NazarenkoV. I., MartirosovaV.G., Cherednichenko I.M., Tikhonova N.S., Beseda O.Y.
State Institution "Kundiiev Institute of Occupational Health of the National Academy of Medical Sciences of Ukraine", Kiev
Introduction. Preventing adverse effects of industrial factors at workplaces of office workers, engaged in intensive mental work, is one of important problems of modern occupational health. One of the factors that can positively affect a human body and promote a high level of work efficiency is comfortable levels of lighting. However unfavorable microclimatic conditions can cause a negative impact. Therefore, studying peculiarities of the combined influence of factors of the work environment on humans is important for development of preventive measures, especially concerning active introduction of energy saving LED light sources.
The purpose of the research was to study peculiarities of the combined effect of lighting and high air temperature in a laboratory experiment and develop hygienic recommendations.
Materials and methods of the research. The combined effect of the air temperature of 21 ºС and 27 ºС and lighting of 200 lx and 600 lx were studied in the laboratory experiment. In general lighting systems, LED light sources with the color temperature of 4000 K were used. Four series of studies, involving healthy male volunteers (N = 8), aged 21 – 22, without any pathology in the organ of vision, were undertaken. The duration and frequency of experimental series were from 9-00 to 12-30 a.m., in a day. The integral parameters of the functional state of specific physiological body systems were evaluated: visual performance (according to the time of execution a complex visual task) and the average body temperature.
Results. The experimental studies of the combined effect of the air temperature in the range of 21oC - 27 ºС and lighting of 200 - 600 lx indicate that these factors actively influence the functional state of the visual analyzer and the thermal state of volunteers. On the basis of the results of the studies, the regression equations were calculated on the dependence of the visual performance and the human thermal state on lighting and the high air temperature. It has been established that the optimal air temperature (21 °C) and lighting (600 lx) within the exposure time of 3.5 hours contribute to 53% improvement of the visual performance as compared to its level at the beginning of the experiment, and the most unfavorable combination of factors (27 °C and 200 lx) results in its decline by 45%. The positive effect of lighting with the level of 600 lx on the thermal state of volunteers was noted only at the background of the air temperature of 21 °С; at the elevated air temperature of 27 °C the effect was not recorded (p <0,05).
Conclusion. Based on the analysis of the regression equations on the dependence of the visual performance and the human thermal state on the levels of factors used in the experiment, it can be concluded that the increase in the levels of lighting up to 600 lux cause a positive effect on the visual performance and the thermal state of volunteers, whereas the increase in the air temperature above the sanitary norms (25 ºС and higher) leads to signs of accumulation of heat in the body and decrease in the level of visual performance when conducting precise visual works.
The results of the research indicate the need of further scientific support in determining the effect of LED lighting on visual performance and the functional human state, taking into account the influence of other factors of the work environment for development of hygienic recommendations.
Key words: combined effect, lighting, high air temperature, visual performance
ORCIDID of authors and their contribution to writing the paper:
Nazarenko V.I. (ORCIDID0000-0002-5238-4312) – a literature review, formulation of the purpose of the study, planning of experimental studies and analysis of the results, conclusions.
Martirosova V.G. – choice of relevant methods for the study, studying visual performance of volunteers, computer processing of the data, analysis of the results, conclusion.
Cherednichenko I.M. (ORCIDID0000-0001-6654-1334) – studies of the thermal state of volunteers, hygienic assessment of physical factors and strain in the experiment.
Tykhonova N.S .(ORCIDID0000-0001-5856-9919) – control of parameters of the lighting environment in the experiment.
Beseda O.Yu. – control of microclimatic parameters in the experiment.