Open AccessMeasurements of ambient atmospheric C 2 H 5 Cl and other ethyl and methyl halides at coastal California sites and over the Pacific Ocean
Author(s) -
Low Jason C.,
Wang Nun Yii,
Williams Jody,
Cicerone Ralph J.
Publication year - 2003
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2003jd003620
Subject(s) - halide , transect , pacific ocean , air mass (solar energy) , chemistry , environmental chemistry , environmental science , analytical chemistry (journal) , oceanography , geology , physics , inorganic chemistry , boundary layer , thermodynamics
Spatial and temporal distributions of atmospheric CH 3 Cl, CH 3 Br, C 2 H 5 Cl, and C 2 H 5 Br were determined by gas chromatography/mass spectrometry measurements at coastal California and inland sites from 1996 through 1999. The median concentrations observed at a clean coastal site were 585, 13.1, 3.3, and 0.3 ppt (parts per trillion) for CH 3 Cl, CH 3 Br, C 2 H 5 Cl, and C 2 H 5 Br, respectively. To our knowledge, these represent the first quantitative measurements of atmospheric C 2 H 5 Cl. High variation was seen in CH 3 Br and C 2 H 5 Cl measurements from the other two California sites, a rural inland site and a coastal site with urban influence. When compared to the California stationary sites, the median Northern Hemispheric results from measurements taken along Pacific Ocean transects between California and New Zealand from 1996 through 1999 were similar for CH 3 Cl (594 ppt) and C 2 H 5 Br (0.3 ppt) but lower for CH 3 Br (10.4 ppt) and C 2 H 5 Cl (2.6 ppt). Median concentrations of Southern Hemispheric CH 3 Br (9.4 ppt), C 2 H 5 Cl (1.6 ppt), and C 2 H 5 Br (less than 0.2 ppt) were lower than the Northern Hemispheric results. No significant correlation was found between the atmospheric concentrations of the methyl halides with the ethyl halides.