Sulfur Dioxide Levels 2008-2010 (IMAGE) NASA/Goddard Space Flight Center Caption This map shows average sulfur dioxide levels measured by the Aura satellite for the period 2008-2010 over a portion of the eastern United States. The black dots represent the locations of many of the nation's top sulfur dioxide emissions sources. Larger dots indicate greater emissions. Credit Credit: NASA's Earth Observatory Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.