Device for applying substance mixtures in each case containing at least one organic solvent to a material web, having - a number of processing heads for applying in each case one substance mixture over the durations of respectively predetermined processing periods to the material web, - a number of drying devices for drying the applied substance mixture by blowing a drying gas flow (2.3) onto the applied substance mixture and sucking off the drying gas flow (2.3) loaded with portions of the solvent as an exhaust gas flow, wherein a drying device is associated with each processing head, - a gas pipeline system having in each case a drying gas inlet (2.1) and an exhaust gas outlet (2.2) per drying device and with an exhaust gas pipe connecting the drying devices and having controllable regulating elements to regulate volume flows in the drying gas inlets (2.1), in the exhaust gas outlets (2.2) and in the exhaust gas pipe and for controlled division of the exhaust gas flow into a first exhaust gas flow portion (5.1) and into a second exhaust gas flow portion (5.2), - a sensor unit for detecting and providing values of a concentration of the at least one solvent in the exhaust gas flow as solvent concentration and - an integrated catalytic oxidation unit for the thermal conversion of the solvent of the second exhaust gas flow portion (5.2), - a control unit, by which the regulating elements are individually controllable and which is configured such that control of the regulating elements takes place to set a constant concentration of the at least one solvent as working concentration based on a comparison of the values of the solvent concentration with a range of values of a desired working concentration of the second exhaust gas flow portion (5.2), characterized in that a regulating unit for regulating an oxygen concentration referred to as O 2 content in the second exhaust gas flow portion (5.2) is present and the regulating unit is in data communication with a database, wherein the database is configured such that at least one general model for regulating the O 2 content is stored in the database in a manner so as to be repeatedly retrievable, by which model a drop in the O 2 content of the second exhaust gas flow portion (5.2) is avoided or at least allowed only to a very small extent. - a number of processing heads for applying in each case one substance mixture over the durations of respectively predetermined processing periods to the material web, - a number of drying devices for drying the applied substance mixture by blowing a drying gas flow (2.3) onto the applied substance mixture and sucking off the drying gas flow (2.3) loaded with portions of the solvent as an exhaust gas flow, wherein a drying device is associated with each processing head, - a gas pipeline system having in each case a drying gas inlet (2.1) and an exhaust gas outlet (2.2) per drying device and with an exhaust gas pipe connecting the drying devices and having controllable regulating elements to regulate volume flows in the drying gas inlets (2.1), in the exhaust gas outlets (2.2) and in the exhaust gas pipe and for controlled division of the exhaust gas flow into a first exhaust gas flow portion (5.1) and into a second exhaust gas flow portion (5.2), - a sensor unit for detecting and providing values of a concentration of the at least one solvent in the exhaust gas flow as solvent concentration and - an integrated catalytic oxidation unit for the thermal conversion of the solvent of the second exhaust gas flow portion (5.2), - a control unit, by which the regulating elements are individually controllable and which is configured such that control of the regulating elements takes place to set a constant concentration of the at least one solvent as working concentration based on a comparison of the values of the solvent concentration with a range of values of a desired working concentration of the second exhaust gas flow portion (5.2),