History of atmospheric SF<sub>6</sub> from 1973 to 2008

Abstract

We present atmospheric sulfur hexafluoride (SF₆) mole fractions and emissions estimates from the 1970s to 2008. Measurements were made of archived air samples starting from 1973 in the Northern Hemisphere and from 1978 in the Southern Hemisphere, using the Advanced Global Atmospheric Gases Experiment (AGAGE) gas chromatographic-mass spectrometric (GC-MS) systems. These measurements were combined with modern high-frequency GC-MS and GC-electron capture detection (ECD) data from AGAGE monitoring sites, to produce a unique 35-year atmospheric record of this potent greenhouse gas. Atmospheric mole fractions were found to have increased by more than an order of magnitude between 1973 and 2008. The 2008 growth rate was the highest recorded, at 0.29 ± 0.02 pmolmol^−1 yr^−1. A three-dimensional chemical transport model and a minimum variance Bayesian inverse method was used to estimate annual emission rates using the measurements, with a priori estimates from the Emissions Database for Global Atmospheric Research (EDGAR, version 4). Consistent with the mole fraction growth rate maximum, global emissions during 2008 were also the highest in the 1973–2008 period, reaching 7.4 ± 0.6 Gg yr^−1 (1-σ uncertainties) and surpassing the previous maximum in 1995. The 2008 values follow an increase in emissions of 48 ± 20% since 2001. A second global inversion which also incorporated National Oceanic and Atmospheric Administration (NOAA) flask measurements and in situ monitoring site data agreed well with the emissions derived using AGAGE measurements alone. By estimating continent-scale emissions using all available AGAGE and NOAA surface measurements covering the period 2004–2008, with no pollution filtering, we find that it is likely that much of the global emissions rise during this five-year period originated primarily from Asian developing countries that do not report detailed, annual emissions to the United Nations Framework Convention on Climate Change (UNFCCC). We also find it likely that SF₆ emissions reported to the UNFCCC were underestimated between at least 2004 and 2005

Overview of the findings from measurements of halogenated compounds at Gosan (Jeju Island, Korea) quantifying emissions in East Asia

“…Previous studies of these compounds based on measurements at global background sites speculated on the importance of emissions from East Asia (Montzka et al 2009;Levin et al 2010;Mu¨hle et al 2010;Rigby et al 2010). However, direct measurements to properly quantify the emissions of these compounds in East Asia have been relatively sparse (Palmer et al 2003;Yokouchi et al 2006;Guo et al 2009).…”

US consumption and supplies of sulphur hexafluoride reported under the greenhouse gas reporting program

“…the emissions reported by Annex 1 countries under the United nations Framework Convention on Climate Change (UnFCCC) and/or estimated in the Emission Database for Global Atmospheric Research). At least two of these studies have indicated that total UnFCCC-reported emissions may be underestimated (levin et al 2010;Rigby et al 2010). the United States reports emissions as an Annex 1 country under the UnFCCC, as do Canada, Japan, Australia, new Zealand, the Russian Federation, turkey and the major industrial countries of Europe.…”

Experimental Study on Performance of SF6+N2Mixed Gas Insulation

“…It seals high-voltage components, such as circuit breakers, disconnectors, grounding switches, in a metal pipe, uses SF 6 as insulating medium [1] . SF 6 has a strong adsorption ability of electrons, the strong electronegative indicates its excellent properties of insulation and arc extinguishing [2,3] , another feature of the SF 6 gas is having a high thermal conductivity [4] . Till now, SF 6 gas is the best insulation and arc extinguishing medium.…”

“…Solves practical application problems of SF 6 alternative gases. 6 and SF 6 /N 2 gas mixture According to the experimental research literature and research institutions [2][3][4] . In frequency AC voltage, SF 6 gas gap electric strength (peak) can be represented by the following empirical formula:…”

“…Base on its excellent properties of insulation and arc extinguishing, there excists a widespread use of SF 6 in power industry including gas-insulated transformers (GIT), transformers, cables (GIC), line (GIL) and combination units (GIS). According to statistics, 80% of SF 6 gas is used in power industry, but during practical application of SF 6, there are also some problems, mainly in the following aspects [6] : 1)SF 6 gas is very serious greenhouse gas, which is about 25,000 times that of CO 2 ; the degradation of SF 6 under atmosphere condition is very slow, takes about 3200 years [7] ; 2)SF 6 gas is sensitive to non-uniform field, in engineering applications, tiny conductive particles and roughness of electrode surface cause the non-uniformity, result in reduction of SF 6 insulating properties [8] ; 3)In alpine region, SF 6 in GIS has a problem of liquefaction and density reduction; 4)Due to the normal operation of the circuit breaker or an internal short, occurrence of arc causes SF 6 decomposes, the reaction produces toxic gases for instance SF 4 , SOF 2 ; 5)When the SF 6 gas contains water, condensation will produce in the insulation material surface, leads to significantly decrease of insulating properties, SF 4 and other decomposition products hydrolysis into HF and SO 2 and other acidic substance, internal members are corrosived, result in operation failure [9] ; 6) SF 6 gas is in higher cost, there exists no natural SF 6 gas, SF 6 gas in industry is synthetic so far [10] . When reducing the use and emissions of SF 6 gas, the selection of alternative gas of SF 6 , 3 main indicatiors are considered: the electric strength (E/N)tbm, greenhouse index (GWP) and liquefaction temperature .…”