This file contains the average number of SARS-CoV-2 virus particles per 100,000 inhabitants per Municipal Health Service (GGD) region, per day, as calculated from measurements of the number of virus particles per sewage treatment plant (RWZI). The file is structured as follows: For each date since 2020-09-07, the number of SARS-CoV-2 virus particles in sewage water per 100,000 inhabitants has been calculated per GGD region. This number is a weighted average of the municipalities that belong to the region in question. For each date, per municipality, the most recent measurement of all WWTPs is weighted according to the number of inhabitants in the municipality served by the relevant WWTP, provided that the most recent measurement is not older than eight days. These values per municipality are summed over the municipalities that belong to a GGD region, and divided by the number of observed inhabitants (i.e., the number of inhabitants in a municipality connected to WWTPs that have a measurement that is less than eight days old). This creates a weighted average for the GGD region expressed per inhabitant. Multiplying this by 100,000 gives the average number of virus particles per region, per date, per 100,000 resident equivalents. If no measurements are available from any of the WWTPs within a GGD region that are more recent than 8 days, the record is “NA”. The file contains all days per GGD region from 2020-09-07 up to and including the most recent date for which a value can be calculated. As a result, the most recent date may vary by region. The figures are calculated on the basis of the municipal classification and classification of GGD regions as they applied on the date of the measurement. Municipal reclassifications are applied on the date of the reclassification. The information on population numbers per WWTP can be found in a turnover table, which is supplied by Statistics Netherlands (CBS). The version for 2020-2021: https://www.cbs.nl/nl-nl/maatwerk/2021/06/inwoners-per-sewage treatment plant-1-1-2021 The version for 2022: https://www.cbs .nl/nl-nl/maatwerk/2022/42/inwoners-per-sewage treatment plant-1-1-2022 You can find out which municipalities fall under a GGD region in the overview of area divisions of Statistics Netherlands (https://www.cbs.nl). nl/nl-nl/dossier/netherlands-regional/geographical-data/cbs-area classifications). All measurements of individual WWTPs on which the GGD region figure is based can be found in the open data set at WWTP record level (https://data.rivm.nl/meta/srv/eng/catalog.search#/metadata/ a2960b68-9d3f-4dc3-9485-600570cd52b9). Description of the variables: Version: Version number of the dataset. When the content of the dataset is structurally changed (so not the daily update or a correction at record level), the version number will be adjusted (+1) and also the corresponding metadata in RIVMdata (data.rivm.nl). Date_of_report: Date on which the file was created (format: yyyy-mm-dd). Date_measurement: Date to which the calculation of the average number of virus particles per 100,000 inhabitants applies (format: yyyy-mm-dd). Region_code: The CBS code of the GGD region. Region_name: Name of the GGD region. RNA_flow_per_100000: The calculated number of SARS-CoV-2 RNA particles measured in the sewage water, based on a weighted average of the measurements at WWTPs that serve the municipalities in the relevant GGD region, shown per 100,000 inhabitants. Because not all measurements are available at the same time, the most recently reported values are subject to change. This may cause differences per publication date of the data. It is also possible that earlier dates are corrected as a result of new laboratory results or corrections in source files of the Water Boards. This file is always based on the most current data.
