'52% of fine dust particles come from domestic sources,' say researchers

It has been identified that about 75 percent of domestic fine dust particles (Particulate Matter 2.5) is secondary airborne pollutants created by chemical reactions in the air. In addition, even when the wind is slow, fine dust particles from foreign sources contributed to half of fine dust in the air. Moreover, some airborne pollutants, which had not been checked from the ground-level monitoring, appeared abundant in the atmosphere, pointing to some issues with the existing emissions measurement method.  

 

The Ministry of Environment of South Korea and the National Aeronautics and Space Administration (NASA) have reported on Wednesday the preliminary analysis results of Korea-U.S. Air Quality (KORUS-AG), a six-week long joint study on air pollution over the Korean Peninsula from May 2 to June 12, 2016. The team tracked the air quality from the sky with a NASA’s latest research aircraft and compared the data with the air quality observed on the ground. The picture of fine dust particle layers of the sky of Korea taken by the team made people realize the severity of situation last year.

 

According to the study, though the atmospheric conditions remain stable for most of the times in May and June last year due to strong Okhotsk sea air mass, fine dust particles from foreign sources took up as much as 48 percent of the total amount. In other words, half of fine dust particles are blamed on foreign countries even when the atmospheric conditions are steady. The biggest contributing region was Shandong, China with 22 percent, followed by Beijing with 7 percent and Shanghai with 5 percent. North Korea was also blamed for 9 percent of fine dust particles.

 

The team also observed large amounts of airborne pollutants with carcinogens over the sky of industrial complexes. The study cited that concentrations of 25 volatile organic compounds (VOCs), including benzene, were relatively high in the sky over the Daesan chemical complexes, and interestingly the concentrations were several tens of times thicker than the ground. “It seems that VOCs rose up and dispersed in the sky as they are highly volatile,” said a researcher at the National Institute of Environmental Research. "We need some changes in the method for measuring airborne pollutants as they are observed mostly from the ground." VOCs in the sky can turn into fine dust particles through atmospheric chemical reactions and fall toward the ground.

 

The study also found that for several days, the amount of fine dust particles, originated from domestic sources only, exceeded the World Health Organization standard of 25 micrograms per cubic meter. The Ministry of Environment called for strong air quality conditions guidelines along with immediate actions. The team also visualized the impact of coal power plants along the west coast on the air quality of the southern part of the Seoul metropolitan area through observation and modeling.

Mee-Jee Lee image@donga.com