First measurements of reactive α-dicarbonyl concentrations on PM2.5 aerosol over the Boreal forest in Finland during HUMPPA-COPEC 2010 – source apportionment and links to aerosol aging 1Institute for Inorganic and Analytical Chemistry, Johannes Gutenberg-University, 55128 Mainz, Germany
17 Jul 2012
2Scripps Institution of Oceanography and the University of California, San Diego, La Jolla, CA 92093, USA
3Max Planck Institute for Chemistry, 55128 Mainz, Germany
4Department of Physics, 00014 University of Helsinki, Finland
*now at: Brigham Young University – Idaho, Dept. of Chemistry, Rexburg, ID 83460, USA
Received: 06 Dec 2011 – Published in Atmos. Chem. Phys. Discuss.: 09 Jan 2012 Abstract. The first dataset for summertime boreal forest concentrations of two
atmospherically relevant α-dicarbonyl compounds, glyoxal (Gly) and
methylglyoxal (Mgly) on PM2.5 aerosol was obtained during the
HUMPPA-COPEC-2010 field measurement intensive in Hyytiälä, Finland.
Anthropogenic influences over the course of the campaign were identified
using trace gas signatures and aerosol particle chemical composition
analysis. The data evaluation allowed the identification of different events
such as urban pollution plumes, biomass burning and sawmill emissions as
sources of high Gly and Mgly concentrations. Mean aerosol concentrations
during periods of biogenic influence were 0.81 ng m−3 for Gly and
0.31 ng m−3 for Mgly. Mgly was generally less abundant in PM2.5,
probably due to its shorter photolysis lifetime and less effective
partitioning into the particle phase due to its smaller effective Henry's
Law constant compared to Gly. This is in contrast with previous urban
studies which show significantly more Mgly than Gly. Peak concentrations for
Gly coincided with nearby sources, e.g. high VOC emissions from nearby
sawmills, urban pollution plumes from the city of Tampere located 50 km
southwest of the sampling site and biomass burning emissions from wildfires.
Calculated ratios of Gly in PM2.5 and total organic matter in PM1
aerosols indicate higher values in less aged aerosols. Irreversible
processing of Gly in the particle phase, e.g. via oxidation by OH radicals,
organo sulfate or imidazole formation are processes currently discussed in
the literature which could likely explain these findings.
Revised: 05 Jun 2012 – Accepted: 21 Jun 2012 – Published: 17 Jul 2012
Citation: Kampf, C. J., Corrigan, A. L., Johnson, A. M., Song, W., Keronen, P., Königstedt, R., Williams, J., Russell, L. M., Petäjä, T., Fischer, H., and Hoffmann, T.: First measurements of reactive α-dicarbonyl concentrations on PM2.5 aerosol over the Boreal forest in Finland during HUMPPA-COPEC 2010 – source apportionment and links to aerosol aging, Atmos. Chem. Phys., 12, 6145-6155, doi:10.5194/acp-12-6145-2012, 2012.