Widespread fires in Alaska produced high levels of pollution that drifted eastward over Canada in early June. The false-color image above shows the measure of carbon monoxide in the lower atmosphere averaged from July 1-10, 2004 . Red and yellow indicate high carbon monoxide levels, while light and dark blue hues represent low values (the unit here is parts per billion by volume). Carbon monoxide is a good tracer of pollution since it is produced as a byproduct of the combustion associated with wildfires and agricultural fires.
The data for this image were collected by the Measurements Of Pollution In The Troposphere (MOPITT) instrument aboard NASA’s Terra satellite.