CO is a poisonous gas that prevents the atmosphere from filtering other pollutants. CO also helps form ozone gas, which is harmful to life when it appears in the lowest reaches of the troposphere where we get the air we breathe. About two-thirds of the world’s CO comes from human activity. CO gas is produced by the burning of fossil fuels in automobiles and industry and by the burning of vegetation for agriculture and land clearing. It is also a product of natural forest and grassland fires.

CO gas persists in the atmosphere for weeks or months, allowing MOPITT to track the gas as it rises above the bottom-most layer of the atmosphere. By tracking CO plumes thousands of miles across the globe, MOPITT’s data help scientists understand the local sources and global consequences of air pollution and the complex chemical changes associated with CO in the atmosphere.

This visualization shows that the Northern Hemisphere produces a steady stream of noxious CO throughout the year. Also evident are massive plumes of CO that form over central Africa and Southeast Asia following annual agricultural burning regimes. Worldwide, clouds of gas are blown and scattered by winds, leaving a trail of CO for thousands of miles downwind of industrial or agricultural burning sites. High levels of contamination are also apparent over major cities.

CO concentrations between 3 and 5 km above the Earth’s surface (just above the air we breathe) are shown as eight-day running averages in parts per billion by volume (ppbv). The MOPITT teams at the University of Toronto in Canada and at the National Center for Atmospheric Research in Boulder, Colorado, provided the data from which this animation was produced. The MOPITT instrument was designed by the Canadian Space Agency as part of a collaborative effort with NASA for deployment on NASA’s Terra satellite.