Objetivo THE OBJECTIVE OF THIS RESEARCH IS TO PROVIDE A BETTER DESCRIPTION OF THE CHEMICAL PROCESSES INVOLVED IN PRODUCTION AND LOSS OF OZONE IN THE TROPOSPHERE. THIS WILL BE ACHIEVED THROUGH THE PROVISION OF KINETICS AND MECHANISTIC DATA FOR SEVERAL REACTIONS OF ORGANIC PEROXY RADICALS INVOLVED IN TROPOSPHERIC CHEMISTRY AND ASSESSMENT OF THE RESULTS USING NUMERICAL SIMULATION MODELS OF ATMOSPHERIC CHEMISTRY. Spectroscopic, kinetic and mechanistic data have been obtained on simple organic peroxy radicals and HO2 through extensive laboratory experiments over a range of pressures and temperatures relevant to the troposphere (ie from ground level to the tropopause). Measurement of reaction rate constants and absorption cross sections were measured for atmospheric peroxy radicals derived from simple alkanes, aldehydes and alkenes, considered representative of major reactive organics in the tropospheres.Experimental methods for kinetic measurements were based on the analysis of the peroxy radicals by ultraviolet (UV) absorption spectroscopy. Particular attention has been drawn to the measurement of absorption cross sections of the most fundamental peroxy radicals. In general the peroxy radicals. In general the peroxy radicals exhibit a broad absorption between 200 and 300 nm, with a maximum near 240 nm. These are some exceptions such as the acylperoxy radicals which display 2 maximal.The kinetics and branching ratios for various reactions between different peroxy radicals, need to be known, since these reactions are chain carrying and/or chain terminating processes which may strongly influence the ozone budget in the troposphere. A large body of kinetics information has been obtained for a series of peroxy radicals which allows some reactivity relationships on the structure of peroxy radicals to be derived.These kinetic data have contributed to a better definition of the lifetime of peroxyacetylnitrate (PAN) in the atmosphere. This lifetime is strongly dependent on temperature (h at ground levels to y in the upper troposphere), PAN being the main nitrogen oxide reservoir species. Precise knowledge of this lifetime is essential to calculate the time and space distribution of nitrogen oxide in the troposphere which influences the ozone distribution.Some new information has been provided on the oxidation mechanism of compounds produced in the subsequent oxidation o f peroxy radicals. This involves;photooxidation of formaldehyde;photooxidation of acetone;formation of acetic acid.ATTENTION WILL BE DIRECTED TO : - SIMPLE ORGANIC PEROXY RADICALS DERIVED FROM VOLATILE ORGANIC COMPOUNDS OF BOTH NATURAL AND MAN-MADE ORIGIN WHICH ARE BELIEVED TO INFLUENCE OZONE IN THE TROPOSPHERE. - THE CHEMICAL REACTIONS INVOLVING THESE RADICALS AT TYPICAL BOUNDARY LAYER NOX CONCENTRATIONS AND IN THE "LOW NOX" REGIME WHERE PEROXY RADICALS MAY REMOVE OZONE. - PROVISION OF RATE DATA FOR A RANGE OF PRESSURES AND TEMPERATURES APPROPRIATE FOR THE ATMOSPHERE FROM GROUND LEVEL TO THE TROPOPAUSE AND MECHANISTIC DATA NECESSARY FOR FORMULATION OF THE ATMOSPHERIC CHEMISTRY. - THE WORK INVOLVES COMPLEMENTARY STUDIES IN 4 LABORATORIES IN EUROPE WITH THE NECESSARY RESOURCES AND EXPERTISE FOR STUDIES OF KINETICS AND MECHANISMS OF ATMOSPHERIC REACTIONS. - THE HARWELL LABORATORY (ENVIRONMENTAL POLLUTION RESEARCH CENTRE) WILL CONDUCT TIME RESOLVED RADICAL KINETICS STUDIES USING U.V. AND INFRARED DIODE LASER SPECTROSCOPY AS WELL AS PRODUCT STUDIES. THIS WILL BE COMPLEMENTED BY SIMILAR STUDIES AT THE MAX-PLANCK INSTITUT FOR CHEMISTRY AT MAINZ WHICH ALSO HAS A GAS PHASE FTIR SPECTROSCOPY CAPABILITY AS WELL AS THE UNIQUE MATRIX ISOLATION FTIR SET UP. FTIR SPECTROSCOPY COUPLED WITH A LARGE VOLUME ATMOSPHERIC SIMULATION CHAMBER COMPRISES THE UNIQUE CAPABILITY AT THE UNIVERSITY OF WUPPERTAL WHICH HAS DEMONSTRATED THE FEASIBILITY OF THE STUDIES OF NOX REACTIONS WHICH FORM PART OF THE PRESENT PROPOSAL. FINALLY THE FLASH PHOTOLYSIS/UV ABSORPTION SYSTEM AT UNIVERSITY OF BORDEAUX, LABORATORY OF MOLECULAR PHOTOCHEMISTRY PROVIDES THE CAPABILITY FOR FIRST TIME RESOLVED KINETICS STUDIES OF THE RADICAL REACTIONS IN A DIFFERENT TIME AND CONCENTRATION REGIME TO THE HARWELL AND MAINZ STUDIES. Ámbito científico natural scienceschemical sciencesorganic chemistryaldehydesnatural scienceschemical sciencesorganic chemistryorganic acidsnatural scienceschemical scienceselectrochemistryelectrolysisnatural sciencesphysical sciencesopticsspectroscopyabsorption spectroscopynatural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologytroposphere Programa(s) FP1-ENVPROT 4C - Multiannual research and development programmes (EEC) in the field of the environment - Protection of the environment -, 1986-1990 Tema(s) Data not available Convocatoria de propuestas Data not available Régimen de financiación CSC - Cost-sharing contracts Coordinador MAX-PLANCK-GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V. Aportación de la UE Sin datos Dirección Johann Joachim-Becher-Weg 27 55020 MAINZ Alemania Ver en el mapa Coste total Sin datos Participantes (3) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo BERGISCHE UNIVERSITAET GESAMTHOCHSCHULE WUPPERTAL Alemania Aportación de la UE Sin datos Dirección Gauss Strasse 20 42097 WUPPERTAL Ver en el mapa Enlaces Sitio web Opens in new window Coste total Sin datos UNIVERSITE DE BORDEAUX I Francia Aportación de la UE Sin datos Dirección Cours de la Libération 351 33405 TALENCE Ver en el mapa Coste total Sin datos United Kingdom Atomic Energy Authority Reino Unido Aportación de la UE Sin datos Dirección 353,Harwell OX11 0RA Didcot - Oxfordshire Ver en el mapa Coste total Sin datos
