Litter in the poultry house is a source of toxic gases (ammonia, hydrogen sulphide and carbon dioxide), dust, and is a favourable place for the life and reproduction of microorganisms and helminths. The number of these secretions in the poultry house depends on many factors: the sanitary status of the poultry house, the species, the age of the birds, the microclimate, the season, feeding conditions, and so on. The purpose of the research was to substantiate the rational construction and modes of operation of the device for the decontamination of microorganisms in the air of the poultry house on the basis of the use of sources of ultraviolet irradiation. The necessity of development and application techniques for cage batteries with a litter removal belt system which provide reduction of microbial contamination of air in poultry houses and the content of harmful gases in it have been substantiated. The device was developed and the effective mode of disinfection of the air of the poultry house in the collector air duct of the litter drying system based on the use of sources of ultraviolet irradiation was determined. The application of the bactericidal device made it possible to reduce microbial air contamination on the 1st day of accumulation of the litter during the cold season - by 2.6 times, in the transitional season - by 2.1 times; on 5th day, the accumulation of the litter decreased by 3.0 and 2.3 times, respectively. During the operation of the air irradiation system, the content of toxic gases in it decreased compared to the period when the air was not treated with the ultraviolet irradiation - ammonia by 19.7% and carbon dioxide by 5.9%. The absolute values of microbial air contamination in the poultry house and the toxic gas content in the transitional season were lower than in the cold season, due to the higher indoor air exchange and the increase of clean outside air in the proportion. The difference in microbial air contamination between the basic and the proposed variants in the cold and transitional seasons was statistically significant. Key words: Poultry house; Microclimate; Air; Bacterial contamination; Toxic gases; Ultraviolet irradiation References Bilgili, S. F. (2006). Sanitary/hygienic processing equipment design. World's Poultry Science Journal, 62(1), 115-122. doi: https://doi.org/10.1079/WPS200588 Broucek, J., & Bohuslav, C. (2015). Emission of harmful gases from poultry farms and possibilities of their reduction. Ekologia (Bratislava), 34(1), 89-100. doi: https://doi.org/10.1515/eko-2015-0010 Chidambaranathan, A. S., & Balasubramanium, M. (2017). Comprehensive review and comparison of the disinfection techniques currently available in the literature. Journal Prosthodont, 28(2), 849-856. doi: https://doi.org/10.1111/jopr.12597 Essam, S. Soliman, Nahla, H. Sallam, & Eman, M. Abouelhassan. (2018). Effectiveness of poultry litter amendments on bacterial survival and Eimeria oocyst sporulation. Vet. World, 11(8), 1064-1073. doi:10.14202/vetworld.2018.1064-1073 Fernanda, C. S., Iida, F. F. T., Jagir, N. S., & Baptista, F. J. F. (2017). Gas emission in the poultry production. Journal of Animal Behaviour and Biometeorology, 5(2), 49-55. doi: https://doi.org/10.14269/2318-1265/jabb.v5n2p49-55 Ishchenko, K. V. (2019). Investigation of the parameters of the microclimate of chickens and the chemical composition of the hens litter for the use of cell batteries with different air removal systems. Scientific and Technical Bulletin of IT NAAN, 121, 127-136. doi: https://doi.org/10.32900/2312-8402-2019-121-127-136 Ishchenko, K. V., Palii, A. P., Kis, V. M., Petrov, R. V., Nagorna, L. V., Dolbanosova, R. V., & Paliy, A. P. (2019). Investigation of microclimate parameters for the content of toxic gases in poultry houses during air treatment in the scrubber with the use of various fillers. Ukrainian Journal of Ecology, 9(2), 74-80. Isohanni, P. M., & Lyhs, U. (2009). Use of ultraviolet irradiation to reduce Campylobacter jejuni on broiler meat. Poultry Science, 88, 661-668. Jiang, L., Li, M., Tang, J., Zhao, X., Zhang, J., Zhu, H., … Zhang, X. (2018). Effect of Different Disinfectants on Bacterial Aerosol Diversity in Poultry Houses. Frontiers in microbiology, 9, 2113. doi: https://doi.org/10.3389/fmicb.2018.02113 Mahami, T., Togby-Tetteh, W., Kottoh, D. I., Amoakoah-Twum, L., Gasu, E., Annan, S., … Adu-Gyamfi, A. (2019). Microbial Food Safety Risk to Humans Associated with Poultry Feed: The Role of Irradiation. International journal of food science, 2019, 6915736. doi: https://doi.org/10.1155/2019/6915736 Mendes, L. B., Tinoco, I. F. F., Ogink, N., Osorio, R. H., & Osorio, S. J. (2014). A refined protocol for calculating air flow rate of naturally-ventilated broiler barns based on CO2 mass balance. Revista DYNA, 81(1), 197-203. doi:10.1590/1807-1929/agriambi.v Milanov, D., Ljubojevi�?, D., �?abarkapa, I., Karabasil, N., & Velhner, M. (2017). Biofilm as risk factor for Salmonellacontamination in various stages of poultry production. Europ. Poultry Science, 81. doi:10.1399/eps.2017.190 Mpundu, P., Mbewe, A. R., Muma, J. B., Zgambo, J., & Munyeme, M. (2019). Evaluation of Bacterial Contamination in Dressed Chickens in Lusaka Abattoirs. Front. Public Health, 7, 19. doi:10.3389/fpubh.2019.00019 Muir, W. M., Cheng, H. W., & Croney, C. (2014). Methods to address poultry robustness and welfare issues through breeding and associated ethical considerations. In: Rauw W. M., editor. Improving Animal Welfare through Genetic Selection. Frontiers in Genetics, Lausanne, Switzerland, 407-420. doi:10.3389/fgene.2014.00407 Naseem, S., & King, A. J. (2018). Ammonia production in poultry houses can affect health of humans, birds, and the environment-techniques for its reduction during poultry production. Environ Science Poultry Res. Int., 25(16), 15269-15293. doi:10.1007/s11356- 018-2018-y Oakley, B. B., Morales, C. A., Line, J., Berrang, M. E., Meinersmann, R. J., Tillman, G. E., Wise, M. G., Siragusa, G. R., Hiett, K. L., & Seal, B. S. (2013). The Poultry-Associated Microbiome: Network Analysis and Farm-to-Fork Characterizations. PLoS ONE, 8(2), e57190. https://doi.org/10.1371/journal.pone.0057190 Palii, A. P., Pylypenko, S. H., Lukyanov, I. M., Zub, O. V., Dombrovska, A. V., Zagumenna, K. V., Kovalchuk, Y. O., Ihnatieva, T. M., Ishchenko, K. V., Paliy, A. P., & Orobchenko, O. L. (2019). Research of techniques of microclimate improvement in poultry houses. Ukrainian Journal of Ecology, 9(3), 41-51. Paliy, A. P., Mashkey, A. M., Sumakova, N. V., & Paliy, A. P. (2018d). Distribution of poultry ectoparasites in industrial farms, farms, and private plots with different rearing technologies. Biosystems Diversity, 26(2), 153-159. https://doi.org/10.15421/011824 Paliy, A. P., Rodionova, K. O., Braginec, M. V., Paliy, A. P., & Nalivayko, L. I. (2018c). Sanitary-hygienic evaluation of meat processing enterprises productions and their sanation. Ukrainian Journal of Ecology, 8(2), 81-88. doi: https://doi.org/10.15421/2018_313 Paliy, A. P., Sumakova, N. V., Mashkey, A. M., Petrov, R. V., Paliy, A. P., & Ishchenko, K. V. (2018a). Contamination of animal-keeping premises with eggs of parasitic worms. Biosystems Diversity, 26(4), 327-333. https://doi.org/10.15421/011848 Paliy, A. P., Sumakova, N. V., Paliy, A. P., & Ishchenko, K. V. (2018b). Biological control of house fly. Ukrainian Journal of Ecology, 8(2), 230-234. doi: https://doi.org/10.15421/2018_332 Potter, B. D., Marcy, J. A., Owens, C. M., Slavik, M. F., Goodwin, H. L., & Apple, J. K. (2012). Impact of performance-based sanitation systems on microbiological characteristics of poultry processing equipment and carcasses as compared with traditional sanitation systems. The Journal of Applied Poultry Research, 21(3), 669-678. https://doi.org/10.3382/japr.2011-00513 Rouger, A., Tresse, O., & Zagorec, M. (2017). Bacterial Contaminants of Poultry Meat: Sources, Species, and Dynamics. Microorganisms, 5(3), 50. https://doi.org/10.3390/microorganisms5030050 Tan, H. Q., Li, M., Jie, D. F., Zhou, Y. F., & Li, X. A. (2019). Effects of different litters on ammonia emissions from chicken manure. International Journal of Agricultural and Biological Engineering, 12(4), 27-33. doi: https://doi.org/10.25165/j.ijabe.20191204.5011 Waring, M. S., & Siegel, J. A. (2011). The effect of an ion generator on indoor air quality in a residential room. Indoor Air, 21(4), 267-276. doi: https://doi.org/10.1111/j.1600-0668.2010.00696.x Wells, J. B., Coufal, C. D., Parker, H. M., & McDaniel, C. D. (2010). Disinfection of eggshells using ultraviolet light and hydrogen peroxide independently and in combination. Poultry Science, 89(11), 2499-2505. doi:10.3382/ps.2009-00604 Zhao, Y., Shepherd, T. A., Li, H., & Xin, H. (2015). Environmental assessment of three egg production systems: Monitoring system and indoor air quality. Poultry Science, 94, 518-533. doi: https://doi.org/10.3382/ps/peu076