To examine particulate matter in more detail

In European countries, there is a reasonably high concentration of particulate matter.

Inhalation of particulate matter is harmful to the health. In the Netherlands, this reduces life expectancy by, on average, half a year. For that reason, it is important to gain an insight into the exact composition of particulate matter, how it finds its way into the air, how it spreads and how the concentration of particulate matter in the air can be reduced.

Particulate matter is a collective term for particles that float in the air. The fraction of the particulate matter of relevance to the policy is also referred to as PM10. PM stands for particulate matter. The number 10 stands for 10 microns. Particulate matter or PM10 comprises particles that are smaller than 10 micrometers (a thousandth of a millimetre). Particulate matter can be introduced to the air by human actions. The main sources of this are transport, industry and agriculture. Examples of natural sources of particulate matter are sea salt crystals and soil dust. Additionally, particulate matter contains molecules that play a role in acidification, such as nitrogen oxides and ammonia. Inhalation of these substances can reduce lung function and aggravate complaints of the airways.

European marginal values

The Policy-oriented Research Programme PM, abbreviated to BOP, was established to reduce uncertainties in the particulate matter dossier and to decrease the number of policy dilemmas in the field of particulate matter. In addition to PM10, the programme also focuses on PM2.5 (even finer particles of particulate matter). Although the air quality has improved over the past ten years in terms of particulate matter, exceedances of European marginal values are still being observed in the Netherlands. Particulate matter can be transported over large distances and is therefore a problem that transcends boundaries.

Atmospheric and chemical transport model

It is important that an improved understanding is gained into how particulate matter finds its way into the atmosphere, its composition, how it spreads and how the concentrations can be lowered. Using this information, better calculations can be made of the particulate matter in Europe and the region. This is done using the global model TM5, a three-dimensional, atmospheric and chemical transport model that provides the opportunity of zooming in on specific large-scale areas. This enables the import and export of particulate matter in Europe to be established. The Meteorology and Air Quality chair group at Wageningen University links TM5 to a model that works at regional scale level. In that way, processes regarding particulate matter in the Netherlands can be modelled and the expertise about particulate matter can be improved. This enables improved ways of determining the most effective way of solving problems involving particulate matter.

Local measures and weather conditions

Research reveals that the marginal values for particulate matter in the Netherlands after 2011 will only be exceeded in just a small number of places in the Netherlands. This is expected, in particular, in the vicinity of motorways around the large cities in the Randstad (the urban agglomeration of Western Holland), the busiest streets in the large cities and in the close vicinity of intensive livestock housing. Whether there will actually be exceedances of particulate matter concentrations will also depend on the impact of local measures and weather conditions.