To assess the amount of mercury present in air, water, soil, biota and other environmental ecosystems, several global-scale measurements were performed using a variety of sampling methods and analytical techniques that are just becoming available and are seeing limited use in research projects. However, applying different sampling and analytical methods could lead to non-equivalent results. EU air quality policy aims to develop and implement appropriate standard methods for assessing air quality. The general objective of the "Framework Directive" (FWD) is to define the basic principles of a common strategy in order to evaluate the following objectives:

Define and establish objectives for ambient air quality in the Community (for 13 air pollutants, including mercury) aimed at avoiding, preventing or reducing adverse effects on human health and the environment as a whole;
Assess ambient air quality in Member States on the basis of common methods and criteria;
Obtain adequate information on ambient air quality and ensure that it is made available to the public, inter alia through alert thresholds;
To keep the ambient air quality where it is good and improve it in other cases.
The quality objectives and evaluation methods are established by the 2004/107 / EC “Daughter Directives” relating to arsenic, cadmium, mercury, nickel and polycyclic aromatic hydrocarbons in air published in January 2005.

Following the requirements of the fourth daughter directive, Member States will have to measure total mercury gas (TGM) in ambient air and total mercury deposition. Several European laboratories perform the determination with manual and automated methods to evaluate the environmental concentrations of TGM and the deposition of mercury streams through wet and dry deposition paths. Therefore, there is a strong need to develop fully validated and traceable European standard methods that ensure the representativeness, comparability, accuracy and precision of the measured data from all Member States and the adoption of the standard QA / QC protocol. The availability of standardized methods will therefore be crucial for effective implementation of EC ambient air quality legislation and for harmonizing current air quality data.

There is currently no standard method for determining the environmental concentration of total gaseous mercury. At this stage there is only the European standard method for determining the concentration of mercury in water samples (EN 13506) but there is no standard method for determining mercury in precipitation, although the OSPAR / EMEP reference methods are currently available for TGM and mercury in precipitation.

The standardized method for measuring concentrations of total gaseous mercury in ambient air shall be an automated method based on sampling by gold traps and analysis by cold vapor atomic absorption spectrometry / cold vapor atomic fluorescence spectrometry.

Technical work includes validation tests for total gaseous mercury (TGM) and mercury deposition. To validate a method, it will be necessary to know the performance of the method and, therefore, to characterize it through the evaluation of some characteristics (eg. Specificity / selectivity, repeatability / reproducibility, linearity, limit of detection). Methods for TGM concentrations as well as different types of deposition samplers (bulk, Bergerhoff and wet-only) have to be tested and the experiments for their evaluation will be defined and optimized. Sampling and analysis methods will be tested for a period of 12 months in both local / industrial and bottom (coastal / rural) sites. To validate the developed method, field tests will be carried out at four different European measurement sites (2 local / industrial and 2 remoti / fund). Field validation tests will last two months at each of the four stations.



Total gaseous mercury (TGM) in ambient air
The instruments are to be located in four locations in Europe (two coastal / bottom sites and two local / industrial sites). Site requirements must comply with the description in directive 2004/107 / EC. Indeed, the scope of a standardized method should cover ambient air concentrations at bottom sites (coastal / rural) and local / industrial sites in order to establish technical procedures that provide quality results over a wide range. of applications (concentration levels for which the methods are applied). It is planned to carry out the cross comparison in two background sites and in two local / industrial sites. For coastal / rural sites an EMEP type station is preferable to reduce the risk of contamination. The location of the sites must take into account the differences in the composition of aerosols (i.e., Saharan, urban, continental, marine dust), prevailing meteorological conditions and type of emission sources (eg. coal combustion, chlor-alkaline incinerators, solid waste). The two coastal / bottom sites are therefore expected to be located one in southern Europe and one in northern Europe, while the two local / industrial sites will have to be located in areas characterized by different types of emission sources, in particular one located in proximity to a coal-fired power plant where most of the mercury emissions are in elemental gaseous form (Hg 0) (> 50%) and a second site must be located near a waste disposal incinerator or chlorine plant alkaline which are both representative of high percentage emissions (> 60%) of mercury compound oxides (i.e., HgCl 2). solid waste incinerators). The two coastal / bottom sites are therefore expected to be located one in southern Europe and one in northern Europe, while the two local / industrial sites will have to be located in areas characterized by different types of emission sources, in particular one located in proximity to a coal-fired power plant where most of the mercury emissions are in the elemental gaseous form (Hg 0) (> 50%) and a second site must be located near a waste disposal incinerator or chlorine plant alkaline which are both representative of high percentage emissions (> 60%) of mercury compound oxides (i.e., HgCl 2). solid waste incinerators).



TGM measurements will be performed at the following sites:

A site remoto / background of central / northern Europe (hinterland);
An industrial site in central and northern Europe (near a coal-fired power station);
A site remoto / against the backdrop of southern Europe (coastal);
A southern European industrial site (near a chlor-alkali plant or incinerator);
A laboratory will be responsible for each site (lab A, B, C, D).

A: Italy (CNR-Institute for Atmospheric Pollution, Rende) Will operate and manage the site remoto / bottom of southern Europe (coastal site).
B: Spain (Instituto de Salud Carlos III, Madrid) Will manage and operate the Southern European industrial site (near a chlor-alkaline plant or incinerator).
C: Sweden (IVL) Will manage and manage the site remoto / background of central / northern Europe (coastal site).
Q: Belgium (VMM) Will operate and operate the industrial site in central and northern Europe (near a coal-fired power station).

Deposition of mercury
Different types of deposition samplers such as Bulk, Bergerhoff and wet only samplers will be used to obtain parallel precipitation samples for mercury analysis.

It is proposed that equipment currently used in Europe will be tested twice for 6 months. Run two Wet only, two Bulk and four Bergerhoff samplers in parallel to perform duplicate measurements. Deposition samplers will be used to collect sufficient precipitation volumes for a sampling period of 6 months for analysis by at least two laboratories to perform a large comparison analysis exercise. The purpose of the cross-comparison is to evaluate the reproducibility of bulk, Bergerhoff and wet-only sampling, as well as to compare sampling methods.

Samples will be collected weekly for Bulk and Wet only, and 4 weekly for Bergerhoff. The equipment must be placed on a site remoto (coastal / rural) and in a local station (urban / industrial). The sampling stations will be managed by qualified personnel involved in the Working Group. Therefore, the entire validation test is expected to involve two laboratories, one for each site. For the coastal / rural site, an EMEP type station is preferable to reduce the risk of contamination. A complete and detailed QA / QC report will be provided on the results obtained from the bulk, Bergerhoff and wet only samplers.

20% of the Bulk samples will be sent to a second laboratory of the participating laboratories;
20% of the Wet only samples will be sent to a second laboratory of the participating laboratories;
20% of Bergerhoff samples will be sent to a second laboratory of the participating laboratories.
It is proposed that the following laboratories are responsible for carrying out the field tests described above:

Laboratory A: Slovenia (IJS) with the contribution of PSA and UBA to analyze 20% of the samples
Laboratory B: Sweden (IVL) with the contribution of PSA and UBA to analyze 20% of the samples