[en] The mechanism of air contamination, caused by radioactive iodine from nuclear objects and the behaviour of iodine isotopes in the atmospheric air described. Methods for controling the air, contaminated by ¹³¹I, based on the utilization of various filtration materials are given. The equipment for ¹³¹I₂ iodine and CH₃¹³¹I methyl iodine generation and for investigating the adsorption efficiency with various filtration materials is described. Presented is the order of determining the filtration efficiency coefficient of filtration materials tested. The results of investigations into the 1₂ and CH₂1 filtration efficiency, into the iodine and methyl iodine settling on the ionodispersion paraphine and atmospheric aerosols are given. Reviewed are the problems of determining the ratio of separate iodine states in the atmosheric air, as well as the problem of practical application of investigation results for controlling air contamination with ¹³¹I