Presence and Fate of Perfluorinated Compounds in the Earth's Atmosphere

Figure: Graduate student Mark Engen with VG ZAB Mass Spectrometer.

During the last two decades, atmospheric scientists have become increasingly concerned with several environmental problems potentially caused by the release of various halogenated compounds into the atmosphere. While most of the attention in this area has focused on chlorinated and brominated compounds and the effects of these compounds on stratospheric ozone, some attention has also been directed towards perfluorinated compounds (PFC's), such as SF6, CF4, C2F6, c-C4F8, C5F14, (CF3)2c-C4F6, c-C6F12, c-C6F11CF3, and C10F18, to mention a few PFC's that have been produced industrially and have undoubtedly been released into the atmosphere. The unique characteristic of the PFC's is that they are expected to have extraordinarily long atmospheric lifetimes (exceeding 50,000 years for the case of CF4) and, when released into the atmosphere, are expected to accumulate for millennia. Since the PFC's will be greenhouse gases, these projections are of concern with respect to man's long-term impact on the temperature of the earth.

In order to detect and monitor the very small amounts of PFC's that are currently in the atmosphere, we are developing what we believe will be the most sensitive and compound-specific analysis system ever to be applied to the trace analysis of atmospheric components. This analysis system is based on a refurbished high resolution VG-ZAB mass spectrometer (shown in the accompanying photograph). With this instrument, detection limits well below 0.1 parts per trillion (molar ratio) are expected, along with unequivocal verification of the PFC's identities by exact mass measurements of the detected ions. An additional goal of this project is to determine the ultimate fate of individual PFC's as they are transported to upper regions of the atmosphere.

Contact Information

Mail:	Dr. Eric Grimsrud
	Department of Chemistry
	Montana State University
	Bozeman, MT 59717-3840