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| Titel |
Introduction to the European Monitoring and Evaluation Programme (EMEP) and observed atmospheric composition change during 1972-2009 |
| VerfasserIn |
K. Tørseth, W. Aas, K. Breivik, A. M. Fjǽraa, M. Fiebig, A. G. Hjellbrekke, C. Lund Myhre, S. Solberg, K. E. Yttri |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 12, no. 12 ; Nr. 12, no. 12 (2012-06-22), S.5447-5481 |
| Datensatznummer |
250011279
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| Publikation (Nr.) |
 copernicus.org/acp-12-5447-2012.pdf |
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| Zusammenfassung |
| European scale harmonized monitoring of atmospheric composition was initiated
in the early 1970s, and the activity has generated a comprehensive dataset
(available at http://www.emep.int) which allows the evaluation of regional
and spatial trends of air pollution during a period of nearly 40 yr.
Results from the monitoring made within EMEP, the European Monitoring and
Evaluation Programme, show large reductions in ambient concentrations and
deposition of sulphur species during the last decades. Reductions are in the
order of 70–90% since the year 1980, and correspond well with reported
emission changes. Also reduction in emissions of nitrogen oxides (NOx)
are reflected in the measurements, with an average decrease of nitrogen
dioxide and nitrate in precipitation by about 23% and 25% respectively
since 1990. Only minor reductions are however seen since the late 1990s. The
concentrations of total nitrate in air have decreased on average only by
8% since 1990, and fewer sites show a significant trend. A majority of the
EMEP sites show a decreasing trend in reduced nitrogen both in air and
precipitation on the order of 25% since 1990. Deposition of base cations
has decreased during the past 30 yr, and the pH in precipitation has
increased across Europe. Large inter annual variations in the particulate
matter mass concentrations reflect meteorological variability, but still
there is a relatively clear overall decrease at several sites during the last
decade. With few observations going back to the 1990s, the observed chemical
composition is applied to document a change in particulate matter (PM) mass
even since 1980. These data indicate an overall reduction of about 5 μg m−3
from sulphate alone. Despite the significant reductions in sulphur
emissions, sulphate still remains one of the single most important compounds
contributing to regional scale aerosol mass concentration. Long-term ozone
trends at EMEP sites show a mixed pattern. The year-to-year variability in
ozone due to varying meteorological conditions is substantial, making it hard
to separate the trends caused by emission change from other effects. For the
Nordic countries the data indicate a reduced occurrence of very low
concentrations. The most pronounced change in the frequency distribution is
seen at sites in the UK and the Netherlands, showing a reduction in the
higher values. Smaller changes are seen in Germany, while in Switzerland and
Austria, no change is seen in the frequency distribution of ozone. The lack
of long-term data series is a major obstacle for studying trends in volatile
organic compounds (VOC). The scatter in the data is large, and significant
changes are only found for certain components and stations. Concentrations of
the heavy metals lead and cadmium have decreased in both air and
precipitation during the last 20 yr, with reductions in the order of 80–90%
for Pb and 64–84% for Cd (precipitation and air respectively). The
measurements of total gaseous mercury indicate a dramatic decrease in
concentrations during 1980 to about 1993. Trends in hexachlorocyclohexanes
(HCHs) show a significant decrease in annual average air concentrations. For
other persistent organic pollutants (POPs) the patterns is mixed, and differs
between sites and between measurements in air versus precipitation. |
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