered: (1) typical dressing behaviour in different temperatures, as observed in the field, resulting in a model of the distribution of clothing over the different body segments in relation to the ambient temperature, (2) the changes in clothing insulation and vapour resistance caused by wind and body movement, and (3) the change in wind speed in relation to the height above ground. The outcome was a clothing model that defines in detail the effective clothing insulation and vapour resistance for each of the thermo-physiological model’s body segments over a wide range of climatic conditions. This paper details this model’s conception and documents its definitions.
International Journal of Biometeorology | 2012
Agnes Psikuta; Dusan Fiala; Gudrun Laschewski; Gerd Jendritzky; Mark Richards; Krzysztof Błażejczyk; Igor B. Mekjavic; Hannu Rintamäki; Richard de Dear; George Havenith
The important requirement that COST Action 730 demanded of the physiological model to be used for the Universal Thermal Climate Index (UTCI) was its capability of accurate simulation of human thermophysiological responses across a wide range of relevant environmental conditions, such as conditions corresponding to the selection of all habitable climates and their seasonal changes, and transient conditions representing the temporal variation of outdoor conditions. In the first part of this study, available heat budget/two-node models and multi-node thermophysiological models were evaluated by direct comparison over a wide spectrum of climatic conditions. The UTCI-Fiala model predicted most reliably the average human thermal response, as shown by least deviations from physiologically plausible responses when compared to other models. In the second part of the study, this model was subjected to extensive validation using the results of human subject experiments for a range of relevant (steady-state and transient) environmental conditions. The UTCI-Fiala multi-node model proved its ability to predict adequately the human physiological response for a variety of moderate and extreme conditions represented in the COST 730 database. The mean skin and core temperatures were predicted with average root-mean-square deviations of 1.35 ± 1.00°C and 0.32 ± 0.20°C, respectively.
International Journal of Biometeorology | 1993
Krzysztof Błażejczyk; Håkan Nilsson; Ingvar Holmér
Different methods have been compared for the estimation of solar heat load on man. The comparison comprised several methods based on the calculation of absorbed solar radiation and one method for calculation of mean radiant temperature (Mrt). Regression analysis was carried out for predicted values and values calculated for a vertical cylinder, assumed as an analog model of a standing man. Regression of mean skin temperature, measured in 10 subjects exposed to solar radiation under a variety of climatic conditions, on predicted radiant heat load was also analysed. Mean skin temperature correlated best withMrt, accounting for more than 50% of the variance. The results indicated that three methods provide a realistic estimation of the radiation heat load, whereas some methods show deviations of several hundred per cent.
Miscellanea Geographica: Regional Studies on Development | 2011
Krzysztof Błażejczyk
Assessment of Regional Bioclimatic Contrasts in Poland Traveling is one of most popular tourism activity. Usually it is associated with the change of climate conditions. In a short time we can move to different environment and our organisms are under great pressure of atmospheric stimuli which have diverse level and range of variability in comparison to home location. The general climate information seem to be insufficient to be prepared to new conditions. The paper presents new complex index which can be used to assess contrasts of bioclimatic conditions (BCI). It was applied to compare differences in bioclimatic conditions in six stations represented various bioclimate regions of Poland: Koszalin (Coastal region), Białystok (North-East region), Warszawa and Wrocław (Central region), Rzeszów (South-East region) and Hala Gąsienicowa (Tatras, Carpathians region).
Miscellanea geographica | 2014
Krzysztof Błażejczyk; Jarosław Baranowski; Anna Błażejczyk
Abstract Evidence of climatic health hazards on the general population has been discussed in many studies but limited focus is placed on developing a relationship between climate and its effects on occupational health. Long working hours with high physical activity can cause health problems for workers ranging from mild heat cramps to severe heat stroke leading to death. The paper presents the possible risk of heat hazard to outdoor workers, using the example of Warsaw. The heat stress hazard, defined by WBGT values above 26 and 28°C and UTCI above 32 and 38°C, is assessed from two perspectives: its spatial distribution on a local scale and its temporal changes during the 21st century due to climate change. City centre and industrial districts were identified as the places with the greatest heat stress hazard. The number of heat stress days in a year (as predicted for the 21st century) is increasing, meaning that heat-related illnesses are more likely to have a direct impact on workers’ health.
International Journal of Biometeorology | 2018
Anna Błażejczyk; Krzysztof Błażejczyk; Jarosław Baranowski; Magdalena Kuchcik
Heat stress is one of the environmental factors influencing the health of individuals and the wider population. There is a large body of research to document significant increases in mortality and morbidity during heat waves all over the world. This paper presents key results of research dealing with heat-related mortality (HRM) in various cities in Poland which cover about 25% of the country’s population. Daily mortality and weather data reports for the years 1991–2000 were used. The intensity of heat stress was assessed by the universal thermal climate index (UTCI). The research considers also the projections of future bioclimate to the end of twenty-first century. Brain storming discussions were applied to find necessary adaptation strategies of healthcare system (HCS) in Poland, to minimise negative effects of heat stress. In general, in days with strong and very strong heat stress, ones must expect increase in mortality (in relation to no thermal stress days) of 12 and 47%, respectively. Because of projected rise in global temperature and heat stress frequency, we must expect significant increase in HRM to the end of twenty-first century of even 165% in comparison to present days. The results of research show necessity of urgent implementation of adaptation strategies to heat in HCS.
Archive | 2010
Krzysztof Błażejczyk; Robert Twardosz
The paper presents variability of bioclimatic conditions in Cracow (Poland) during the period of 1826–2006. The data was gathered at the meteorological station situated in Botanical Garden in Cracow. Several bioclimate indices were applied to assess changes in winter (January), spring (April), summer (July) and autumn (October) seasons.
Grana | 1991
Krzysztof Błażejczyk
Abstract The problem of the heat balance of the human body under unstationary thermal conditions was examined. A heat balance model was used. Some days with different weather conditions were taken for comparative analysis of the heat balance and thermal stress hazard. During all warm and hot days, thermal stress was observed. Problems of thermal sensations and state of pleasantness were discussed also.
Chronobiology International | 2016
Joanna Wieczorek; Krzysztof Błażejczyk; Takeshi Morita
ABSTRACT Most of the research in the field of Chronobiology is focused on the problem of the circadian rhythms (CR) desynchronization. In travelers, it results mostly from the changes of surrounding: photoperiod, local climate conditions (radiation and thermal load) and behavior (e.g. type and place of tourism and activity level). Until now, it was not documented whether the changes in melatonin (MLT) secretion occur in effect of mid-distance transparallel travels (TpT), without complications arising due to time-zone transitions (e.g. jet-lag syndrome). To cope with this problem, a special field experiment was carried out. In the experiment, MLT characteristics were examined twice a year in real conditions through a group of young tourists (23–26 years old) at their place of habitual residence (Warsaw, Poland), and at their tourist destination (Tromso, Norway). Transition to circumpolar zone in summer has resulted in insignificant reduction in melatonin peak value (MPV) compared to preflight control (2 days before travel) and the melatonin peak time (MPT) was delayed. However, after traveling southward on the returning flight, MPV was lower compared to control and MPT was advanced. In winter, MPV was insignificantly higher in comparison to preflight control and MPT was almost unchanged. While changes in MPV do not depend on season, flight direction and day of stay after flight than MPT was differentiated seasonally and due to direction of flight. MPV and MPT were significantly modified by characteristics of individual light exposure during daytime and evening. The experiment showed also that in real conditions activity level is an important factor affected melatonin peak in tourists. In winter, greater daytime activity significantly influenced earlier MPT occurrence, both after northward and southward flights.
International Journal of Biometeorology | 2018
Gholamreza Roshan; Robabe Yousefi; Krzysztof Błażejczyk
This study presents a spatiotemporal analysis of bioclimatic comfort conditions for Iran using mean daily meteorological data from 1995 to 2014, analyzed through Physiological Equivalent Temperature (PET) index and Universal Thermal Climate Index (UTCI) indices, and bioclimatic clustering. The results of this study demonstrate that due to the climate variability across Iran during the year, there is at any point in time a location with climatic condition suitable for tourism. Mean values demonstrate maxima in bioclimatic comfort indices for the country in late winter and spring and minima for summer. Seven statistically significant clusters in bioclimatic indices were identified. Comparing these with clustering performed on PET and UTCI, the maximum overlaps between the two indices. In the following, the outputs of this research showed that most appropriate bioclimatic clustering for Iran includes seven clusters. These clustering locations according to climatic suitability for tourism provide a valuable contribution to tourism management in the country, particularly through marketing destinations to maximize tourist flow.