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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 Nov 2012

Exposure of ecosystems to acidification, eutrophication and ozone (CSI 005) - Assessment published Nov 2012

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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 (O3)
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. Concentrations in 2009 were on the average lower than in 2008. The effect-related accumulated concentrations, addressing exposure of crops to ozone over several summer months, shows large year-to-year variations. Over the period 1996-2009 there is a tendency to increased exposure, although 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 2009

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 (μg/m³).h) in EEA member countries

Note: The figure shows the exposure of forest area to ozone (exposure expressed as AOT40f in (μg/m3).h) in EEA member countries . By the UNECE a critical level for protection of forest is set to 10000 (μg/m3).hour. Since 2004 a growing number of EEA member countries have been included. In 2004 Bulgaria, Greece, Iceland, Norway, Romania, Switzerland, and Turkey have not been included. In 2005-2006 Iceland, Norway Switzerland and Turkey are still excluded 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. 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 2009

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.


Target values for ozone
The EU has the objective of 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 (microgram/m3).hour. The long term objective is 6 000 (microgram/m3).hour.

There is a substantial fraction of the agricultural area in EEA-32 member countries (excluding Turkey, see note 1) where the target value is exceeded (in 2009, about 22% of a total area of 2.052 million km2). Exceedances of the target values have notably been observed in southern and eastern Europe, see Figure 2. The long-term objective is met in 20% of the total agricultural area, mainly in Ireland, Iceland, United Kingdom and Scandinavia.

In 2003 the meteorological conditions were very favourable for ozone formation resulting in exceptional high concentrations. 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 observed. The average ozone concentrations in 2006 are only slightly higher than in 2005. However, June and July 2006 were characterized by a large number of ozone episodes[1]  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 2008, the AOT40 values in 2009 were lower in northwestern Europe but higher in southeastern Europe.

There is great concern that the validated data for 2010 will show that the 2010 target value was not met. Further, 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 and UNECE protocols.

 In addition to the EU target value, within the UN-ECE Convention on Long-range Transboundary Air Pollution a critical level has been defined for the protection of forest. This critical level related to the accumulated sum during the full summer (April-September) and is set to 10,000 (μg/m3).h. Figure 3 shows this 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 n 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 3.

Figure 4 summarizes the exposure of forested areas in 2009; during the last six years (2004 to 2009) large variations are observed. While in 2004 and 2006 almost all forest were exposed to levels exceeding the critical level, in 2007 40% was exposed to lower levels. Similar to the AOT40 for crops (see below) no significant up- or downward trend could be detected.


[1] 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.

Data source:
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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.

Data source:
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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.

Data source:
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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, 1996-2009

Note: Average values over all rural stations which reported data over at least eleven years in the period 1996-2009. 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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Estimated trend in AOT40 for crops (May-July) at rural stations operational during the period 1996-2008

Note: Estimated trend in AOT40 for crops values (May-July) at stations operational during the period 1996-2008. Only rural background stations are included. Note that at more than 90 % of the stations no significant up- or downward trend has been estimated.

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Specific assessment

  • Eutrophication, ecosystem area at risk
    The percentage of ecosystems at risk of eutrophication and negative changes in nutrient balances has been calculated as the share of sensitive ecosystems for which deposition of oxidized and reduced nitrogen compounds exceeds the critical loads. In 13 EEA member countries the percentage of sensitive ecosystem area at risk will still be (close to) 100 % in 2010 (see Figure 11), assuming that current legislation for reducing national emissions will be fully implemented (CLE scenario). Only in five EEA member countries the area at risk is estimated to be lower than 50 %, with values below 20 % for the United Kingdom, Norway and Romania. No significant improvements are predicted for 2020 in almost all EEA countries according to the CLE scenario (see Figure 12). Nevertheless, significant improvements can be seen in 2020 in almost all countries when assuming a maximum feasible reduction scenario (MFR; see Figure 13). However, even in the case of MFR in four EEA member countries the percentage of ecosystem area at risk would still be between 90 % and 95 % (Lithuania, Latvia) or even close to 100% (Czech Republic, Denmark and Luxembourg).

 

  • Acidification, ecosystem area at risk

The percentage of sensitive ecosystems at risk of chemical changes with negative effects on ecosystem function and structure caused by acidification has been calculated as the share of sensitive ecosystems for which critical loads for acidification are exceeded by deposition of acidifying nitrogen and sulphur compounds. In general the percentage of ecosystem area at risk of acidification is much lower than the percentage of ecosystem area at risk of eutrophication. For some countries, for example Germany and Poland, the percentage of sensitive ecosystem area at risk of acidification is predicted to decrease between 2010 and 2020 according to the current legislation scenario (CLE, see Figure 14 and 15). For many other countries the suggested improvements are around five percent (e.g. for Denmark and the United Kingdom) or less (e.g. for Latvia, the Netherlands or Sweden).

With the exception of the Netherlands the sensitive ecosystem areas at risk of acidification for the maximum feasible reduction (MFR) scenario is predicted to be well below 10 % in all EEA member countries in 2020 (see Figure 16). A detailed overview of ecosystem areas at risk in EEA countries is given in Figure 17. The computed European area at risk of acidification decreases from 11 % in 2000 to 6 % and 1 % in 2020 for the CLE and MFR scenarios, respectively. The Netherlands, Poland and Denmark are the countries for which the areas at risk have been assessed to be above 30 % for the CLE scenario in 2010. With the exception of the Netherlands the sensitive ecosystem areas at risk of acidification for the MFR scenario were in 2020 well below 10 % in all EEA member countries.

The comparison of ecosystem areas exceeding the critical loads for acidification in 1990 and 2010 show that the area for the whole of Europe declined  by 83 %. A high percentage (84 %) of the 50 x 50 km2 EMEP grid cells with critical loads exceedances in 1990 show a decline in exceeded area of more than 50 %. The National Emissions Ceiling Directive (2001) states that 'the area where critical loads are exceeded shall be reduced by at least 50 % (in each grid cell) compared with the 1990 situation'. Although this interim environmental objective given in the directive has not strictly speaking been achieved, the improvements are considerable.

 

  • Ecosystem exposure to ground-level ozone
    Observed AOT40 for crops concentrations indicate increasing ecosystem exposure, but with large variation. Over the period 1996-2009, there were 256 rural background stations providing valid data to AirBase during at least 10 years in this 13-year period. At 40% of the stations (99) the time series have a tendency to increase although at only 3 stations this increase is - based on a Mann-Kendal test - statistically significant. Of the other 157 stations having a downward tendency, 12 stations show a 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 2042 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)
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