An air cleaning device (Aerobiotix Illuvia® Sense, Miamisburg, OH) that recirculates air at a rate of 450 cfm after passing through HEPA filtration and a UV chamber was present in the corner of the room and used for formaldehyde removal experiments. An activated carbon filter for adsorbing VOCs and measuring approximately 46 x 46 cm was placed in a slot at the air inlet. The activated carbon filter had a thickness of approximately 0.3175 cm and density of approximately .034 g/cm . The activated carbon filter was positioned just behind the inlet of the device so that when the device is on all incoming air is forced to pass through it. For formaldehyde removal, a proprietary polyurethane foam containing transition metal oxide was placed behind the activated carbon filter. The material catalytically transforms formaldehyde to CO2 and H2O at room temperature. A calibrated gas sensitive semi-conducting formaldehyde sensor (Aeroqual, Aukland, New Zealand) was stationed near the opposite corner of the room, approximately 5.5 m away from the air recirculating device. The sensor measures from 0-10 ppm with an accuracy of < ±0.05 ppm within the range of 0-0.5 ppm and ±10% within a range of 0.5-10 ppm.