On the relationship between acetone and carbon monoxide in different air masses M. de Reus1, H. Fischer1, F. Arnold3, J. de Gouw2, R. Holzinger1, C Warneke2, and J. Williams1 1Max Planck Institute for Chemistry, Airchemistry Department, Mainz, Germany 2National Oceanic and Atmospheric Administration (NOAA), Aeronomy Laboratory, Boulder, USA 3Max Planck Institute for Nuclear Physics, Atmospheric Physics Division, Heidelberg, Germany
Abstract. Carbon monoxide and acetone measurements are presented for five aircraft
measurement campaigns at mid-latitudes, polar and tropical regions in the northern hemisphere. Throughout all campaigns, free tropospheric air
masses, which were influenced by anthropogenic emissions, showed a similar
linear relation between acetone and CO, with a slope of 21-25 pptv
acetone/ppbv CO. Measurements in the anthropogenically influenced marine
boundary layer revealed a slope of 13-16 pptv acetone/ppbv CO. The different
slopes observed in the marine boundary layer and the free troposphere indicate that acetone is emitted by the ocean in relatively clean air masses
and taken up by the ocean in polluted air masses. In the lowermost stratosphere, a good correlation between acetone and CO was observed as
well, however, with a much smaller slope (~5 pptv acetone/ppbv CO)
compared to the troposphere. This is caused by the longer photochemical lifetime of CO compared to acetone in the lower stratosphere, due to the
increasing photolytic loss of acetone and the decreasing OH concentration with altitude. No significant correlation between acetone and CO was
observed over the tropical rain forest due to the large direct and indirect
biogenic emissions of acetone.
The common slopes of the linear acetone-CO relation in various layers of the
atmosphere, during five field experiments, makes them useful for model calculations. Often a single observation of the acetone-CO correlation,
determined from stratospheric measurements, has been used in box model applications. This study shows that different slopes have to be considered for
marine boundary layer, free tropospheric and stratospheric air masses, and
that the acetone-CO relation cannot be used for air masses which are strongly
influenced by biogenic emissions.
Citation: de Reus, M., Fischer, H., Arnold, F., de Gouw, J., Holzinger, R., Warneke, C, and Williams, J.: On the relationship between acetone and carbon monoxide in different air masses, Atmos. Chem. Phys., 3, 1709-1723, doi:10.5194/acp-3-1709-2003, 2003.