Figure : Formaldehyde levels produced during electrosurgery were monitored with the air recirculation device on and equipped with catalyst and activated carbon (blue), activated carbon without catalyst (orange) and neither activated carbon nor catalyst (gray). The results show that the air recirculating device significantly reduces formaldehyde levels in an enclosed simulated OR when interfaced with a catalytic transition metal oxide. Pre-polluted levels can be reduced or the build-up of formaldehyde from a constant exposure source can be inhibited. While activated carbon is typically used to remove VOCs from polluted indoor air, removal of formaldehyde is more complicated. In our set-up, activated carbon shows no noticeable effect on reducing the formaldehyde concentration. Regardless, adsorption processes are limited in that the adsorbing media ultimately becomes ineffective upon saturation and is affected by the presence of co-pollutants that can compete and displace less energetically favored adsorbent-adsorbate adducts. In an open and dynamic environment under constant airflow as is the case for an air recirculating device in an OR environment, the potential for desorption is enhanced. The use of a catalytic material provides a significant advantage in that it can be re-used and is less dependent on favorable surface interactions. The chemical transformation of formaldehyde to CO2 and H2O is not reversible and the catalyst is not limited to a single use, allowing for constant removal of formaldehyde in the local environment as the air recirculating device constantly passes polluted air at a rate of 450 cfm through the open cell structure of the polyurethane foam supporting the catalytic metal. While the activated carbon tested was not effective at formaldehyde removal, it is still beneficial to have the activated carbon present as it removes additional VOCs from the air and helps in keeping the catalytic material clean. Inclusion of the catalyst in the device has a strong impact on formaldehyde levels in the OR air. The air recirculation capability of the device combined with the catalytic properties of the transition metal reduce formaldehyde levels considerably, even in the absence of room ventilation and in the presence of supplementary pollutants from surgical smoke.