A metal air battery having an air purification module and a method of operating the metal air battery, the metal air battery including: a battery cell module configured to generate electricity using oxidation of a metal and reduction of oxygen; an air purification module including a first adsorption unit and being configured to supply air purified by the first adsorption unit to the battery cell module, the first adsorption unit being configured to adsorb an impurity; and a detection module configured to detect a concentration of the impurity, wherein the air purification module further includes a recycling unit configured to desorbs the impurity adsorbed into the first adsorption unit;and a controller configured to control an operation of the recycling unit based on the concentration of the impurity detected by the detection module.