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Content archived on 2023-01-04

Global Change, 1992-1994

Objective

To study the transport, diffusion and chemical fate of biogenic and anthropogenic emissions in the perturbed troposphere: a) laboratory and in-field studies on biosphere/atmosphere interactions with emphasis on the Mediterranean area; b) trends of trace atmospheric species relevant to the photochemistry and the planetary radiation budget with emphasis on sulphur containing gases; c) theoretical modelling and experimental validation of mesoscale and long range atmospheric physico- chemical transformation and transport processes.
Evaluation was made of the seasonal and diurnal variation of monoterpene content in conifer needles. Monoterpene total amount in the needles decreased from July to October by 42%, whereas the relative distribution of the individual compounds (EG alpha pinene, beta pinene, camphene, limonene, borneol, camphor) remained constant.

Field measuring campaigns have been undertaken in the Bavarian forest and Veluwe (NL) to follow the conifer emission behaviour and the seasonal variation in terpene release and concentration; to estimate the concentration of carbonyls, as the result of enhanced atmospheric reactivity in remote and semiremote areas and to check the suitability of sampling and analytical techniques under field conditions.

Laboratory studies of nighttime tropospheric chemistry include: kinetics and mechanisms of the transformation of isoprene, dimethylsulphide and the interconversion of nitroagenonide species.

Mechanisms of tropospheric degradation of freon substitutes have been studied.

Analysis of photochemical oxidants in the prealpine regions has included pattern and trend of tropospheric ozone; evaluation of historical data of surface ozone records, the Moncalieri series (1876-1893).

An experimental facility for aerosol research (gas-to-particle conversion: from gaseous sulphur compounds to cloud condensation nuclei; interaction gas-aerosols) has been constructed.

An atmospheric tracer technique has been developed (perfluorocarbons) for studying mesoscale transport. A denoxing process of waste gases by absorption of nitrous oxide (No) in an aqueous solution of a complexing agent, combined with production of hydroxylamine from the NO rich gas after desorption with hydrogen has been developed, involving the construction and operation of a laboratory scale continuous plant. A theoretical study has been made of the mechanism of catalyst poisoning by trace sulphur dioxide in the direct catalytic reduction of NO with hydrogen.

Research into global change encompasses five activities;
tropospheric chemistry;
environmental monitoring;
atmospheric sulphur and climate;
atmospheric/biosphere interaction;
pollution abatement.

With respect to tropospheric chemistry laboratory studies of kinetics and mechanisms of atmospheric chemical reactions have addressed the degradation processes of biogenic species having potential consequences on the oxidizing capacity of the troposphere and on the planetary radiation transfer. In this context, the reactions of the nitrate radical at night were the main focus.

The activities for environmental monitoring of atmospheric pollutants involved the extension of the reevaluation of historical data of tropospheric ozone levels.
During the 1991-1992 European Arctic Stratospheric Ozone Experiment (EASOE), the Environment Institute acted as a network station of the ground based observing system, set up to provide, on a daily basis, maps of the total ozone fields over Europe and the Arctic.

Atmospheric sulphur and climate studies concerned the formation of aerosols from the gaseous precursors dimethyl sulphide (DMS) and sulphur dioxide and their role in cloud formation. 2 new modules of the model were developed the DMS kinetics and for aerosol to cloud transition respectively.
2 scenarios for the production of cloud condensation nuclei (CCN) from DMS have been compared.

Work on atmospheric biosphere interactions involved the study of biogenic emissions from Mediterranean ecosystems and their potential role in tropospheric chemistry. To this aim, a project on Biogenic Emissions in the Mediterranean Area, the BEMA project, has been developed in collaboration with European laboratories.
The core of BEMA is a series of intensive field campaigns conducted at representative sites in Italy, France and Spain.

Within the framework of the pollution abatement activity focused on the removal of nitrogen oxides from waste gases. Gas absorption experiments in a 4 cm diameter laboratory column have been continued to study the absorption of nitrogen oxide in a iron (II) nitrilotriacetic acid complex. A suitable reaction model was developed.
Progress to end 1991
- Evaluation of seasonal and diurnal variation of monoterpene content in conifer needles. Monoterpene total amount in the needles decreased from July to October by 42%, whereas the relative distribution of the individual compounds e.g. alpha, beta-pinene, camphene, limonene, borneol, camphor remained constant.
- Field measuring campaigns in the Bavarian forest and Veluwe (NL) (coll. to EUREKA/EUROTRAC sub-project BIATEX) to follow the conifer emission behaviour and the seasonal variation in terpene release and concentration; to estimate the concentration of carbonyls, as the result of enhanced atmospheric reactivity in remote and semi-remote areas and to check the suitability of our sampling and analytical techniques under field conditions.
- Laboratory studies of nighttime tropospheric chemistry: kinetics and mechanisms of the transformation of isoprene, dimethylsulphide and the interconversion of NOy species (coll. to EUREKA/EUROTRAC sub-project LACTOZ; collaboration with Danish Centre for Atmospheric Research).
- Mechanisms of tropospheric degradation of freon substitutes.
- Analysis of photochemical oxidants in the prealpine regions: pattern and trend of tropospheric ozone. Evaluation of historical data of surface ozone records, the Moncalieri series (1876-1893).
- Construction of an experimental facility for aerosol research (gas-to-particle conversion: from gaseous sulphur compounds to cloud condensation nuclei; interaction gas-aerosols).
- Development of an atmospheric tracer technique (perfluorocarbons) for studying mesoscale transport; application to several international campaigns in the EUREKA/EUROTRAC framework (TRACT-TRANSALP).
- Development of a denoxing process of waste gases by absorption of NO in an aqueous solution of a complexing agent, combined with production of hydroxylamine from the NO-rich gas after desorption with hydrogen; construction and operation of a laboratory scale continuous plant. Theoretical study of the mechanism of catalyst poisoning by trace SO2 in the direct catalytic reduction of NO with hydrogen.

Detailed description of work foreseen in 1992
- Biogenic emissions from vegetation in the Mediterranean area: qualitative inventory; role of the emissions in the chemical and photochemical transformation of atmospheric pollutants and on the deposition processes. Laboratory studies of chemical kinetics and mechanisms with special attention to the influence on the tropospheric NOx budget, experiments under simulated atmospheric conditions (environmental chambers), in-field measuring campaigns.
- Laboratory studies to evaluate the photooxidant creation potential in relation to biogenic and anthropogenic VOCs.
- Experimental investigations of parameters governing the atmospheric sculphur cycle (gas-to-particle conversion and the formation of cloud condensation nuclei). The studies will emphasize the use of fossil fuel for energy production and the particular European situation.
- Dimenthylsulphide in the marine environment and its influence on cloud formation processes: tropospheric chemistry and development of a comprehensive model for gas-to-particle conversion.
- Development of suitable European scale models to describe the impact of atmospheric sulphur on the radiative properties of the atmosphere.
- Mechanisms of chemical degradation of freon substitute (HCFCs, HFCs) in the troposphere: formation of stable intermediates, evaluation of infrared radiation trapping properties.
- Follow-up of the work on the new denoxing process leading to NO-rich gas. Analysis of the effect of trace SO2 in the waste gas. Scale-up of the process to the existing bench scale plant (10 Nm3/h of flue gas).
- Improvement of the atmospheric tracer technique to extend its range of application to one thousand kilometers (validation of long range transport models).
- Assessment of climatology and photochemistry in the prealpine areas as a case study of atmospheric pollution in the Mediterranean countries.

Short description of evolution of work in 1993
Work will mostly continue along the above mentioned lines with special emphasis on:
1) in-field measuring exercices and model validation
2) development of comprehensive models on the evolution of biogenic and anthropogenic emissions and aerosols to be utilized in global climatic change models.
3) preparation of process design studies and direct application of developed processes for denoxing.

Topic(s)

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Call for proposal

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Funding Scheme

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Coordinator

Joint Research Centre (JRC)
EU contribution
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Address
Edificio 29
21020 Ispra
Italy

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Total cost
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