Emission measurements of heavy metals with the European standard reference methods EN 14385 and EN 13211—observations from interlaboratory comparison (ILC) measurements performed at waste-to-energy plant in Finland

ABSTRACT

This study presents the heavy metal results obtained during Finnish interlaboratory comparison (ILC) measurements made during 2019. The aim of this measurement campaign was to verify the skills of accredited emission measurement teams and also to evaluate the challenges that stack testing teams face in the future when emission levels decrease. ILCs have been organized in Finland since the 1970s. ILCs provide an important platform for stack testing teams so that they can verify their measurement skills and also for the dissemination of knowledge. The knowledge about the measurement standards and their requirements has improved among stack testing teams during past years in Finland. As emission levels get lower, they still need to pay more attention to some quality assurance procedures, e.g. to method and field blanks. Based on the observations of this ILC for heavy metals it can be noted that the challenges that stack testing teams face are related to the fact that no guidance is given in the standard reference methods EN 13211 and EN 14385 for example on the calculation of measurement uncertainties and how results below limit of quantification should be taken into account. These reference methods were suitable for their purpose at the time they were validated. However, emission levels are now more stringent and it is challenging to measure them with acceptable uncertainty criteria. As a consequence, there is a clear need for harmonized approaches in Europe for consistent implementation of standards and regulations. Key issues where guidance should be provided include realistic measurement uncertainties at low concentration levels, reporting low concentrations and guidance on how measurement uncertainties should be taken into account when the results are used for compliance assessment. The overall aim is to ensure that even with low emission levels, the emission measurement results would be transparent and robust throughout the EU.

Implications: Interlaboratory comparison measurements between stack testing teams are the most important tool to verify the quality of the measurements. Participation in an appropriate ILC is often mandatory to successfully achieve accreditation under ISO/IEC 17025. Such campaigns also provide an efficient platform for dissemination of knowledge. In addition, ILCs can be used to clarify the challenges that teams nowadays face when measuring low emission levels, thus creating important information for the revision work of standards.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was carried out as part of a project funded by Finnish partners (such as Ministry of the Environment, VTT Technical Research Centre of Finland, Energy Industry’s Environmental Research Pool, Finnish Forest Industries, AX Consulting Ltd, South-Eastern Finland University of Applied Sciences XAMK, Envimetria Ltd, Eurofins Nab Labs Ltd, Ramboll Finland Ltd, AFRY Finland Ltd, Wärtsilä Finland Oy, Outotec (Finland) Oy, Boliden Kokkola and Valmet Technologies) which we gratefully acknowledge. We also thank the Finnish waste- to-energy plant for providing the possibility to perform the field measurements in their stack and for all their support during the measurement campaign.

Notes on contributors

Tuula Pellikka

Tuula Pellikka is a Principal Scientist at VTT Technical Research Centre of Finland. Her research interest is on emission measurements and their quality assurance and she represents Finland at the European standardization organization CEN/TC264.

Tuula Kajolinna

Tuula Kajolinna is a Research Scientist within the same institution, working as an expert on emission measurements and their quality assurance.