UC Irvine

Carbon monoxide exerts strong control over the chemistry of the troposphere and lower stratosphere through its influence over hydroxyl radical (OH) and ozone concentrations. Thus, CO affects the oxidizing power of the atmosphere and the concentrations of greenhouse gases. Because of its short atmospheric residence time (two or three months) the determination of a secular trend in CO concentrations is very difficult. Temporal increases of CO are expected because certain sources under human control have been growing; these include fossil-fuel usage and increasing atmospheric methane. From the data, it is likely that CO has increased in the Northern Hemisphere in the past 15-30 years. Southern Hemispheric data indicate no positive trend. -from Author