1. European air pollution trends 1980-2010 Leonor Tarrasón EMEP/MSC-W Workshop on Review and Assessment of European Air Pollution Policies 25-27 October 2004, Gothenburg, Sweden

2. EMEP Assessment Part I : European Perspective EMEP Assessment Part II: National Assessment 20 national contributions, CCC, MSC-E, MSC-W, IVL Gun Löblad

3. Main questions addressed by the EMEP Assessment Report Meteorologisk Institutt met.no What is the result of emission reductions for air quality ? What are the reasons behind the trends and are the trends in line with current understanding? What is the present status of environmental air quality and what is the need for further actions?

4. SULPHUR TRENDS Meteorologisk Institutt met.no

5. Sulphur emissions 1980-2000 CountriesSO 2 CE = Czech Rep., Hungary, Poland and Slovak Rep. -73% CW = Austria, Switzerland and Germany -89% E = Estonia, Latvia, Lithuania and Russia (European part)* -73% N = Denmark Finland Iceland, Norway and Sweden -87% NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom -76% S = France, Greece, Italy, Portugal and Spain -62% SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia -40% TOTAL EUROPE (excluding ships ) -67% The decrease is not achieved in one single sector, and is generally larger after 1990

6. Daily means measured at SE02 1978-2000 Episodes with high SO 2 have decreased both in frequency and magnitude

7. Episodes occurred during winter. The decrease in SO 2 concentrations has been larger in winter than in summer, most likely due to a larger emission decrease in the cold season. However, weather may also have contributed to the change. GB04 DK03 The seasonal variation of SO 2 has changed

8. Sulphate in air has also decreased, … but not as much as the sulphur emissions and SO 2 in air FR05 IT04 How to explain this? FI04

9. Meteorologisk Institutt met.no EMEP/MSC-W Meteorologisk Institutt met.no EMEP/MSC-W Sulphate formation is determined by availability of oxidants (OH,H 2 O 2,O 3 ) No oxidant limitation With oxidant limitation:

10. Ammonia plays also a role in explaining sulphur trends SO 2 /(SO 4 air+SO 4 prec) Meteorologisk Institutt met.no Increases the pH inside clouds (added effect to SO2 concentration decrease) which affects the oxidation rate from SO2 to SO4.

11. Decreasing sulphur emissions have also resulted in decreased sulphate in precipitation PL02 AT02 The decrease in sulphate in precipitation is similar to that of particulate sulphate in air LV10

12. The reduced sulphate in precipitation has further resulted in: Generally, increasing pH in precipitation Decreased deposition Decreased dry and wet deposition to forests as measured in a Swedish throughfall monitoring network CZ01

13. SULPHUR Meteorologisk Institutt met.no Overall decrease of emissions by nearly 70%, largest in Central European countries. Sulphur dioxide concentrations have decreased accordingly. In addition, the frequency and magnitude of episodes has decreased and the seasonal variations have changed. Sulphate concentrations in air and precipitation have not decreased at the same rate as the emissions. This is because SO4 is a secondary pollutant controlled by chemical precursor & oxidant availability, pH dependences (…NH3!)

14. NITROGEN TRENDS Meteorologisk Institutt met.no

15. Nitrogen emissions 1980-2000 CountriesNOxNH3 CE = Czech Rep., Hungary, Poland and Slovak Rep. -42%-46% CW = Austria, Switzerland and Germany -49%-23% E = Estonia, Latvia, Lithuania and Russia (European part)* +21%-48% N = Denmark Finland Iceland, Norway and Sweden -21%-10% NW = Belgium, Luxemburg, the Netherlands, Ireland and United Kingdom -36%-13% S = France, Greece, Italy, Portugal and Spain -4%+1% SE = Albania, Armenia, Belarus, Bosnia-Herzegovina, Bulgaria, Croatia, Cyprus, Georgia, Kazakhstan, Republic of Moldova, Romania, Slovenia, The FYROM Macedonia, Turkey, Ukraine and Yugoslavia -26%-12% TOTAL EUROPE (excluding ships ) -24%-20% Regional differences in N emission changes are more pronounced than for sulphur emissions.

16. The decrease is lower than for sulphur, but is of the same magnitude for oxidised (NOx) and reduced (NH 3 ) nitrogen Comparison of ammonia and Nox emissions Million tons/year

17. Sector allocation of emissions NOx emissions 1000 tons NO 2 /year NH 3 emissions 1000 tons/year NOx reductions mainly due to changes in combustion sectors (40%) and transport (25%) Decreased NH 3 is due to activity changes and control measures in agricultural sector

18. As for sulphur, the most oxidised nitrogen oxide compound show a slightly lower decrease due to the decreased sulphur emissions leaving more of the oxidants in the atmosphere Total nitrates and ammonium at DK03 and GB02 Trends are similar for total nitrate and total ammonium at most of the sites available, even if the local emissions reductions are different Total nitrates and ammonium in precipitation at CH02 and FI04

19. Example: trends in Nordic countries Meteorologisk Institutt met.no Increases in total N deposition may be due to influence not only from local but also from more distant contributions. In addition, the changes may be due to changes in the rates of chemical interactions between pollutants p.e.NH 4 +NH 3 /SO 4, due to a changing atmospheric composition

20. NITROGEN - I Meteorologisk Institutt met.no Overall decrease of emissions by 20-30%, similar for NOx and NH 3 emissions. As for sulphur, the most oxidized nitrogen compound (NO 3 ) shows a less pronounced trend. This is probably due to the fact that reduced sulphur emissions leave a potential for further oxidation in the atmosphere. Trends of ammonium in air and precipitation are more similar to trends nitrate in air and precipitation, that what national emission trends would suggest. The explanation is not straigthforward. Less monitoring sites with long-term data, need for further studies to analyse the nitrogen trends also in relation to the ratios between NH3+NH4/SO4

21. NITROGEN -II Meteorologisk Institutt met.no Some interesting differences: Over land areas, reduced nitrogen depositions and air concentrations generally dominate over oxidized nitrogen (since 1995) Over sea areas, oxidized nitrogen is the dominant form of nitrogen …. This brings the attention to ship traffic emissions

22. Comparison of oxidized and reduced nitrogen trends 1980-2010 Meteorologisk Institutt met.no EMEP Land areas Sea areas

23. Influence of ship emissions in 2010 to PM2.5 air concentrations (CLE-15%) Meteorologisk Institutt met.no μg/m3 reduction % reduction

24. Influence of ship emissions in 2010 to SOMO35 (CLE – 15%) Meteorologisk Institutt met.no ppb days reduction% reduction

25. Concentrations in air (S,N) Meteorologisk Institutt met.no

26. The contribution to PM 10 mass from SO 4 and NO 3 dominates over NH 4 contribution Meteorologisk Institutt met.no

27. In addition to SIA, there is a primary and organic component Meteorologisk Institutt met.no

28. OZONE TRENDS Meteorologisk Institutt met.no

29. Maps produced by M Coyle Example from UK Mean AOT40 calculated for for the five years 1994-1998. CropsForests CL=3000 ppbhCL=10000 ppbh Surface ozone Threshold conc of O 3 are exceeded over large parts of Europe

30. Peak ozone vs. exceedance to critical levels Meteorologisk Institutt met.no A reduction in peak ozone values during the 1990s is reported from several regions in Europe, while there is no clear trend in the exceedances of the critical level (expressed as AOT40). AOT40 values for forests in Austria (April – September, daylight hours)

31. Trend evaluation for O 3 Long-term trends for O 3 are difficult to assess: - O 3 is formed in the air via photochemical reactions between NOx and VOCs, closely linked to the weather situation and its variations between years. - The hemispheric background of O 3 - determined by emissions and processes outside Europe - is a considerable source. Model calculation by R Derwent

32. Stations in the north and west show increasing hemispheric background concentrations, which partly counterbalance the reduced peak values. The risk for high ozone conc remains. Climate effects may increase the conditions for “ozone summers” Data from Mace Head

33. Health exposure to ozone: SOMO35 Meteorologisk Institutt met.no 2000 SOMO35 is high and will continue to be high … 2010

34. Ozone Meteorologisk Institutt met.no The reduction in peak ozone values is in line with model predictions based on the decreased precursor emissions in Europe and is a very likely result of emission abatement. Intermediate ozone more difficult to reduce. Stations in the North and West report increasing hemispheric background concentrations of 0.3-0.5 ppbv year -1. The declining trend of the peak values is to some extent counterbalanced by the gradual rise in background ozone and may also be counteracted by climatic change giving higher risks of hot and ozone-rich summers. Further policies to reduce the emission of all ozone precursors including the cross-continental, hemispherical perspective will be necessary to reduce the harmful effects from ozone on the environment, crops and human health.

35. Conclusions I Meteorologisk Institutt met.no Considerable reductions of air emissions since 1980 have resulted in improved air quality in Europe Despite this considerable reduction, pollution levels are still high and exceedances of critical loads and levels still represent a significant risk for ecosystems and health.

36. Conclusions II: Meteorologisk Institutt met.no Improved understanding of the inter-relations between atmospheric air pollutants – PM,O 3 policies need to consider links to other greenhouse gases and climate policies In particular, more focus should be given to NH3 control smallest level of reduction so far, reduced nitrogen generally dominates over land areas controls the formation and deposition of SIA Sources outside Europe are becoming increasingly important (international ship traffic, aircraft emissions, intercontinental sources ) – Link to hemispheric scale and global change