A Beijing event to promote green transport in 2008. [Photo provided to China Daily]

Dudek himself began a long-term engagement with China in 1991, when the National Environmental Protection Agency, the predecessor of the current Ministry of Environmental Protection, invited him to Shandong province to share his experience of tackling the acid-rain problem using market-based methods.

Since then, Dudek has been traveling between the two countries, introducing the successful experience from the US while learning about Chinese laws and institutions, so that he could advise on how to make the idea practical in China.

"We have to build an emission-trading program with Chinese characteristics," says Dudek.

After earning his PhD in agricultural economics in 1979 at the University of California at Davis, he went to work as an agricultural economist for the US government.

Later, after going to teach at the University of Massachusetts at Amherst, in 1982, he saw how northeastern states of the US were dramatically affected by acid rain caused by excessive sulfur dioxide from coal burning in the region.