A new measurement strategy for the precipitation chemistry network in the Dutch National Air Quality Monitoring Network
Een nieuwe meetstrategie voor de metingen van de chemische samenstelling van neerslag in het Landelijk Meetnet Luchtkwaliteit
Buijsman E, Dekkers ALM, Aben JMM, van Jaarsveld JA
RIVM Report 723101033
The precipitation chemistry network, part of the Dutch National Air Quality Monitoring Network, has been in operation since 1978. In this report are described the evaluation of the measurement strategy and proposed changes. Redefining the measurement strategy was based on the following principles: a) current information requirements, b) a possibility to produce deposition fields with a given quality for the whole of the Netherlands and c) an optimal use of the monitoring-modeling combination. Information requirements included knowledge on: a) acidifying compounds and basic cations (related to acidification and eutrophication) , b) heavy metals, c) Persistent Organic Pollutants and d) contributions to international cooperation programs. Two options for a new measurement strategy are presented. The primary tool in the first option is a monitoring network of approximately eight measurement sites to be supported by a spatial statistical Kriging-like model. This model enables the objective spatial translation of the results of the monitoring stations into deposition fields. The proposed sampling strategy would use two samplers on each location and a sampling period of two weeks. In the second option a dispersion model is the primary tool. The model results are calibrated with measurement results from a limited number of measurement sites (approximately five). Supplementary information on emissions and meteorology is required in this option. The proposed sampling strategy here would use three samplers at each location and a sampling period of one week. Accuracy estimates for measurement results and spatial patterns are presented, along with proposals for technical changes to increase quality and strengthen quality control.