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          Institute: MPI für Chemie     Collection: Publikationen MPI für Chemie     Display Documents

ID: 18282.0, MPI für Chemie / Publikationen MPI für Chemie
Organic trace gas measurements by PTR-MS during INDOEX 1999
Authors:Wisthaler, A.; Hansel, A.; Dickerson, R. R.; Crutzen, P. J.
Date of Publication (YYYY-MM-DD):2002-09
Title of Journal:Journal of Geophysical Research
Journal Abbrev.:J. Geophys. Res.
Issue / Number:D19
Sequence Number of Article:8024
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:[1] A proton-transfer-reaction mass spectrometer (PTR-MS) was used for fast-response measurements of volatile organic compounds (VOCs) onboard the NOAA research vessel Ronald H. Brown during leg 2 (4 March-23 March) of the INDOEX 1999 cruise. In this paper, we present a first overview of the distribution of acetonitrile, methanol, acetone, and acetaldehyde over a broad spatial extent of the Indian Ocean (19degreesN-13degreesS, 67degreesE-75degreesE). The prevailing atmospheric circulation during the winter monsoon transported polluted air from India and the Middle East over the Indian Ocean to meet pristine southern hemispheric air at the intertropical convergence zone (ITCZ). The chemical composition of air parcels changed according to their geographic origin, which was traced by backtrajectory analysis. The relative abundance of acetonitrile, a selective tracer for biomass burning, to that of carbon monoxide, a general tracer for incomplete combustion, reflected the signature of biomass burning or fossil fuel combustion. This indicated a strong biomass burning impact in W-India, mixed pollution sources in NE-India, and the dominance of fossil fuel combustion in the Middle East. Biomass burning impacted air was rich in methanol (0.70-1.60 ppbv), while acetone (0.80-2.40 ppbv) and acetaldehyde (0.25-0.50 ppbv) were elevated in all continental air masses. Pollution levels decreased toward the ITCZ resulting in minima for methanol, acetone, and acetaldehyde of 0.50, 0.45, and 0.12 ppbv, respectively. The observed abundances suggest that there are unidentified sources of acetone and acetaldehyde in biomass burning impacted air masses and in remote marine air.
Free Keywords:INDOEX; PTR-MS; VOCs; biomass burning; acetone; acetonitrile
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Chemie/Chemie der Atmosphäre
External Affiliations:Innsbruck Univ, Inst Ionenphys, A-6020 Innsbruck, Austria; Univ Maryland, Dept Meteorol, College Pk, MD 20742 USA; Univ Maryland, Dept Chem, College Pk, MD 20742 USA
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