Whilst air pollutant emissions from land-based sources are gradually being brought into line with non-exceedance and health standards, the emissions from ships continue unabated. Large cargo ships rely on fossil fuels and produce around a billion tonnes of CO2 annually. Heavy fuel oil can contain 3,500 times more sulphur than diesel that is used for land traffic vehicles. Ships do not have exhaust abatement technologies like particulate filters that are standard on passenger cars and lorries.
No limits exist for the sulphur content of marine heavy fuel oils, the most widely used of ship fuels, with an average sulphur content of around 2.7%, or 27,000 parts per million (ppm) compared to 350 ppm for diesel used by road transport to be reduced to 10 ppm by 2009. It was estimated that by 2010 emissions of sulphur and nitrogen oxides from ships in European sea areas would reach levels equivalent to over 70-85% of EU land-based emissions. Air pollution from international shipping accounts for around 50,000 premature deaths per year in Europe alone, at an annual cost to society of more than €58bn ($65bn) according to the Brussels-based Transport and Environment group (2016).
Partly due to past exemptions, the cost of reducing emissions from ships is now considerably lower that many further abatement measures in land-based sectors.
If the shipping industry was a country, it would be the 6th largest climate polluter in the world.