Impact of Chinese air pollutants on a record-breaking PMs episode in the Republic of Korea for 11-15 January 2019

Abstract

A record-breaking episode of highly concentrated particulate matter (PM) with diameters <= 2.5 mu m (PM2.5) and <= 10 mu m (PM10) occurred in the Republic of Korea during the period January 11-15, 2019: the hourly PM2.5 (PM10) in Seoul was 188 mu g m(-3) (262 mu g m(-3)) on January 14. At the Baengnyeong and Socheongcho stations, located in the Yellow Sea between China and Korea, the hourly PM2.5 concentration reached up to 155 mu g m(-3) and 119.8 mu g m(-3), respectively, 16-19-h prior to this episode. This and the fact that the maximum PM10, concentration at Baengnyeong was 199 mu g m(-3) indicated a westerly transport of air pollutants. Satellite observations and 72-h back trajectory analysis clearly indicate that air pollutants from China flowed into Korea via the westerlies. According to contribution analysis using particulate matter source apportionment technology in the Comprehensive Air-quality Model with extension, air pollutants originating from northeastern China including Hebei and Shandong provinces were largely linked to the present record-breaking high concentration event in Seoul. This study will elucidate the mechanism of transboundary transport of air pollutants and help East Asian countries cooperate on air quality management.