Publications·January 04, 2025·SEI – Stockholm Environment Institute
The UNEP publication “Achieving Clean Air for Blue Skies in Seoul, Incheon and Gyeonggi, Republic of Korea” (2023) provides a comprehensive, evidence-based assessment of air pollution management in the Republic of Korea’s largest metropolitan area. Covering a population of 26 million people across more than 12,000 km², the Seoul–Incheon–Gyeonggi (SIG) region generates nearly half of the national GDP and represents one of the most densely urbanized areas in East Asia. The report documents significant progress in reducing air pollution between 2005 and 2020 through the development of a robust governance, legal, and technical framework for air quality management. It identifies the key drivers of emission reductions, the policy instruments that have enabled cleaner air, and the remaining challenges to achieve sustainable air quality improvements. Over the past fifteen years, SIG has experienced large declines in concentrations of particulate matter (PM2.5 and PM10) and nitrogen oxides (NOX), resulting from sector-specific mitigation policies, investment in clean transport technologies, and improved energy efficiency. The study quantifies these improvements using data from Korea’s Clean Air Policy Support System (CAPSS) and the Low Emissions Analysis Platform (LEAP), which model both historical and projected emissions under different scenarios. It estimates that PM2.5 levels in Seoul have fallen by over 30–40% since 2005, while road transport PM10 emissions declined by more than 70%. The assessment, however, highlights that greenhouse gas (GHG) emissions have not declined concurrently, with national CO2 emissions increasing by approximately 25% between 2005 and 2020. To address this disconnect, the report evaluates future mitigation scenarios aligned with Korea’s Carbon Neutrality Act (2021) and Nationally Determined Contribution (NDC) under the Paris Agreement. These projections suggest that implementing carbon neutrality measures—such as vehicle electrification, fuel switching in industry, and enhanced energy efficiency—could reduce CO2 emissions by 88% and PM2.5 emissions by up to 78% by 2050 compared to the baseline. The publication outlines the scientific basis for integrated air quality and climate policies, emphasizing co-benefits of reducing short-lived climate pollutants (SLCPs) such as black carbon and methane. It recommends prioritizing measures addressing remaining emission sources, notably non-road machinery and agricultural ammonia (NH3), which contribute to secondary particulate formation. With comprehensive data and modelling, the report presents Seoul’s experience as a transferable example for other Asian megacities seeking to strengthen legal, institutional, and technical capacity for urban air quality management. It emphasizes the importance of sustained investment, multi-sectoral coordination, gender-responsive policies, and transparent data sharing. Through its science-policy integration and regional outreach, this UNEP-led collaboration underscores that urban clean air transformation is achievable when supported by strong governance, robust monitoring, and targeted emission reduction strategies, positioning the Republic of Korea as a leading case study in sustainable air quality management for East and North-East Asia.
According to UNEP’s Global Environment Outlook (GEO) 6 for Cities, air pollution is currently the largest environmental health risk in cities. As such, cities are an integral part of the solution in fighting air pollution and the climate crisis. Cities in low and middle-income countries need evidence-based solutions to improve air quality. This publication documents the story of air quality over 15 years (2005-2020) in Seoul, Incheon, and Gyeonggi, Republic of Korea. It presents a comprehensive analysis of various air pollutants (PM2.5, NOx, SOx, ozone, and greenhouse gases like Methane, along with their sources and health impacts and documents the progress made during the period. It highlights the initiatives undertaken by the government of Korea, such as the Clean Air Conservation Act and the National Fine Dust Reduction Plan to improve air quality. Exploring the linkages between air pollution and climate change, the report recommends future actions to further reduce air pollution in Korea. By providing insights and recommendations on improving air quality and protecting public health, the report aims to serve as a valuable reference for policymakers, researchers, and citizens in Republic of Korea and beyond.