Abstract: Disclosed is an antimicrobial air permeable substrate comprising a high concentration of a dry powder. Also disclosed is the use of the antimicrobial material to kill, denature or otherwise deactivate microbes, particularly airborne or droplet-borne microbes. The invention also relates to a functionalised fabric that will deactivate air borne virus upon contact. In particular, it relates to a fabric within which is contained an active compound or compounds that have been demonstrated to deactivate air borne virus and other pathogens when said virus or pathogens make contact with the active compound within the fabric. The active compound or compounds described are harmless to humans, animals, marine and plant life and are prolifically available from sustainable resources.