Quantifying aluminum and semiconductor industry perfluorocarbon emissions from atmospheric measurements

Abstract

The potent anthropogenic perfluorocarbon greenhouse gases tetrafluoromethane (CF 4 ) and hexafluoroethane (C 2 F 6 ) are emitted to the atmosphere mainly by the aluminum and semiconductor industries. Global emissions of these perfluorocarbons (PFCs) calculated from atmospheric measurements are significantly greater than expected from reported national and industry-based emission inventories. In this study, in situ measurements of the two PFCs in the Advanced Global Atmospheric Gases Experiment network are used to show that their emission ratio varies according to the relative regional presence of these two industries, providing an industry-specific emission "signature" to apportion the observed emissions. Our results suggest that underestimated emissions from the global semiconductor industry during 1990-2010, as well as from China's aluminum industry after 2002, account for the observed differences between emissions based on atmospheric measurements and on inventories. These differences are significant despite the large uncertainties in emissions based on the methodologies used by these industries.

Atmospheric histories, growth rates and solubilities in seawater and other natural waters of the potential transient tracers HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116

“…This could be attributed to the changing sources of both PFC-14 and PFC-116. PFC emissions from the aluminium industry dominated for a long time but have likely been declining for the past decade or so, while emissions by the electronics industry (Kim et al, 2014) and probably the rare earth elements industry became more important. The very long lifetimes of PFCs in the atmosphere makes a decrease in the atmospheric mole fraction unlikely in the foreseeable future.…”

Inverse modelling of CF<sub>4</sub> and NF<sub>3</sub> emissions in East Asia

“…2.2) but also the sensitivity of changes in domain border conditions on measured mixing ratios; x is a vector of emissions and domain border conditions; y is a vector of observations; R is a matrix of combined model and observation uncertainties; x p is a vector of prior estimates of emissions and domain border conditions; and B is an error matrix associated with x p . The cost function is minimised using a non-negative least squares fit (NNLS) (Lawson and Hanson, 1974), as previously used for volcanic ash (Thomson et al, 2017;Webster et al, 2017). The NNLS algorithm finds the least squares fit under the constraint that the emissions are non-negative.…”

Continuous Emission Monitoring of Tetrafluoromethane Using Quantum Cascade Lasers

“…Atmospheric Concentration Lifetime (y) GWP 500-y The aluminum smelting process, also known as the Hall-Héroult process, is one of the largest anthropogenic contributors to atmospheric PFCs [2]. When the dissolved alumina content in the cryolitic bath falls below~1.5%, a rapid rise in the operating voltage occurs and the carbon anodes begin to react with the fluoride-based electrolyte (Na 3 AlF 6 ) forming PFCs.…”