NOx and NH3: Nitrogen in Construction, Infrastructure and Transport
Nitrogen has been at the centre of Dutch news for years and for good reason. The consequences are felt across construction, infrastructure and transport: from delayed projects to stricter requirements in tenders. Two substances play a central role: nitrogen oxides (NOx) and ammonia (NH3). In this article, we explain what they are, why they are harmful, and what that means for your organisation.
What is nitrogen?
Nitrogen (N2) is a colourless and odourless gas that surrounds us everywhere. In its pure form, nitrogen is completely harmless to humans and the environment. But when nitrogen forms compounds with other elements, that changes. The nitrogen compounds emitted by humans (through traffic, industry and construction) can be harmful. The two most important are nitrogen oxides (NOx) and ammonia (NH3).
What are nitrogen oxides (NOx)?
NOx is a collective term for nitrogen oxides. The two most common are nitric oxide (NO) and nitrogen dioxide (NO2). They are produced by the combustion of fossil fuels at high temperatures, such as in diesel engines of trucks, excavators and other construction machinery.
During combustion, nitrogen and oxygen from the air react with each other. The nitric oxide released in this process is quickly converted to nitrogen dioxide in the air. NOx spreads easily and can travel hundreds of kilometres before settling somewhere.
Is NOx harmful?
Yes, both to humans and to nature. NOx penetrates deep into the airways and impairs lung function. This can lead to respiratory complaints, asthma attacks and increased susceptibility to infections. In addition, NOx contributes to the formation of fine particulate matter, further deteriorating air quality.
In nature, NOx contributes to acidification and eutrophication of the soil. Too much nitrogen causes nutrient-rich plants such as grass and nettles to crowd out rare plant species. In vulnerable nature areas, this leads to a loss of biodiversity.
What is ammonia (NH3)?
Ammonia is a colourless gas with a characteristic sharp odour. It is a compound of nitrogen and hydrogen. Unlike NOx, ammonia spreads less far. It settles closer to the source.
The largest source of NH3 in the Netherlands is agriculture, through manure and artificial fertiliser. But NH3 is also released in the construction and infrastructure sector. Modern diesel engines use a system that reduces NOx emissions via AdBlue, a urea-based fluid. As a by-product of this SCR system (Selective Catalytic Reduction), ammonia can be released in exhaust gases, particularly if the system is not functioning optimally.
Is NH3 harmful?
At high concentrations, ammonia is harmful to health. It irritates mucous membranes, airways and eyes. In outdoor air, such high concentrations rarely occur.
For nature, NH3 is a greater problem. Like NOx, ammonia contributes to eutrophication and acidification of the soil. In Natura 2000 areas, the damage from nitrogen deposition is already so severe that new economic activities must meet strict requirements.
Why is nitrogen such a major problem in the Netherlands?
The Netherlands is among the countries with the highest nitrogen emissions per hectare in Europe. Roads, agriculture and nature areas are located close together. This makes the nitrogen problem particularly acute here. Strict rules apply to activities that cause nitrogen deposition near Natura 2000 areas. For construction and infrastructure, this has major consequences.
Why are NOx and NH3 relevant for construction and infrastructure?
Construction projects near Natura 2000 areas must demonstrate through AERIUS calculations that NOx and NH3 emissions from machinery and vehicles remain within the established limits. The more accurate the emission data, the more reliable the AERIUS calculation. This means that estimates based on machinery manuals are increasingly insufficient. Clients and permit authorities require substantiated figures per project location and period.
What is AERIUS?
AERIUS is the official calculation tool of the Dutch government for calculating nitrogen deposition. It is developed in collaboration between provinces, ministries, RIVM and BIJ12. The AERIUS Calculator is the component used in permit granting. It calculates, based on emission data, how much nitrogen is deposited in Natura 2000 areas as a result of an activity. As input, it requires emission data: how much NOx and NH3 do vehicles and machines emit at a specific location and during a specific period?
For construction companies and contractors, this means they must be able to demonstrate per project that nitrogen deposition remains below the threshold value. The more accurate the emission data, the more reliable the AERIUS calculation.
How do you measure NOx and NH3 in construction, infrastructure or transport?
For construction and infrastructure companies, as well as in transport, the provision of reliable emission figures is becoming increasingly important. The data is already in the vehicles and machines. Fuel consumption, operating hours and AdBlue consumption are recorded via the on-board computer. Based on this data and the emission class of the vehicle or piece of equipment, NOx and NH3 can be calculated per project location.
The calculation method converts data from vehicles and machines into CO2, NOx and NH3 per project location and period. GPS-Buddy has had its IT controls regarding emission and reporting methodology independently assessed within an ISAE 3000 assurance process, carried out in collaboration between TÜV NORD Netherlands and its partner Diggle BV. The report is exportable in PDF, XLSX or CSV format and directly usable with permit authorities, clients and tenders.
Permits, tenders and clients are setting ever-higher standards for emission data. Those who have this data available automatically and reliably are in a stronger position on every project.
Want to know more about emission reporting?
This article describes a situation in the Netherlands. For the most up-to-date laws and regulations, please consult the relevant government authorities. Situations may change. No rights can be derived from this article.