Three years ago the City Council of Frederiksberg decided to improve the area around Langelands plads. Frederiksberg is fully surrounded by Copenhagen, but has maintained its independency. It is also the city in Northern Europe with the highest population density, and it remains a popular place to live.
One of the trademarks of Langelands plads are the NOx-reducing stones. They cover approx. 2.000 squaremeters, and the amount of NOx reduced will be around 43 kg NOx pr. year. The NOx reducing stones also remove organic material, like volatile organic compounds. However, this reduction has not yet been quantified.
The costs of improving the square with NOx reducing capabilities was approx 40.000 DKK (5,300 euro). Particularly when the NOx reducing stones are incorporated from the beginning, the project costs are neglectable.