Research project EV/06 (Research action EV)
The composition of the troposphere is strongly affected by biogenic and anthropogenic emissions of chemical compounds, including hydrocarbons, carbon monoxide, and the nitrogen oxides. The emissions of non-methane hydrocarbons, in particular, have a large impact on the oxidizing capacity of the atmosphere (which determines the fate and lifetime of a large number of pollutants and greenhouse gases) and on the budget and distribution of tropospheric ozone and aerosols. In this project, we propose specifically to study their impact on the formation of oxidants (including the hydroxyl radical OH) and aerosols on the global scale. Laboratory data and theoretical results quantifying photochemical processes in the atmosphere will be integrated in chemistry/transport models of the global troposphere. These models simulate the distribution of key important compounds, including ozone and its precursors.
The first goal of this project is to reduce uncertainties in the processes (emissions, chemistry) that determine the global distribution of tropospheric constituents. For this purpose, a number of chemical and photochemical mechanisms which have been identified from model calculations to be potentially important will be studied though concerted laboratory, theoretical and modelling investigations. The degradation mechanisms of selected non-methane hydrocarbons will be established, and the potential formation of long-lived intermediates, including aerosols, will be identified. A special care will be devoted to the quantification of the remaining uncertainties in the emissions and atmospheric degradation of these compounds.
A second goal of the project is to quantify the impact of non-methane hydrocarbons on the oxidizing capacity of the atmosphere and on the chemistry of ozone in the upper troposphere. This region is of particular interest in the context of global change, because the injection of anthropogenic pollutants at these altitudes (through aircraft emissions or deep convection of polluted air) is known to have a strong influence on the budget of radicals and hence, ozone. For this purpose, a well-established chemical/transport model, which calculates the global climatological distributions of chemical constituents, the IMAGES model, will be used.
The third goal of the project is to determine the influence of human activity on the chemical composition and the oxidizing capacity of the atmosphere. For this purpose, scenarios accounting for future changes in population, energy consumption, changes in land-use, etc. will be introduced in the global model, in order to predict the possible future evolution of the atmospheric composition.
These assessment studies should help understanding the impact of global pollution on climate forcing and on the biosphere. They should provide to decision-makers indispensable scientific information that will contribute to ensure sustainable development.
Methodology
- use of the fast-flow reactor technique for the simulation of atmospheric chemistry processes at a laboratory scale;
- development and application of new analytical techniques for the determination of the terpenes oxidation products;
- development and application of theoretical techniques (quantum calculations, Structure-Activity Relationships, etc.) for the determination of the terpenes oxidation products, including aerosols;
- development of a comprehensive chemical mechanism for the oxidation of terpenes in atmospheric conditions, and validation of this mechanism by confrontation with laboratory results;
- determination of the global emissions of biogenic hydrocarbons, and investigation of their uncertainties.
Interactions between the different partners
- close collaboration between the teams of C. Vinckier (KULeuven) and E. Arijs (BIRA-IASB) for the application of the fast-flow reactor technique to the terpenes oxidation ;
- close collaboration between the teams of J.-F. Müller (IASB-BIRA) and J. Peeters (KULeuven) for the development and validation of the terpenes oxidation mechanism ;
- the mechanistic data obtained from the laboratory and theoretical studies will be integrated in a chemical model of the troposphere by the team of J. -F. Müller in order to determine their impact on the tropospheric composition.
Link with international programmes:
- EUROTRAC2 : contributions of the KULeuven teams to the subproject CMD (Chemical Mechanism Development) ;
- IPCC (Intergovernmental Panel on Climate Change) : contribution of J .-F. Müller to e.g. the 3d Assessment Report IPCC/TAR ;
- Integration in European research networks of the 5th Framework Programme.
Expected results
- new laboratory and theoretical techniques for investigating the oxidation of biogenic hydrocarbons (monoterpenes);
- new comprehensive mechanisms representing the oxidation of several important biogenic hydrocarbons (monoterpenes) in laboratory as well as in atmospheric conditions;
- better assessment of the role of these hydrocarbons on the global troposphere, in particular regarding the production of aerosols;
- better assessment of the impact of anthropogenic emissions on the composition of the global troposphere.
Partners
Activities
The groups of Vinckier and Arijs conduct laboratory studies of the oxidation of several monoterpenes by OH in the presence of NO. They benefit from the experience gained by Vinckier’s team during the previous PODO program. In addition, Arijs and Peeters’s teams investigate other selected organic reactions.
The groups of Peeters and Müller combine theoretical and modelling studies in order to construct an oxidation mechanism for monoterpenes in general conditions. Peeters’s team focuses on the gas-phase reaction steps, while Müller’s group works at their integration in a model that includes gas/particle-partitioning effects. The latter group also assesses the biogenic emissions as well as global impacts using a 3-dimensional chemical model.
Coordinates/Details
Project co-ordinator:
Jean-François Müller
Belgian Institute for Space Aeronomy (BIRA-IASB)
Avenue Circulaire 3, B-1180 Brussels
Tel: +32 (0)2 373 04 86; Fax: +32 (0)2 374 84 23
jfm@bira-iasb.oma.be
Project partners:
Jozef Peeters
Katholieke Universiteit Leuven - Chemistry Department
Celestijnenlaan 200F, B-3001 Heverlee
Tel: +32 (0)16 32 73 82; Fax: +32 (0)16 32 79 92
jozef.peeters@chem.kuleuven.ac.be
Christiaan Vinckier
Katholieke Universiteit Leuven - Chemistry Department
Celestijnenlaan 200F, B-3001 Heverlee
Tel: +32 (0)16 32 73 76; Fax: +32 (0)16 32 79 92
chris.vinckier@chem.kuleuven.ac.be
Etienne Arijs
Belgian Institute for Space Aeronomy (BIRA-IASB)
Ringlaan 3, B-1180 Brussels
Tel: +32 (0)2 373 04 76; Fax: +32 (0)2 374 84 23
earijs@bira-iasb.oma.be
Users Committee
Bob Nieuwejaers - AMINAL
Alex Guenther - National Center for Atmospheric Research
Guy Brasseur - Max-Planck-Institut für Meteorologie
Ulrich Schurath - Institut für Meteorologie und Klimaforschung, FZK
Anthropogenic and biogenic influences on the oxidation capacity of the atmosphere : final report
Muller, J.-F. - Vinckier, C. - Peeters, J. ... et al Brussels : Belgian Science Policy, 2005 (SP1515)
[To download]
[To order]
Antropogene en biogene invloeden op de oxiderende capaciteit van de atmosfeer : samenvatting
Brussel : Federaal Wetenschapsbeleid, 2005 (SP1516)
[To download]
Influences anthropiques et biogéniques sur la capacité d'oxydation de l'atmosphère : résumé
Bruxelles : Politique scientifique fédérale, 2005 (SP1517)
[To download]
Anthropogenic and biogenic influences on the oxidation capacity of the atmosphere : summary
Brussels : Belgian Science Policy, 2005 (SP1518)
[To download]
Bibliografic references :
I. Hermans, J.F. Müller, T.L. Nguyen, P.A. Jacobs, J. Peeters
The Journal of Physical Chemistry, A, 109, 2005
L. Vereecken, J. Peeters Journal of Chemical Physics, 119, 2003
