Nowadays the ecosystem approach is widely applied in many countries globally to evaluate economic losses from pollution of the natural environment. In Ukraine, it is reasonable to develop both the methodology of evaluation of economic losses from pollution of the natural environment and the methodology of calculation of correlating coefficients of ecosystems’ assimilative properties for differentiation of the volumes of repayment of economic losses from pollution of nature. The following methods were used in the research: economic and mathematical modeling – for formalization of the evaluation of economic losses from partial loss of the air ecosystem’s assimilative capacity; synthesis and analysis, system approach – for analysis of existing mathematical models, evaluation of economic losses from air pollution and forming of institutional environment of calculation of economic losses from partial loss of the air ecosystem’s assimilative capacity; inductive – for making conclusions over the best methodological approach to be used for calculation of oxygen production costs. The condition of the institutional environment is analyzed, including the regulatory and organizational maintenance of evaluation of economic losses from air pollution. The paper proves that the existing relevant institutional environment is partially coordinated with international formal rules and organizational structures, which evaluate such economic losses; however, their further efficient evaluation requires timely transformation based on the ecosystem approach to EU directives. The recommendations regarding the institutionalization of the process of ecosystem calculation of caused and prevented losses from the partial loss of the air ecosystem’s assimilative capacity are suggested: application of 2008/50/EU Directive of European Parliament and Council as of May 21, 2008 on Ambient Air Quality and Cleaner Air for Europe; review of the amounts of harmful substances TLV in the air; the need to take into account certain factors while calculating economic losses from air pollution (including the calculation of damage to life and health of each person due to air pollution), approval of the documents already developed and adopted but suspended by the Ministry of Justice of Ukraine, etc. New methodological approaches to alternative evaluation of economic losses from partial loss of the air ecosystem’s assimilative capacity as opposed to the current one are suggested, including methodological approaches to calculation of the oxygen and nitrogen production costs on the basis of the carbon offsets realization; methodological approaches to calculation of the oxygen production costs based on installation of artificial photosynthesis; methodological approaches to calculation of the oxygen production costs based on natural photosynthesis – planting and conservation of forests; methodological approaches to calculation of the oxygen and nitrogen “production” costs in metallurgical production; methodological approaches to calculation of prevented economic losses from partial loss of the air ecosystem’s assimilative capacity, which are manifested in the long run or those of indirect nature.