In 2015 new rules from the IMO and legislation from EU (Sulfur directive) and the US requires ships to run with maximum fuel sulfur content (FSC) of 0.1 % m/m in northern European and North American waters. In order to promote a level playing field within the shipping sector, there is a need for measurement systems that can make effective compliance control and this is the main objective of the CompMon project, funded through the European CEF program (Connecting Europe Facility). As part of this project, a sensor system has been certified for ship surveillance measurements in a Piper Navajo aircraft and it has been demonstrated for airborne measurements of FSC in individual ships on the English Channel.

The measurement system consists of an optical module which measures total emissions of SO2 and NO2 in g/s and a sniffer system by which FSC is retrieved from extractive measurements of SO2 and CO2. It can be used from fixed sites, patrol vessels and from aircraft. The advantage with airborne surveillance is the capability to check ships that are operating in the main shipping lanes, up to 200 nautical miles from shore. The precision of the estimated FSC from the sniffer system is 0.05 % m/m and hence at the 95 % confidence limit, ships above a FSC of 0.2 % m/m can be checked. The sniffer system also has a negative bias in the FSC of approx- imately 0.04 % m/m which is accounted for in the FSC calculations.