More detailed time trends are available in specific locations. Urban surface waters around Beijing were sampled in 2002 , and resampled in 2012 , showing up to a 17-fold increase in TFA concentrations over 10 years, while tap water detections went from non-detection to 0.16 µg/L in 2012 . Freeling et al. reported an increase in wet deposition in Germany from 22 to 30 t/year during 1995-1996 to 68 to 98 t/year in 2019 . Pickard et al. used dated Arctic ice cores to show a rapid increase in deposited TFA after the entry into force of the Montreal Protocol, from non-detection or a few ng/L in segments before 1989 to 0.13 and 0.15 µg/L in segments dated 2015 and 2017, respectively . In 2021, Cahill et al. reported a 6-fold increase in TFA in a stream transect in California since 1998 . Freeling et al. analyzed archived leaf samples of different tree species for TFA and observed increases by factors of up to 12.5 in TFA concentrations in some species from 1989 to 2020 . A study in indoor and outdoor dust found a four-fold increase in TFA between 2013 and 2017 .