Evaluation of the laboratory comparison exercise for SO2, CO, O3, NO and NO2, 19th-23rd of October 2015, Ispra : 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) is organizing Inter-Laboratory Comparison Exercises (IE) in the facility of Ispra (Italy). From the 19 to the 23 October 2015 in Ispra (Italy), eight Laboratories of AQUILA (Network of European Air Quality Reference Laboratories) and one of French regional network (AIRPARIF) met for a comparison exercise to evaluate their proficiency in the analysis of inorganic gaseous pollutants. In order to cover the prescription of the European Directive 2008/50/EC [1] and its the recent amendment 2015/1480/EC [42] about air quality, the following pollutants were measured: sulphur dioxide (SO2), nitrogen dioxide (NO2), nitrogen monoxide (NO), carbon monoxide (CO) and ozone (O3). The proficiency evaluation, where each participant's bias was compared to two criteria, provides information on compliance with Data Quality Objectives (DQO) and measurement capabilities of the National Air Quality Laboratories to the European Commission (EC) and can be used by participants in their laboratory's quality system. On the basis of criteria imposed by the EC, 75.6% of the results reported by the participants was satisfactory both in terms of measured values and reported uncertainties. Part of the results (18.1%) had acceptable measured values, but the reported uncertainties were either too high (10.8%) or too small (7.3%). Against the usual tendency during this IE a great number of results (2.2%) were unsatisfactory for both the value and the uncertainty. Comparability of results among AQUILA participants at the highest concentration level, excluding outliers, is acceptable for almost all pollutants measurements. CO and NO2 show a deviation from the objectives.