Yields of perfluorocarboxylic acids from the atmospheric oxidation of Montreal Protocol related gases

Abstract

We present here a systematic evaluation of the molar yields of trifluoroacetic acid (TFA), perfluoropropanoic acid (PFPrA), and perfluorobutanoic acid (PFBA) from the atmospheric degradation of gases relevant to the Montreal Protocol and its Amendments. The yields are dependent on the molecular structure of the parent compound and the primary degradation products and radical intermediates formed. We incorporate new data into the Tropospheric Ultraviolet Visible (TUV) model and discuss how recent studies improve our understanding of the relative importance of the photochemical pathways for perfluoroaldehydes, CxF2x+1C(O)H, which are key degradation products from some chlorofluorocarbon (CFC) replacement compounds. We identify areas for further research that could advance our understanding of the environmental fate of precursors to short-chain length perfluorocarboxylic acids.