 |
| Titel |
Measurements of aerosol chemical composition in boreal forest summer conditions |
| VerfasserIn |
M. Äijälä, H. Junninen, M. Ehn, T. Petäjä, A. Vogel, T. Hoffmann, A. Corrigan, L. Russell, U. Makkonen, A. Virkkula, J. Mäntykenttä, M. Kulmala  , D. Worsnop |
| Konferenz |
EGU General Assembly 2012
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067651
|
|
|
|
|
|
| Zusammenfassung |
| Boreal forests are an important biome, covering vast areas of the northern hemisphere and
affecting the global climate change via various feedbacks [1]. Despite having relatively few
anthropogenic primary aerosol sources, they always contain a non-negligible aerosol
population [2]. This study describes aerosol chemical composition measurements using
Aerodyne Aerosol Mass Spectrometer (C-ToF AMS, [3]), carried out at a boreal forest area in
Hyytiälä, Southern Finland. The site, Helsinki University SMEAR II measurement station
[4], is situated at a homogeneous Scots pine (Pinus sylvestris) forest stand. In addition to the
station’s permanent aerosol, gas phase and meteorological instruments, during the HUMPPA
(Hyytiälä United Measurements of Photochemistry and Particles in Air) campaign
in July 2010, a very comprehensive set of atmospheric chemistry measurement
instrumentation was provided by the Max Planck Institute for chemistry, Johannes
Gutenberg-University, University of California and the Finnish Meteorological institute.
In this study aerosol chemical composition measurements from the campaign are
presented.
The dominant aerosol chemical species during the campaign were the organics, although
periods with elevated amounts of particulate sulfates were also seen. The overall AMS
measured particle mass concentrations varied from near zero to 27 μg/m observed during a
forest fire smoke episode. The AMS measured aerosol mass loadings were found to agree
well with DMPS derived mass concentrations (r2=0.998). The AMS data was also compared
with three other aerosol instruments. The Marga instrument [5] was used to provide a
quantitative semi-online measurement of inorganic chemical compounds in particle phase.
Fourier Transform Infrared Spectroscopy (FTIR) analysis was performed on daily filter
samples, enabling the identification and quantification of organic aerosol subspecies.
Finally an Atmospheric Pressure Chemical Ionization Ion Trap Mass Spectrometer
(APCI-IT-MS, [6]) was measuring gas and particle phase aerosol composition, offering
additional information on molecular compositions. Overall, the availability of a
variety of aerosol chemical characterization instruments provided a good opportunity
for a comparison of the results obtained by these four very different measurement
approaches. Overall the results were found to agree. The inorganic particulate masses
measured with the AMS and Marga were found to correlate especially well for
sulphates (r2=0.92) and ammonia compounds (r2=0.82). The organic mass seen by the
AMS was correlated with the FTIR filter analysis (r2=0.87) and the APCI-IT-MS
(r2=0.88).
References
[1] Bonan G.B. et al. (2008). Science, 320:1444-1449.
[2] Tunved P. et al. (2006). Science, 312:261-263.
[3] Drewnick F., et al. (2005). AST, 39:7:637-658.
[4] Hari P. and M. Kulmala (2005). BER, 10:315–322.
[5] ten Brink H et al. (2007). Atmos. Environ., 41:2768-2779.
[6] Hoffmann T. et al. (2002), Spectrochim. Acta B, 57:1635-1647. |
|
|
|
|
|
|