Tropospheric processes and air quality

European Commission Directorate-General For Research And Innovation

Description

Overview of research and results within the fifth environmental R& D programme (1989-92)(STEP: Science and technology for environmental protection)
Environment policy and protection of the environment
Environmental research

Sujets

• Air pollution
• Environmental Research
• Research program

Informations

• Publié par: EUROPEAN-COMMISSION-DIRECTORATE-GENERAL-FOR-RESEARCH-AND-INNOVATION
• Nombre de lectures: 12
• Langue: English
• Poids de l'ouvrage: 10 Mo

Extrait

European Commission***
*'*
Directorate-General for Science,
**
Research and Development**
*** Environment research programme
T?opospheric processes
qualityand air
Overview of research and results
within the fifttr environmental (1989-92)R&D programme
(STEP: Science and technology for environmental protection)
G. Le Bras G. Angeletti
- CNRS LCSR EC, DG XII/D.I
Orldans Brussels (B)G)
1995JULY Publlshed by the
EUROPEAN COlrtiflSSlON
Dl rectorate-General Xl I
SclenGe, Research and Development
B-10/tg Brussels
LEGAL NOTICE
Neither the European person acting on behalf ofCommission nor any
the Commission is responsible for which might be made of thethe use
following information
publicationCataloguing data can be found at the end of this
Luxembourg: Office for European Communities, 1995Official Publications of the
fsBN 92-827-ß53-7
@ ECSC-EC-EAEC, Brussels. Luxembourg, 1995
Prtnbd in BelgiumTOREWORI)
The 5th Environmental Research (STEP: and Development Programme Science
and Technology periodfor Protection), was implernented during the
1989-1992 and processescovered a number of different areas including üopospheric
quallty.and air
Within there research projects around 70areas, thirteen were fimded involving
groups research from 13 European The projects with analysis, sources,countries. dealt
Eanspor! fiansformation and deposition of species arising from antluopogenic and
natural emissions. The priority new research topics were those defined under the terms
*Physico-Chemical of reference of the Concerted Action, Behaviour ofCOST 6ll,
Atnrospheric Pollutants." HALIPPFour of these projects were also part of LACTOZ,
or BIATEX (EUREKA) projec't (LACTOZ:subprojects of the EUROTRAC
Laboratory studies of chemistry related to tropospheric ozone, HALIPP:
Heterogeneous phase processes, and liquid BIATEX: Biosphere-aünosphere exchange
'pollutants). of
general The objectives of the programme were to improve our knowledge of
regional air pollution iszues, (acid mainly related to afnospheric acidity deposition)
photochemical and oxidant formation. results of theIt was intended that the
progranrme would provide a scientific and technical basis for implementation of the
Community's policy promote environmental and long-term research to support a
preventive approach to environmental protection
The present report of each project,outlines the context, aims and achievements
preceded and is a major pogramme. Thesummary of the achievements of the fu
report programme. also contains a number of selected refereed publications from the A
list of EC publications prograrnme is given. Thecontaining contributions from the also
publications EC cited Proceedingsare the EC Air Pollution Research Reports and the
of the Sixth European Synposium of Physico-Chemical Behaviour of Atmospheric
Pollutants held in (It) Varese in 1993.
The report prepared has been by Georges Le Bras (CNRS-Orlöans) and
Giovanni Angeletti (EC/DGXII). The in typing thiscontribution of Laötitia OlgarJ
report is acknowledged.
illq,pNTENT$
. SUMMARY
. PARTICIPATING LABORATORIES AND PRINCIPAL 5
INVESTIGATORS OF THE PROJECTS
I REPORTS ON THE PROJECTS
Title Project no
- Afinospheric degradation of volatile STEP-0008 ll
organic compounds : peroxy radical
reactions (ADVOPOX)
- Reactions of OH radicals with aromatics STEP-0007 19
and formation fate and of the adducts
and other intermediates in presencethe
ofNOx ffid 02
- Kinetics and mechanisms for the reactions STEP-0004 25
of halogenated organic compounds in the
troposphere
- Laboratory studies of the aqueous chemisüy STEP-0005 31
of free radicals, transition metals
and formation of acidlty in clouds
- Measurements of biogenic non methane STEP-0060 39
hydrocarbon emissions from vegetation
representative of european ecoqystems
- The fate of N-compounds STEP-0003 45
around the North Sea
- Transformation and removal STEP- a047 5l
of N-compounds in the atmosphere
- The chemistry of oxides of nitrogen STEP-005 1 57
in orographic clouds
V- 63Regional of airpollution in STEP-0006 rycles
the west-central mediterranean area
(RECAPMA).
- 7IPolar atuospheric chemistry STEP-0077
- 77EUROCORE follow-up STEP-OO&I
- 83Peroxyapetylnitrate intercalibration STEP-0222
- STEP-0014 87Ionization and dissociation shrdies
of molecules in liquids and high
density media
. 89LIST EC PT]BLICATIONS CONTNI\IINGOF
FROM TIIE PROGRAMMECONTRIBUTIONS
. 9lLIST OF SELECTED PUBLICATIONS
OF TIIE PROGRAMME
VISUMMARY
Th9 general objective of the programme STEP was to elucidate the important
physico-chernical processes in the troposphere. The operative goals were :
' to contibute to the definition of strategies for the reduction of ernissions to the
atuosphere;
provide to data necessary for the assessment pollution of effects on health and
ecosystems.
The major atmospheric issues addressed within programme the were related to
acid deposition and photooxidant formation. The issue of süatospheric ozone depletion
was also indirectly addressed through a study of the tropospheric oxidation of
halogenated organic compounds. Tropospheric degradation controls the input of these
ozone depleting compounds to the stratosphere
A significant part progamme of the has been devoted to studies of the
gFqsprteric chemisty of nitogen-containing compounds, especially of No*, (No,
NO2). Nitogen oxides precursors are of both photooxidant pollutants acid and and are
important in the nutient balance of ecosystems and consequently in euthrophication.
The programme has unployed complenrentary methodologies within the areas
of laboratory field and modelling activities in order to shrdy the sources, tansport,
chemioal and physical nansformations, ffid deposition of the species involved in acid
deposition photooxidant and formation. Analytical techniques for use in the field have
also been particularly developed" with respect to analysis volatile of organic
(VOCs) compounds and nifiogen-containing compounds.
Laboratory studies have involved investigations on gas and muttiphase chemical
p-rocesses, and physical process€s, on mainly involving deposition of species at
different surfaoes. Field experiments have been caried at a large out variety of
oharacteristic marine, urbaq and nral European sites. Measurements have also been
polar undertaken in regions. Modelling studies have been performed both in support of
field measurements and to test the data from laboratory based investigations, (e.g.
kinetic and mechanistic data on chemical processes or deposition velocity data).
The research carried out within programme the STEP has provided a large
ntmber of significmt new data on tropospheric processes which are summarisöd
below.with the chemicalTwo laboratory-based projects have been concerned
processes of VOCs and the consequentinvolved in the atuospheric oxidation
on peroxyphotooxidants. These two projects have focused formation of ozone and
radical reactions of aromatic compounds.and the oxidation
VOCs and un{erintermediates in the oxidation of Perory radicals are key
peroxy radicals. Thereact with NOx, HO2 or other ahospheric conditions can
reaction rates ofrelative abundances and importance of these reactions depends on the
the formation ofROz Reaction of RO2 with NO leads to these species with radicals.
R'Oz effectively inhibit OrNOz and hence ozone, while reactions with NOz,HO2 or
products andthe oxidation formation. Thus, the reactions of ROz radicals determine
previous project, datathe in As a continuation of a CEC ozone budget the fioposphere.
Theperoxy radicals. have been obtained in the STEP project for reactions of complex
perory radicalaspects of results conüibute to a better understanding of different
integration of themechanisms. The chemistry, both in terms of reactivity and reaction
givesmodels kinetic mechanistic for ROz radicals into atmospheric available and data
spatialin the toposphere over different an improved description of the ozone budget
scales.
of for the oxidation aromaticThe initial steps of the OH-initiated mechanisns
projectThis (e.g. rylenes) have been established. compounds benzene, toluene,
short-initiation process are very showed that the pero{y radicals formed following the
for andNOz as is the case alkane lived and are therefore unable to oxidise NO to
project, together with morein the STEP alkene atnospheric oxidation. Data obtained
give a reasonable,results steps of the oxidation mechanism, recent on the firther
of aromaticoxidation although still incomplete, description of the aünospheric
play pollution.compounds which an important role in urban
of bothfor halogenated compotmds The aünospheric oxidation mechanisms
emphasis in thenatural origln have been investigated. Particular anthropogenic and
fordegradation mechanisms project was directed towards providing detailed
HCFCs, used as.substituteshydrofluorocar,bons, HFCs, and hydrochlorofluorocarbons,
oxidise to formindicate that these species for chlorofluorocarbons, CFCs. The data
to the süatosphere.carbonyl compounds which are too short lived to be transported
not'