Physical and chemical properties of pollution aerosol particles transported from North America to Greenland as measured during the POLARCAT summer campaign 1Laboratoire de Météorologie Physique, Université Blaise Pascal, CNRS UMR6016, Aubière, France
04 Nov 2011
2Particle Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
3Norwegian Institute for Air Reasearch (NILU), Kjeller, Norway
4UPMC Univ. Paris 06, Université Versailles St-Quentin, CNRS/INSU, LATMOS-IPSL, UMR8190, Paris, France
*now at: Swiss Federal Institute of Technology, Zurich, Switzerland
**now at: NASA Langley Research Center, Hampton, Virginia, USA
Received: 28 March 2011 – Published in Atmos. Chem. Phys. Discuss.: 15 April 2011 Abstract. Within the framework of the POLARCAT-France campaign, aerosol physical,
chemical and optical properties over Greenland were measured onboard the
French ATR-42 research aircraft. The origins of CO excess peaks detected in
the aircraft measurements then have been identified through FLEXPART
simulations. The study presented here focuses particularly on the
characterization of air masses transported from the North American continent
to Greenland. Air masses that picked up emissions from Canadian boreal forest
fires as well as from the cities on the American east coast were identified
and selected for a detailed study. Measurements of CO concentrations, aerosol
chemical composition, aerosol number size distributions, aerosol volume
volatile fractions and aerosol light absorption (mainly from black carbon)
are used in order to study the relationship between CO enhancement
(ΔCO), aerosol particle concentrations and number size
distributions. Aerosol number size distributions (normalised with their
respective ΔCO) are in good agreement with previous studies.
Nonetheless, wet scavenging may have occurred along the pathway between the
emission sources and Greenland leading to a less pronounced accumulation mode
in the POLARCAT data. Chemical analyses from mass spectrometry show that
submicrometer aerosol particles are mainly composed of sulphate and organics.
The observed bimodal (Aitken and accumulation) aerosol number size
distributions show a significant enhancement in Aitken mode particles.
Furthermore, results from the thermodenuder analysis demonstrate the external
mixture of boreal fire (BF) air masses from North America (NA). This is
particularly observed in the accumulation mode, containing a volume fraction
of up to 25–30% of refractory material at the applied temperature of
280 °C. NA anthropogenic air masses with only 6% refractory
material in the accumulation mode can be clearly distinguished from BF air
masses. Overall, during the campaign rather small amounts of black carbon
from the North American continent were transported towards Greenland during
the summer POLARCAT observation period, which also is a valuable finding with
respect to potential climate impacts of black carbon in the Arctic.
Revised: 20 October 2011 – Accepted: 26 October 2011 – Published: 04 November 2011
Citation: Quennehen, B., Schwarzenboeck, A., Schmale, J., Schneider, J., Sodemann, H., Stohl, A., Ancellet, G., Crumeyrolle, S., and Law, K. S.: Physical and chemical properties of pollution aerosol particles transported from North America to Greenland as measured during the POLARCAT summer campaign, Atmos. Chem. Phys., 11, 10947-10963, doi:10.5194/acp-11-10947-2011, 2011.