Trifluoroacetic acid levels in 1994–1996 fog, rain, snow and surface waters from California and Nevada

Trifluoroacetic acid (TFA) is an atmospheric breakdown product of the chlorofluorocarbon replacements HCFC-123, HCFC-124, and HFC-134a. Due to its low Henry's law constant, TFA will partition into the various aqueous phases that occur throughout the environment. TFA was detected and measured in fog, rain, snow, and surface water obtained in 1994–1996 from several locations in California and Nevada. Fog and rain samples contained 31 – 3779 ng 1−1 TFA. Snow samples taken in more remote areas had 51 – 584 ng 1−1. Surface water varied from 55 ng 1−1 – 41 μg 1−1 depending on type and location. Washout of TFA from the lower atmosphere was observed in both rain and fog samples. There was a trend toward decreasing TFA in precipitation samples taken at later stages during a single storm event, indicating cleansing of TFA from the lower atmosphere by precipitation. The magnitude of TFA levels suggest that formation in the environment from HCFC and HFC degradation is occurring more rapidly than expected, or that alternate sources of TFA exist.