Shipping is responsible for 18-30% of all the world's nitrogen oxide (NOx) pollution and 9% of the global sulphur oxide (SOx) pollution.
One large ship can generate about 5,000 tonnes of sulphur oxide (SOx) pollution in a year
70% of all ship emissions are within 400km of land.
85% of all ship pollution is in the northern hemisphere.
Shipping is responsible for 3.5% to 4% of all climate change emissions.
http://www.airclim.org/