Proficiency testing scheme, measurement of inorganic gaseous pollutants (SO2, CO, O3, NO and NO2) in filtered ambient air (27-30 March 2023, Ispra-Italy) : European Commission harmonisation programme for air quality measurements

Within the harmonisation programme of Air Quality monitoring in Europe the European Reference Laboratory of Air Pollution (ERLAP) organises Proficiency Tests (PT). During the period 27-30 of March 2023, including ERLAP, seven Laboratories of AQUILA (Network of European Air Quality Reference Laboratories) met for a laboratory comparison exercise in Ispra (IT) to evaluate their proficiency in the analysis of inorganic gaseous air pollutants (NO, NO2, SO2, CO and O3) covered by the European Air Quality Directive 2008/50 EC [1] and its last amendments 2015/1480/EC [42]. Two laboratories (D and I) didn't participate for CO measurement. The proficiency evaluation, where each participant's bias was compared to two criteria (z/z'-score and En-score), provides information on the current situation and capabilities to the European Commission and can be used by participants in their quality control system. In agreement with all participants an evaluation of SO2 concentration measured as interference during NOx measurement has been carried out. Based only on the z/z'-score evaluation all results reported were 100% satisfactory. Considering the En-score, 97% of all value were found satisfactory. The overall performance for both the indicators has to be considered good. Considering the repeatability and reproducibility evaluation, the results among AQUILA participants at the highest generated concentration levels are satisfactory for measurements of all pollutants.