Roy, Christiaan en Jan voor de keet bij Proeftuin luchtkwaliteit

A Testing Ground full of noise barriers and measuring equipment (32/50)

Specially designed sound barriers that changed shape every 3 months, 13 measuring points behind and next to the barriers, and a mountain of measuring equipment. The Testing Ground for air quality was a major study commissioned by Rijkswaterstaat. Christiaan Tollenaar and Roy van der Heijden participated in the study in 2006 and 2007.

With their diploma in their pocket, a little bit of experience in noise measurement, and a message from project leader Jan Hooghwerff that they were allowed to arrange much of it themselves, they started this air quality pilot project. Christiaan first, in 2006. He carried out much of the preparatory work. Roy followed him in 2007. It was indeed quite an arrangement to get and keep the Testing Ground running on the A28, near Nulde beach.

Crash course in measuring air quality

“I had already done something with sound but had no experience with air quality, and Roy had only been employed for a short time. Fortunately we received some great guidance from the Belgian company that supplied the measuring equipment, as well as a crash course in ‘How do I measure air quality?’”, says Christiaan, who remembers that the research was preceded by a competition organised by Rijkswaterstaat. “The challenge was to design a barrier that would improve air quality along the motorway. Quite a few barriers were put in place during the research: smooth barriers, barriers with special paint, with a rough surface, with plants on them, etc. This was a really extensive project for Rijkswaterstaat.”

The effect ofdifferent types of noise barriers

“The idea behind it was that the air would be pushed upwards through the noise barriers where it would be mixed with the air layers above, lowering the particulate matter concentrations. The measuring equipment was placed at 5, 10 and 28.5 metres behind the barriers – in the shadow zone – and at these distances we had to measure the effect on the quality of the air over the barrier,” explains Roy. “Each measurement session lasted 3 months. Before the next test with other variants of noise barriers began, major maintenance was carried out and a meeting held with the guidance group committee to discuss the interim results. The research was expanded with new measurements time and again. In the end there was an enormous amount of equipment and the research lasted a year and a half. This showed that the surface material of the noise barrier does make a great deal of difference.”

Meetapparatuur Proeftuin voor luchtkwaliteit

One day a week on the road togetheRented vans were driven up and down, poles and concrete slabs towed, electricity arranged and expensive mobile data subscriptions – we are talking about a number of years ago – purchased to transfer the enormous amount of data we collected. Meanwhile, both young men loved to be able to go out every week for a day. Driving or walking from one measuring point to another, replacing particulate filters, enjoying a nice lunch in the nearby shack, and hanging laptops and gas bottles on the equipment to perform calibrations. “Remember that time water poured out of 4 of the 5 connected laptops?” Roy asks. Christian remembers it very well. “The system administrator asked us: “How come this laptop is broken?” I told him that it actually tolerated water exposure for a short time, but after half an hour in the rain it started to act up.”

A beuatiful and educational starter project
Now, many years later, neither gentlemen can be considered a novice; they have extensive experience with all kinds of measuring equipment. But they still remember the feeling they had on their first big project very well. “It was a great opportunity to gain a lot of experience,” says Christiaan. “We learned a lot about carrying out analysis. Measurements were taken every minute at 13 measurement points, and this was more than Excel could handle. It was hard work to make it all run smoothly, but it was a wonderful experience!”