Frequently asked questions - ultrafine particles
General
What are ultrafine particles?
The air is full of dust particles. When they are smaller than 0.1 micrometres, we refer to them as ultrafine particles. To get an idea of how small these particles are: 0.1 micrometre is 10,000 times smaller than a millimetre. Ultrafine particles cannot be seen with the naked eye.
Where do ultrafine particles come from?
Most ultrafine particles are produced during the combustion of fossil fuels like diesel or kerosene, used by cars and planes. You can also be exposed to ultrafine particles indoors, including when you cook on gas, fry and deep fry food, smoke, burn candles and light the fireplace.
What are the biggest sources of ultrafine particles at Schiphol?
At Schiphol, ultrafine particles mainly come from aircraft engines, diesel vehicles and diesel-powered machinery, such as the ground power units (GPUs) that provide planes on the apron with electricity.
What is the difference between particulate matter and ultrafine particles?
Both are dust particles, the difference is the size. Particulate matter refers to dust particles less than 10 micrometres. Ultrafine particles are less than 0.1 micrometres. Aircraft engines mainly produce ultrafine particles. Diesel-powered vehicles emit both.
Can you see ultrafine particles?
No, ultrafine particles cannot be seen by the naked eye.
Is the amount of ultrafine particles increasing?
It’s hard to tell right now. Ultrafine particles is a fairly recent topic of investigation. At the moment, the National Institute of Public Health and the Environment is researching ultrafine particles in the area around Schiphol. And we are working on a study into exposure at work for individual employees.
Are there ultrafine particles only at airside or landside too?
There are many sources of ultrafine particles and they can be found everywhere: airside, landside, in cities, along motorways, in tunnels and even in your home. The concentrations of ultrafine particles differ per location.
Does Schiphol measure ultrafine particle concentrations?
Schiphol has been researching and trying to reduce ultrafine particle levels for a while. The Ultrafine Particles Action Plan was drawn up in 2019, together with other parties at the airport. One of the measures was a study into ultrafine particle concentrations at the airport by TNO, an independent research institute. The study was concluded in October 2021. It showed that the concentration of ultrafine particles outside the terminal and piers was around 100,000 to 120,000 particles per cubic centimetre. These measures do not say anything about the exposure for individual Schiphol employees; additional research will need to be carried out that takes work time and exact locations into account. We are currently working on setting up and conducting an exposure and health effects study among employees.
That is why we are carrying out additional research. In September and October 2023, an independent research firm carried out a large-scale exposure study. Measurements were carried out for various functions on the apron. We are also installing sensors to measure the concentrations of ultrafine particles on the aprons, two of which are already being monitored. This will give us good insight into ultrafine particle emissions and into the long-term effect of measures.
Health
Are ultrafine particles bad for my health?
We do not yet know what the health effects of ultrafine particles are. Too little research has been done to make reliable statements about this. Research published by the Health Council of the Netherlands at the end of 2021 showed that it can be harmful in the case of both short and long-term exposure.
What are the potential health effects of being exposed to ultrafine particles?
Too little research has been done to be able to make reliable statements about this. However, according to the Health Council, studies have shown what effect ultrafine particles can have on your health. There are indications of adverse effects on the cardiovascular system and the respiratory tract in the event of short-term exposure to ultrafine particles. Long-term exposure increases the risk of cardiovascular disease. There is also evidence of an increased risk of developing respiratory diseases and of a negative influence on the growth of a foetus. The RIVM has conducted a study into the health effects of ultrafine particles among people living in the vicinity of Schiphol. The results of this study can be found here. Schiphol is currently busy setting up a study into exposure and health effects among employees.
How can I find out if my health has already been affected?
That’s not possible at the moment. A lot of research still needs to be done into the effect on health. That is why Schiphol considers it important that research is carried out into the health of employees and that the exposure of employees to ultrafine particles from aircraft is assessed. And that employees' exposure to ultrafine particles from aircraft is assessed. That is why we are conducting a large-scale exposure study next summer. The Periodic Occupational Health Examination (PAGO) is key to detecting medical conditions that may arise due to exposure to ultrafine particles. Specific questions and/or medical tests related to ultrafine particles will be added to the PAGO from summer 2023. As an employee, you can voluntarily participate in a PAGO.
Which measures are best for my health?
We know that ultrafine particles are mainly produced during the combustion of fossil fuels. Measures that lower the consumption of fossil fuels will therefore have the greatest effect. The same goes for keeping a distance from sources of ultrafine particles.
If you work at airside, wear an FFP2 face mask. Your employer can provide you with more information about this. An FFP2 mask can provide up to 97% protection against ultrafine particles. Wear this mask when exposed to exhaust gases from aircraft and diesel engines, as well as when close to busy traffic at covered parts of the RH road. You can of course wear it anytime you wish too.
What obligations does Schiphol have regarding the health and protection of employees?
As an employer, Schiphol has a duty to provide its employees with a healthy and safe workplace. To this end, risks are identified by means of a risk inventory and evaluation (RI&E) and the measures required to further minimise these risks are determined. For example, exposure to hazardous substances during the performance of work should be limited as much as possible. Responsibility for the measures lies primarily with the employer, but employees can also play a role. Employees are informed about the risks that the work can entail and about the necessary measures.
Measures taken by Schiphol
When did Schiphol start taking measures against harmful emissions from engines?
We have been looking at diesel engine emissions since 2007. Since then, a lot of measures have been taken to reduce the consumption of diesel. A study by the National Institute for Public Health and the Environment (RIVM) drew attention to ultrafine particles. Schiphol subsequently published the Ultrafine Particles Action Plan, focusing on more research and a large number of measures.
What are the main priorities for Schiphol in terms of ultrafine particles?
Ultrafine particles are produced during the combustion of fossil fuels like diesel and kerosene. Schiphol is therefore taking measures to reduce the use of both diesel and kerosene. We are also increasing the distance between vehicles, aircraft and our employees. Furthermore, we are investigating how we can make the air cleaner.
Which measures to reduce ultrafine particles is Schiphol focusing on?
Regarding the journey to and from the airport, there are measures to encourage the use of public transport and to have as many electric buses and taxis as possible at and around Schiphol. At the airport, measures include the creation of low-emission zones (as of 2025) and making ground operations more sustainable. Examples are replacing diesel vehicles with electric ones, providing shore power and taxiing sustainably. In the air, the measures being taken concern fleet renewal and the use of sustainable aviation fuel. Furthermore, employees at airside can also make use of FFP2 masks that can offer 97% protection against ultrafine particles. Ask your employer for more information if you work at Schiphol. Read more about the measures here. It’s also important that we conduct more research in order to have a better understanding of which measures have the greatest impact.
Who is Schiphol collaborating with?
Schiphol is working with all parties involved: handling companies and airlines in the aviation industry, and the FNV (on behalf of the unions), Dutch government and research institutions outside of the sector.
TNO is suggesting that aircraft on the apron are towed ‘away from the area where ground staff are before they start their engines’. What is Schiphol doing with this recommendation?
Determining personal exposure was not part of the TNO study. It did, however, show that ultrafine particle concentrations are highest around the terminal and piers. We are working with the aviation sector to find out how we can better protect employees who are exposed to high concentrations. This includes other start-up or taxi procedures and how these can contribute to reducing the emission of ultrafine particles.
Why isn’t sustainable taxiing standard procedure at Schiphol yet?
We can’t implement sustainable taxiing just like that; it has a significant impact on the operation. Schiphol carried out a first sustainable taxiing pilot study in 2020. Sustainable taxiing is when a special towing vehicle takes aircraft to and from the runways. This procedure means that the aircraft engines can remain switched off for longer. Currently, there is only one certified type of vehicle for this procedure. This special vehicle is needed because standard pushback trucks are not suitable for these distances and speeds – too much force would be applied to the nose wheel.
Many of the adjustments that need to be made for sustainable taxiing are new to aviation. The first pilot and feasibility study showed that significant adjustments to infrastructure, processes and technology are required. At the end of 2022 we started follow-up trails. The aviation industry has presented a step-by-step plan in which the goal is for sustainable taxiing to become standard procedure at Schiphol by 2030. The first step is the acquisition of two towing vehicles that have been deployed at Schiphol. The next step is to test, introduce and scale up the new procedures for sustainable taxiing to and from the Polderbaan, among others, from mid-2024.
Does Schiphol look to other international airports for potential measures?
Yes. Schiphol collaborates with other airports internationally in order to share knowledge and experience with regard to ultrafine particles. However, not all measures can simply be copied and implemented at Schiphol – airports differ too greatly for that. Furthermore, we only introduce new procedures when it is safe to do so.
When does Schiphol want ground operations to be emission free?
Schiphol aims to be an emission-free airport by 2030. Ultrafine particle emissions will need to be significantly reduced before then.
Measures for employees
What can I do to reduce ultrafine particle emissions?
- Connect the aircraft to shore power or an e-GPU as soon as it is safe to do so (and if available). That way, you ensure that the jet engines and APU are used for the shortest possible period of time.
- It sometimes looks as though the shore power is out of order due to there being a diesel GPU next to it. Always check the screen of the shore power unit to check whether there really is a malfunction. And to see if the malfunction can be fixed with a simple reset.
- Perhaps stating the obvious, but don’t let your vehicle idle unnecessarily.
What can I do to reduce my exposure to ultrafine particles?
If you are driving in a vehicle with closed cabin, keep the windows shut. Especially when you are driving on perimeter roads or aircraft stands with taxiing aircraft close by.
Wear an FFP2 face mask. Ask your employer for information about this. Wearing the face mask is voluntary, but we do recommend it if you work at airside. If you use the mask properly, it can provide up to 97% protection against ultrafine particles. Wear this mask when exposed to exhaust gases from aircraft and diesel engines, as well as when close to busy traffic at covered parts of the RH road. You can of course wear it anytime you wish too.
Standards
Is there an official standard for ultrafine particles?
No. Because we know too little about ultrafine particles, the government cannot establish an official standard. We first need to know more about ultrafine particles and the potential health effects.
Can Schiphol set its own standard?
In the past, we set a business standard of 10 micrograms per cubic metre for diesel engine emissions. In 2020, the government set a national standard (also 10 micrograms per cubic metre). The level of diesel engine emissions at Schiphol is measured twice a year. Recent measurements show that we are well under this norm.
When will there be an ultrafine particles standard?
It’s hard to say. More research needs to be carried out first.
Research
Which studies have been carried out at and around Schiphol so far?
2015: exploratory research by the National Institute for Public Health and the Environment (RIVM) showed that ultrafine particles around Schiphol come from air traffic.
2017: RIVM study looking at the health effects of ultrafine particles in the area around Schiphol.
2019: interim results of RIVM study into the health effects of short-term exposure to ultrafine particles around Schiphol. Th health effects of long-term exposure to ultrafine particles will follow in 2022.
2021: TNO study into ultrafine particle concentrations around the terminal and piers. Concentrations of around 100,000 to 120,000 particles per cubic centimetre were measured.
2022: taskforce set up to investigate the consequences of ultrafine particles for apron employees. Also focused on the efficacy of measures, such as wearing PPE while working on the apron, modifying the pushback procedure and further reducing APU use.
2022: Results RIVM ultrafine particles study: health effects of long-term exposure to ultrafine particles around Schiphol.
2023: start of experimental research into cleaning the air at the apron.
2023: large-scale study into exposure of apron employees to aircraft engine emissions (carried out by an independent party).
2023: adjusted PAGO introduced (specific questions/tests relating to complaints that may be linked to ultrafine particles).
2023: Start of study into personal respiratory protection. Apron employees test various types of respiratory protection to find out which mask offers the best protection and is most comfortable to wear at work.
Read more about research into ultrafine particles at and around Schiphol.