Atmospheric mixing ratios of methyl ethyl ketone (2-butanone) in tropical, boreal, temperate and marine environments

• Published in: Atmospheric chemistry and physics Vol. 16; no. 17; pp. 10965 - 10984
• Main Authors: Yáñez-Serrano, A. M, Nölscher, A. C, Bourtsoukidis, E, Derstroff, B, Zannoni, N, Gros, V, Lanza, M, Brito, J, Noe, S. M, House, E, Hewitt, C. N, Langford, B, Nemitz, E, Behrendt, T, Williams, J, Artaxo, P, Andreae, M. O, Kesselmeier, J
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 06-09-2016; European Geosciences Union; Copernicus Publications
• Subjects: Acetone; Air temperature; Ambient temperature; Anthropogenic factors; Atmosphere; Atmospheric mixing; Biomass; Butane; Carbon monoxide measurements; Chromatography; Continental interfaces, environment; Forests; Human influences; Industrial plant emissions; Instruments; Ketones; Marine environment; Mass spectrometry; Methyl ethyl ketone; Mixing ratio; Ocean, Atmosphere; Offshore structures; Organic compounds; Oxidation; Profiles; Rainforests; Ratios; Sciences of the Universe; Scientific imaging; Smear; Tropical climate; Vegetation; Vertical profiles; VOCs; Volatile organic compounds; Brazil; Austria; Estonia
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 10.5194/acp-16-10965-2016

Methyl ethyl ketone (MEK) enters the atmosphere following direct emission from vegetation and anthropogenic activities, as well as being produced by the gas-phase oxidation of volatile organic compounds (VOCs) such as n-butane. This study presents the first overview of ambient MEK measurements at six different locations, characteristic of forested, urban and marine environments. In order to understand better the occurrence and behaviour of MEK in the atmosphere, we analyse diel cycles of MEK mixing ratios, vertical profiles, ecosystem flux data, and HYSPLIT back trajectories, and compare with co-measured VOCs. MEK measurements were primarily conducted with proton-transfer-reaction mass spectrometer (PTR-MS) instruments. Results from the sites under biogenic influence demonstrate that vegetation is an important source of MEK. The diel cycle of MEK follows that of ambient temperature and the forest structure plays an important role in air mixing. At such sites, a high correlation of MEK with acetone was observed (e.g. r2 = 0.96 for the SMEAR Estonia site in a remote hemiboreal forest in Tartumaa, Estonia, and r2 = 0.89 at the ATTO pristine tropical rainforest site in central Amazonia). Under polluted conditions, we observed strongly enhanced MEK mixing ratios. Overall, the MEK mixing ratios and flux data presented here indicate that both biogenic and anthropogenic sources contribute to its occurrence in the global atmosphere.