|Potential cancer risk resulting from exposure to diesel PM from ocean-going vessels (OGV), 2005 baseline. Note the hot spot around the Southern California ports. Click to enlarge.|
The California Air Resources Board adopted a regulation that requires ocean-going vessels (OGV) within 24 nautical miles of California’s coastline to use lower-sulfur marine distillates in their main and auxiliary engines and auxiliary boilers, rather than the dirtier heavy-fuel oil called bunker fuel. (Earlier post.) About 2,000 ocean-going vessels visiting California ports annually are subject to this restriction.
Separately and earlier in the week, US President George Bush signed into law the Maritime Pollution Protection Act of 2008, which clears the way for US ratification of the international treaty regulating emissions—MARPOL Annex VI—from diesel-powered OGVs.
The proposed California regulation requiring ships to use more refined fuel with lower sulfur content would be implemented in two steps. In 2009, MGO (marine gasoil) would have a sulfur limit of 1.5% (15,000 ppm), while MDO (marine diesel oil) would have a limit of 0.5% (5,000 ppm). In 2012, the limits for both fuels drops to 0.1% (1,000 ppm). Both US-flagged and foreign-flagged vessels are subject to the regulation which is the most stringent and comprehensive requirement for marine fuel-use in the world.
In 2009 about 75% percent of current levels of diesel PM, more than 80% of the sulfur oxides and 6% of the nitrogen oxides will be eliminated. In 2012, when the very low sulfur fuel requirement is implemented, reductions of diesel particulate matter will be 15 tons daily, an 83% reduction compared to uncontrolled emissions. Sulfur oxides will be reduced by 140 tons daily, a 95% reduction and nitrogen oxides will be reduced by 11 tons per day, a 6% reduction.
Diesel exhaust contains more than 40 known cancer-causing compounds. Currently in California, diesel PM emissions from ocean-going vessels expose more than twenty-seven million people or 80% of California's total population, to cancer risk levels at or above 10 chances in a million.
With the new ruling, an estimated 3,600 premature deaths between 2009 and 2015 will be avoided, and the cancer risk associated with the emissions from these vessels would be reduced by more than 80%. In addition, the measure will aid the South Coast Air Quality Management District meet its federal clean air requirements for fine particulate matter by 2014 and move California closer to its goal of reducing diesel particulate matter 85% by 2020.
This fall the ARB will consider further measures to reduce emissions from heavy-duty diesel trucks.
|The new ARB sulfur limits and the proposed changes in sulfur limits in MARPOL. Click to enlarge.|
US and MARPOL. The president’s signature of the act brings into statute Annex VI to the International Convention on the Prevention of Pollution from Ships (known as MARPOL). The US Senate gave its formal advice and consent to Annex VI in 2006. The final step of the ratification process is for the President deliver a letter—known as diplomatic instrument of ratification—to the International Maritime Organization. The US becomes a party three months later. MARPOL Annex VI entered into force beginning in May of 2005, although ships have met most provisions since 2000.
Under MARPOL Annex VI, container ships, tankers, cruise ships and bulk carriers must limit NOx emissions from their Category 3 diesel engines. Category 3 marine diesel engines are those with per-cylinder displacement at or above 30 liters. It also sets a cap on the sulfur content of the fuel they burn and includes a program for designating areas where more stringent fuel controls apply, such as near coastlines that have more severe air quality concerns.
This October, the parties to MARPOL will work to strengthen NOx and SO2 standards and the sulfur requirements in fuel.
In April, the Marine Environment Protection Committee (MEPC) of the International Maritime Organization (IMO) approved proposed amendments to the MARPOL Annex VI regulations that implements a progressive reduction in sulfur oxide (SOx) emissions, with the global sulfur cap reduced initially to 3.50% (35,000 ppm) from the current 4.50% (45,000 ppm), effective 1 January 2012; then progressively to 0.50% (5,000 ppm), effective 1 January 2020, subject to a feasibility review to be completed no later than 2018. Should the 2018 review reach a negative conclusion, the effective date would default to 1 January 2025.
The limits applicable in Sulfur Emission Control Areas (SECAs) would be reduced to 1.00% (10,000 ppm), beginning on 1 March 2010 (from the current 1.50%, 15,000 ppm); being further reduced to 0.10% (1,000 ppm), effective from 1 January 2015. In the current Annex VI, there are two SECAs designated: the Baltic Sea and the North Sea area, which also includes the English Channel. (Earlier post.) The US Environmental PRotection AGency (EPA) has said that it intends to investigate this special designation for one or more areas in the United States.
Emissions from large ships comprise an increasing share of the nation’s pollution inventory. In 2001, in terms of mobile sources, oceangoing vessels contributed nearly 6% of NOx, more than 10% of PM2.5, and about 40% of SO2 to the nation’s air pollution. Without further controls, those numbers will rise to about 34% of NOx, 45% of PM2.5, and 94% of SO2 emissions by 2030.