Air contamination and odour nuisance

Good air quality is very important for people and ecosystems. Air contamination usually consists of particles (particulate matter) and harmful gases such as nitrogen dioxide and ozone (smog). Air pollution is not only caused by traffic and industry, but also by agriculture and Dutch households.

In order to limit the harmful effect of air pollution, the government sets threshold values for the amount of harmful substances in the air. When doing so, the government has to weigh up the importance of protecting public health, ecosystems and economic interests.

Besides air quality, odour nuisance also plays a role in how we experience our living environment. Smell is all around us. If smell has a negative effect, we refer to it as odour nuisance.

Measurements and calculations

RIVM continuously measures air pollution at various locations in the Netherlands. You can find the most recent observations on the Air Quality Monitoring Network [Luchtmeetnet]. They are indicated by dots with a certain colour. The results from both RIVM and other parties are shown on that site.

Besides measurements based on a number of points, RIVM also performs calculations. Measurements reveal the concentration of the substance in question immediately around the measuring point. The concentrations for a large area can be determined using model calculations. Calculations can be accessed via various maps in this Atlas. For example, you can study for up-to-date hourly maps, namely the current air quality index, the particulate matter concentration (PM10), the ozone concentration and the concentration of nitrogen dioxide. There are also maps showing the annual average concentrations of various substances, such as the annual average concentration of particulate matter in 2015.

Current calculations, as well as calculations for tomorrow and the next day, can also be found at On that same site you can also choose a substance and see how it develops over time (until the day after tomorrow).

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Air and health

Air contamination can exacerbate respiratory complaints and cardiovascular conditions. Smog can occur on summer days. When exposed to it, people may experience dizziness, nausea, headache, irritation of the eyes and breathing difficulties, particularly if they already have respiratory complaints. Vulnerable groups are the elderly, children, people with asthma or lung diseases, cardiovascular diseases or diabetes.

Air contamination can have an effect on people's health after both short-term high exposure and long-term exposure to low levels. You can read about the specific health effects on the background pages on particulate matter, nitrogen dioxide and soot. In addition to this, odour nuisance can also affect people's health.

Traffic and air pollution

Exhaust fumes and particles which are released due to wear and tear of road surfaces and tyres constitute a key source of air pollution. Exhaust fumes contain, among other things, nitrogen dioxide (NO2), particulate matter (PM10 and PM2.5), ultrafine particles (PM0.1) and soot. Ozone is not emitted by traffic. Under the effects of sunlight it is created in the air from nitrogen oxides, carbon monoxide and volatile hydrocarbons. Ozone concentrations can increase rapidly when the weather is hot and there is little wind.

Traffic is a major source of nitrogen dioxide, soot and ultrafine particles (<PM0.1). The concentration is high close to a busy road. It decreases rapidly as the distance to the road increases. The concentration of particulate matter, which is measured as PM10 and PM2.5, does not decrease so strongly because sources other than traffic are more important for the production of this particulate matter. Nitrogen dioxide and soot are therefore more reliable criteria than particulate matter (PM10 of PM2.5) when it comes to determining how much air pollution traffic causes and what effects this has on people's health.

Traffic and health

People who live close to a busy road have a slightly greater chance of their health being affected than people who live further away. Observed health effects are a reduced pulmonary function, (chronic) respiratory complaints, exacerbation of cardiovascular diseases and lower life expectancy. It affects people who live within a distance of 100 metres from a motorway, or within 50 metres from a busy urban road.

Children who live or go to school along busy roads have, on average, more respiratory complaints than children who live or go to school a long way from busy roads. They also have a slightly reduced pulmonary function, on average. There is a link particularly to the number of lorries on a motorway. The assumption is that the soot particles in exhaust fumes (from, above all, diesel engines) play an important role in this respect.

It is difficult to determine exactly which individual substance or substances cause these health effects. It is also difficult to determine at which distance from the motorway no more health effects will occur.

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Weighing up interests

The government has to take various factors into account and weigh up the importance of protecting both public health and economic interests. Increasing the speed limit can, for example, lead to a slightly shorter journey time, but also to more traffic accident victims and an increase in emissions of particulate matter, nitrogen dioxide and carbon dioxide (a greenhouse gas).

Examples of measures which the government takes to reduce the health risks of air pollution are:

  • Designating areas which only clean vehicles can access (environmental zones).
  • Ensuring cleaner public transport.
  • Making soot filters obligatory.

    National Air Quality Cooperation Programme [Nationaal Samenwerkingsprogramma Luchtkwaliteit] (NSL)

     In the National Air Quality Cooperation Programme (NSL) the state, the provincial governments and the municipalities collaborate in order to implement the European requirements for air quality. The NSL's main task was to ensure that, as of January 2015, the entire Netherlands stays below the threshold values for particulate matter and nitrogen dioxide. The annual NSL Monitoring Report for 2016 was published at the end of 2016. This report stated that the calculated concentrations of particulate matter and nitrogen dioxide were below the European standards in most areas of the Netherlands in 2015. However, the standard for nitrogen dioxide is still being exceeded in a number of busy streets in town centres and the standards for particulate matter are still exceeded particularly in a few intensive livestock farming and industrial areas.

The National Air Quality Cooperation Programme may well continue its work for a couple more years. From the moment that the Environmental and Planning Act [Omgevingswet] comes into effect, work will probably be based on air quality focal areas. This will be a significantly streamlined form of the current monitoring, with work concentrating on areas which still have to improve as regards particulate matter or nitrogen dioxide.

The state has set up the Air Quality Innovation Programme [Innovatieprogramma Luchtkwaliteit]. Within this framework the Ministry of Infrastructure and the Environment (I&M) is able to assess which measures can be used to improve the air quality in densely populated areas along motorways. The focus is on, for example, the possible covering of motorways, the use of coatings on noise barriers which break down nitrogen dioxide and the planting of trees and shrubs along motorways.

Remediation Tool

The Remediation Tool was developed for the NSL and provides a mathematical basis. It was used to map out the locations in which the threshold values were being exceeded. The required traffic data was provided by the municipalities involved in the NSL, the provincial governments and the state. The Remediation Tool was used for the centralised calculation of the air quality. It was adopted in September 2009 and contains local, regional and state measures for resolving all bottlenecks for particulate matter (PM10) and nitrogen dioxide.

Monitoring Tool

The Monitoring Tool was developed on the basis of the Remediation Tool to enable the monitoring of air quality. In other words to determine whether the bottlenecks are actually resolved with the NSL. The results of the Monitoring Tool have been published every year since 2010 and show the changes at all surveying locations. The next monitoring tool report is to be published at the end of 2017. Now that we have fulfilled all the European standards, the question is whether such a detailed report will be issued in the coming years.

Threshold values

The European Union has drawn up threshold values for substances in the air. The focus is on the harmful substances of sulphur dioxide, particulate matter, nitrogen dioxide, lead, benzene and carbon monoxide. Threshold values may not be exceeded.

Target values have also been drawn up. The government has a best-efforts obligation for target values, meaning it has to do its best to keep the concentration below the target value.

You can find an overview of the standards and the target values in the Environmental Data Compendium. This also states whether the standard focuses on protecting people's health or on protecting nature.

A number of air standards are:

Substance                                                   Standard                             Status
Sulphur dioxide (SO2) 125 µg/m3

Daily average: may not be exceeded on more than 3 days per year

Treshold value
Nitrogen dioxide (NO2) 40 µg/m3 Annual average Treshold value as 2015
Particulate matter (PM10) 40 µg/m3
50 µg/m3

Annual average
Daily average: may not
be exceeded on more than 35 days per year

Treshold value
Particulate matter (PM2,5) 40 µg/m3

50 µg/m3
Annual average
Annual average, determined on measurements at
urban background locations
Treshold value as from 2015
Ozone (O3) 120 µg/m3 Progressive average
over 8 hours
Target value
Carbon monoxide (CO) 10.000 µg/m3 Progressive average
over 8 hours
Target value
Benzene 5 µg/m3 Annual average Treshold value

The progressive average is an average that is calculated again and again over the past 8 hours, but whereby the 8 hour period shifts up, for example from 2 to 10 o'clock, from 3 to 11 o'clock and from 4 to 12 o'clock.

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Approved calculation method

Two standard calculation methods are permitted when calculating the error concentrations alongside roads. For roads within an urban environment, standard calculation method 1 (SRM1) has to be used and for roads in the open field, standard calculation method 2 (SRM2) applies. The air quality relating to industry of agriculture is calculated with SRM 3, the calculation method of the New National Model (NNM).

Standard calculation method 1, SRM1

SRM1 can be used to calculate the concentrations of air pollutants at relatively short distances to the road axis. Depending on the type of road this can be up to 30 or 60 metres. SRM1 is not suitable for calculating the air quality behind buildings. It is not possible to use this method to take account of the influence of a raised or sunken road location, nor of protective constructions such as noise barriers and tunnels. Standard calculation method 1 does take account of the influence of existing trees on air quality.

Standard calculation method 2, SRM2

SRM2 can be used to determine the air quality along roads through an open, usually rural, area. If buildings are situated along the road, SRM2 can only be used if the distance between the buildings and the road is greater than three times the height of the buildings. SRM2 can calculate concentrations at a relatively large distance from the road. In practice, the calculations are usually limited to a distance of 1,000 metres. SRM2 does not take any account of the influence of tunnels.

Standard calculation method 3, SRM3

SRM3 is prescribed in the Netherlands in order to calculate the consequences of point or surface sources for air quality. SRM3 is based on the agreements which have been made within the framework of the New National Model (NNM).

Approved calculation methods

Various bodies have developed calculation models which are based on one of the calculation methods described above. In the Air Quality Assessment Regulation 2007 [Regeling beoordeling luchtkwaliteit 2007] the government has indicated which calculation models may be used to calculate air quality. This regulation states that the CAR model complies with SRM1 and that the Air Quality Forecasting System For Road Design Variants [Voorspellingssysteem Luchtkwaliteit Wegtracévarianten] (VLW) complies with SRM2. A different model may only be used if it has been approved by the Minister of Infrastructure and Water Management. The approved calculation method is published on the website of the Ministry of Infrastructure and Water Management. The list with approved models is regularly updated.

The difference between calculating and measuring

Measurements of nitrogen dioxide and particulate matter provide information about the situation immediately around the measurement position while the measurements are being taken. Measurements are therefore strongly influenced by sources in the immediate surroundings. It is sometimes difficult to choose an optimally representative location for the measurement position.

Model calculations can be used to obtain information about the concentrations in a large area. In the Netherlands, the results of model calculations are regularly compared with measurements and calibrated where necessary. A check is performed annually for calculations in urban areas. Within the framework of the NSL monitoring, RIVM not only performs regular measurements but also extra measurements for nitrogen dioxide and particulate matter.

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