Systems and methods of reducing airborne contaminants, such as airborne microorganisms, including bacterial, viral, and fungal microbes, in an indoor space are disclosed. The method includes positioning a portable photo-catalytic oxidation system proximate a source of contaminants in the indoor space and activating the photo-catalytic oxidation system to circulate air through the photo-catalytic oxidation system at a rate ranging from approximately 16 to approximately 24 air exchanges per hour in the indoor space. The photo-catalytic oxidation system is configured to oxidize contaminates in the air.
