According to South Korean SBS TV reported on May 1, most Koreans believe that the smog in South Korea comes from China, but in fact half of the smog in South Korea originated in South Korea. Especially in the capital region, more than 40% of the inhalable particulate matter emissions come from old diesel vehicles. South Korean researchers compared the exhaust of three 20-year-old diesel vehicles, two-year-old diesel and gasoline vehicles directly to the anti-fog mask to compare the emissions of inhalable particulate matter. The first is a 20-year-old old diesel car. In less than 5 minutes, the white mask becomes dark. Even the part of the mask that is close to the mouth is blackened by the exhaust gas; on the contrary, the new diesel and gasoline vehicles do not blacken the mask. The researchers then measured the emissions of respirable particulate matter. At the moment when the old diesel car started for 20 years, the emission of inhalable particulate matter exceeded 8,000 micrograms, more than 200 times that of new car emissions. Researchers say that the exhaust from diesel combustion is exhausted through the engine, so if a device that reduces smoke is installed at that location, it will reduce emissions of inhaled particulate matter by 90%. The report also said that although the South Korean government has already provided financial support for the installation of emission reduction devices for old diesel vehicles, there is still a long way to go to improve the status of smog due to insufficient public attention. Huaian Yige New Material Co., Ltd. , https://www.cnygplastic.com