During the past decade, mainland China has been experiencing rapid economic development and urbanization, and this has led to significant level of environmental harm. There are thus calls for joint efforts on both sides of the Taiwan Strait to achieve greater environmental protection. In July 2011, both the Taiwan Environmental Protection Administration (TEPA) and National Sun Yat-Sen University initiated the Cross-strait Environmental Protection Forum, with the aim of promoting dialogue and cooperation among scientists, researchers, engineers, and regulatory agencies from both sides of the Strait. This annual Forum series alternates between mainland China and Taiwan, with the first Forum being held in Kinmen on June 30–July 1, 2011. During March 28–30, 2012, the second Forum was held in the city of Xiamen, which was held in conjunction with the Ninth Cross-Strait Aerosol Conference. This Forum was organized by the Institute of Urban Environment-Chinese Academy of Sciences, National Sun Yat-Sen University, and Xiamen University, with the following sponsors: the Chinese Academy of Sciences, National Natural Science Foundation of China (NSFC), Committee on Aerosol Research under Chinese Society of Particuology, and Taiwan Association for Aerosol Research (TAAR).
A total of 136 participants from mainland China, Taiwan, Hong Kong, and the United States attended the Forum, featuring more than 100 oral presentations (including seven plenary presentations) and over 100 abstracts and proceedings papers in the fields of aerosol science, air quality control and management, marine and costal pollution, water resource management, water and wastewater treatment technology, and waste management. Amongst the total of 40 papers in this special issue, 12 were selected from the proceedings of the Second Cross-strait Environmental Protection Forum. The other 28 papers, although not presented at this Forum, were also selected because they are highly relevant to the issue of environmental protection.