Case studies of HM pollution assessment (EMEP/TFMM)
Assessment of heavy metal airborne pollution of the environment involves different aspects including estimates of atmospheric emissions, monitoring of pollution levels and application of chemical transport models. However, European-scale assessment is complicated by a number of factors. First of all, available regular measurements of heavy metals only partly cover the EMEP domain. Besides, estimates of heavy metal emissions are often characterized by significant uncertainty and unaccounted emission sources [ECE/EB.AIR/GE.1/2008/6]. In addition, modelling of heavy metal pollution includes parameterisation of the pollutants re-suspension with wind-blown dust which requires detailed gridded specific information and contains considerable uncertainty. In order to improve the assessment MSC-E and EMEP/TFMM organized special country-specific case study on a complex investigation of heavy metal pollution in one or a few EMEP countries involving all available information on European, national and local scales. The experience which will be gained in this case study could be applied to other EMEP countries.
- Detailed assessment of heavy metal pollution with fine spatial resolution
- Evaluation of effect of spatial resolution on the assessment results
- Analysis of factors affecting quality of pollution assessment
- Improvement of the assessment means (model, measurements, emissions data) for EMEP region based on the experience gained in country-specific studies.
MSC-E, national experts, CCC, CCE. TFMM assists in the evaluation of the results of the Case studies. Currently the Czech Republic, Croatia, the Netherlands and Spain are involved in country-specific studies.
General scheme of the case study includes several steps. First of all, necessary initial data on emissions, monitoring, meteorological and geophysical information are prepared. These data are used as input to atmospheric transport model. The calculation results, model parameterizations, monitoring data, emission information are analysed in detail in co-operation with national experts. On the base of the results of the analysis the components (emissions, monitoring information, modelling) of the assessment is improved. New round of calculations have to be carried out and improved heavy metal pollution assessment for a country will be produced.
The activities under the case study are organized into six work packages:
WP1. Emission data preparation for modelling and analysis.
WP2. Collection and analysis of monitoring data for pollution assessment.
WP3. Preparation of input geophysical and meteorological data for modelling and modification of the model.
WP4. Atmospheric modelling.
WP5. Complex analysis of modelling results.
WP6. Improved model assessment of pollution levels in a country.
General description of each of the work package is given here. For each country-participant the Case Study programme differs depending on country’s requests and availability of initial information.
Expected output for a country:
Depending on the availability of initial information and specific requests of a country-participant, items of output information for a country may differ. General country-related information can include the following:
- Calculated concentrations and deposition with high (e.g., 10x10 km) spatial resolution
- Contributions of administrative regions and neighbouring countries to pollution levels
- Contributions of global sources to country’s pollution levels (for Hg)
- Contributions of source categories to pollution levels
- Contributions of large point sources to pollution levels
- Critical loads exceedances maps
- Simulations based on national future emission scenarios
Some of results of the Case Study activities are available below. Detailed description of the results is presented in the EMEP status reports and MSC-E technical reports.
Results of these country-specific studies were reported and discussed at various EMEP forums, such as meetings of TFMM (see document) and EMEP Steering Body. Presentations of MSC-E and of countries-participants related to this activity are available here.
The Czech Republic
The Czech Republic provided information on cadmium concentrations in air from 72 national monitoring stations, and concentrations in precipitation – from 30 stations. Eight background regional stations with co-located measurements (i.e., measurements of concentrations both in air and in precipitation) were selected for the detailed analysis of pollution levels in the country. Two of them (Kosetice and Svratouch) report annually information on heavy metal concentrations and deposition to EMEP.
Stations measuring Cd concentrations in air and in precipitation at the Czech national monitoring network. Green circles denote all stations, white circles – priority stations selected for the analysis, red squares – EMEP stations
Modelling of cadmium concentrations and deposition was carried out for 2007 with spatial resolutions of 50x50 km and 5x5 km. Calculations with resolution 50x50 km were performed on the base of EMEP officially reported emission data. For simulations with resolution 5x5 km emission data for the Czech Republic were provided by national experts, while for other countries the EMEP emissions were re-gridded from 50-km to 5-km resolution.
Calculated fields of cadmium concentrations in air and total deposition generally reflected spatial distribution of the emissions. Patterns of pollution levels simulated with 5x5 km and 50x50 km resolution were similar. However, maps with finer resolution demonstrated much more detailed picture of country-scale pollution levels.
Spatial distribution of emission data with resolution 50x50 km (left) and 5x5 km (right). Location of priority stations is depicted by circles
Calculated concentrations of Cd in air with resolution 50x50 km (left) and 5x5 km (right) in the Czech Republic in 2007
Calculated total deposition of Cd with resolution 50x50 km (left) and 5x5 km (right) in the Czech Republic in 2007
Refinement of spatial resolution of emission and meteorological data resulted to reduction of discrepancies between modelled and measured annual mean concentrations of Cd at the priority stations.
Annual mean observed and modelled concentrations of Cd in 2007 at priority Czech monitoring stations
Time series of calculated concentrations modelled with different spatial resolution are compared with time series of concentrations observed at the Czech stations. Analysis of selected short-term pollution episodes allows to examine factors responsible for Cd levels in the atmosphere. Analysis of some of episodes is available in technical and status reposts. Further analysis will be continued.
Time series of modelled and observed concentrations of Cd in 2007 at priority Czech monitoring stations.
Calculations of lead pollution levels for Croatia was carried out with resolution 50x50 km on the base of the official EMEP emission data and with resolution 10x10 km using emissions submitted by national experts. To perform modelling with high resolution emissions from neighbouring countries were re-gridded from 50-km grid to 10-km gridcells.
Emissions of lead in Croatia in 2007 officially submitted with 50-km resolution (left) and prepared in the framework of the Case Study with 10-km resolution (right). Location of measurement stations is indicated by blue stars (Croatia) and white triangles (EMEP)
Model simulations of lead pollution levels were carried out with resolutions 50x50 and 10x10 km. Maps with 10-km resolution were more detailed compared to those with 50-km resolution
Calculated concentrations of Pb in air (top row) and total deposition (bottom row) in Croatia in 2007 with resolution 50x50 km (left column) and 10x10 km (right column) resolution
Monitoring data on concentrations in air is provided for three Croatian stations: Zagreb, Sisak and Rijeka. Since these stations are urban, the measurements at these stations should be used in the pollution level analysis with some caution because they could be not representative even for modelling with 10-km resolution. To overcome this difficulty the data from EMEP stations (Ilmitz in Austria and Iskbra in Slovenia) located in the modelling domain were also involved. Changes of resolution from 50x50 km to 10x10 km resulted in improvements at some stations (Rijeka, Ilmitz, Sisak), but increased discrepancies between modelled and measured values at other sites (Zagreb, Iskbra).
One of factors responsible for Pb levels in air is wind re-suspension of lead which had been accumulated in top soils for decades. On annual level the contribution of wind re-suspension to calculated concentrations in air was significant. It varied from 40% to almost 90%. Modification of parameterization of this process is now ongoing. More details are available in EMEP status reports and MSC-E technical reports.
Modelled and measured concentrations of Pb
in air for Croatian measurement stations
and EMEP background stations
Observed and modelled (10x10km) annual
mean concentrations of lead in air in 2007
Two emission data sets were involved in the Case Study for the Netherlands: emissions officially reported to EMEP with resolution 50x50 km and national emissions with resolution 5x5 km. The major difference in spatial distribution of these emission fields was location of large emission source northward from Amsterdam. This source made more than 50% of total emission of lead in the Netherlands.
Emissions of lead in 2007 with resolution 50x50 km (left) and 5x5 km (right)
Modelled mean annual concentrations and total deposition of lead as well as location of the Dutch monitoring stations were demonstrated in figures below. Simulated 5-km concentrations in air were generally smaller than 50-km ones, especially in the southern and the south-western parts of the modelling domain. The reason was the use of smaller wind re-suspension of lead from urban areas. Another marked difference between the results was area of high pollution levels in the north-west from Amsterdam. This ‘hot spot’ was caused by source with significant emissions, which was indicated in emission map with 5-km resolution but was not revealed in maps with 50-km resolution.
Concentrations of lead in air (top row) and total deposition (bottom row) in 2007 with resolution 50x50 km (left column) and 5x5 km (right column)
Calculated concentrations of lead in air were compared with monitoring data collected at five Dutch stations and one EMEP Belgium station (BE14, Koksijde) located within the considered region. As seen from the figure below, the results with 5-km resolution were closer to measurement values compared to the results with 50-km resolution at most of stations. Certainly, more detailed analysis of these results is needed.
Mean annual air concentrations of lead, modelled with resolutions 5x5 and 50x50 km and observed at monitoring stations
Active cooperation between MSC-E and Spain in the field of the country-specific Case Study was started in 2011. Spain submitted to MSC-E large amount of national data on observed pollutant levels and meteorological parameters. Example of measured concentrations of lead in air at Spanish stations in 2007 is demonstrated in figure below.
Observed concentrations of lead at Spanish measurement stations in 2007
EMEP/TFMM meeting (May 2010, Larnaka, Cyprus)
Heavy metal emissions, measurements and needs for modelling in Croatia
EMEP case study on heavy metal pollution assessment
State-of-the-art synthesis of available information and modelling efforts on heavy metals in Italy
EMEP case study on heavy metal pollution assessment: Current progress and further activities
The Heavy Metal Case study for the Netherlands
Lead and Cadmium in ambient air and participation over the territory of Slovakia
Preliminary Results for the simulation of some non- reactive heavy metals in Spain
EMEP/TFMM meeting (May 2011, Zurich, Switzerland)
Modeling of heavy metlas:study of impacts due to climate change
EMEP case study on heavy metal pollution assessment
EMEP case study on heavy metal pollution assessment
Country-specific assessment of HM pollution levels: progress and directions of further research
Work on modelling of gaseous mercury emissions from natural sources in Portugal
EMEP Steering Body (September 2011, Geneva, Switzerland)
Multi-scale assessment of heavy metal pollution