A method for monitoring pollutant emissions during the operation of a combustion engine and/or an exhaust-aftertreatment device in a motor vehicle includes determining one or more pollutant-limit values for one or more pollutant categories using an emission limit-value model and as a function of one or more operating-state variables of the motor vehicle; ascertaining a pollutant-concentration variable for each pollutant category using sensors; and detecting an error in the form of an exceeding of the one or the plurality of pollutant-limit vales as a function of the pollutant-concentration variable for each pollutant category.