Hygienic standards of dust . air in industrial premises and underground workings, approved by the USSR Gossaninspektsiya, are differentiated by type and composition of dust (SN 245-63). They do not take into account a number of factors that affect the amount of dust penetrating into the human body: different heights of mines and mines, climatic conditions, the degree of severity of the work performed, the duration of human stay in a dusty environment ...