Research project EV/11 (Research action EV)
Atmospheric aerosols are of importance for a wide range of geophysical and environmental problems ranging from local issues to global scale. Carbonaceous aerosols, i.e., organic carbon (OC) and elemental carbon (EC), make up a large fraction of the (fine) aerosol, often up to 50% or more, and are thought to play a major role in the climatic and health effects of aerosols. Yet, our knowledge about them is very deficient. This is to a large extent due to their complexity and to problems associated with their collection.
In this project we will develop improved collection procedures, whereby the sampling artifacts are better controlled or can be corrected for, and develop improved methods for the characterisation of the carbonaceous atmospheric aerosol, going from (a) a better discrimination between EC and OC over (b) separation into a number of main classes, for which the major functional groups are characterised, to (c) a more complete molecular characterisation, whereby special attention will be given to high-molecular weight organics and highly polar compounds. It will be attempted to identify new organic compounds in continental aerosols that can be used as markers for specific sources, source types or processes, and/or atmos-pheric processes.
The already existing and newly developed samplers (including devices with high size resolution) and analytical methods will be used for detailed carbonaceous aerosol characteri-sation studies at a number of selected sites in Europe within the framework of the EUROTRAC-2 AEROSOL subproject. They will also be employed for studies in tropical and equatorial regions (southern Africa, South America), i.e., within large international campaigns that are organised under the auspices of IGBP-IGAC activities, such as those of the Large Scale Biosphere-Atmos-phere Experiment in Amazonia (LBA). The data sets on the carbonaceous aerosol will be used in combination with data on the inorganic aerosol constituents and on the particulate mass (PM) for source (source type) identification and apportionment, for estimating the contributions to the carbonaceous aerosols from anthropogenic and natural sources and from various source types within each of these broad categories, for assessing the relative proportions of secondary organic aerosol (SOA) and primary OC, and for chemical mass "closure" work (that is for examining to which extent the experimental PM can be reconstituted on the basis of the measured aerosol types and components).
The chemical mass "closure" work will not only be done for the fine aerosol as a whole, but also for several different size fractions therein, down to about 50 nm. Furthermore, in co-operation with other groups (especially within the IGBP-IGAC activities), we will examine the relationships between volatile organic compounds (VOCs) and organic aerosol in order to arrive at a better understanding of SOA formation, and between the carbonaceous aerosol char-acteristics and physical and optical/radiative aerosol properties (e.g., condensation nuclei (CN) and cloud condensation nuclei (CCN) concentrations and particle number size distributions, light scattering and absorption coefficients) in order to assess the contribution of the carbonaceous aerosol to the direct and indirect effects of aerosols on climate.
Part of the work will be done within international co-operation with Central European countries and with China. Special attention will be given to the exploitation of the research results. This will include transfer of knowledge and results from this project to policy advisers and makers, admin-istrators, the members of the users committee and the general public.
Methodology
Two approaches are employed to correct for the artefact collection of gaseous organic compounds in aerosol sampling. In the first approach use is made of filter holders that contain two filters in series. In the second approach, a denuder is placed upstream of the aerosol collector. Improved methods are developed for the differentiation between organic and elemental carbon. For this, one resorts to a thermal-optical transmission technique. This technique is evaluated by participating in intercomparison studies with foreign research groups. Methods are also developed for the determination of the water-soluble organic carbon (WSOC) in the aerosol. A "Total organic carbon" analyser is used for this work. For the fractionation of the WSOC, one resorts to anion exchange with high-performance liquid chromatography. Methods based on ion chromatography are used to measure low-molecular weight water-soluble organic compounds. For a whole series of other water-soluble and apolar organic compounds, one utilises capillary gas chromatography / mass spectrometry (GC/MS) in combination with appropriate derivatisation methods. The source identification and apportionment work is done with the aid of receptor models.
Interaction between the different partners
The RUG team performs the aerosol collections and the work for the development and implementation of improved sampling procedures. It also performs the analyses with the thermal-optical transmission (TOT) technique, with the "Total organic carbon" analyser and with ion chromatography. On the basis of the TOT results, samples are selected for the fractionation of the WSOC and for the extensive GC/MS analyses. These two activities are carried out by the UIA team. The source identification and apportionment is a joint activity of the RUG and UIA teams, whereby chemical analysis results of both teams are being used.
Link with international programmes
The development of improved collection and analytical procedures and the aerosol studies in Europe are carried out within the framework of the EUROTRAC-2 AEROSOL subproject. The aerosol studies in tropical and equatorial regions fit in IGBP-IGAC activities and in components of it, such as the "Southern African Regional Science Initiative" (SAFARI 2000) and the "Large Scale Biosphere-Atmosphere Experiment in Amazonia" (LBA). Part of the research in Brazil is linked with the EC-funded project SMOCC ("Smoke Aerosols, Clouds, Rainfall and Climate: Aerosols from Biomass Burning Perturb Global and Regional Climate"). Finally, our studies in Europe are also utilised to contribute to the 2003 revision of the EU "Particulate Matter Directive".
Expected results and/or products
The project will give rise to publications in international journals with peer review. In addition, it will result in communications at international and national conferences, symposia or workshops. The project and its results will be presented on a Website, which will be set up by ourselves. Furthermore, pertinent data, data summaries and information will be made available for use in national and international databases and Websites. It is expected that many of our results will be of value for modellers and for environmental policy makers and advisers.
Partners
Activities
The RUG team has many years of experience in atmospheric aerosol research and in aerosol collections and analyses. It was an active participant in several international field campaigns. It has a large expertise in the inorganic analysis of aerosol samples and performs analyses for organic and elemental carbon, water-soluble organic carbon and low-molecular weight water-soluble organic compounds.
The UIA team has a very large experience in mass spectrometric methods for the characterisation of biomolecules and complex organic compounds. It has a great expertise in capillary gas chromatography / mass spectrometry and in derivatisation techniques, which aim at structure determination or sensitive analysis. It is an essential partner for the detailed organic analyses of the aerosol samples.
Contact Information
Promoter
Willy Maenhaut
Universiteit Gent (RUG)
Vakgroep Analytische Chemie, Instituut voor Nucleaire Wetenschappen
Onderzoeksgroep Troposferisch Aërosolonderzoek en Nucleaire Microanalyse
Proeftuinstraat 86, B-9000 Gent
Tel: +32 (0)9 264 65 96; Fax: +32 (0)9 264 66 99
Willy.Maenhaut@rug.ac.be
Partner
Magda Claeys
Universiteit Antwerpen (UIA)
Departement Farmaceutische Wetenschappen
Onderzoeksgroep Bio-organische Massaspectrometrie
Universiteitsplein 1, B-2610 Antwerpen
Tel: +32 (0)3 820 27 07; Fax: +32 (0)3 820 27 34
claeys@uia.ua.ac.be
Users Committee
Harry Ten Brink - Netherlands Energy Research Foundation (ECN)
Bob Nieuwejaers and Mirka Van Der Elst - Ministerie van de Vlaamse Gemeenschap - Administratie Leefmilieu en Infrastructuur (LIN - AMINAL)
Edward Roekens and Christine Matheeussen - Flemish Environmental Agency (VMM) - Department Measuring Networks and Research - Air Quality Networks
Hedwig Duflou - SGS Depauw & Stokoe N.V.
Characterisation and sources of carbonaceous atmospheric aerosols : final report
Maenhaut, Willy - Claeys, Magda Brussels : Belgian Science Policy, 2007 (SP1855)
[To download]
[Exhausted]
Karakterisering en bronnen van koolstofhoudende atmosferische aërosolen : samenvatting
Brussel : Federaal Wetenschapsbeleid, 2007 (SP1865)
[To download]
Characterisation and sources of carbonaceous atmospheric aerosols : summary
Brussels : Belgian Science Policy, 2007 (SP1866)
[To download]
Characterisation and sources of carbonaceous atmospheric aerosols : final report
Brussels : Federal Science Policy, 2010 (SP2173)
[To download]
Bibliografic references :
