Nitrogen dioxide

Nitrogen dioxide

Nitrogen dioxide (NO2) is a gas that, in the Netherlands, is largely produced by traffic. It is therefore an important indicator for air pollution by traffic. Exposure to nitrogen dioxide (NO2) will cause a reduced pulmonary function, an increase in respiratory complaints and asthma attacks and an increased sensitivity to infections.

The concentration of nitrogen dioxide (NO2) in the Netherlands is relatively low in the north and higher primarily in the Randstad conurbation in the west of the Netherlands and the middle of the country. In 2015, nitrogen dioxide exceeded the standard primarily at a number of inner-city locations in the Randstad conurbation where there is lots of traffic. It has proved difficult to reduce these emissions.

Current situation

NO2 occurs along busy roads and wherever there is lots of industry and factories. Concentrations are relatively high particularly in the morning due to the morning rush hour combined with a weak wind or a cold lower layer of air, which all mean that the NO2 is scarcely able to dissipate.

The highest NO2 concentrations are observed at the street monitoring stations of the Air Quality Monitoring Network [Luchtmeetnet]. There you will find up-to-date measurement data on NO2. This data is updated every hour. In the Atlas of the Living Environment you can find the hourly calculations of nitrogen dioxide. You can also take a look at the annual average calculations for 2013 and 2014 and 2015.

Nitrogen dioxide contents can also be excessive inside. The indoor concentrations of NO2 may be higher than those outside due to the use of flue-less geysers and gas-fired stoves.

Trend

In recent years concentrations of NO2 have decreased by an average of approximately 0.5 micrograms/m3 per year. There was a more significant decrease in 2015. You can read about the causes of this decrease in the frequently asked questions. Measurements have shown that the introduction of catalytic converters in cars has led to a clear decrease in NO2 concentrations since the end of the Nineteen Eighties. In recent years concentrations have not declined as strongly as they did then. This may have to do with the introduction of soot filters, combined with oxidation-type catalytic converters, which has led to an increase in the proportion of nitrogen dioxide in exhaust fumes. The decrease in emissions of nitrogen dioxides by traffic is partially being cancelled out by an increase in the number of kilometres driven.

edited February 13th 2018

Health effects of nitrogen dioxide

Nitrogen dioxide (NO2) can penetrate to the smallest branches of our airways. Exposure to NO2 will lead to a reduced pulmonary function and sometimes to an increase in respiratory complaints and asthma attacks and increased sensitivity to infections. These effects are found at levels under the current threshold values for short-term exposure. It is currently unclear whether the associations observed indeed reflect a causal link between NO2 and the health effects, or whether this is a statistical association, whereby the NO2 levels are an indication of a complex mixture of air pollutants of which one or more substances cause the effects found. NO2 is therefore a useful criterion in terms of the mixture of air pollution from traffic and the related health effects.

edited February 13th 2018

Air Quality Directive

A new European directive for air quality came into effect in 2008. The Netherlands was given a deferment for nitrogen dioxide until 2015 on the basis of the remediation measures described in the National Air Quality Cooperation Programme [Nationaal Samenwerkingsprogramma Luchtkwaliteit] (NSL). As from 1 January 2015 the Netherlands has had to comply with European air quality standards detailed below.

Standards

Two threshold values have been established for nitrogen dioxide: one for the annual average concentration and one for the hourly average concentration to set a limit to peak concentrations.

  • The annual average threshold value is 40 micrograms/m3.
  • The hourly average threshold value is 200 micrograms/m3. This is not allowed to be exceeded more than 18 times per year in the case of roads with at least 40,000 vehicles per day.
     

The maps in the Atlas of the Living Environment are an indication and are intended to give an impression of air quality. The maps in the Atlas therefore do not contain any official testing locations, nor the data used to make the official assessment on the threshold values. You can find the official testing locations in the NSL Monitoring Tool.

Plans of action

If a threshold value for nitrogen dioxide is exceeded, the municipality, provincial government or the state must take measures to reduce the concentrations and describe these in an action plan.

Decree on sensitive developments [Besluit gevoelige bestemmingen]

In December 2008 the 'National policy Decree on sensitive developments (air quality requirements)' stipulated that schools, childcare facilities, nursing homes, care homes and homes for the elderly may only be built within 300 metres of the edge of a motorway of 50 metres or the edge of a provincial road if there is no (risk of) exceeding (of) the threshold values for air quality (PM10 and NO2). This applies to new construction, but also to expansions by more than 10% of the capacity.

The Minister also wrote: "…Damage to health can, however, also occur if there is no exceeding of the standard. For that reason administrative bodies are advised to be reticent when it comes to deciding on and realising sensitive developments within the zones referred to along roads, even where the standards are not exceeded. The various factors should be weighed up within the context of the principle of proper spatial planning…".

edited February 13th 2018

Things you can do yourself to combat air pollution

You can also do things yourself to limit air pollution or its effects. You can, for example, opt for environmental friendly transport, or for a cycling route which takes you past less contaminated areas, or reduce the amount of energy you consume at home. The Environment Centre [Milieu Centraal] provides practical tips on how you can reduce any harmful health effects of air pollution yourself.

Although exercising is healthy, when taking part in sporting activities you should take the location or route into account. Avoid busy roads with high-rise buildings and numerous trees where pollution tends to accumulate. You should also avoid busy crossroads. You should not forget that the positive effects of, for example, cycling more than outweigh the detrimental effects of air pollution.

edited February 13th 2018