NO2 peak concentrations in the Netherlands, 1986-2002
The EU standard for peak concentrations of nitrogen dioxide (NO2) was not exceeded in the Netherlands in 2002.
Favourable trend in concentration of nitrogen dioxide
The EU standard for peak concentrations of nitrogen dioxide (NO2) is not being exceeded in the Netherlands. Hourly values of about 200 µg/m3 are reached once or twice a year. For example, in 2002, the concentrations at two urban stations and a street station went above 200 µg/m3 for an hour.
The EU standard allows exceedance of the limit of 200 µg/m3 for a maximum of 18 hours a year. This was last observed in 1994 at two street stations. The concentration exceeded for 18 hours during a year fell in the last ten years by an average of 2.5% a year. The NO2 concentration exceeded for 18 hours was highest in the Randstad urban agglomeration. This is to be expected because the average annual concentration is also highest there.
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). NO2 concentration in the Netherlands (annual average), 1990-2002
- 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.
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 is increasingly likely that traffic emissions impact on health. Here, NO2 is seen as an indicator of the mixture of particulate air pollution, which 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. Overview of environmental themes and impact on nature in the Netherlands
