Jacob+Wrubel



Sulfur Hexafluoride is a non-toxic, inert, odorless gas, and has a density of 6.164g/L (air has a density of 1.29g/L). Because of its inertness, it is used as a gaseous dielectric (an insulator) in high-voltage industrial circuit breakers because it is more durable than oxygen and other gases, but not as corrosive and unpure as liquid insulators (Dervos et al.). Sulfur Hexafluoride itself is safe, however when exposed to electrical discharges, such as arcs or coronas, SF6 can form toxic gases, [|Hydrogen Fluoride]and Sulfur Tetra-Fluoride being the most common (Dervos). The symptoms of these toxins are especially dangerous since the symptoms aren't visible, and eat the lungs of workers from the inside. According to the Environmental Protection Agency, Sulfur Hexafluoride is among the three gases with the highest [|Global Warming Potential](GWP). SF6 has an extremely long atmospheric lifetime, due to its aforementioned durability, and due to this, it's accumulation is nearly irreversible ("High GWP"). Because of this, Sulfur Hexafluoride's GWP is estimated to be approximately [|23,900 times that of CO2], making it the most potent greenhouse gas the Intergovernmental Panel of Climate Change (IPCC) has analyzed. Like most high GWP gases, there are very few natural sinks (things that absorb SF6), so all industrial emmisions of SF6 directly contribute to its accumulation in the atmosphere ("High GWP"). The reason SF6 is so dangerous is that because of its density, it is far more likely to absorb heat and reflect it back toward the earth than less dense gases (as per the greenhouse effect).

Until now, Sulfur Hexafluoride has not been a serious atmospheric threat; because of its high density, it tends to accumulate closer to the earth's surface. However, over the course of its long lifetime, SF6 invariably gets dispersed into higher levels of the atmosphere. during the 80s and 90s, SF6 concentration has increased 7%, from 1 ppt to about 4 ppt.

Works Cited

Dervos, C.T., and P. Vassiliou. 2000. Sulfur hexafluoride (SF6): Global environmental effects and toxic byproduct formation. J. Air and Waste Manage. Assoc. 50:137-141.

"EPA's SF6 Emission Reduction Partnership: Maximizing the Benefits of SF6 Emission Reductions for Electric Utilities." __OAI__. 24 Mar. 2009 .

"High GWP Gases and Climate Change." __U.S. Environmental Protection Agency__. 19 Oct. 2006. EPA. 4 Mar. 2009 

"Hydrogen Fluoride." __Occupational Safety and Health Administration - OSHA HOME PAGE__. OSHA. 24 Mar. 2009 .

Sturges, W. T. Concentration of Sulfur Hexafluoride. Raw data. Carbon Dioxide Information Analysis Center. 2000.