Onset of Winter Brings Dust Pollution to Korea

Air pollution warnings were issued for Seoul and surroundings on Thursday for the first time this autumn.

In Seoul an ultrafine dust advisory was issued as PM2.5 density stood above 75 ㎍/㎥ for longer than two hours, while in some provinces PM10 concentration stood at over 150 ㎍/㎥.

Ultrafine particles can be harmful when they enter the lungs and blood vessels. The government reduces traffic of official vehicles and operating hours of public agencies if an ultrafine dust advisory is issued. Patients with pulmonary or cardiovascular diseases, the elderly and children are encouraged to stay indoors or wear masks outside.

The Seoul Research Institute of Public Health and Environment said, "The fine dust level goes up every winter and spring because air pollutants are emitted from heating homes and buildings and contaminants are blown in from China."

Fine dust has been rising since early this week as a result of air stagnation. However, the latest onslaught will dissipate gradually from early Saturday morning as an air depression is approaching and a rainstorm arrives from the West Sea.

When Chinese homes and factories start heating with coal in November, more fine dust arrives in Korea on westerly winds. Coal power generation is expected to increase in China this year.

According to the Korea Trade-Investment Promotion Agency, China produced 3,285 TWh of thermal power until the first half of this year, far exceeding half of last year's total, and coal took up a whopping 89 percent.

Coal emits more than three times the pollutants of gas. China's thermal power generation is expected to soar amid sky-high energy prices in the wake of Russia's invasion of Ukraine. Korea, by contrast, has slashed thermal power generation from 391,891 GWh in 2018 to 366,344 GWh last year.

Korea and China agreed in 2019 to work together to clear the air. Ultrafine dust concentration decreased 30.7 percent in Korea and 34.8 percent in China last year compared to 2015. But the number of days with a high level of ultrafine dust concentration above 50 ㎍/㎥ has not shrunk significantly.

In Seoul, the number of days with a high level of ultrafine dust concentration was 20 in 2017 and 2018 and 26 in 2019 but dropped to eight in 2020 amid the coronavirus pandemic and increased to 17 again last year. The Environment Ministry expects fine dust concentration to increase slightly this winter.