Utrecht diesel ban linked to 17 percent air quality improvement

Sign indicating whether or not your diesel car is allowed to enter the Utrecht environmental zone (Picture: Twitter/@iWeethetbeter)Sign indicating whether or not your diesel car is allowed to enter the Utrecht environmental zone (Picture: Twitter/@iWeethetbeter)

Air quality in Utrecht improved more than air quality in Amsterdam and Rotterdam over the past year, according to a study done by research institute TNO. This can likely be attributed to Utrecht's implementation of an environmental zone banning old cars, but other factors may also be involved, the research institute concluded, the Volkskrant reports.

TNO did a study to assess the impact Utrecht's environmental zone had on air quality in the city. To do so, the research institute measured air quality on the busiest streets in Utrecht, Amsterdam and Rotterdam and compared them to measurements done the previous year year.

Measurements were made between 13 June 2014 and 7 November 2014 and then again between 8 June 2015 and 28 November 2015.

On Utrecht's Catharijnesingel the first measurements found 1.68 milligrams of soot particles per kilogram of air. The second measurement found 1.39 milligrams, a decrease of 0.29 milligrams or 17 percent.

On Amsterdam's Van Diemenstraat 1.72 milligrams were first measured and then 1.58 milligrams - a decrease of 0.14 milligrams or 8 percent. On Rotterdam's Pleinweg it was 2.24 milligrams and 2.28 milligrams - a decrease of 0.14 milligrams or 5.7 percent.

"It is likely that the in Utrecht implemented environmental zone explains a part of the difference in the decrease of concentration of soot between Utrecht on the one hand and Amsterdam and Rotterdam on the other", TNO writes. But the institute adds that the weather, traffic levels and other variables may also have played a role, so it can not give a guarantee.

"The report fails to deliver the dram evidence of the effectiveness of the environmental zone, but it is a compelling story", Utrecht's Traffic alderman Lot van Hooijdonk (GroenLinks) responded to the Volkskrant. "The car fleet is cleaner and the air is cleaner. For the political debate, it would have helped had there been a stronger than casual relationship with the environmental zone. The entire Utrecht college finds the health benefits of cleaner air important. It's a pity that the government nullifies much of our efforts by increasing the speed limit to 130 kilometers per hour."

Van Hooijdonk asked the RIVM to examine the implications of extending the environmental zone. If it will have a positive effect, she will propose an expansion.