The recent rise of air pollution, represented by an increase in particulate matters, has grown into an important economic, social and diplomatic issue in Korea amidst growing concerns over a significant proportion of domestic air pollutants coming from neighboring countries. Transboundary air pollution, which causes adverse effects in areas under the jurisdiction of other countries, has become a serious matter that requires the joint response of surrounding countries, not the problem of an individual country. The objective of this study is to propose policy implications to cope with the rise of air pollution in Northeast Asia by analyzing policies and cases of international cooperation in the global society.
  Policies and regulatory measures introduced by major countries to improve air quality can be summarized as possessing the following characteristics. The European Union (EU), China and the United States (U.S.) have all established and supplemented domestic environmental laws, policies and regulations. In accordance with improved legal and institutional frameworks, they have being taking practical measures including setting national air quality standards, controlling air pollutant emissions and strengthening monitoring systems. As a result, they have achieved a certain level of air pollutant emission reductions, in particular improvements centered on pollutants for which emission ceilings or standards have been arranged. In the case of China, it has been strengthening its supervision authority, regulatory measures and management standards for severely polluted areas such as Jing-Jin-Ji (Beijing, Tianjin and Hebei province) since 2010. However, emission levels of PM10 and PM2.5 are still in need of improvement, as their annual means exceeded both national and international standards in 2016.
  At the international level, bilateral or multilateral cooperative regimes have been established with the aim of solving transboundary air pollution problems. In Europe, North America and Southeast Asia, official agreements concerning air pollution across countries have been concluded, together with the establishment of relevant organizations and monitoring systems under these agreements. The Convention on Long-Range Transboundary Air Pollution (CLRTAP) in Europe, the U.S.-Canada Air Quality Agreement (AQA) and the U.S.-Mexico La Paz Agreement in North America, as well as the ASEAN Agreement on Transboundary Haze Pollution (AATHP) in Southeast Asia, were all signed with the goal of establishing joint response mechanisms for preventing and reducing air pollution in their regions. Above all, these agreements provided important opportunities for member countries to seek solutions based on scientific evidence or data gathered through collaborative research projects, and to strengthen environmental cooperation. Since then, they have been adopting protocols, annexes, roadmaps and others for supplementing insufficient contents within these agreements or resolving new environmental matters.
  The CLRTAP, adopted in 1979, has established a multilateral cooperation mechanism in Europe with a total of 51 parties, and is recognized as the most successful case with the largest scale and longest history among the four agreements reviewed. The AATHP in Southeast Asia is an agreement concluded to solve haze pollution caused by fires originating mainly in Indonesia. Both regions share the characteristic that they have been able to effectively utilize their organizations and systems, i.e. the EU and ASEAN, in implementing the agreements. Meanwhile, the agreements in North America have focused on solving environmental pollution problems in the border areas, including acid rain, and have contributed to the development of U.S.-Canada and U.S.-Mexico bilateral cooperative relationships.
  Agreements between Southeast Asian countries on transboundary air pollution have mainly focused on presenting principles and guidelines for addressing haze pollution, as opposed to setting emission ceilings and regulatory standards for main pollutants, which were the focus of agreements in Europe and North America. Therefore, although the AATHP has achieved several accomplishments through cooperation, such as sharing data collection and enhancing joint monitoring systems on certain areas (mainly peatland) and periods (dry season, etc.) that are most affected by haze pollution, it still lacks legally binding measures to limit air pollutant emissions, unlike other agreements. However, the AATHP is meaningful in that it reflects the ASEAN principles regarding respect for national sovereignty and consensus; thus, one solution might be to induce all ASEAN members to take part in the AATHP.
  Taking into consideration the cooperative experiences of other regions as described above, our recommendation is to develop multilateral agreements aimed at addressing transboundary air pollution in Northeast Asia. The AATHP's approach in Southeast Asia and the approach of the CLRTAP in Europe encourage the idea that rather than placing regulations on air pollutant emissions, implementing a more realistic multilateral agreement to exchange information and strengthen air quality monitoring networks will induce Northeast Asian countries to participate. It is fundamentally necessary to establish regional environmental regimes for the areas or periods that are most affected by air pollution, and gradually intensify cooperation among member countries, including the adoption of further protocols or annexes in the agreement. It will also be advisable to refer to the AQA and include a clause suggesting that each country promptly notify neighboring countries in the event of policy action or projects that might cause considerable environmental damage, promote joint research to provide relevant scientific data, and ensure a periodic evaluation of progress in the implementation of the agreement.
  Based on the results of the above analysis, we suggest the following measures to reduce air pollution in Northeast Asia. First, we propose that Korea participate directly in the CLRTAP, which may encourage the participation of other Northeast Asian countries and provide the basis for multilateral cooperation in Northeast Asia in the future. Since the grace period for the value of the emission limit may be extended by up to 15 years, this will alleviate the burdens associated with emission regulations, at least in the short term. Under political conflicts like the Terminal High Altitude Area Defense (THAAD) dispute between South Korea and China, it may also be a realistic alternative to attempt to induce China to participate in a multilateral cooperation system under existing successful mechanisms such as the CLRTAP. Second, it is necessary to accumulate more objective data through consultations and the participation of experts in advanced countries and through the European Monitoring Evaluation Program (EMEP). Third, we recommend that governments support the private sector to take the lead in implementing an initiative that responds to transboundary environmental problems. Lastly, Korea, China, and Japan can explore ways to strengthen their cooperation with respect to natural gas. If Korea, China, and Japan, the world's leading importers of liquefied natural gas, jointly seek ways to increase the utilization of natural gas and develop advanced pollution abatement technology, the three countries will be able to help tackle environmental challenges in Northeast Asia.