Sulphur dioxide emissions from shipping have sharply decreased in EU ports thanks to an EU policy which limits sulphur content in fuels for ships at berth or at anchor in ports. Scientists at the European Commission's Joint Research Centre measured key air quality parameters in Mediterranean harbours before and after the entry into force of the low-sulphur requirements in January 2010. In European harbours they found an average decrease of 66% in concentrations of sulphur dioxide, a chemical compound that poses risks to health and the environment. Measurements taken in a non-EU port showed that levels of this noxious substance remained the same.