Its most dramatic images are of vast clouds of pollution from burning forests and grasslands in Africa and South America. Invisible gas plumes travelled across the Southern Hemisphere as far as Australia last July. There was another strong source of carbon monoxide in Southeast Asia during April and May 2000 that sent air pollution across the Pacific Ocean to North America. While fires are the major source contributor, investigators believe industrial burning sources contributed to this pollution. The troposphere is the lowest layer in the atmosphere.
Carbon monoxide is both a pollutant in itself and a major ingredient in smog.
Mr. Drummond said yesterday.