Objective of the study--to forecast morbidity (of respiratory diseases) among adolescents via mathematic modelling during primary exploitation of new aluminium production (exemplified by Taishet city). Incidence during 2003-2011 of all diseases in the adolescents equalled 1129,1 per thousand, of respiratory diseases--627,4 per thousand. The mathematic model was designed to reveal role of environmental hazards in morbidity formation. According to medium-term forecast results, launching the aluminium production plant in East Siberia in 3 years will increase by 67% the morbidity with respiratory diseases in the adolescents.