The only way to get a complete picture of air pollution around the globe is to measure it from space. This new image compiles data from 18 months of observations by the European Space Agency's Envisat satellite.

It shows concentrations of nitrogen dioxide (NO2), a mostly man-made gas that comes from power plants, heavy industry, trucks and the burning of biomass. Lightning in the air and microbial activity in soil also produce NO2, which can cause respiratory problems.

For a large view of the image, click here.

Steffen Beirle of the University of Heidelberg's Institute for Environmental Physics, responsible for the map, discussed what he sees in the image, which was released this week:

"High vertical column distributions of nitrogen dioxide are associated with major cities across North America and Europe, along with other sites such as Mexico City in Central America and South African coal-fired power plants located close together in the eastern Highveld plateau of that country.

"Then a very high concentration is found above north eastern China. Also across South East Asia and much of Africa can be seen nitrogen dioxide produced by biomass burning. Ship tracks are visible in some locations: look at the Red Sea and the Indian Ocean between the southern tip of India and Indonesia. The smoke stacks of ships crossing these routes send a large amount of NO2 into the troposphere. "

This map is average of the data over time, which smoothes out seasonal variations in biomass burning and also those due to human activity changes due to the time of year.

-- SPACE.com Staff

Credits: University of Heidelberg