Comparison of advanced offline and in situ techniques of organic aerosol composition measurement during the CalNex campaign
| Autor: | Rupert Holzinger, T. Dorst, Beatriz Oyama, Arthur W. H. Chan, Allen H. Goldstein, J. Timkovsky |
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| Přispěvatelé: | Marine and Atmospheric Research, Sub Atmospheric physics and chemistry |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Atmospheric Measurement Techniques, 8(12), 5177. Copernicus Publications Atmospheric Measurement Techniques, Vol 8, Iss 12, Pp 5177-5187 (2015) |
| ISSN: | 1867-1381 1867-8548 |
| Popis: | Our understanding of formation processes, physical properties, and climate/health effects of organic aerosols is still limited in part due to limited knowledge of organic aerosol composition. We present speciated measurements of organic aerosol composition by two methods: in situ thermal-desorption proton-transfer-reaction mass spectrometry (TD-PTR-MS) and offline two-dimensional gas chromatography with a time-of-flight mass spectrometer (GC × GC/TOF-MS). Using the GC × GC/TOF-MS 153 compounds were identified, 123 of which were matched with 64 ions observed by the TD-PTR-MS. A reasonable overall correlation of 0.67 (r2) was found between the total matched TD-PTR-MS signal (sum of 64 ions) and the total matched GC × GC/TOF-MS signal (sum of 123 compounds) for the Los Angeles area. A reasonable quantitative agreement between the two methods was observed for most individual compounds with concentrations which were detected at levels above 2 ng m−3 using the GC × GC/TOF-MS. The analysis of monocarboxylic acids standards with TD-PTR-MS showed that alkanoic acids with molecular masses below 290 amu are detected well (recovery fractions above 60 %). However, the concentrations of these acids were consistently higher on quartz filters (quantified offline by GC × GC/TOF-MS) than those suggested by in situ TD-PTR-MS measurements, which is consistent with the semivolatile nature of the acids and corresponding positive filter sampling artifacts. |
| Databáze: | OpenAIRE |
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