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Minor towns with population size of 50-100 thousand people are much rarely studied in regards of the ecological-hygienic assessment of human environment, in spite of the fact that they are characterized by specific ecological problems. The objective of the study was the hygienic assessment of the impact of urban environment on population health status in Tikhvin and Gatchina towns of the Leningrad region. Morbidity rate in the population of Tikhvin and Gatchina in 2005-2015, atmospheric emissions of industrial enterprises, findings on monitoring for both atmospheric air pollution and centralized drinking water supply, as well as motor transport noise levels were studied. Population health risk stipulated by industrial emissions and noise exposure was calculated. Statistical data treatment with correlation analysis of the relationship between environmental pollution indices and population morbidity was carried out. The study revealed increased atmospheric air pollutant concentrations in Gatchina, which might be connected with motor transport effect. Acute non-carcinogenic risk levels resulting from air pollutants are on the borderline of the admissible level, while in Tikhvin town those values are significantly lower. Estimated concentrations of atmospheric pollutants produced by industrial emissions are by 1.5-2 times lower than the actual levels shown by monitoring. Noise levels and predicted health risks in Gatchina are on the borderline of the admissible level, while in Tikhvin they are significantly reduced. The statistically significant gain in the general primary morbidity rate indices due to respiratory diseases in Gatchina town, correlated with atmospheric air pollution, was revealed. Our study showed that despite the presence of large industrial enterprises in studied towns, motor transport proved to be the key factor that forms air pollution and noise load, more typical of large cities.

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The constant expansion of the applicable scope of optical technologies has led to the need to create optical coatings not only with certain frequency characteristics, but also high performance properties. This article contains the results of a research of a thin optical film from an advanced material SrYF4. On the basis of this film, a multilayer coating was synthesized, which has high transparency in the near and middle infrared range. The coating has successfully passed the climatic tests on resistance to cold and heat.

A BaF2 films, characterized by low refraction coefficient in the infrared region of the spectrum, are widely used in the production technology of optical structures. Their serious drawback is the low mechanical strength and moisture resistance. This paper presents the results of an experimental study of the optical properties of a new type of MgBaF4 films made from a vacuum-sintered mixture of MgF2 and BaF2 to a homogeneous composition.