6 October 2005

The California Air Resources Board (ARB) has released a draft report “Diesel Particulate Matter Exposure Assessment Study for the Ports of Los Angeles and Long Beach”, which found out that the ports were responsible for 21% of the total diesel PM emissions in the California South Coast Air Basin in 2002.

The sources of diesel PM emissions from ports were:

  • ships—73% of total port emissions, due to transiting, maneuvering, and hotelling,
  • commercial harbor craft vessels—14%,
  • cargo handling equipment—10%,
  • in-port heavy duty trucks—2%,
  • in-port locomotives—1%.

The study also includes an assessment of the potential health impacts due to PM emissions from the ports over a 20-mile by 20-mile study area. The non-cancer health effects considered by the study include premature deaths (29 per year), asthma attacks (750), work loss days (6,600), and minor restricted activity days (35,000).

The increased cancer risk from diesel PM exposure in areas near the port boundaries exceeds 500 cancer cases in one million people, according to the study. At a distance of 15 miles from the ports, the added cancer risk is 50 in a million. For comparison, the overall risk of cancer in California—from all causes, such as diet, lifestyle and environmental causes—is about 250,000 in 1 million.

The methodology to quantify cancer risks from diesel PM exposure was developed in 1998, when diesel particulates were identified as a “toxic air contaminant” under California law, but many scientists consider the ARB diesel risk factors controversial. The US EPA has determined that the ARB methods were too uncertain for the purpose of quantitative risk assessment from diesel exhaust.

The ports of Los Angeles and Long Beach combined are the third-largest port complex in the world.

Source: California ARB (marine vessels page | full report)