Impacts of refrigerant usage on the environmental presence of trifluoroacetic acid and other persistent chemicals

Heat pumps are energy-efficient alternatives to traditional air conditioners that function by using refrigerants. New refrigerants have been introduced to protect the ozone layer and reduce greenhouse gases. Newer refrigerants degrade quickly in the environment, however, they form the highly persistent and potentially toxic trifluoroacetic acid (TFA). This work investigates the fate of TFA formed as degradation products of past and present-use refrigerants. We use remote ice cores to gain historical trends of TFA deposition from atmospheric sources, to obtain a baseline of previous contamination, and see how recent changes in usage have increased concentrations over the past 5 years. Laboratory studies will probe two poorly understood reactions that impact environmental TFA: 1) hydrolysis of haloacetyl fluorides, important intermediates in the gas-phase formation of TFA from refrigerant gases; 2) photochemical oxidation of TFA as a potential, but slow, loss mechanism in the environment.