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Emissions of greenhouse gases from a North American megacity
Author(s) -
Wunch D.,
Wennberg P. O.,
Toon G. C.,
KeppelAleks G.,
Yavin Y. G.
Publication year - 2009
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl039825
Subject(s) - megacity , greenhouse gas , methane , environmental science , carbon dioxide , nitrous oxide , atmospheric methane , atmospheric sciences , trace gas , carbon monoxide , emission inventory , meteorology , geography , geology , chemistry , air quality index , oceanography , economy , organic chemistry , economics , biochemistry , catalysis
Atmospheric column abundances of carbon dioxide (CO 2 ), carbon monoxide (CO), methane (CH 4 ) and nitrous oxide (N 2 O) have been measured above the South Coast air basin (SCB), a densely populated urban region of Southern California, USA, which includes Los Angeles and the surrounding suburbs. Large diurnal variations in CO and CH 4 are observed which correlate well with those in CO 2 . Weaker correlations are seen between N 2 O and CO 2 , with large uncertainties. We compute yearly SCB emissions of CO and CH 4 to be 1.4 ± 0.3 Tg CO and 0.6 ± 0.1 Tg CH 4 . We compare our calculated emissions to the California Air Resources Board (CARB) and the Emission Database for Global Atmospheric Research (EDGAR) estimates. Our measurements confirm that urban emissions are a significant source of CH 4 and in fact may be substantially higher than currently estimated. If our emissions are typical of other urban centers, these findings suggest that urban emissions could contribute 7–15% to the global anthropogenic budget of methane.