Measuring nitrogen dioxide together with Palmes tubes
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Short content
What: Measuring NO2 with Palmes tubes
Where: Throughout the Netherlands
Sign up: No longer possible
General information
Also in 2020, nineteen volunteers committed themselves to monthly measurements of nitrogen dioxide (NO 2 ) with Palmes tubes. In this way we learn more about air quality in more remote places and on the edges of the Netherlands, where few official measurements are taken. This is especially important for calibrating model calculations to make them even more accurate. The analyzes show that the measured values show the same kind of trend over the country as in 2019. Only the NO 2 values are generally lower. The corona crisis is very likely partly the cause of the lower values. Due to the corona crisis, there was less traffic in 2020 and therefore there was less NO 2 in the air. However, that is not the whole story, because the weather, for example, also influences the values every year. We will explore this further.
Maps 1 and 2 show the annual mean, calibrated NO 2 values in µg/m 3 from the calibrated Palmes tube measurements at each of the volunteer sites in 2020 and 2019. The numbers next to each colored dot represent the mean NO 2 concentrations. measured with the tubes. The legal annual average limit value is 40 µg/m 3 , the values at all these locations fall well below that. This is to be expected, since NO 2 is largely produced by traffic and the volunteer locations have been selected because there is very little traffic in the area. There was a need for measuring points of this kind because relatively much is already being measured at locations with a lot of traffic. As expected, concentrations are lowest in the northern provinces. The background load there is lower than in the south or in the Randstad, because emission sources are located at a somewhat greater distance.
NO 2 Palmes tubes
The nitrogen dioxide (NO 2 ) was measured with Palmes tubes. These are tubes over 7 cm long that contain a chemical on a gauze on one side that can bind NO2. By hanging the tube outside without the cap, the contaminant collects in the chemical. The tubes are changed every month by the volunteers. With a chemical analysis in the laboratory, it can be determined afterwards what the average NO 2 concentration was per month at the location where the tube was hung.
Previous years and in particular the project in 2019 and 2020 have shown that measurements with Palmes tubes are quite reliable. This is good news because it means they can be used as a supplement to the official measurements. The citizen measurements thus provide broader coverage of background areas throughout the Netherlands, resulting in a more complete picture of air quality.
Follow measurements on the Meten Together data portal
The monthly averages per location can be found in the Samen Meten data portal, by clicking on “NO 2 Palmes”. The analysis of the nitrogen dioxide measuring tubes takes 3 to 4 months. So the January readings are available around April, and so on. These are still accident-identified data. Now that we have a year of measurement data for 2020, that data has been validated on the basis of official measurements. These validated data will still be available on the Meten Together data portal and can already be seen on airmeetnet.nl .
The data portal also contains the NO 2 tubes results from the Palmes tubes project in the Rijnmond and from Palmes tubes in Zaandam of the GGD Amsterdam.
How does RIVM use the measurement results?
RIVM uses all these measurement results to support the calculation models that form the basis for important reports on air quality. In addition to its own measurements, RIVM also uses the measurements of airmeetnet.nl and local authorities for this purpose. This concerns the national reports of the National Air Quality Cooperation Program and the Large-Scale Concentration and Deposition Maps (GCN) . In addition, local authorities use the models for regional air quality assessments.
The measurements are important for checking whether assumptions about the background concentrations are correct: are we making the correct estimate of substances that blow in from far away? This concerns domestic sources and also what comes from the sea or from abroad. For this reason, only locations with low emissions from local sources such as cars, factories, etc. were selected for this volunteer study. The participating volunteers live in the north and east of the Netherlands and in Zeeland, especially in rural areas where there is little traffic.
