Another intriguing piece of evidence comes from
measurements of sulfur dioxide concentrations in the atmosphere, which were found to drop by a factor of ten between 1978 and 1986.
However, while field
measurements of sulfur dioxide emissions are increasing, they still remain too sparse to piece together a cohesive global picture.
Researchers at NASA's Goddard Space Flight Center in Greenbelt, Maryland, are using already available satellite
measurements of sulfur dioxide (SO2), a main components of volcanic emissions, along with the more recent ability to map the location and vertical profiles of volcanic aerosols.
They analyzed ozone measurements taken from weather balloons and satellites, as well as satellite
measurements of sulfur dioxide emitted by volcanoes, which can also enhance ozone depletion.
Not exact matches
Current,
sulfur dioxide monitoring activities include the use
of emission inventories that are derived from ground - based
measurements and factors, such as fuel usage.
While this number is higher than the previous estimate made in the late 1990s based on ground
measurements, the new research includes data on more volcanoes, including some that scientists have never visited, and it is still lower than human emissions
of sulfur dioxide pollution levels.