In 2018, the calculated concentrations of particulate matter (PM10 and PM2.5) and nitrogen dioxide (NO2) were below European limit values in most parts of the Netherlands. There are still a few exceedances at the local level. In some inner cities, this is due to heavy traffic and in the countryside because of livestock farms. As a result, the Netherlands does not yet comply everywhere with the European limit values for nitrogen dioxide and particulate matter. This is revealed by a report of the National Air Quality Cooperation Programme (NSL), the NSL 2019 monitoring report.
Locally, the concentrations of nitrogen dioxide and particulate matter were higher than the limit values. For nitrogen dioxide, there were fewer exceedances in several busy streets in the various inner cities. In 2018 it was less than in 2017. Compared to 2017, the average nitrogen dioxide concentration in the Netherlands has decreased slightly. For the coming years, RIVMNational Institute for Public Health and the Environment expects a further decrease in the average concentration and the number of exceedances of limit values.
Concentrations of particulate matter higher than the limit values do occur especially in areas with intensive livestock farming. As in the previous year, the number of exceedances has risen slightly compared to last year. The number of times that the limit value was exceeded in these locations increased in comparison to 2017. This is in part because more livestock farms were included in the 2018 calculations. In 2018, the dry weather in combination with more easterly winds and somewhat lower wind speeds also contributed to higher average concentrations in the vicinity of livestock farms. This resulted in more exceedances of the limit values for particulate matter in 2018. In recent years we have seen a decrease in the average concentrations of particulate matter, but this will not continue. RIVM expects the concentration of particulate matter and the number of exceedances of the limit values to decrease again in the coming years. However, the pace of this decrease is difficult to predict.
Quality of the data
Local and regional governments provide up-to-date data on traffic and livestock farms for the NSL calculations. The quality of the data has once again improved substantially this year. This time, extra attention was paid to supplementing the NSL with possibly missing livestock farms.
In several locations, the concentrations of nitrogen dioxide and particulate matter were again close to the European limit values in 2018. Small increases in these concentrations can have a strong impact on the number of exceedances. Therefore, the number of exceedances is sensitive to uncertainties in the calculations. A strong focus on data quality remains important to provide a reliable picture of air quality.