Concentrations of carbonyl compounds and the carbon isotopy of formaldehyde at a coastal site in Nova Scotia during the NARE summer intensive

TitleConcentrations of carbonyl compounds and the carbon isotopy of formaldehyde at a coastal site in Nova Scotia during the NARE summer intensive
Publication TypeJournal Article
Year of Publication1996
AuthorsTanner, RL, Zielinska, B, Uberna, E, Harshfield, G, McNichol, AP
JournalJournal of Geophysical Research-Atmospheres
Volume101
IssueD22
Pagination28961-28970
Date PublishedDec 20
ISSN2169-897x
Accession NumberWOS:A1996VZ78800029
Abstract

The concentrations of gaseous atmospheric carbonyl compounds have been measured at a coastal site on the southern tip of Nova Scotia during August 1993 as part of the National Oceanic and Atmospheric Administration's North Atlantic Regional Experiment (NARE) summer intensive. The DNPH-cartridge technique was used for sampling, with analysis by HPLC with UV absorbance detection. The carbon isotopic content of formaldehyde was measured using a novel collection technique on bisulfite-coated fillers followed by accelerator mass spectrometric determination of C-14 content and C-13/C-12 isotopic ratios. Results from this study indicate that quantifiable levels above about 100 parts per trillion by volume were found at the Chebogue Point, Nova Scotia, site for several carbonyls, formaldehyde, acetaldehyde, acetone, propionaldehyde, methyl ethyl ketone, and benzaldehyde, for most 6-hour sampling periods. Six-hour averaged formaldehyde levels of <0.5 to about 3.5 parts per billion were found during periods of local influence and during influence of continental air masses crossing eastern Canada and northeastern US. In contrast, background levels of formaldehyde of 200-400 pptv were found under conditions of predominantly marine back trajectories. Large fractions of contemporary carbon (of the order of 80%) were found in collected formaldehyde samples for all transport regimes and formaldehyde concentrations, suggesting that biogenic sources of hydrocarbon precursors to formaldehyde predominated during the summer season.

DOI10.1029/95jd03574