Investigation of pollution levels on national/local scale

Case studies of HM pollution assessment (EMEP/TFMM)

Scope:

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.

Objectives

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.

Participants:

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.

Approach:

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

Current results

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.

Czech Republic

Croatia

The Netherlands

Spain

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.

PRESENTATIONS

The Czech Republic

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

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.

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.