The article actualizes the problem of ammonia emission in industrial and residential buildings into the indoor air. In the process of research, it was found that the sources of ammonia emission into indoor air are concrete structures (concrete walls, ceilings, columns, etc.) and finishing materials. In concrete, ammonia is formed as a result of the hydrolysis of urea (NH2)2CO contained in concrete, and carbamide (urea) and other similar substances are used as hardening accelerators and antifreeze additives, as well as ammoniated fly ash. It is emphasized that the concrete structure is simultaneously a reactor that produces ammonia and a desorber that ensures its emission into the room. Currently, sanitary and hygienic requirements set the maximum allowable concentrations of ammonia (daily average – 0,04 mg/m3 and single – 0,2 mg/m3). It was noted that when commissioning new monolithic multi-apartment residential buildings, large developers in megacities do not control the content of ammonia in the premises, and the established standards for the concentration of ammonia are not observed. Obviously, it is possible to prevent the emission of ammonia into indoor air by organizing a control system for concrete used in construction, as well as checking building materials to identify cases of exceeding the maximum permissible concentration of urea in them. The purpose of the article is to present the results of studies, during which a method for calculating the maximum allowable concentration of urea in a concrete mixture is proposed, which does not lead to an excess of ammonia concentration in rooms during their operation above a given value, and also approximate standards for the content of amide nitrogen in building materials are established.