China's Ministry of Environmental Protection (MEP) has unveiled the second version of limits and measurement methods for marine engine standards for public consultation.

The marine engine standards will be applied to inland vessels, coaster vessels, river-sea ships, as well as channel ships in China.

Compared with the first version, the second version has adjusted the regulations on fuels used by marine engines, increasing the categories of bunker, and added the requirements on the durability of engines on entertainment vessels.

Test methods and calculation of gas fuels, criteria for exemption from inspections, as well as age limits of durability have also been put in the new version, according to the ministry.

As of the end of 2013, China has 172,600 vessels, 244 million dwt in total, and eight of the top 10 ports in the world are located in China, handling about one-fourth of global cargo, showed data released by the ministry.

SO2 and nitrogen oxide emission from ships amounted to 8.4% and 11.3%, respectively, of the country's total emission, according to Xiong Yuehui, director of the Science, Technology and Standards Department under MEP. He noted that port cities suffer the most from ship emissions, followed by cities along the rivers.

The application of marine engine standards will cut the emissions of nitrogen oxides and particulates, as well as the secondary pollutants such as airborne particulate matters and ozone, said Xiong, adding that the quality of bunker fuel will also be improved.

About 950,000 tonnes SO2 emission and 110,000 tonnes particulate matters is anticipated to be reduced every year once the standards come into force, according to Xiong.

MEP released the first version last July to solicit public opinion and received 156 pieces of advice. The final version is expected to come out this year.