EPA leads crackdown on dirty ships

The US Environmental Protection Agency is to tighten up nitrogen oxide emissions rules at sea, in an attempt to curb air pollution from the global shipping industry.

It has proposed two new sets of standards that will tighten existing restrictions under the Clean Air Act, forcing shipping operators to invest in more efficient and cleaner engine technologies.

The agency says the additional standards are required to cut the number of premature deaths caused as a result of air pollution near major ports.

Set one would come into effect in 2011, and would require more efficient use of current engine technologies, including engine timing, engine cooling, and advanced computer controls, said the EPA, which hopes that they would result in a 15 to 25 per cent reduction in NOx emissions.

The second standard would become effective in 2016, and would require an 80 per cent reduction from current levels, using high efficiency after-treatment technology such as selective catalytic reduction.

The new standards for shipping apply to category three ocean-going vessels, that have compression-ignition engines with a capacity of 30 litres or more per cylinder.

Emissions standards for these vessels already exist in the Annex VI to the International Convention on the Prevention of Pollution from Ships, otherwise known as MARPOL.

The new standards are particularly significant as the US proposed an emission control area (ECA) using criteria designated under MARPOL in March. The proposal could mean that the new standards would apply in a massive zone reaching 200 miles off the coast of the US and Canada.

The agency has also revised land-based emissions rules for nitrogen dioxide (NO2), which it first set in 1971.

The new standards restrict levels of the gas, which is emitted by larger vehicles such as buses and trucks, on a temporal basis for the first time. A one-hour standard restricts levels of the gas to 80-100 parts per billion, and adds NO2 monitoring within 50m of major roads in cities with more than 350,000 residents.