To avoid being the first to undertake the obligation of emission reduction,many developed countries strongly object to set mid-term emission reductions objective under the Post-Kyoto Arrangement.

Carbon permit allocation under the long-term mitigation target would impact development space for all countries,involving the fundamental interests.

New members of EU might help EU meet its first commitment,nevertheless,they will bring more challenges against EU\'s commitments for post-Kyoto emission reduction targets,because their emissions might be rebounded along with the social and economic development in these countries.

Taking Guangzhou city as example, the reduction target of vehicle NOX emission, reduction potential and cost of the control measures were analyzed quantitatively.