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Observation of upper tropospheric sulfur dioxide‐ and acetone‐pollution: Potential implications for hydroxyl radicaland aerosol formation
Author(s) -
Arnold F.,
Schneider J.,
Gollinger K.,
Schlager H.,
Schulte P.,
Hagen D. E.,
Whitefield P. D.,
van Velthoven P.
Publication year - 1997
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 - 10.1029/96gl03693
Subject(s) - troposphere , acetone , aerosol , stratosphere , atmospheric sciences , sulfur dioxide , carbon dioxide , nucleation , tropopause , air pollution , pollution , isoprene , air mass (solar energy) , environmental science , boundary layer , environmental chemistry , chemistry , geology , inorganic chemistry , physics , organic chemistry , thermodynamics , ecology , biology , copolymer , polymer
Aircraft‐based measurements of sulfur dioxide, acetone, carbon dioxide, and condensation nuclei (CN) were made over the north‐eastern Atlantic at upper tropospheric altitudes, around 9000 m. On October 14, 1993, strong SO 2 ‐ and acetone‐pollution (both up to 3 ppbv) were observed, which were accompanied by a CO 2 ‐enhancement of up to 6 ppmv, and large CN‐concentrations of up to about 1500 cm −3 (for radii ≥ 6 nm). CN, excess CO 2 , and to a lesser degree also acetone, were positively correlated with SO 2 . Air mass trajectory analyses indicate, that most of the air masses encountered by our aircraft originated from the polluted planetary boundary layer of the North‐Eastern U. S. approximately 4–5 days prior to our measurements, and that polluted boundary layer air experienced fast vertical transport to the upper troposphere as well as horizontal transport across the Atlantic. From our data we conclude, that in the polluted air mass around 9000 m altitude HO x ‐formation, photochemical SO 2 ‐conversion to gaseous H 2 SO 4 , and eventually also CN‐formation by homogeneous bimolecular (H 2 SO 4 ‐H 2 O) nucleation may have taken place with enhanced efficiency.