Toxic Haze Returns

Korea's autumn skies have filled with toxic haze being blown over from China's polluted cities and coal-fired power plants. The concentration of ultrafine or PM2.5 dust particles was bad on Monday in most parts of the country at 36-75 ㎍/㎥, with 44 ㎍/㎥ in Seoul, 51 ㎍/㎥ in Gyeonggi Province, and 45 ㎍/㎥ in Incheon and North Chungcheong Province.

The last time Seoul saw fine dust concentration on this level was on June 25.

The Korean Peninsula bears the brunt of toxic smog as winter approaches and strong northwesterly winds blow from China.

"It's difficult to make mid- and long-term predictions because toxic smog is a mixture of very fine particles and is influenced significantly by the atmospheric environment," the National Institute of Environmental Research said. 

But statistics since 2015 show a pattern of toxic smog occurring from November to May and clearing in the summer.

According to the Korea Environment Corporation, the nationwide monthly average concentration of ultrafine particles stands at 50-60 ㎍/㎥ in winter and spring but drops to 20-30 ㎍/㎥ in the summer.

The rapid increase in the winter is due to the air stagnation that occurs as a result of the daily temperature difference and the northwesterly winds. Heo Gook-young of the NIER said, "If atmospheric emissions increase when Chinese people start home heating, causing severe smog, a huge quantity of fine particles are blown into our country on strong winds."

Generally, the contribution of pollution from overseas is between 50 and 70 percent depending on the season. The China factor was a whopping 69 percent in March, when NIER analyzed the high concentration of ultrafine dust particles in Seoul.

According to international environmental group EndCoal, China topped the list of countries in terms of coal-fired power generation at 957,280 MW in July. To solve the problem, Beijing began last year to force homes to replace coal-fired heating systems with gas or electric heating.