An Industrial City
Seoul has consistent air pollution problems. On an average day, city residents breathe in air that has an impact on the body similar to smoking six cigarettes and when the Air Quality Index (AQI) is particularly bad, ten cigarettes.1 Air pollution causes an estimated 20,000+ premature deaths each year, which is 42.7 deaths per 100,000 people.2 Unfortunately, even government reported AQI is often a lower estimate than the true on-the-ground quality and residents are not aware of the extent of the air pollution issue, as was found by a visiting researcher. The main five contributing factors to Seoul’s air pollution are as follows: vehicle emissions, industrial activities, energy production, domestic heating, and construction and road dust.3
The Density Problem
In most major metropolises, population density poses a significant challenge with regard to air quality, as more people crowded in less land area means that the effects of emission-releasing activities is much more heavily concentrated. Seoul is no different. This has led to one of the city’s major contributing factors to air pollution being from vehicles: cars, buses, trucks (particularly those that burn diesel), are all significant sources of nitrogen oxides (NOx) and particulate matter (all hazardous solids and liquids suspended in the air, most frequently in Seoul is PM2.5), two types of greenhouse gas emissions contributing to the heating of the atmosphere causing global warming. Heating systems employed during the winter in Seoul often still rely on fossil fuels, contributing to both outdoor and indoor pollution. Denser urban areas also lead to increased construction and development, leading to the release of large amounts of dust and PM2.5.3
Sources of Air Pollution
Seoul is known as a hub of industry and has a history of housing power plants that burn fossil fuels like coal and oil, contributing to haze. Industrial factories release sulfur dioxide (SO2) and volatile organic compounds (VOCs) and energy plants SO2, NOx, and PM2.5.3 While these facilities are partially shut down when city PM2.5 levels exceed 50 µg/m3, the city often suffers from levels way above this limit.4 In a report released by Greenpeace and IQAir, South Korea was one of the countries with the highest ranked annual average PM2.5 concentration in 2022. Additionally, 30-50% of Seoul’s air pollution is blown in from China, with the remaining 50-70% is domestically produced.5
Air quality gets worse in the spring. “Yellow dust” is blown over from the deserts of Mongolia and northern China, picking up pollutants and then settling over the city. These storms have worsened in recent years due to increased deforestation. The summer brings the monsoon season, which often sees an improvement in air quality because the rain washes away airborne pollutants like PM2.5. In both of these warmer times of the year, secondary pollutants such as secondary organic aerosols and ozone are also formed as a result of the sunlight reacting with VOCs and NOx from factories and vehicle exhaust. The winter also sees a decrease in surface air quality because of the increase in the use of domestic heating and due to the cold temperature of the air, it doesn’t disperse like it does in the warmer months.3
Policy & Regulations
Stricter environmental regulations by the Ministry of Environment (MOE) have seen the phasing out of reliance on fossil fuels across the country. Coal has been limited in residential (limited use in heating and cooking), industrial (limiting hours of operation), and commercial (utilizing more sources of green energy) sectors to improve air quality since 1985 with stricter enforcement after 1995. Since then, levels of lead (Pb), carbon monoxide (CO), SO2 (Seoul had one of the highest concentrations of sulfur in the world in the 1980s), and total suspended particles (TSP) in the air have plummeted (see Fig 1).6 More recently, the MOE’s Comprehensive Plan on Fine Dust Management (2017) had the goal of reducing PM2.5 emissions by 35.8% from standards in 2014 by 2022 and decrease the number of poor AQI days by 180 (70%), much more ambitious than previous legislation.7 The original plan and its 2019 update have seen the decrease of emissions from larger businesses and coal-fired power plants and fewer high emission vehicles on the roads8 through the implementation of legislation including various emission standards and charges for lack of compliance.9
An environmental justice focus on vulnerable groups caused the government to provide subsidies to encourage the use of liquified petroleum gas for school buses; supplying air purifiers in classrooms; and “Clean Zones” near daycare centers, schools, and elder care facilities, with more strict air quality requirements.7 Recent decades have seen an increase in Seoul’s air quality as the city government has started to tackle the issue through the Metropolitan Air Quality Management Office branch of the MOE. The Special Act on the Improvement of Air Quality (2003) which began the process of regulating industrial emissions of NOx and sulfur oxides (SOx) through a cap-and-trade system throughout the Seoul Metropolitan Area in 2008. However, the MOE struggles with providing proper funding for all its local initiatives (60% of their total budget) across South Korea, meaning that monitoring and enforcement of regulations can’t always be properly carried out.10 Additionally, air pollution blowing in from China is out of South Korea’s legislative oversight, and will continue to plague the country and Seoul specifically until it deals with its own emissions.
Conclusion
When looking at our working definition of sustainability, we can see that while Seoul struggles with the transparency of the issue to the public, the government is making an effort to improve the city’s air quality through a systems thinking approach. However, the cap-and-trade system – while it has demonstrated results and is economically viable for the companies involved, the government, and taxpayers – isn’t enough of an encouragement for companies that purchase their ability to pollute from others to actually invest in green energy, as this process is cheaper. Additionally, due to a lack of emission collection devices for many plants, companies can underestimate their actual emission totals, continuing to pollute the environment at higher rates than reported.12 The same issue is found with regulations and fines for lack of compliance for regulations: if companies are unable to under report, they are able to underpay and under-contribute to the city’s goals of better air quality. Implementing better technology to track pollutants exiting these plants to ensure that the industrial sector is operating within code would increase the effectiveness and efficiency of cap-and-trade and regulation fining. While South Korea can’t directly legislate in or for China to limit the pollution blowing into Seoul, deals can be struck between the two countries in an attempt to mitigate it.
Despite these barriers, Seoul has still experienced a dramatic decline in emissions. Over time, regulations have gotten incrementally tighter as South Korea anticipates the worsening of the climate crisis and the importance of weaning off of fossil fuels. Seeing the improvement since the 1980s shows that scientists are being taken seriously and there is a serious effort to improve the quality of life of the citizens locally and nationally. Cleaner air empowers people to live fuller and healthier lives. But with an average “moderate” air quality and increasing environmental obstacles from beyond Seoul’s borders, there is a lot of work left to be done as Seoul continues to fight this uphill battle.