During February 2004, there was considerable outflow of pollution from China and southeast Asia. The false-color image above shows concentrations of carbon monoxide at an altitude of roughly 3 km (700 millibars) in the atmosphere over eastern China blowing eastward off the coast of Asia and out over the Pacific Ocean. Carbon monoxide is a good indicator of this pollution since it is produced during combustion processes such as the burning of fossil fuels in urban and industrial areas as well as by wildfires and biomass burning.
Over China, industrial emissions are mainly responsible for the high levels of carbon monoxide observed in the image, whereas the emissions in South-East Asia are due to agricultural fires. The Asian plume can be followed as it propagates out over the Pacific Ocean, and in some instances this plume reaches the west coast of the United States.
This image represents a composite of data collected over a 25-day period, from February 1-25, 2004, by the Measurements Of Pollution In The Troposphere (MOPITT) instrument aboard NASA’s Terra satellite. The colors represent the mixing ratios of carbon monoxide in the air, given in parts per billion by volume. The grey areas show where no data were collected due to persistent cloud cover.
The image above corresponds well with true-color images captured over the region by the SeaWiFS and Aqua MODIS instruments on February 15 and February 19, 2004.