Pollution from Container Ships in the Port of Seattle: Can Voluntary Shore Power Use Clear the Air?

International trade is dominated by the maritime shipping industry. Transportation of goods and raw materials is a key component of the United Nations Sustainable Development Goals. The World Bank Group reported in 2003 that the maritime industry handles over 80% of all trade from developing nations. The economic value of these goods is over $1.5 trillion globally. Global maritime shipping impacts over 13 million jobs directly and indirectly. (1) According to the US. Department of Transportation, the United States economy used maritime shipping for 53% of imports and 38% of exports. The west coast ports of the United States account for over 48% of the container shipping into the United States. (2) In contrast to the positive economic impact of transporting goods across large distances at an economical scale, the maritime industry has a negative externality of producing a large amount of greenhouse gases. Most of the large ships at sea burn the lowest grade of diesel fuel to power their engines. This fuel is known as bunker fuel, and while it helps reduce operating costs to keep shipping rates lower, it also produces a higher volume of negative exhaust emissions around the world. Marine vessel emissions account for 14% of Nitrous Oxide (NOx), 2.2% of global human-caused Carbon Dioxide (CO2), and 5% of Sulphur Oxide (Sox) worldwide. In the United States, marine vessel pollution accounts for 7% of all NOx and 6% of Particulate Matter (PM)