Abstract

Within the frame of the cooperation between the air quality monitoring networks of RIVM, GGD Amsterdam and DCMR Environmental Protection Agency comparative measurements are performed between RIVM and both regional networks at locations in Amsterdam (RIVM-GGD) and Rotterdam (RIVM-DCMR): - Rotterdam: nitrogen dioxide and PM10 at location Bentinckplein/Statenweg. - Amsterdam: nitrogen dioxide and PM10 at location Overtoom The purpose of these comparisons is demonstrating comparability of results obtained by the different networks. In case of sufficient comparability, mutual use can be made of their results. All networks use the European Union reference methods for nitrogen dioxide and PM10 The evaluation involves comparison of hourly average results for nitrogen dioxide and of daily average results for PM10 by applying orthogonal regression analysis and by examination of differences between results as a function of measurement period and concentration level Evaluation of the comparisons between RIVM and DCMR for the year 2012 shows that for nitrogen dioxide results averaged over the whole year agree to within ±4 per cent. The relationship between the results deviates from the expected relationship y=x (where x-values are results of RIVM): the slope is significantly lower than 1. The relationship is nearly the same as that for the year 2011 Results for PM10 results agree within ±3 per cent. RIVM systematically measures 3 per cent lower than DCMR Evaluation of the comparisons between RIVM and GGD for the year 2012 shows that for nitrogen dioxide results averaged over the whole year to within ±2 per cent. The relationship between the results has improved compared to the year 2011: the slope is now close to 1 Results for PM10 results agree within ±3 per cent. However, RIVM systematically measures 1 µg/m3 higher than GGD. This situation is comparable to that for the year 2011 Evaluation further shows that the resulting measurement uncertainties in all cases are well within the criteria given in EU Directive 2008/50/EC. As all networks have an ISO 17025 accreditation for the measurements compared it may be assumed that the quality levels and, consequently, the comparability of the results determined in these comparisons are representative for the networks as a whole. Consequently, it should be possible for networks to make mutual use of results for the components compared (nitrogen dioxide and PM10)