39 unreported sources of SO2 pollution discovered by NASA scientists

The unreported emission sources were found in the analysis of satellite data from 2005 to 2014. These sources are clusters of coal-burning power plants, oil and gas operations and smelters notably found in West Asia, Mexico and parts of Russia.

SO2 is a known health hazard and cause of acid rain. Currently, SO2 monitoring activities include the use of emission inventories that are derived from ground-based measurements and factors, such as fuel usage.

Points to remember

• The satellite-based estimates of the emissions were 2 or 3 times higher than those reported from known sources in these regions.


• The unreported and under-reported sources account for about 12% of all human-made emissions of SO2. This discrepancy can have a large impact on regional air quality.


• Researchers using a new satellite also have located 75 natural sources of SO2 in the form of non-erupting volcanoes that are slowly leaking the toxic gas.


• The satellite-based data is the first to provide regular annual information on these volcanic emissions as they are located remote locations and not monitored.

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