INTRODUCTION For many years@ carbon monoxide (CO) has been considered to be an important atmospheric pollutant. Recent estimates indicate that over 400 million metric tons of CO are produced annually due to man's activities alone (6). At this rate of production@ the ambient concentration of CO could be expected to double every two to three years; however@ ambient levels have apparently not changed appreciably in the last decade (6)@ The fate of CO liberated into the atmosphere is poorly defined. A number of possible mechanisms for its removal have been postulated with little confirming evidence. Due to the potential health hazard of increased levels of CO and ever-increasing emissions@ the search for natural sinks for CO has become a field of increasing interest during the last few years. A series of research contracts was awarded to Stanford Research Institute by the Coordinating Research Council and the National Air Pollution Control Association (later transferred to the Environmental Protection Agency) to provide insight into the fate of atmospheric CO. The objective was to investigate the biosphere as a possible sink for atmosphere CO. Research conducted under the initial contract by Mrs. Elaine Levy (10) showed that nonsterile soil depleted CO from test atmospheres@ whereas steam-sterilized soil did not; this finding suggested a role for soil or soil microorganisms as a sink for CO. During the second year of the study@ laboratory experiments conducted by Drs. R. E. Inman and R. B. Ingersoll (5) showed that@ potentially@ soil had a capacity to serve as a sink for all the CO produced globally and that this activity was due to soil microorganisms??in particular@ a number of soil fungi. Estimates of the soil sink potential obtained from that study were based on a limited number of laboratory observations and@ since soils were shown to vary widely in their activity@ the estimates could be significantly different from the actual potential of soils in their natural state. The research described in this report@ conducted under a third contract@ was designed as an extension of the first two studies. The objectives were to: (1) Determine the potential CO uptake of soils under natural conditions m the major ecological habitats of North America. (2) Determine what influence environmental variables exert on the potential CO uptake rates of soils. (3) Estimate the potential of soils of North America to serve as a sink for atmospheric CO.
API 4184-1972 history
1972API 4184-1972 THE CAPACITY OF THE SOIL AS A NATURAL SINK FOR CARBON MONOXIDE