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Ships are the most energy efficient means of moving good across the surface of the earth.  Goods moved by ship have the lowest carbon foot-print of goods moved by any other means. At the same time, modern ships are significant polluters.  How can ships be so green and yet also so dirty.  The answer is the fuel burned on most ocean-going ships. It goes by various names – residual oil, bunker C, No. 6 oil.  Whatever you call it, it is dirty; high in sulfur, nitrogen dioxide and particulates.  The exhaust gases from ocean going ships has become so bad that it can be observed from space by satellite.  Thanks to Mai Armstrong of the Working Harbor Committee for pointing out the news.

A Satellite’s View of Ship Pollution

Data from the Dutch and Finnish-built Ozone Monitoring Instrument (OMI) on NASA’s Aura satellite show long tracks of elevated nitrogen dioxide (NO2) levels along certain shipping routes. NO2, is among a group of highly-reactive oxides of nitrogen, known as NOx, that can lead to the production of fine particles and ozone that damage the human cardiovascular and respiratory systems. Combustion engines, such as those that propel ships and motor vehicles, are a major source of NO2 pollution.