Organizers of the 2010 World Expo Shanghai will run an online carbon calculator to help visitors check carbon dioxide emissions from their choice of transport.

The calculator, part of efforts to ensure a green event, will be available from mid-January on Expo-themed section at Websites such as qq.com, Expo's environment official Zhang Jianyu told today's Oriental Morning Post.

Visitors can calculate their emissions by typing in their departure points and transport taken to the site, Zhang revealed.

To help cut emissions, residents living close to Expo Park are advised to cycle or walk to the venue, while those on buses or driving cars should travel in groups, the organizer suggested.

Overseas visitors can donate to professional carbon-offset agents who will plant trees or take part in other ecology programs to offset their flights to Shanghai.