Size-resolved characterisation of organic compounds in atmospheric aerosols collected at Welgegund, South Africa
- 871 Downloads
The organic fraction of atmospheric aerosols is 20 to 90 % of which only a small percentage has been chemically characterised. Two-dimensional gas chromatography with a time-of-flight mass spectrometer (GCxGC-TOFMS) is a powerful instrument used to chemically characterise organic compounds. Size-resolved characterisation and semi-quantification of ambient organic aerosol compounds were performed with a GCxGC-TOFMS for the first time in South Africa. Twenty-four-hour samples were collected for 1 year for three different size ranges. A combined total of 1056 different organic compounds could be tentatively characterised. The largest number of organic compounds tentatively identified was PM2.5–1 (particles in the size range 1–2.5 μm), while this size fraction also had the highest total number of normalised response factors (∑NRF). On average, 52, 26, 6, 13 and 3 % of species tentatively identified were oxygenated species, hydrocarbons, halogenated compounds, N-containing compounds and S-containing compounds, respectively. Oxygenated compounds were the most abundant species. Alkane and mono-aromatic species were the largest number of hydrocarbons tentatively identified with the highest ∑NRFs. The largest number of oxygenated species tentatively characterised were carboxylic acids and esters, while ether compounds had the highest ∑NRFs. Most of the halogenated compounds tentatively identified were chlorinated species with the highest ∑NRFs in two size fractions. Iodate species had a significantly higher ∑NRF in the PM2.5–1 size fraction. The largest number of N-containing species tentatively characterised with the highest ∑NRFs were amines. A small number of S-containing compounds with low ∑NRFs were tentatively identified. The major sources of organic compounds measured at Welgegund were considered to be biomass burning and air masses moving over the anthropogenically impacted source regions.
KeywordsAtmospheric aerosols Organic compounds Characterisation and semi-quantification GCxGC-TOFMS Size-resolved Welgegund
The authors wish to acknowledge Diederik and Jackie Hattingh and their family who are the owners of the commercial farm on which the Welgegund measurement station is situated.
Compliance with ethical standards
Conflict of interest: The authors declare that they have no conflict of interest. Disclosure of potential conflict of interest forms was signed by all the authors.
The research did not involve any human participants and/or animals.
- Alves, C.A., Vicente, A., Evtyugina, M., Pio, C.A., Hoffer, A., Kiss, G., et al.: Characterisation of hydrocarbons in atmospheric aerosols from different European sites. World Acad. Sci. Eng. Technol. 57, 236–242 (2009)Google Scholar
- ATSDR: Agency for toxic substances and disease registry. A toxicological profile for iodine. U.S. Department of Health and Human Services. http://www.atsdr.cdc.gov/ToxProfiles/tp158.pdf (2004). Accessed 25 Nov 2013
- Beukes, J.P., Vakkari, V., Van Zyl, P.G., Venter, A.D., Josipovic, M., Jaars, K., et al: Source region plume characterisation of the interior of South Africa, as measured at Welgegund. In preparation for submission to Atmospheric Chemistry and Physics (2014)Google Scholar
- Bredenkamp, G., Joubert, A., Bezuidenhout, H.: A reconnaissance survey of the vegetation of the Potchefstroom-Fochville-Parys area. S. Afr. J. Bot. 55, 199–206 (1989)Google Scholar
- Dewulf, J., Van Langenhove, H: Hydrocarbons in the atmosphere. In: Environmental and Ecological Chemistry II, pp. 1–24. United Nations Educational, Scientific and Cultural Organization: Encyclopedia of Life Support Systems (EOLSS) (2003)Google Scholar
- George, I.J., Abbatt, J.P.D.: Heterogeneous oxidation of atmospheric aerosol particles by gas-phase radicals. Nat. Geosci. 2, 713–722 (2010)Google Scholar
- Graedel, T.E., Hawkins, D.T., Claxton, L.D.: Carboxylic Acids in Atmospheric Chemical Compounds: Occurrence and Bioassay. Academic, Orlando (1986)Google Scholar
- Hirsikko, A., Vakkari, V., Tiitta, P., Manninen, H.E., Gagne, S., Laakso, H., et al.: Characterisation of sub-micron particle number concentrations and formation events in the western Bushveld Igneous Complex, South Africa. Atmos. Chem. Phys. 12, 3951–3967 (2012). doi: 10.5194/acpd-12-3951-2012 CrossRefGoogle Scholar
- Kallio, M., Jussila, M., Rissanen, T., Anttila, P., Hartonen, K., Reissell, A., et al.: Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry in the identification of organic compounds in atmospheric aerosols from coniferous forest. J. Chromatogr. A 1125, 234–243 (2006)CrossRefGoogle Scholar
- Laitinen, T., Martín, S.H., Parshintsev, J., Hyötyläinen, T., Hartonen, K., Riekkola, M., et al.: Determination of organic compounds from wood combustion aerosol nanoparticles by different gas chromatographic systems and by aerosol mass spectrometry. J. Chromatogr. A 1217, 151–159 (2010)CrossRefGoogle Scholar
- Ringuet, J., Leoz-Garziandia, E., Budzinski, H., Villenave, E., Albinet, A.: Particle size distribution of nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) on traffic and suburban sites of a European megacity: Paris (France). Atmos. Chem. Phys. 12, 8877–8887 (2012)CrossRefGoogle Scholar
- Ruiz-Jimenez, J., Parshintsev, J., Hartonen, K., Riekkola, M.-L., Petäjä, T., Virkkula, A., et al.: Aerosolomics profiling: application to biogenic and anthropogenic samples. Report Series in Aerosol Science, Finnish Association for Aerosol Research (2010)Google Scholar
- Ruiz-Jimenez, J., Parshintsev, J., Laitinen, T., Hartonen, K., Riekkola, M.-L., Petäjä, T., et al.: A complete methodology for the reliable collection, sample preparation, separation and determination of organic compounds in ultrafine 30 nm, 40 nm and 50 nm atmospheric aerosol particles. Anal. Methods 3(2501–2509), 2011 (2011a). doi: 10.1039/C1AY05362K Google Scholar
- Ruiz-Jimenez, J., Parshintsev, J., Laitinene, T., Hartonen, K., Riekkola, M., Petäjä, T., et al.: Comprehensive two-dimensional gas chromatography, a valuable technique for screening and semiquantification of different chemical compounds in ultrafine 30 nm and 50 nm aerosol particles. J. Environ. Monit. 13, 2994–3003 (2011b). doi: 10.1039/c1em10486a CrossRefGoogle Scholar
- Seinfeld, J.H., Pandis, S.N.: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, 2nd edn. John Wiley and sons, New York (2006)Google Scholar
- Subramanian, M.S.: Organic air pollutants. In: Environmental Chemistry and Analysis, pp. 2063–2101. India Atmospheric Environment, Indian Institute of Technology Madras (2000)Google Scholar
- Tasic, M., Rajsic, S., Novakovic, V., Mijic, Z.: Atmospheric aerosols and their influence on air quality in urban areas. Phys. Chem. Technol. 4(1), 83–91 (2006)Google Scholar
- Venter A.D., Jaars K., Booyens W., Beukes J.P., van Zyl P.G., Josipovic M., et al.: Plume characterisation of a typical South African braai. Submitted for publication to South African Journal of Science (2014)Google Scholar
- WMO/UNEP: World Meteorological Organization / United Nations Environment Programme. Scientific Assessment of Ozone Depletion. http://www.esrl.noaa.gov/csd/assessments/ozone/1998/ExecSum98.pdf (1998). Accessed 25 Nov 2013