This animation shows tropospheric column amounts of nitrogen dioxide from the Ozone Monitoring Instrument (OMI) from late 2004 to the middle of 2008. Darker blues represent low amounts. Light blue, green, and yellows to reds indicate high amounts. Higher amounts are found in more heavily populated areas and result primarily from the burning of fossil fuels for transportation and electricity. NO2 is also produced from fires and lightning. The lifetime of NO2 near the ground is about a day but varies slightly with season. Lifetimes are longer in the winter months.

Tropospheric NO2 data are available from the NASA Goddard DISC http://daac.gsfc.nasa.gov/Aura/OMI/ and the Aura Validation Data Center (AVDC) http://avdc.gsfc.nasa.gov. OMI is a Dutch/Finnish contribution to NASA's Earth Observing System (EOS) Aura satellite. Animation courtesy of the Aura Validation Data Center (AVDC). (less info)