2019 IPCC GHG Guidelines – New Guidance on Estimating F-GHG Emissions from PCB Waterproofing
(Edwards Ltd. and ACRG, School of Chemistry, University of Bristol)
The recently-published 2019 United Nations Intergovernmental Panel on Climate Change document  is a refinement of the 2006 guidelines, taking account of the recognised gap between bottom-up inventory estimates and measured (top-down) atmospheric concentrations , particularly for anthropogenic greenhouse gases (GHGs) like perfluorocarbons (PFCs). Factors were considered which might help account for this gap were considered, and a new mechanism associated with electronics (printed circuit board, PCB) manufacture is discussed in this paper, namely the application of conformal fluorinated waterproof polymer films using plasma deposition techniques. Such processes typically result in the emission of fluorinated GHGs, which has been characterised and quantified. Other industrial processes for forming waterproof PCB coatings are compared and contrasted. The resulting by-product emission factors have been deduced and cross-checked; these are included in the 2019 guidance document (these were not included in the 2006 Guidelines).
 J. Mühle et Al., Perfluorocarbons in the global atmosphere: tetrafluoromethane, hexafluoroethane, and octafluoropropane, Atmos. Chem. Phys., 10, 5145–5164, 2010, www.atmos-chem-phys.net/10/5145/2010/