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NO2 concentration in the Netherlands (annual average), 1990-2002

The concentration of nitrogen dioxide (NO2) fell in the last ten years by approximately 2% a year. This fall meant that the EU standard for the average annual concentration of nitrogen dioxide in the Netherlands was only exceeded close to busy roads.

Favourable trend in concentration of nitrogen dioxide


In 2002, the average annual concentration of nitrogen dioxide (NO2) in most of the Netherlands remained below the EU norm (40 µg/m3). The only exceedances in that year were close to busy roads. In towns, the concentrations in places that were not near busy roads or close to motorways did not exceed the standard. The highest concentrations were measured at the 'street stations' in the National Air Quality Measurement Network (LML).
In 1990, the NO2 concentration was above the current EU standard in 5% of the Netherlands. These were mainly urban areas.
The average fall in the NO2 concentration of 2% a year in the last ten years is the result of measures taken by the Traffic and transport, Industry and Energy sectors. The fall in emissions of nitrogen oxides (NOx) from traffic and transport, among other things as the result of stricter requirements for emissions by motor vehicles, is partly negated by an increase of the number of kilometres travelled.

Different standards for prolonged and brief exposure to NO2


The EU has adopted two limit values for NO2 concentrations for the protection of public health: one for prolonged exposure and one for brief peak concentrations (EU, 1999).
  • For prolonged exposure, the limit value is 40 µg/m3 for the annual average NO2 concentration (see the figure above).
  • For exposure to peak concentrations of NO2, the limit value is 200 µg/m3 for the hourly average of NO2. This value must not be exceeded more than 18 times a calendar year.

With effect from 19 July 2001, these standards have been enacted in Dutch law in the Air Quality Decree (Staatsblad, 2001). Conformity with the limit values is required by 1 January 2010. Until then, the plan thresholds apply. They decline annually until they reach the limit value in 2010. In 2002, the plan threshold for the annual average NO2 concentration was 56 µg/m3 and 280 µg/m3 for the hourly value, exceedance of which is permitted no more than 18 times a year.

Impact of nitrogen dioxide on nature and public health


Adverse effects of NO2 on people and ecosystems occur after brief exposure to high levels of NO2 and after prolonged exposure to low levels of NO2.
  • It seems increasingly likely that traffic emissions have an impact on health. Here, NO2 is seen as an indicator of the mixture of particulate air pollution, that mainly comes from traffic exhaust fumes. Effects such as impaired lung function may be found in large sectors of the population. Other effects such as more asthma attacks, hospital admissions, cardiovascular disease and premature mortality are less common and often affect people whose health is weaker.
  • Effects on nature include leaf damage as a result of the conversion of NOx in leaf moisture to nitrogen compounds. There is also conversion in the atmosphere of NO2 to nitrate. This contributes to the acidification and eutrophication of soil and surface water.

References


Relevant sections and indicators in the Environmental Data Compendium


Relevant information outside of the Environmental Data Compendium
This page was last changed on November 22, 2005  (version 01).