The European Space Agency (ESA) released results of atmospheric observations and measurements by its ERS-2 satellite, revealing that the concentration nitrogen dioxide (NO2) in the troposphere has fallen over the past 15 years. However, the decline has only been observed over parts of Europe and parts of the U.S., while there has been an increase above Asia and the Middle East.
ESA contributed the partial improvement to technologies such as cleaner cars. Increased use of fossil fuels is causing a worse environment in Asia and the Middle East, ESA said.
Nitrogen dioxide is one of the nasty gases in our air. All combustion engines produce NO2, which is a key part in the chemical reaction that creates ground-level ozone and, as a result, smog. 30 percent of global NO2 production is attributed to road vehicles, while 40 percent is caused by all other types of transportation types such as airplanes and trains.
Commenting on the changes of NO2 concentration, ESA researcher Andreas Richter said that “these changes in pollution levels are surprisingly rapid, and satellites are the only way to monitor them globally."