“Masks again?” Why you should wear a mask again this winter.

[iNews24 Reporter Jang Yumi] Predictions suggest that the fine dust this winter could be denser than last winter, making masks an essential item once again.

According to the three-month fine dust (PM2.5) forecast pilot results submitted by the National Institute of Environmental Sciences to the National Assembly on the 19th, the concentration of fine dust this winter (from December to February next year) has a 50% chance of being similar to the recent 8-year average (27.1 micrograms per cubic meter), and a 20% chance of being higher or lower.

Compared to last year, the likelihood of a higher fine dust concentration this winter is 50%, while the chances of it being similar or lower are 30% and 20% respectively.

The number of days with high concentrations of fine dust (over 50 micrograms per cubic meter, excluding yellow dust days) this winter has a 50% chance of being similar to the recent 8-year average (20 days), and a 30% and 20% chance of being higher or lower respectively. Compared to last year, the likelihood of there being more days is 50%, while the chances of it being similar or fewer are 30% and 20% respectively.

The reason for the prediction of denser fine dust this winter is the expected continuation of the El Niño in the eastern Pacific during the winter season. When El Niño occurs, the high-pressure circulation to the east of Japan strengthens, causing southerly or southwesterly winds to blow towards Korea, which increases the temperature and the concentration of fine dust.

The higher sea surface temperature in the Bering Sea, which is expected to frequently cause high-pressure circulation around Korea, was also analyzed as a factor that will make the fine dust denser this winter. If located at the center of high pressure, the atmosphere becomes stagnant, making it easier for domestically produced or foreign fine dust to accumulate in the atmosphere.

The North Atlantic sea surface temperature being higher than the average is also a significant factor as it weakens the northwesterly winds blowing towards the Korean Peninsula. While the cold northwesterly wind brings a cold wave, it also sweeps away the fine dust.

On the other hand, the continuation of the ‘negative Arctic Oscillation’ from early last month and the smaller than average ice cover in the Barents-Kara Sea in the Arctic could be factors that lessen the fine dust this winter. In the ‘negative Arctic Oscillation’ state, where the cold air vortex in the Arctic is weak, more cold Arctic air descends to the mid-latitudes. In this case, although the wind blowing towards Korea is cold, it is clean.

The National Institute of Environmental Sciences plans to officially provide this ‘three-month fine dust forecast’ from next winter. They also plan to provide the ‘fine dust concentration over 50 micrograms per cubic meter’ forecast, which is currently provided for the metropolitan area, to the Chungcheong and Honam regions from around the 27th. Next year, they plan to provide the fine dust concentration over 50 micrograms per cubic meter forecast for Gangwon, Yeongnam, and Jeju as well.