Evaluation of the inter- laboratory comparison exercise for SO2, CO, O3, NO and NO2 : 2-7 September 2018 Langen (D) : European Commission harmonisation programme for air quality measurements

From the 2nd to the 7th of September 2018, six Laboratories of the World Health Organization (WHO) European-Region met for another joint JRC-ERLAP/WHO inter-laboratory comparison exercise (ILC). They met at the National Air Quality Reference laboratory at the German Federal Environment Agency in Langen, Germany, to evaluate their proficiency in the analysis of inorganic gaseous pollutants (NO, NO2, SO2, CO and O3) covered by the European Air Quality Directive 2008/50 EC and recent revision 2015/1480/EC. The proficiency evaluation, where each participant's bias was compared to two criteria, provides information on the current situation and capabilities to the European Commission and can be used by participants in their quality control system. On the basis of adopted criteria, 59.6% of the results reported by WHO laboratories were good both in terms of measured values and reported uncertainties. The rest of the results had good measured values, but the reported uncertainties were too high (40.4%). Based on the z'-score evaluation all values were found to be satisfactory. Comparability of results among WHO participants at the highest generated concentration levels is satisfactory for measurements of all pollutants.