Qualité de l’air à Seoul

What is the air quality index of Seoul?

Officially known as Seoul Special City, Seoul is the capital and largest city in South Korea. It is situated in the northwest of the country and has a population of 10 million people. The Seoul Capital Area is home to the headquarters of 14 “Fortune Global 500” companies, including Hyundai, Samsung and LG. Towards the end of 2020, Seoul was experiencing a bout of “Good” air quality with a US AQI figure of 50. The main pollutant was the fine dust particulate matter of PM2.5 with a concentration level of 12 µg/m³. Other recorded pollutants were as follows: - PM10 - 29 µg/m³, ozone (O₃) - 40 µg/m³, nitrogen dioxide (NO₂) - 40 µg/m³, sulphur dioxide (SO₂) - 40 µg/m³ and carbon monoxide - 40 µg/m³. With levels such as these outdoor activities are encouraged and doors and windows can be opened to let the fresh air into the home.

Why is Seoul polluted?

There are three main factors affecting the concentration of fine dust in Seoul's atmosphere: emissions from itself, generation by reaction, and smog that drifts across from its neighbours, China and North Korea. Current measurement data are not sufficient to define the trend of the chemical composition of fine dust in Seoul's atmosphere so it is difficult to distinguish between long-distance movement from the outside and formation by reaction. Ground-level ozone (O₃) is formed through the influence of ultraviolet rays from the sun. Nevertheless, when the measurement data and the simulation results are combined, it was found that in the case of Seoul, the effect of generation by reaction is as great as the discharge and inflow from outside. This means that although it is important to reduce direct emissions to reduce the concentration of fine dust in Seoul, it is also important to reduce the generation of photochemical reactions and inflow from the outside.

Is air pollution in Seoul getting worse?

The government says that domestic air pollution emissions are slowly decreasing, but the fine dust pollution in Seoul appears to be on the increase.

Having reviewed changes over the last 2 decades in the concentration of atmospheric environmental standards such as sulphur dioxide (SO₂) and fine dust (PM2.5), an indicator of perceived air pollution, it was found that Seoul's atmospheric environment has been improving since 1990. However, Seoul's air environment related to the microscopic particles is still worse than some of the other large cities in Korea.

According to the local Government, the average monthly concentration of ultrafine dust (PM2.5) in Seoul was 45 µg/m³ (microgram, 1 µg = 1 millionth of a gram). This is the highest monthly average concentration in Seoul since the official measurement of ultrafine dust concentrations since 2015.

It was 30 µg/m³ in March 2015, 32 µg/m³ in March 2016, and 35 µg/m³ in March last year, and this year it is gradually deteriorating to 45 µg/m³.

What can be done to improve the air quality in Seoul?

In December 2003, the local government put together a strategy to reduce the amount of air pollution in Seoul, primarily PM2.5 particles were to be targeted. In order to establish effective fine dust reduction countermeasures, it is necessary to know the current trends, up-to-date status and major contributors. This study comprehensively reviewed and analysed the results of research published in domestic and international academic journals and academic conferences until September 2006 to identify changes in Seoul's atmosphere, and identify major factors affecting concentration.

Various aspects of air quality problems caused by aerosols in Seoul have been discussed. Based on the available data, it was found that the general air quality in Seoul has improved during the last two decades. However, PM10 concentration in Seoul is still higher than in other cities in Korea and worldwide. In Seoul, it was suggested that secondary aerosols are as important as primary aerosols whether directly emitted in Seoul or transported from outside.

An eco-friendly condensing boiler is a boiler whose evaporation amount is less than 0.1 ton per hour or heat capacity is less than 61,900 Kcal per hour, and it refers to a boiler that satisfies the standards set by environmental labelling products and certification standards. Certification standards have an energy efficiency rating of 91% or more, nitric oxides (NOx) 40ppm (parts per million) or less, and carbon monoxide (CO) 200ppm or less.

According to a study on the management of air pollutants in combustion devices for heating buildings published by the Seoul Institute, older, inefficient boilers have 80 per cent energy efficiency and produce nitric oxide NOx emissions of 173ppm. General boiler energy efficiency is 83 per cent with NOx emissions of 85ppm, whereas, eco-friendly boilers have an energy efficiency 91 per cent with a NOx emission of 40ppm.

This scheme targets citizens living in Seoul who replace ordinary boilers with eco-friendly condensing boilers and only one application per household can be applied for.

What are the effects on health through breathing in Seoul’s polluted air?

There are various types of pollutants suspended in the air that can affect your health. When the weather is warmer, ozone (O₃) can make it difficult for some people to breathe. This gas is created when sunlight starts a chemical reaction between oxygen and certain pollutants emitted from cars, factories, and other sources. Ground-level ozone can irritate the lining of your airways and lungs. People with asthma and other respiratory conditions are more likely to feel its effects.

Another type of outdoor pollutant that seriously can affect health is particulates, (PM2.5 and PM10). These are fine and coarse particles that are released into the atmosphere when fuel is burned. They can come from things such as cars, power plants, and wildfires. Research has linked particulates to short and long-term lung problems. They can also be responsible for some types of cancer and are known to shorten the lifespan for some individuals.

Even healthy people can suffer from the effects of polluted air but people that are more sensitive to pollution should be extra careful. The extent of the effects depends on several conditions such as the type of pollutant suspended in the air and the amount of time the body is exposed to it.