Cho Jang-hun remembers a time in the 1990s when it was almost impossible to escape the dirty air from exhaust fumes, coal-fired power plants and massive industrial projects that hung over his home in Gyeonggi, Republic of Korea.
The smog used to be so bad that the collars of the white shirt that Cho wore in the morning were black with soot by the evening.
But in recent years, the 47-year-old schoolteacher has noticed a marked reduction in the air pollution that once plagued Gyeonggi, which, together with Seoul and Incheon, forms the Seoul metropolitan region.
“The air is much healthier, and the skies are clear,” he said.
Data published in a recent UN Environment Programme (UNEP) report on air quality in the metropolis bears this out. It found that concentrations of the most damaging air pollutants, such as particulate matter (PM), far exceeded national standards and World Health Organization (WHO) air quality guidelines in 2005 but fell significantly by 2020.
When inhaled, particulate matter—tiny, invisible airborne particles—can penetrate deep into the lungs and enter the bloodstream, causing heart disease, stroke and respiratory issues.
The report found that annual average concentrations of particulate matter smaller than 10 micrometers (PM10) were 30–40 percent lower in 2021 compared to 2005. Across the Republic of Korea, emissions of PM2.5 fell by 19 percent between 2005 and 2020, with even greater reductions in Seoul and Gyeonggi.
The improvement in Seoul’s air quality is the culmination of decades of work by the government of the Republic of Korea to tackle air pollution, which claims almost 7 million lives globally every year. Its approach is seen as a success story in the Asia-Pacific region where 92 percent of the population–some 4 billion people–are breathing unhealthy air with the risk of damage to the heart, lungs and brain.
The Seoul metropolitan region is home to 26 million people, around half the population of the Republic of Korea.
The region, a key driver of the country’s economy, was responsible for 48 percent of national gross domestic product in 2016, according to the World Bank. However, much of the economic activity that makes it such a powerhouse has led to increased transport, industry, waste and electricity production, which often contribute to higher air pollution.
Over the past couple of decades, the government has responded by creating a robust legal framework to manage air quality in the Seoul metropolitan region. It has also made long-term air quality data publicly available and invested heavily in air quality management systems, among other key measures.
The air quality regulatory framework in the Republic of Korea consists of multiple levels of planning and policy making. A governing act serves as an overarching framework at the national level. Meanwhile, distinct plans outline how the act will be implemented at the national and local levels.
“The air quality legislation provides a strong foundation for action to combat air pollution in the Seoul metropolitan region,” said Mushtaq Memon, UNEP Coordinator of Chemicals and Pollution Action for Asia and the Pacific. “It has been particularly effective because it identifies the roles and responsibilities of different organizations at national and sub-national levels. This has created clarity as to who is responsible for implementing different components of air quality management.”
To assess compliance with the legal framework, hundreds of monitoring sites providing data on air pollution were set up across the Seoul metropolitan region and elsewhere in Korea. The data is publicly available via a real-time air quality information website, which allows researchers to identify trends and provides information on which government agencies can act.
Substantial investment has been critical to improved air quality. Between 2007 and 2020, the Seoul, Incheon and Gyeonggi governments invested US$9 billion on air quality management, with 56 percent of the funding focused on measures to reduce emissions from the transport sector. Some US$3.2 billion was also devoted to evidence generation and public engagement on air quality. UNEP News