How Do Ships in Port Contribute to Air Pollution?

Ports are a vital part of the United States & world economy, with seaports, Great Lakes ports, and inland river ports serving as gateways for moving freight and passengers across the country and around the world. As nations adopt to meet economic and infrastructure demands, it is critical to understand the potential impacts on air pollution, greenhouse gases (GHGs), and the people living, working, and recreating near ports. Diesel engines are the modern-day workhorse of the shipping economy, and although they can be reliable and efficient, older diesel engines can emit significant amounts of air pollution.

A vessel’s diesel engines run on HFO (heavy fuel oil), IFO (intermediate fuel oil), LSMGO (low sulfur maritime gas oil), VLSMGO (very low sulfur), ULSMGO (ultra-low sulfur), showing a decrescent content of sulfur. Currently, the regulations in force stated that, while in harbors, the ships must feed the diesel engines with LSMGO and this is a good thing since, by doing so, the ships emit less sulfur dioxide.

In developed countries, SO2 emissions have been dropping so that now SO2 pollution is rare in urban environments. The main SO2 source remaining is from ships stationed in port. Unfortunately, however, LSMGO doesn’t prevent the formation of several other pollutants. In fact, NOx, PM, heavy metals, VOCs are emitted as if the ship would use the worst fuel, and that is HFO. Moreover, due to the remarkable difference in cost and in availability, LSMGO has limited use.