A new joint study seeks to use satellite images to detect the emission of sulphur (SOX) and nitrogen dioxide (NOX) from sea-going vessels. The study is being conducted by the Dutch Environment and Transport Inspectorate (ILT) and the universities of Leiden and Wageningen.

As of 1 January 2020, the rules for the emission of SOX from seagoing vessels have been tightened. The maximum allowed sulphur content in fuel oil has been lowered from 3.5 to 0.5 per cent. For the emission of NOX, stricter standards have been set from 2021 onwards for new build vessels in the North and Baltic Sea.

At present, there is a lack of instruments to monitor the tens of thousands of seagoing vessels worldwide that, far out of sight of regulators, have to use cleaner, but more expensive fuel or have to install expensive waste gas treatment systems onboard.

For the Environment and a Level Playing Field

ILT supervises international rules for the emission of seagoing vessels for the Netherlands. ‘The emission of sulphur and nitrogen oxides from seagoing vessels is harmful to people and to the environment,’ says Jan van den Bos, Inspector General of ILT. ‘Part of the emissions above sea also reaches land. We already monitor sulphur in ports and off the coast in various ways. Monitoring via satellites far away at sea is a good step in improving enforcement. We do this for our living environment, as well as for a level playing field in the shipping industry.’


Wageningen University & Research provides expertise in interpreting satellite data and modelling the emission and spread of pollutants. Folkert Boersma, associate professor of Meteorology and Air Quality: ‘We are already able to measure exact emissions from large cities using the “Dutch” satellite instrument TROPOMI. But the satellite also does measurements above open sea. This allows us to zoom in on the emissions from individual ships. It would be great if we could use TROPOMI to check whether the ships comply with the rules at sea.’

‘Our most important goal is to calculate the degree of pollution per ship,’ adds Jacqueline Meulman, Professor of Applied Statistics at Leiden University. ‘We provide the knowledge for verification algorithms that can identify patterns in the huge flow of data. We use intelligent, self-learning algorithms, as well as (statistical) theories about missing values in the measurements.’

Picture: Measuring SOX emissions from a seagoing ship with a plane (by ILT).