Proficiency testing scheme, Measurement of inorganic gaseous pollutants (SO2, CO, O3, NO and NO2) in filtered ambient air (04-07 April 2022, 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 04-07 of April 2022, ten Laboratories of AQUILA (Network of European Air Quality Reference Laboratories), including ERLAP, 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 and its last amendments 2015/1480/EC. Laboratory B didn't participate for CO measurement. Two laboratories (E and F) participated only for NO/NO2 and O3 analysis. 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. On the basis of adopted criteria (z/z'-score and En-score), 5.3% of the results were identified as outliers. Based only on the z/z'-score evaluation, between all the results reported, 91.5% were satisfactory and 3.2% of the values were found to be questionable and 5.3% were unsatisfactory. Considering the repeatability and reproducibility evaluation, the results among AQUILA participants at the highest generated concentration levels are generally in line with the previous similar PTs, only SO2 shows an underperforming result.