Tunnels are an integral part of the ways and artificial constructions of the railway. Objective assessment of working conditions is important, because current regulations fail to allow to give a definite hygienic assessment of some factors of the production environment of the tunnels. Objective: to reveal the peculiarities of the formation of working conditions in railway tunnels with the subsequent hygienic assessment for the development of preventive measures. Measurement of the factors of working process and working environment is carried out with the use of the certified equipment for the approved the hygienic and sanitary-chemical methods in workplaces in tunnels of the East-Siberian railway. Specific conditions were shown to be formed due to constructive solutions, climate and geographical location, the length of railway tunnels, the composition of the rocks through which the tunnel, the nature of the maintenance tunnels, ventilation system, repetition rate and type of passing rolling stock. All employees from occupational groups from examined tunnels were established to be exposed to high concentrations of aerosols with predominantly fibrogenic action, noise levels, adverse climate (low positive and negative temperatures, high relative humidity and mobility of air), the lack of natural lighting, low levels of artificial light, hard exertion of labor (dynamic physical load, working position, the slopes of the body, movement in space). Additionally, high levels of the vibration, nonionizing and ionizing radiation were typical for jobs of the Baikal and the North-Muya tunnel. There is proposed the algorithm of hygienic assessment of the microclimate, light environment at the working places depending on the time of the works in the underground conditions and constructional features of tunnels, methods of accounting personnel dose rates from natural sources.

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The aim of the study was a comparative assessment of radiation doses to the population of the Voronezh and Irkutsk regions according to the unified state system for monitoring individual doses and radiation-hygienic certification. The objects of research were the territories of the Voronezh and Irkutsk regions, significantly differing in climatic conditions and resources, industrial potential, but comparable in terms of population. The subject of the study was the average territorial values of radiation doses to personnel due to the normal operation of anthropogenic sources, radiation doses to the population due to natural sources and anthropogenic background, radiation doses to patients due to the use of ionizing radiation in medical diagnostics. The method of comparative analysis of effective collective and individual average annual radiation doses was used. In the Voronezh and Irkutsk regions, the priority dose-generating factor is natural radiation, which contribution to the annual effective collective dose is 83.33 and 89.18%, respectively. At the same time, the average individual annual effective doses to the population due to natural sources of ionizing radiation in the Irkutsk region in relation to the Voronezh region are significantly higher for radon – 2,81 times, due to the content of radionuclides in drinking water – 1,93 times and external terrigenous radiation – 1,46 times, which leads to a two-fold difference in the total individual effective doses associated with natural sources of ionizing radiation. These differences are explained by the features of the physical and geographical location of territories. There are significant differences in the values of the average effective annual doses of the population due to global fallouts and past radiation accidents, because a part of the territory of the Voronezh region was exposed to radioactive contamination as a result of the accident at the Chernobyl nuclear power plant (in the Voronezh region – 0.062 mSv / year, in the Irkutsk -0.005 mSv / year). Radiography (63.15 and 67.27%) makes the leading contribution to the value of medical radiation doses, which occupy the second place in the structures of the effective collective annual doses to the population (in the Voronezh region make up 16.46%, in the Irkutsk region – 10.74%) and fluorography (31.29 and 27.41% in the regions, respectively). It was established that the radiation situation in the Voronezh and Irkutsk regions remains stable and safe.

The aim of the study was to assess the professional risk of developing diseases in workers of the railway car repair enterprise. The Voronezh Car Repair Plant, a branch of Vagonremmash Joint-Stock Company, was chosen as the object of study. Methods: «The methodology for calculating individual occupational risk depending on the working conditions and the health status of the employee», developed by the Klin Institute for Protection and Working Conditions in conjunction with the Research Institute of Occupational Medicine (2013), the main professions; cohort study with the calculation of the relative risk of morbidity with temporary disability, the odds ratio, the etiological share of factors in the formation of morbidity (group size: 250 people, experimental group — workers of the main specialties, 95 people — comparison group). Results. According to the research results, the priority factors of occupational health risk include: chemical, noise, heating microclimate, low light level. For certain professions, the share of the contribution of priority factors to the risk profile (PV) reaches 40 %. The indicator of individual occupational risk is 0.12 to 0.26 units. The high level of professional risk (0.22 ÷ 0.26) is characterized by the working conditions of the mechanics for the repair of rolling stock, machine tools (woodworking), casters (metal), thermists, plastic casters. In professional groups with medium and high risk, the indicator of the relative risk of morbidity with temporary disability is higher than 1 (RR = 1.75 and 1.39, respectively), and the etiological share of production factors in the formation of diseases is from 27.95 (subgroup with secondary professional risk) up to 42.88 % (a subgroup with high professional risk), which indicates the professional condition of the disease. Discussion. In general, our data are consistent with the results of similar studies conducted earlier at the car building and car repair enterprises. In order to ensure hygienically safe working conditions and preserve the health of workers, it is necessary to reduce the level of exposure to production factors, including through the introduction of modern equipment and improvement of technological processes.