Atmospheric Abundances, Trends and Emissions of CFC-216ba, CFC-216ca and HCFC-225ca

Atmosphere

Paul J. Fraser¹  Johannes C. Laube²  David E. Oram²  Corinna Kloss²  Thomas Röckmann³  Carl A. M. Brenninkmeijer⁴  Mike J. Newland⁵ 

[1] Centre for Australian Weather and Climate Research, Commonwealth Scientific and Industrial Research Organisation, Aspendale, VIC 3195, Australia;Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, NR47TJ Norwich, UK;Institute for Marine and Atmospheric Research, Utrecht University, 3512 JE Utrecht, The Netherlands;Max Planck Institute for Chemistry, Air Chemistry Division, NR4 7TJ Mainz, Germany;School of Geography, College of Life and Environmental Sciences, University of Birmingham, B15 2TT Birmingham, UK;

关键词: CFC-216ba;    CFC-216ca;    HCFC-225ca;    Montreal Protocol;    ozone depletion;    ODP;    lifetime;    fractional release;    emission;   

DOI  :  10.3390/atmos5020420

来源: DOAJ

【 摘 要 】

The first observations of the feedstocks, CFC-216ba (1,2-dichlorohexafluoropropane) and CFC-216ca (1,3-dichlorohexafluoropropane), as well as the CFC substitute HCFC-225ca (3,3-dichloro-1,1,1,2,2-pentafluoropropane), are reported in air samples collected between 1978 and 2012 at Cape Grim, Tasmania. Present day (2012) mixing ratios are 37.8 ± 0.08 ppq (parts per quadrillion; 1015) and 20.2 ± 0.3 ppq for CFC-216ba and CFC-216ca, respectively. The abundance of CFC-216ba has been approximately constant for the past 20 years, whilst that of CFC-216ca is increasing, at a current rate of 0.2 ppq/year. Upper tropospheric air samples collected in 2013 suggest a further continuation of this trend. Inferred annual emissions peaked 421 at 0.18 Gg/year (CFC-216ba) and 0.05 Gg/year (CFC-216ca) in the mid-1980s and then decreased sharply as expected from the Montreal Protocol phase-out schedule for CFCs. The atmospheric trend of CFC-216ca and CFC-216ba translates into continuing emissions of around 0.01 Gg/year in 2011, indicating that significant banks still exist or that they are still being used. HCFC-225ca was not detected in air samples collected before 1992. The highest mixing ratio of 52 ± 1 ppq was observed in 2001. Increasing annual emissions were found in the 1990s (i.e., when HCFC-225ca was being introduced as a replacement for CFCs). Emissions peaked around 1999 at about 1.51 Gg/year. In accordance with the Montreal Protocol, restrictions on HCFC consumption and the short lifetime of HCFC-225ca, mixing ratios declined after 2001 to 23.3 ± 0.7 ppq by 2012.

【 授权许可】

Unknown