More than half of all particulate pollution in Seoul in 2018 resulted from domestic causes such as heating and vehicles, while China was responsible for 38 percent, a report showed Thursday.

Some 58 percent of PM 2.5 emissions -- ultrafine airborne particles smaller than 2.5 micrometers in diameter and harmful to the human body -- originated within South Korea, up from 45 percent in 2016, according to a study released by the Seoul Metropolitan Government.

Seoul contributed 26 percent of the emissions, while the rest of the country was responsible for 32 percent, mostly due to fossil fuels (31 percent), vehicles (26 percent) and construction sites (22 percent).

Foreign countries contributed 42 percent -- of which China was responsible for 38 percent and other countries combined, including North Korea, just 4 percent. According to the 2016 report, overseas factors accounted for 55 percent of PM 2.5 emissions in Seoul.

The impact of China, however, increases in winter. In January 2019, China’s contribution to the particulate pollution shot up to 47 percent, while South Korea’s declined to 22 percent.

In general, emissions of PM 2.5 in Seoul decreased by 18 percent from 3,316 tons in 2016 to 2,714 tons in 2018, the report showed.

Typically, high levels of PM 2.5 affect South Korea from fall through spring as the wind blows from west to east, with pollutants flowing in from China.  

By Ock Hyun-ju (laeticia.ock@heraldcorp.com)