Analysis of Mid-Tropospheric Carbon Monoxide Data Using a Three-Dimensional Global Atmospheric Chemistry Numerical Model

Carbon monoxide is an important atmospheric trace species. It has long been recognized as a major contributor to urban air quality and in high concentrations is known to adversely affect health (Seinfeld, 1986). CO is the third most abundant carbon-containing species in the atmosphere and its reaction with hydroxyl radical (OH) represents a 2000–3000 Tg/yr (1 Tg = 1012 g) source of carbon dioxide. On a global basis, through its reaction with OH, CO plays a significant role in the troposphere’s overall oxidative capacity (Crutzen and Zimmerman, 1991). Furthermore, depending on the local abundance of nitrogen oxides, CO can participate in reactions that either increase or decrease the formation of tropospheric ozone (Logan et al., 1981).