Until now the world has not had a consistent standard establishing the maximum permissible concentrations of aerosols, that is, of nanosize particles in the air. At the same time, in the foreign literature it is proved that nanoparticles upon deposition in the human lungs may stay there for longer time than larger-size particles because of a more complicated process of a human body self-cleansing and stronger interaction of such particles with human body tissues and organs. Some types of nanosize particles (for instance, titanium or carbon dioxides) more easily penetrate the barrier layer of an epithelial cell and enter interstitial tissue or blood flow. The article presents the results of a pioneering research into concentrations of ultrafine and finely dispersed aerosols in the atmosphere of a mining region. The available literature data on concentrations of submicron-size particles (0.5-5 μm) in the atmosphere of mining regions and operating areas of underground mines and open pits cannot be referred to as nanoparticles. They must be classified as medium and coarse aerosols having a radically different effect on a human body. The studies are performed with the supportof the Russian Science Foundation (Project No14-37-00050) © The Authors, published by EDP Sciences, 2018.