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Weakening of the weekend ozone effect over California's South Coast Air Basin
Author(s) -
Baidar S.,
Hardesty R. M.,
Kim S.W.,
Langford A. O.,
Oetjen H.,
Senff C. J.,
Trainer M.,
Volkamer R.
Publication year - 2015
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 - 10.1002/2015gl066419
Subject(s) - weekend effect , ozone , structural basin , environmental science , nitrogen dioxide , recession , climatology , atmospheric sciences , meteorology , geography , geology , medicine , emergency medicine , paleontology , keynesian economics , economics
We have observed lower nitrogen dioxide (NO 2 ) and ozone (O 3 ) during a hot weekend (summer 2010) from aircraft over the entire South Coast Air Basin (SoCAB). Surface concentrations of NO 2 , O 3 , and temperature from 1996 to 2014 corroborate that this lower O 3 on weekends is increasingly likely in recent years. While higher surface O 3 on the weekends (weekend ozone effect, WO3E) remains widespread, the spatial extent and the trend in the probability of WO3E occurrences ( P WO3E ) have decreased significantly compared to a decade ago. This decrease is mostly the result of lower O 3 on hot weekends in recent years. P WO3E is lowest in the eastern SoCAB. The major decrease happened during the 2008 economic recession, after which P WO3E has stabilized at a 15–25% lower level throughout most of the basin. Future NO x reductions are likely to be increasingly effective at reducing O 3 pollution initially under hot conditions in the coming decade.