In the article there are presented the results of the substantiation of a harmonized mean year maximum permissible nickel concentrations (MPNC) in ambient air according to the results of epidemiological studies and mathematical modeling of the evolution of risk Data of the analysis of hygienic standards of the nickel content in the air used both in Russia and abroad, as well as the results of the own research allow us to recommend as a harmonized mean year MPNC-0.00005 mg/m3, and as critical effects--disorders of the respiratory organs.