Pro or contra green? ‘That one leg is just as long!’ - 24/10/2011


RIVM (Dutch National Institute for Public Health and Environmental Protection) recently published the report ‘The effect of vegetation on air quality’. SHFT, in cooperation with RIVM, has also carried out a lot of modelling work on the effects of green on the air quality in the city over the past few years, mainly in the Stadsbos (city forest) project.

The most important thing that we learned is that filtering fine dust through planting is mainly a search for a balance between the filtering and the aerodynamic effects of the plants. And that, through planting, we can contribute to air quality and many other factors for wellbeing in the city, but that we cannot solve the fine dust problem (the emission of it) by means of trees and plants.

It is a pity that the outcome of the RIVM report is read in such a negative way. As if green has suddenly lost its value. Any green element filters fine dust from the air; RIVM does not deny this. It just very much looks as if RIVM does not want to ‘approve’ of green as a compensating measure; the fine dust problem is so large in scale that the real solution is on the emission side, not on the filtering side. Nevertheless, any piece of green does filter air.

In the report ‘Climate change in urban areas: green and water storage in relation to the soil’, on the other hand, which was very recently published by RIVM as well, the message regarding the functions of green in urban areas as far as water storage is concerned, is very positive. It is a pity that the media do not elaborate on that. The fact is, this report demonstrates that the chances for innovative green in the city are numerous.

As a ‘green’ person who is involved in this matter, I do not think that we should create a division between ‘advocates’ and ‘opponents’ of green, because green always has a positive effect on our minds. Statements ‘pro’ or ‘contra’ green have the same value to me as a statement like ‘that one leg is just as long’. It is, however, more and more important to carefully use the ever-growing knowledge base in order to be able to realise the right green for the right functions at the right places in a balanced manner.

So, there’s work to be done!

Joris Voeten