The reasons cited for air quality improvements include bigger ships carrying cargo more efficiently; newer ships with cleaner engines; the 1 Jan 2012 deadline for full implementation of the Clean Trucks Program; increasing use of shore power; and a new low-sulfur fuel rule for ships that started in August 2012.

Compared to 2005 emissions levels, all of the key air pollutants from port-related sources were reduced in 2012. In addition to the drop in diesel emissions, smog-forming nitrogen oxides and sulfur oxides have been cut 54% and 88% respectively. Greenhouse gases were lowered by 24%. The reduction in pollutants far outpaced a 10% decline in containerized cargo activity in the same period.

The report examines data from the 2012 calendar year. The study’s results were reviewed by the US Environmental Protection Agency, the California Air Resources Board and the South Coast Air Quality Management District.

The annual emissions inventory is conducted to check the Port’s progress in improving air quality. The San Pedro Bay Ports Clean Air Action Plan—created in 2006—maps out a strategy to reduce or prevent pollution from the ships, trucks, locomotives, tractors and cranes that move cargo.