1) Understanding the problem
Understanding impact of individual pollutants, their sources and evolution of concentrations helps develop the policy and supports effective abatement.
Pollutants covered by 1st Daughter Directive 1999/30/EC
Pollutants covered by 2nd Daughter Directive 2000/69/EC
Ozone, covered by 3rd Daughter Directive 2002/3/EC
Pollutants covered by 4th Daughter Directive 2004/107/EC
Methods and criteria
The Framework Directive, as well as its Daughter Directives, requires the assessment of the ambient air quality existing in Member States on the basis of common methods and criteria. In the Directives, the minimum assessments requirements are written. They are linked to the specific concentration thresholds as well as the population within each air quality zone or agglomeration. While in specific cases continuous monitoring is mandated, modelling is always encouraged in order to provide better information on spatial distribution of concentrations.
The Commission with the extensive support of the national experts in Working Group on Implementation has prepared several guidances to facilitate implementation of these provisions:
In order to ensure comparability between measurements of PM10 from the 1st Daughter Directive, the Commission prepared the following guidance:
Guidance to Member States on PM10 monitoring and intercomparisons with the reference method, also available in Spanish (pdf ~370Kb)
Regarding the 3rd Daughter Directive relating to ozone, the Commission has prepared guidance for implementing this directive. Annex III includes guidance on strategy for measurement of ozone precursors in ambient air as requested in the 3rd Daughter Directive:
Another guidance, which is based on Note 2003/3 of the former CAFE Working Group on Implementation, gives recommendations on how to assess air quality around point sources.
When monitoring is being used for the assessment, it is extremely important to select appropriately the siting of the monitoring station. Siting has bearing on the ability to use the monitoring information to assess compliance in the specific area and to obtain further information as regards exposure, source apportionment that supports further development of air policy as well as air pollution management in the area.
The EU Air Quality Directive 2008/50/EC requires that as a minimum one rural background station is installed every 100 000 km2 for measuring PM2.5 in order to get data on the total mass concentration and the chemical speciation. This minimum is larger than the total surface area of several Member States. The Directive further states that Member States shall set up at least one measuring station or may by agreement with adjoining Member States set up together one or several common measuring stations. This document provides guidance to Member States regarding the selection and implementation of these stations.
Commission Staff Working Paper establishing guidelines for the agreements on setting up common measuring stations for PM2.5 under Directive 2008/50/EC on ambient air quality and cleaner air for Europe.
The Directive 2008/50/EC provides Member States with the possibility to subtract the contribution of natural sources under certain conditions before comparing the ambient air pollutant concentrations to the limit values. This document aims to give guidance on which sources can be regarded as natural in this context and on methods to quantify and subtract the contribution of these sources:
Commission Staff Working Paper establishing guidelines for demonstration and subtraction of exceedances attributable to natural sources under the Directive 2008/50/EC on ambient air quality and cleaner air for Europe
Member States may under the Directive 2008/50/EC indicate that for designated zones or agglomerations within which limit values for PM10 are exceeded in ambient air such exceedance is due to the re-suspension of particulates following winter sanding or salting of roads. This document recommends methods for the determination of the contributions of these processes to the ambient concentrations of PM:
Commission Staff Working Paper establishing guidelines for determination of contributions from the re-suspension of particulates following winter sanding or salting of roads under the Directive 2008/50/EC on ambient air quality and cleaner air for Europe
Work in progress
In 2007, a study has been conducted for the Commission by the UBA that would facilitate more harmonized approach to monitoring stations. The interim report of this study can be downloaded here:
The Commission is reviewing and updating the available guidance documents, where considered necessary in order to include more recent implementation experience and potential new elements brought forward through the new revised legislation.
Reference measurement methods
For each regulated pollutant a reference measurement method has been prescribed. At the time of the adoption of directives standardised methods have not been developed for all pollutants. The situation has since developed, and an updated list of reference measurement method is now available, which is explicitly referenced in the new proposal for ambient air quality directive, but also available below.
SO2: EN 14212:2005
NO2 and NOx: EN 14211:2005
Pb, Cd, As, Ni: EN 14902: 2005
PM10: EN 12341:1999
PM2,5: EN 14907:2005
Benzene: EN 14662:2005
CO: EN 14626:2005
The standards can be obtained through the national standardisation organisation.
Work in progress
The development of the new standards for pollutants under 4th daughter directive, as well as periodic review and potential revision of the developed standards continues under CEN Technical Committee 264. For organisation and work of CEN see www.cen.eu.
In addition, the certified reference materials for calibration of measurements of heavy metals and PAH is currently being developed at JRC-IRMM. Feasibility report will be available in autumn 2007.
Non-reference measurement methods can also be used provided they respect provisions for equivalence set out in the Directives (see for example 2008/50/EC, Annex VI). A Commission Working Group on Equivalence has prepared a document describing principles and methodologies to be used for the demonstration of the equivalence of alternative (non-reference) measurement methods to the reference methods described by the EN Standard methods. This document has been discussed at a workshop in May 2007 in Ispra and subsequently updated. The air quality committee established under Directive 2008/50/EC has endorsed the new guidance for the implementation of the Directive 2008/50/EC:
Guidance for the Demonstration of Equivalence of Ambient Air Monitoring Methods (pdf ~680Kb) from January 2010
The corresponding tool to facilitate the use of the guidance (in particular for checking the equivalence of non-reference methods for PM-monitoring) has been developed in MS-Excel. The updated version is now available below:
Test the equivalence (xls)
The template provides the formulas and macros with the statistical calculations needed.
In the Directive modelling is considered to provide supplemental information to air quality monitoring, and to be used where modelling is not mandatory. Modelling is becoming a principal assessment tool that is validated by monitoring and provides much more comprehensive information as regards public exposure, supports identification of sources and future projections based on different measures scenarios.
Use of modelling has been also developed under specific initiatives such as HARMO. Under the 6th Research Framework programme an Air4EU project has recently been concluded which facilitates combined use of monitoring and modelling for the air quality assessment through the developed guidance and IT tools.
A Forum for AIR quality MODElling (FAIRMODE) of modellers and users has been established to support the widespread and harmonised use of models through model validation and intercomparison exercises and through the management of the modelling network. FAIRMODE webpage contains links to current activities.
Objective estimation is reserved for the air quality zones with very good air quality and no large conurbations. It is usually combined with modelling. By identification of local pollution sources and information of regional air quality an estimation of concentration of a regulated pollutant is made.
3. Ensuring quality of assessment information
Ensuring quality of assessment information either generated through monitoring, modelling or objective estimation is one of the paramount provisions of the directives. Data quality objectives are prescribed which define maximum allowed uncertainty, time coverage and data coverage.
While Member States are responsible to ensure appropriate quality assurance of the assessment as well as the appropriate quality control of the information provided to the public and through the assessment reports, the Commission set-up a community-wide process, managed by the Joint Research Centre. JRC organises intercomparison exercises for the national reference laboratories and manages AQUILA – network of national reference laboratories which follows the implementation of assessment by monitoring, serves as exchange forum and provides expert advice to the Commission.
AQUILA has recently prepared an extensive document that summarizes the roles and responsibilities of the national reference laboratories and of the network itself, describes the quality assurance procedures and EU-wide comparisons. Document also includes the interpretation of obligations for the national reference laboratories and the monitoring networks under the new Directive. Document received positive opinion when presented at the Air quality committee under the Directive on 1 July 2009.
European Environment Agency together with its Topic Centre is supporting the efforts through further quality control of the reported assessment information and through facilitating exchange of best practices by the data providers within EIONET.
The new Directive does not significantly change provisions for the assessment, but does introduce some streamlining and further quality requirements and assessment requirements for fine particulate matter PM2.5.