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You are here: Home / Data and maps / Indicators / Exposure of ecosystems to acidification, eutrophication and ozone / Exposure of ecosystems to acidification, eutrophication and ozone (CSI 005) - Assessment published Dec 2013

Exposure of ecosystems to acidification, eutrophication and ozone (CSI 005) - Assessment published Dec 2013

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Generic metadata

Topics:

Air pollution Air pollution (Primary topic)

Tags:
eutrophication | soer2010 | csi | baseline | air pollution | forests | air | ozone | thematic assessments | aot40 | air quality | acidification
DPSIR: State
Typology: Performance indicator (Type B - Does it matter?)
Indicator codes
  • CSI 005
Dynamic
Temporal coverage:
1996-2010, 2020
 
Contents
 

Key policy question: What progress is being made towards the targets for reducing the exposure of ecosystems to acidification, eutrophication and ozone?

Key messages

    Eutrophication
    The magnitude of the risk of ecosystem eutrophication and its geographical coverage has diminished only slightly over the years. The predictions for 2010 and 2020 indicate that the risk is still widespread over Europe. This is in conflict with the EU's long-term objective of not exceeding critical loads of airborne acidifying and eutrophying substances in sensitive ecosystem areas (National Emission Ceilings Directive, 6th Environmental Action Programme, Thematic Strategy on Air Pollution).

    Acidification
    The situation has considerably improved and it is predicted to improve further. The interim environmental objective for 2010 (National Emission Ceilings Directive) will most likely not be met completely. However, the European ecosystem areas where the critical load will be exceeded is predicted to have declined by more than 80 % in 2010 with 1990 as a base year. By 2020, it is expected that the risk of ecosystem acidification will only be an issue at some hot spots, in particular at the border area between the Netherlands and Germany.

    Ozone

    Most vegetation and agricultural crops are exposed to ozone levels exceeding the long term objective given in the EU Air Quality Directive. A significant fraction is also exposed to levels above the 2010 target value defined in the Directive. Compared to 2009, the ozone indicators show a mixed behavior  Averaged over all rural background stations, the concentration relevant for the exposure of crops is slightly higher. However, the agricultural area exposed to concentrations above the target value did not increase in 2009 and 2010 compared to previous years, but the area exposed to levels between 12 000 and 18 000 (µg/m3).hour is larger than in the previous years. With respect to the exposure of forests, the concentrations are similar compared to previous years.

    The effect-related concentrations, addressing exposure of crops to ozone over several summer months, show large year-to-year variations. Over the period 1996-2010 there is a tendency to increased exposure until 2006; and a tendency to decreasing levels after 2006. However, due to the large year-to-year variations, this development has not proven to be statistically significant.

    Exceedance of critical loads for eutrophication due to the deposition of nutrient nitrogen in 2000

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for eutrophication due to the deposition of nutrient nitrogen in 2010

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for eutrophication due to the deposition of nutrient nitrogen in 2020 under current legislation to reduce national emissions

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for eutrophication due to the deposition of nutrient nitrogen in 2020 assuming a maximum feasible reductions scenario

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for acidification by deposition of nitrogen and sulphur compounds in 2000

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for acidification by deposition of nitrogen and sulphur compounds in 2010

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for acidification by deposition of nitrogen and sulphur compounds in 2020 assuming a Maximum Feasible Reductions scenario

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exceedance of critical loads for acidification by deposition of nitrogen and sulphur compounds in 2020 under Current Legislation to reduce national emissions

    Note: The results were computed using the 2008 Critical Loads database hosted by the Coordination Centre for Effects (CCE).

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    Exposure of agricultural area to ozone (exposure expressed as AOT40 in (μg/m³).h) in EEA member countries

    Note: Exposure of agricultural area to ozone (exposure expressed as AOT40 in (μg/m3).hour) in EEA member countries . In the Air Quality Directive (2008/50/EC) the target value for protection of vegetation is set to 18000 (μg/m3).h while the long-term objective is set to 6000 (μg/m3).hour. Until 2006 Iceland, Norway Switzerland and Turkey have not been included in the analyses due to lack of detailed land cover data and/or rural ozone data, in 2007 Switzerland and Turkey are not included; since 2008 only Turkey is not included

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    Rural concentration map of the ozone indicator AOT40 for crops, year 2010

    Note: AOT40 for crops are vegatation exposure related indicators and are based on rural background station observation only.

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    Exposure of forest area to ozone (exposure expressed as AOT40 in (mg/m³).h) in EEA member countries

    Note: Please consider that since 2004 a growing number of member countries has been included. In 2004 Bulgaria, Greece, Iceland, Norway, Romania, Switzerland, and Turkey have not been includedwere added. In For 2005/2006 Iceland, Norway Switzerland and Turkey are were still excluded in the analyses due to lack of detailed land cover data and/or rural ozone data. In 2007 Switzerland and Turkey are were not included. Since 2008 only Turkey is has not beennot included. Calculations of forest exposure are not available for year prior to 2004.

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    Rural concentration map of the ozone indicator AOT40 for forest in 2010

    Note: The gradient of the AOT40f values is similar to those of the AOT40c for crops: relative low in northern Europe, and the highest values observed in the countries around the Mediterranean. The critical level is met in north Scandinavia, Ireland, part of the UK and in the coastal regions of the Netherlands (total forested area with concentrations below the critical level is 22 % of a total area of 1.44 million km2). In south Europe levels may be as high as 4-5 times above the critical level.

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    Key assessment

    Critical loads for nutrient nitrogen
    The EU has a long-term objective of not exceeding critical loads for nutrient nitrogen. Excess inputs of nitrogen to sensitive ecosystems may cause eutrophication and nutrient imbalances. The critical load of nutrient nitrogen is defined as the highest atmospheric deposition of nitrogen compounds below which harmful effects in ecosystem structure and function do not occur, according to present knowledge. In 2000 rather large areas show high exceedances of critical loads for nutrient nitrogen, especially in the western part of Europe, following the coastal regions from north-western France to Denmark. In southern Europe high exceedances are only found in northern Italy.

    The predictions for 2010 and 2020 indicate that the risk of exceedances is high irrespective of whether we assume that the current policies and measures to reduce eutrophying nitrogen emissions will be fully implemented (the current legislation CLE scenario) or that all technically and economically feasible additional policies are applied (the maximum feasible reduction MFR scenario).

    More specifically, the area with exceedances above 1200 eq ha-1a-1 in 2010 hardly changes under the CLE scenario in 2020, while exceedances in this highest range do not occur according to the MFR scenario (see Figure 4). However, in the latter case still broad areas in Europe remain at risk of eutrophication and negative changes in nutrient balances. In these areas exceedances that range from 200 to 1 200 eq ha-1a-1 are predicted (see the border area between the Netherlands and Germany, in particular).

    Critical loads for acidification
    The EU has a long-term objective of not exceeding critical loads for acidity in order to protect Europe's ecosystems from acidification. The critical load of sulphur and nitrogen acidity is defined as the highest deposition of acidifying compounds that will not cause chemical changes leading to long-term harmful effects on ecosystem structure and function.

    In addition to the long-term objective, the EU has a 2010 interim environmental objective to reduce areas where critical loads are exceeded by at least 50 % in each grid cell for which critical loads exceedances are computed, compared with the 1990 situation. The exceedances of critical loads for acidification caused by the deposition of air pollutants in 1990, 2000, 2010 (current legislation scenario; CLE) and 2020 (CLE as well as maximum feasible reduction scenarios, MFR) were calculated. 84 % of the grid cells with critical loads exceedances in 1990 show a decline in exceeded area of more than 50 % by 2010. Though the interim environmental objective has strictly speaking not been met, the improvements are considerable.

    Figures 5-8 show that in 2000 large areas with exceedances (i.e. higher than 1 200 eq ha-1a-1, shaded red) are mostly located in Belgium, Germany, the Netherlands and Poland. For the CLE scenario, the size of the area where critical loads are exceeded is considerably reduced in 2020. The MFR scenario shows that many areas in Europe will no longer be at risk of acidification in 2020 if all technically and economically feasible additional policies are also implemented. Nevertheless, high exceedance peaks between 700 and 1 200 eq ha-1a-1 would still be expected for ecosystems in the Netherlands.

    Ozone

    The EU has an objective for protecting vegetation from high ozone concentrations, accumulated over the growing season (defined as the summer months May to July). The target value for 2010 is 18 000 (µg/m3).hour [1]. The long term objective is 6 000 (µg/m3).h.

    This target is exceeded in a substantial fraction of the agricultural area in EEA-32 member countries (excluding Turkey). In 2010, this is the case in about 21 % of a total area of 2.054 million km2. Exceedances of the target values have notably been observed in southern and eastern Europe, see Figure 10. The long-term objective is met in 15 % of the total agricultural area, mainly in Ireland, Iceland, United Kingdom, Scandinavia and the Baltic States.

    In 2003, the meteorological conditions were very favorable for ozone formation resulting in exceptional high concentrations. Year 2004 was a less exceptional year and substantial lower ozone levels, similar to the levels in 2001/2002, were observed. In 2005 ozone concentrations were higher than in 2004 but the high levels of 2003 were not reached. The average ozone concentrations in 2006 were only slightly higher than in 2005. However, June and July 2006 were characterized by a large number of ozone episodes [2] resulting in much higher AOT40 value compared to 2005. In 2007 levels are lower again, similar to the situation in 2004. In 2008 ozone levels showed a general increase. Compared to 2009, the AOT40 values in 2010 were lower in southern Europe, in particular in the Balkan region.

    The data show that the target value set in the Air Quality Directive for 2010 was not met in the whole EU-27. Furthermore, it is expected that exposure of vegetation to ozone concentrations in the next decade will remain well above the long-term objective despite emission reductions of anthropogenic ozone precursor pollutants through EU legislation (National Emission Ceilings Directive, NECD) and UNECE protocols (under the Convention on Long Range Transboundary Air Pollution, LRTAP).

    The NECD contains two interim objectives (to be met in 2010) concerning vegetation-related ozone exposure. The first of these is a one third reduction objective for 2010 in all grid cells compared to the 1990 situation, while the second addresses the absolute concentration limits to be attained by 2010. Based on model calculation this objective has been met in the European Union except in parts of Spain and Portugal. The second objective – no exceedance of a critical level of 20 (mg/m3).h  during the summer season –  is clearly not achieved in most of Europe. An evaluation of the two objectives on the basis of measurements is hardly possible, due to the lack o f monitoring stations in the early nineties. However, the limited number of available time series suggests a less optimistic situation than the assessment based on model calculations (EEA, 2012).

    In addition to the EU target value, a critical level for the protection of forest has been defined under the LRTAP Convention. This critical level relates to the accumulated sum during the summer (April-September) and is set to 10 000 (μg/m3).h. Figure 12 shows the 2010 results for the AOT40 for forests (AOT40f). The gradients of the AOT40f values are similar to those of the AOT40c for crops: relative low in northern Europe, and the highest values observed in the countries around the Mediterranean. The critical level is met in Scandinavia, Ireland, part of the UK and in the coastal regions of the Netherlands (total forested area with concentrations below the critical level is 35% of a total area of 1.44 million km2). In southern Europe, levels may be as high as 4-5 time above the critical level, see Figure 12.

    Figure 11 summarizes the exposure of forested areas in 2010; during the period 2004 to 2010 large variations are observed. While in 2004 and 2006 almost all forests were exposed to levels exceeding the critical level, in 2007 40% was exposed to levels lower than the critical level. Similar to the AOT40 for crops no significant up- or downward trend could be detected.

    [1] Microgram/m3 can be abbreviated as 'µg/m3' and hours as 'h'. To avoid large numbers, the AOT40 is expressed in (mg/m3).hour; 1 (mg/m3).hour equals 1 000 (µg/m3).hour.

    [2] See: EEA (2007) Air pollution by ozone in Europe in summer 2006. EEA Technical report 5/2007.

    Specific policy question: Which areas in Europe remain most affected by eutrophication, acidification and ground-level ozone?

    Percentage of ecosystem area at risk of eutrophication for EEA Member Countries and EEA Cooperating Countries in 2010 for a current legislation (CLE) scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

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    Percentage of ecosystem area at risk of eutrophication for EEA Member Countries and EEA Cooperating Countries in 2020 for a CLE scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

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    Percentage of ecosystem area at risk of eutrophication for EEA Member Countries and EEA Cooperating Countries in 2020 for a maximum feasible reduction (MFR) scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

    Data source:
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    Percentage of ecosystem area at risk of acidification for EEA Member Countries and EEA Cooperating Countries in 2010 for a current legislation (CLE) scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

    Data source:
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    Percentage of ecosystem area at risk of acidification for EEA Member Countries and EEA Cooperating Countries in 2020 for a CLE scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

    Data source:
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    Percentage of ecosystem area at risk of acidification for EEA Member Countries and EEA Cooperating Countries in 2020 for a maximum feasible reduction (MFR) scenario

    Note: The results were computed using the 2008 Critical Loads database. Deposition data was made available by the LRTAP Convention EMEP Centre for Integrated Assessment Modelling (CIAM) at the International Institute for Applied Systems Analysis (IIASA) in autumn 2007.

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    Percentage of natural ecosystem area at risk of acidification (left) and of eutrophication for the 32 EEA member countries and EEA cooperating countries in 2000 and for two emission scenarios: current legislation (CLE) in 2010 and 2020, maximum feasible r

    Note: Hettelingh J-P, Posch M, Slootweg J (eds.) (2008) Critical load, dynamic modelling and impact assessment in Europa: CCE Status Report 2008, Netherlands Environmental Assessment Agency.

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    Annual variation in the ozone AOT40 value for crops (May-July) in (μg/m³).h, 1996–2010

    Note: Average values over all rural stations which reported data over at least eleven years in the period 1996-2010. The black line corresponds to the 5-year averaged value. Variations over Europe in observed values is large, eighty percent of the observations falls with the red shaded area.

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    Agricultural area (in 1 000 km²) in EEA member countries for each exposure class

    Note: A data summary of agricultural area (in 1000 km²) for EEA countries for each exposure class is given in the table below. The total agricultural area in the EEA-32 member countries excluding Iceland, Norway, Switzerland and Turkey amounts to be 2.024 million km2; since 2007 Iceland and Norway are included in the analysis increasing the total agricultural area to 2042 million km2. Since 2008 data for Switzerland is available

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    Specific assessment

    Ozone

     

    Observed AOT40 concentrations for crops indicate increasing ecosystem exposure, but with large variation. Over the period 1996-2010, 285 rural background stations were providing valid data to AirBase during at least 11 years. At 37 % of the stations (106) the time series have a tendency to increase although at only 4 stations this increase is (based on a Mann-Kendal test) statistically significant. The remaining 179 stations show a downwards development in ozone levels, 18 of these stations show a statistically significant trend. 

    A data summary of agricultural area (in 1000 km2) for EEA countries for each exposure class is given in the table below. The total agricultural area in the EEA-32 member countries excluding Iceland, Norway, Switzerland and Turkey amounts to be 2.024 million km2. Since 2007, Iceland and Norway are included in the analysis, increasing the total agricultural area to 2.042 million km2. Since 2008 data for Switzerland is available.

    Data sources

    More information about this indicator

    See this indicator specification for more details.

    Contacts and ownership

    EEA Contact Info

    Michel Houssiau

    Ownership

    EEA Management Plan

    2012 2.0.1 (note: EEA internal system)

    Dates

    Frequency of updates

    Updates are scheduled every 1 year in October-December (Q4)
    Document Actions
    European Environment Agency (EEA)
    Kongens Nytorv 6
    1050 Copenhagen K
    Denmark
    Phone: +45 3336 7100