32 percent of Korea's ultrafine dust originates from China while 50 percent is generated domestically.
This is according to a joint study by Korea, China, and Japan which analyzed the source and amount of pollutants smaller than 2.5 micrometers, or ultrafine particles, in the three countries,..between 2013 and 2017.
The study is part of a broader tripartite project known as Long-range Transboundary Air Pollutants in Northeast Asia, which was launched in 1996 to improve regional air quality.
The research breaks down the origins of the three countries' annual average concentrations of ultrafine dusts into two factors - internal and external.
Korea, China, and Japan were responsible for 51%, 91% and 55% respectively for their own pollution.
China was also a major external contributor of pollutants among the three countries.
China generates 32 percent of Korea's ultrafine dust and 25 percent of Japan's.
In a sharp contrast, Korea's impact on its neighboring countries was notably low, contributing with only 2 percent to China's pollution and 8 percent over in Japan.
Beijing's contribution becomes even greater between December and March.
The publisher of the study, Korea's National Institute of Environmental Research, had previously said that China attributes a staggering 70 to 80 percent of Korea's ultrafine dust pollution during those months.
The joint research also showed improving figures. The annual concentration of pollutants, between 2015 and 2018, declined in all three countries, with Korea by 12 percent and China by 22 percent.
Another takeaway from the research is that China now officially admits its contribution to regional air pollution.
However, experts say there is still more to do regarding air quality, such as further slashing exhaust gas emissions, both domestically and across the region.
Lee Kyung-eun, Arirang News.