New Greenhouse Gas Identified by Mass Spectrometry
An international team of environmental researchers have discovered a potentially new greenhouse gas, trifluoromethyl sulfur pentafluoride (SF5CF3), after studying stratospheric air samples by gas chromatography-mass spectrometry (GC-MS).
The gas which exists in the stratosphere at concentrations of about 0.1 parts per trillion has the largest greenhouse warming potential of any gas found in the atmosphere at up to 17500 times that of carbon dioxide on a per-molecule basis. The unsettling discovery, is that the atmospheric concentration of the compound is increasing by about 6% per year. This is alarming given that SF5CF3 has a lifetime of about 1,000 years.
According to researchers, the way in which SF5CF3 entered the atmosphere is still unknown, but the chemical itself is certainly of human origin. The researchers speculate that the compound is the breakdown product of sulfur hexafluoride, SF6, a gas used in electrical switches to suppress sparks and in the production of tennis balls and automobile tyres. Its potential precursor SF6 is a well-known greenhouse gas whose production is restricted under the "Kyoto Protocol", an international agreement to control greenhouse gases.
Concluding their paper in the July 28 issue of Science magazine, the researchers write that "we think that it is important to continue monitoring the atmospheric concentration of SF5CF3 in order to determine and control its sources and to guard against its accumulation in the atmosphere."