Last year, the air quality in Seoul was reported on the 9th to be the best since monitoring began in 2008. The strong easterly winds helped disperse the fine dust (PM 2.5) coming from China.
According to the city, the average concentration of fine dust last year was 17.6 µg per cubic meter, the lowest since 2008 (26 µg). For 176 days of the year, the fine dust concentration was rated as good (0–15 µg), while 24 days were rated as bad (36–75 µg) or very bad (over 75 µg). The city plans to reduce the fine dust concentration to 13 µg per cubic meter by 2030.
Fine dust is usually carried in from China by the prevailing westerly winds. However, last year, there were more easterly winds that reduced the influx of fine dust from China. Additionally, the fine dust emissions from China also decreased. The days with easterly winds amounted to 175, which is higher than the recent three-year average of 161 days. The average concentration of fine dust in northeastern China was 36 µg per cubic meter, lower than the recent five-year average of 40 µg.
The seasonal management system, which concentrates on managing fine dust from December to March each year, also had an impact. The city is restricting the operation of level 5 emission vehicles that have not taken low-emission measures. Level 5 diesel vehicles are subject to early scrapping, or subsidies are provided for vehicles equipped with diesel particulate filters (DPF). The city plans to expand eco-friendly construction sites and distribute electric excavators. Kwon Min, head of the Climate and Environment Bureau of Seoul, noted, "We will ensure that the clear sky in Seoul is felt."