Disclosed herein are base metal catalyst devices for removing ozone, volatile organic compounds, and other pollutants from an air flow stream. A catalyst device includes a housing, a solid substrate disposed within the housing, and a catalyst layer disposed on the substrate. The catalyst layer includes a first base metal catalyst at a first mass percent, a second base metal catalyst at a second mass percent, and a support material impregnated with at least one of the first base metal catalyst or the second base metal catalyst. The preferred catalyst composition is a combination of manganese oxide and copper oxide.