INTRODUCTION The incomplete combustion of organic materials results in emission of carbon monoxide which is probably the most abundant man-made pollutant in the atmosphere (carbon dioxide is not considered a pollutant since it is a normal expiratory gas@ and is an important link in the ecological cycle). It has been estimated that 102 million tons of carbon monoxide were emitted in the United States in 1968 (1). Because the density of carbon monoxide is relatively close to that of air@ carbon monoxide readily permeates spaces through natural air movements. The exact half-life of carbon monoxide in the lower atmosphere is not known@ nor is there adequate knowledge of the mechanisms of its removal. Despite the enormous amounts of carbon monoxide emitted annually into the atmosphere@ background levels of carbon monoxide (uncontaminated air) do not appear to increase appreciably (2). The chemical oxidation of carbon monoxide by molecular oxygen in the lower atmosphere is very slow and@ therefore@ insignificant. Since known chemical reactions cannot account for the rate of carbon monoxide disappearance@ attention has been focused on biologic and/or physical scavenger mechanisms. Atmospheric sampling by high flying aircraft indicates that the bulk of the carbon monoxide is found mainly in the troposphere where it is relatively inert (3).