Hydrofluorocarbons (HFC's), used as refrigerants and in other applications, are potent greenhouse gases with a global warming potential (GWP up to 1000 times greater than carbon dioxide). Hydrofluoroolefins (HFO's) are an alternative to HFC's and have zero ozone depleting potential and a low GWP. The study will look at HFO's and their degradation products, summarise chemical processes related to atmospheric fate, assess degradation products most likely to be formed as well as impurities that can contribute to pollutant emissions.