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| Titel |
Implications from the changes in the levels of halocarbons and the compliance with the Montreal Protocol |
| VerfasserIn |
Chih-Chung Chang, Jia-Lin Wang, Neng-Huei Lin, Wen-Tzu Liu, Clock Chew, Chang-Feng Ou-Yang, Bo-Ru Lee, Chih-Yuan Chang |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250073044
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| Zusammenfassung |
| An extensive air sampling made at 51 sites in metropolitan Taipei was conducted in 2012.
The results were compared with the sampling made in 1998 using almost identical sampling
approach. The goal is to investigate the changes in concentration levels and variability of
ozone depleting substances (ODS) in urban atmosphere over the period of 14 years. Seven
major halocarbons, i.e., CFC-11 (CCl3F), CFC-12 (CCl2F2), CFC-113 (CCl2FCClF2),
CH3CCl3, CCl4, CHCl=CCl2 and CCl2=CCl2, with the latter two being non-ODS but
possible carcinogens, were analyzed to assess how successful the transition to an
era of ceased emissions of ODS is. After 14 years, the concentrations of CFC-11,
CFC-113 and CCl4 were found to be within the proximity of the background levels in
the Northern Hemisphere. Moreover, we used concentration variability to imply
emissions and usage of ODS. The variability of CFC-11 and CCl4 was less than
4% expressed as one standard deviation, indicating negligible usage for these two
ODS in this city of five million residents. Surprisingly, a few samples showed high
values for CFC-113, indicating that sporadic usage of CFC-113 still existed. The
decline in concentration variability over the 14-year period was particularly dramatic
for CFC-12 and CH3CCl3, which may be related to the fact that cars made after
mid-1994 were required to use HFC-134a to replace CFC-12 as the air conditioning
refrigerant, and other chlorine-free solvents largely replaced CH3CCl3 in the past decade. |
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