The present paper is a review on methods and technologies for air cleaning from micro organisms andviruses, which are applicable with the present HVAC practices. The advantages and the drawbacks ofair dilution, filtration (HEPA, ULPA), ultraviolet germicidal irradiation (UVGI), photocatalytic oxidation(PCO), plasmacluster ions and other technologies for air disinfection and purification is criticallyanalyzed with respect to the used today air distribution principles. The importance of indoor aircharacteristics, such as temperature, relative humidity and velocity on the efficiency of the methods isanalyzed with consideration of nature of the pathogens themselves. Recent encouraging studies showthe benefit of using essential oils as antimicrobial and anti-fungal agents (thyme, bay, cinnamon, clove,etc.). Though their application is confined to the food industry and pharmaceutics, some promisingresults show possible applicability in the field of ventilation and air conditioning to deactivate theairborne micro-organisms. The applicability of the methods with different types of ventilation used atpresent indoors, i.e. total volume ventilation (mixing and displacement), as well as advanced airdistribution techniques (such as personalized ventilation) is discussed.