Tålegrænser for lufforurening - DCE - Nationalt Center for Miljø og ...

Tålegrænser for lufforurening - DCE - Nationalt Center for Miljø og ... Tålegrænser for lufforurening - DCE - Nationalt Center for Miljø og ...

27.07.2013 Views

10 Tålegrænse-konceptet har således en central placering i integrerede modeller, i RAINS men også i IMIS. Tålegrænser er et værktøj, som har kunnet leve op til udfordringen om at kunne anvendes i opgørelsen af effekter af forskellige politiske tiltag til reduktion af luftforurening. En af tålegrænsekonceptets styrker er, at det er et mål, der har en biologisk mening, dvs. at den kan relateres til økosystemets reaktion. Overskridelser af tålegrænser kan beregnes ud fra regionale luftforurenings modeller. Kombineres disse med samfundsøkonomiske modeller kan effekter af forskellige tiltag og styringsmidler overfor luftforureningen vurderes. Den regionale fordeling af tålegrænsen kan endvidere visualiseres ved hjælp af kort. Tålegrænsen udtrykker en syntese af kompleksiteten og usikkerhederne af den videnskabelige viden repræsenteret ved et tal. I det omfang man vælger de mest følsomme receptorer som grundlag for tålegrænsefastsættelser, er det i overensstemmelse med forsigtighedsprincippet. Det er af meget stor betydning, at man har sammenhængende operative systemer, der kan belyse de national- og sektorøkonomiske konsekvenser af konsekvenserne af de miljøpolitiske tiltag på de relevante receptorer eller økosystemer.

Critical loads/levels emerging as concept Executive summary This report describes and discusses the fundamental criteria behind and major steps towards the development of an Integrated Environmental Assessment System for air pollution in Denmark. The report is a state of the science of a broad interdisciplinary research area involving aspects of economics, atmospheric processes as, chemical processes, transport, deposition, soil chemistry, critical loads/levels setting and mapping. In continuation of this a number of political abatement measures are to be analysed. The concepts of critical loads and critical levels are thoroughly revised, exemplified and discussed for acidifying and eutrophying substances and for tropospheric ozone in relation to national and international strategic environmental planning. This report is the first Danish attempt to bring together all these approaches in one publication and the intention is to bridge the traditional gap between formerly separate disciplines. Most of the presented information has been presented elsewhere, but the process of combination is novel in Denmark and is reflected in the report. Interdisciplinary approaches are the basis for strategic environmental planning and research. Historically the critical load/level concept has been developed in Europe and North America since the late 1960’ies. Transboundary effects of air pollutants were slowly accepted and the work was formally agreed upon by United Nations Economic Commission for Europe in 1979 by the establishment of the Geneva Convention on Long Range Transboundary Air Pollution. The work under this convention has succeeded in establishing several international agreements for reduction of sulphur and nitrogen compounds. The emissions of sulphur is about half of the level in 1980, whereas the emission of nitrogen oxides and ammonia have not been reduced significantly until now. Ozone levels have increased during the same period. ozone thresholds are exceeded regularly every year in Europe and in Denmark. At present a new multi-pollutant protocol is being prepared including both acidifying and eutrophying pollutants as well as ozone precursors. The EU is at present strengthening the work of the Geneva convention by preparing an acidification strategy for EU-15 resulting in binding emission ceilings for the involved countries. Critical loads and levels are doses of air pollution above which significant effects on vegetation and ecosystems as well as effects on human health are expected. Direct damages are caused by elevated concentrations in air pollutants, especially ozone, damaging the plant tissue and thereby changing the competitive relations between species in the ecosystem. Often significant damages are observed on agricultural crops and trees. Ozone causes damages on the respiratory system of humans. Indirect damages are caused by exceeding critical loads of depositions of acidifying and eutrophying pollutants which affect the chemical composition of the soils and thereby the ecological 11

10<br />

Tålegrænse-konceptet har således en central placering i integrerede<br />

modeller, i RAINS men <strong>og</strong>så i IMIS. <strong>Tålegrænser</strong> er et værktøj, som<br />

har kunnet leve op til ud<strong>for</strong>dringen om at kunne anvendes i opgørelsen<br />

af effekter af <strong>for</strong>skellige politiske tiltag til reduktion af luft<strong>for</strong>urening.<br />

En af tålegrænsekonceptets styrker er, at det er et mål, der har<br />

en biol<strong>og</strong>isk mening, dvs. at den kan relateres til økosystemets reaktion.<br />

Overskridelser af tålegrænser kan beregnes ud fra regionale<br />

luft<strong>for</strong>urenings modeller. Kombineres disse med samfundsøkonomiske<br />

modeller kan effekter af <strong>for</strong>skellige tiltag <strong>og</strong> styringsmidler over<strong>for</strong><br />

luft<strong>for</strong>ureningen vurderes. Den regionale <strong>for</strong>deling af tålegrænsen<br />

kan endvidere visualiseres ved hjælp af kort.<br />

Tålegrænsen udtrykker en syntese af kompleksiteten <strong>og</strong> usikkerhederne<br />

af den videnskabelige viden repræsenteret ved et tal. I det omfang<br />

man vælger de mest følsomme receptorer som grundlag <strong>for</strong> tålegrænsefastsættelser,<br />

er det i overensstemmelse med <strong>for</strong>sigtighedsprincippet.<br />

Det er af meget stor betydning, at man har sammenhængende<br />

operative systemer, der kan belyse de national- <strong>og</strong> sektorøkonomiske<br />

konsekvenser af konsekvenserne af de miljøpolitiske tiltag<br />

på de relevante receptorer eller økosystemer.

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